Manufacturing Heat Treat Technical Content Archives

The Heat Treat Robotic Paradigm Shift

As Thomas Bauernhansl, professor of Production Technology & Factory Operations at the University of Stuttgart, aptly states, “We are going from more supply-oriented production to a demand-oriented one. In many cases, the customer determines which version he wants to have [of] a product — the manufacturer adapts to this and his processes accordingly.”

This shift is critical for the heat treat industry, where the need for advanced automation and robotics integration is paramount to achieve higher efficiency, consistent quality, and reduced costs. In this Technical Tuesday, Dennis Beauchesne, general manager at ECM USA, discusses the increase in use and installation of automation and robotics in manufacturing and specifically how companies within the heat treat industry have adapted to their implementation—and become innovators in their usage.

This informative piece was first released in Heat Treat Today’s January 2025 Technologies To Watch in Heat Treating print edition.

Industry Automation

In the last 10–15 years, an upward trend is consistent with the increased investment value of integrated automation within a heat treatment plant. At the beginning of the 2000s, it was common to have an automatic transport car transporting batches to different stations, but, in the last five years, far more complex automation solutions are in demand. In order to meet the requirements of future industry robotics and automation, our industry must adapt to the new and improved technology offerings and standards that are being used in other industries.

Figure 1. Annual robotics installation by industry 2021-2023

According to World Robotics, there has been a significant increase in robotics usage and installations since 2020 (Figure 1). For example, the automotive industry shows installations almost doubled from 2020 to 2022 with 83,000 installations in 2020, compared to 136,000 installations in 2022. The industrial robot market was expected to grow by 7% in 2023 to more than 590,000 units worldwide. Although it exceeded 500,000 installations, robotics were down 2% (possibly due to COVID-19) compared to the prior record year. Of interest to note for the automotive industry, the industry increased its robotics demand in 2023 to surpass electronics with a 25% share (electronics was close with 23%, down by 5% due to inventory levels stabilizing after supply chain bottlenecks mostly vanished).

Table 1. North America’s robotics comparison 2022 to 2023
Source: World Robotics

Specifically for the United States and Mexico, peak robotics installation demand was documented in 2022, but demand has been consistent within +/-5% (Table 1). The future of robot installations is trending to grow and exceed 50,000 units in North America for 2024. Nearshoring of supply chains will create demand for automation technology in the years to come, according to Christopher Müller in his World Robotics 2024 – Industrial Robots presentation.

Manufacturing Concepts

The company SEW has previously published its ideas and concepts of autonomous transporters distributing the raw parts to the production cells, after the soft processing to the hardening plant, and finally the hard machining (Figure 2). All steps are configured within the component so the process steps can be well documented on a component basis.

Figure 2. SEW concept from Hiller, “The networked hardening shop,” 2019
Source: ECM GmbH

As can be seen in the SEW Figures, the original hardening plant is shown as a continuous furnace. However, this type of plant technology can be seen as contradictory to current production needs. To be compliant with this new philosophy, plant technology must be as modular, flexible, and automatable as the rest of the production layout and components. Heat treatment must also be controllable and unloadable with automatic transport units. Robots must be able to load batches and navigate the plant (according to CHD, steel, part numbers, etc.). The smaller the batch size, the larger the value of robotic component documentation. Furthermore, a reduction in batch size is advantageous for flexibility, costs, and heat treatment of many requirements for production runs.

Heat Treatment & Robotics

A heat treatment plant can implement
recommendations for the future of industry
automation by acquiring technology for:

Automatic loading/unloading
Component recognition systems
Automatically loaded/read recipe systems
Smaller batch sizes with a wide variety of variants
Heat treatment of different applications or steels in small quantities
Maintenance/repair detection

Benefits of automating part or all production line steps include:

Shorter process times
High CHD (Case Hardening Depth) uniformity and lower distortion
Lower operating costs and labor reduction

These technologies have existed and are being implemented in heat treat operations for a few years now. The results are clear and the benefits are proven through higher quality parts, highly efficient heat treat operations, and overall more efficient production facilities.

As many machining operations have been robotized, this allows the downstream heat treat operations to easily take advantage of part placement in dunnage and plant transport systems, whether manual or automated.

Figure 3. ECM Vision System
Source: ECM Robotics

Batch Loading with Robotics

Bulk goods-loading (such as clips, links, and other small parts via weight detection) as well as loading and unloading of truck shafts in fixtures and in straightening machines are just a few examples of production areas that can benefit from robotics/automation. Visual recognition systems can identify gears/parts based on the diameter or by the number of teeth on the gear and can then sort them by these features (Figure 3).

Like the visual locating of the parts by cameras, they can also be used for tracking parts and loads within a heat treatment cell. A good amount of work has been done in this area for heat treating. This work covers part marking, tray/fixture encoding, and part weighing scenarios, and allows the heat treat system to accurately process all the different parts coming through the heat treat system with the correct process recipe.

Some of the work being done has been implemented with a QR code marking system for each part before heat treatment. To ensure the correct recipe or heat treatment is performed on the proper part, this scanned code works with the heat treatment system controls to upload the correct recipe to the proper cell. This information can be further analyzed to indicate precise placement in the heat treat tray through virtual tracking.

Figure 4. QR code heat treat test picture
Source: ECM USA Synergy Center

In Figure 4, you can see in the details that this client has reviewed and tested to assure the code is visible before and after heat treating with a carburizing and hardening process.

These parts are tracked when entering the system and also noted as to which heat treat tray they are on by using a binary code with holes in a tray or on a strategically placed bar code plate on the tray. With this system, they can be scanned by a camera before entry and upon exit of the furnace (Figure 5). This tray scanning can also indicate how many cycles the trays have on them to ensure the trays stay in good condition and can be cycled efficiently.

Figure 5. Lohmann Steel barcode scan plate (Images courtesy of Lohmann Steel, heat resistant castings — grates, trays, baskets, fixtures and more)
Source: Lohmann Steel

Networked Hardening

Let’s look at the SEW production concept again and re-imagine it with a more efficient vacuum furnace technology with robotic integration. In this concept, the vacuum furnace system forms the “spatially distributed production reserve” which helps autonomous transport units as “situationally self-controlling” material is delivered.

The QR code on the component represents the “knowledge-based” running card. The robots recognize the components by means of the QR code and are loaded onto the appropriate heat treat trays. The heat treatment can then be carried out on a component-related, flexible, and documented basis. Traceability of production can also be ensured (Figure 6).

Figure 6. Robotics concept
Source: ECM Technologies

Loading of the parts can be done efficiently through a series of dunnage that hold the part in specific locations which assist the robot to locate, lift, and place the parts in the heat treat tray. This method doesn’t always need to be a perfect location for the incoming work as we now have 2D and 3D cameras that can work in tandem to locate parts, even in odd stacking or randomly loaded bins.

In a recent installation, a heat treater automated their gear cutting operation to prepare the dunnage before heat treat. Therefore, the heat treat robotics phase was simplified by storing each part in a specification location for the robot to “see” with its vision system. These parts are then scanned and automatically connected to the part’s recipe as stored in the system. In a modular system using low pressure carburizing, individual cells are utilized, and production is recipe driven. These recipes are pre-developed and stored to allow each cell to utilize the recipes for many different parts. In this case, after a part is scanned, the recipe is uploaded into the next available cell and the scanned parts and heat treat fixture is moved to the cell (Figure 7).

Figure 7. Modular vacuum furnace for low pressure carburizing
Source: ECM USA

Figure 8 was designed to use over 175 different parts with nine different heat treat processes which included carburizing and slow cooling, hardening, tempering, cooling after tempering and cryogenic treatment.

With further considerations for additional benefits of the automated system, fixtures were optimized by using CFC (carbon fiber composite) base trays. These trays are not only extremely stable and have non-existent growth/warpage, but they also help with robotic placement before and after heat treatment. CFC trays are flat, or can be machined to conform to part geometry, which helps to reduce or minimize distortion related to fixture warpage or creep.

Figure 8. LPC and robotics configuration
Source: ECM USA

Many system designs have been proposed to a variety of clients; however, the end goal is to design a system that is “standard.” This standard design needs to incorporate different forms of dunnage, bins, boxes, and pallets to allow a commercial heat treater to easily program the system whenever the next part comes in from their client, whatever it may be. This is a challenging task and needs to be broken out by weight category to design the robot’s reach and end tool design. In this case a robot cell offline of the heat treat furnace can be built and utilize, and ultimately use, an AMR (automated mobile robot) or AGV (automated guided vehicle) to bring the built loads to the furnaces (Figure 9).

Figure 9. AGV configurations
Source: ECM GmbH & ECM Technologies

Vacuum Advantages

Vacuum furnace systems have a clear advantage over traditional atmospheric systems with many features which lend themselves to integrate into the machining area with robotics and automation.

The fact that an LPC (low pressure vacuum) furnace system can process loads via a recipe input and each cell can be used to process a different case depth, or hardening cycle is highly advantageous when processing a wide variety of parts. In addition, the LPC process provides a more uniform case depth throughout the part to make a stronger part along with high quality processing. The vacuum furnace cells can be arranged in many ways to fit into existing facilities and to be able to use many methods of automation especially including robotics.

Quenching is also a key element in any hardening heat treat process. LPC furnace systems are usually associated with high pressure gas quenching (HPGQ) in a separate chamber to provide the best quenching performance. This gas quenching technique provides a clean process for each part and allows the use of CFC fixtures. There is also no requirement for post cleaning as is necessary with oil quenching.

Providing quality low pressure carburizing, clean and precise gas quenching, CFC trays for better uniformity and keeping the parts flat, and the automation benefits of robotics makes for a state-of-the-art heat treating production operation and thus completes the heat treat paradigm shift.

Figure 10. Robot loading
Source: ECM USA

Conclusion

The heat treat industry wants and needs automation and robotics integration to advance production, reduce costs, and improve the overall quality of production. With traditional technology, process data evaluation and self-configured recipe values are not possible. Therefore, component analysis should be automated to meet and achieve consistent and reliable recipe values (mass flow, time). With the increase in robotics demand, vacuum furnace technology meets the variable requirements of “demand-oriented” production. Due to the flexibility of this technology, small batch size systems can be automated with robots or as bulk material.

References

Hiller, Gerald. “The networked hardening shop – the challenge to the hardening plant in the world of Industry 4.0.” ECM GmbH. Paper presentation, 2019.
Müller, Christopher. “World Robotics 2024 – Industrial Robots.” IFR Statistical Department, VDMA Services GmbH, presentation in Frankfurt am Main, Germany, 2024.

About the Author:

Dennis Beauchesne
General Manager
ECM USA

Dennis Beauchesne brings experience of over 200 vacuum carburizing cells installed on high pressure gas quenching and oil quenching installations. He has worked in the thermal transfer equipment supply industry for over 30 years, 23 of which have been with ECM USA.

For more information: Contact Dennis at DB@ECM-USA.com.

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Digitalization Propels Heat Treating to Industry of the Future

January 7, 2025 / CONTROLS TECHNICAL CONTENT, INSTRUMENTATION TECHNICAL CONTENT, Manufacturing Heat Treat Technical Content, TECHNOLOGY

If you work in a standards-driven industry, you may already feel the imperative of digitalization. In today’s Technical Tuesday, Mike Loepke, head of Nitrex Software & Digitalization, posits how, even if you aren’t necessitated to track compliance digitally, you are probably looking to synthesize and leverage the strengths of multiple advanced operations — furnace and process record-keeping, knowledge of furnace past operations, juggling different new equipment capabilities — across just one platform. In other words, you are looking to bring digitalization system management to your operations.

This informative piece was first released in Heat Treat Today’s December 2024 Medical & Energy Heat Treat print edition.

The Future of Heat Treatment Relies on Digitalization

The ultimate goal for heat treaters, whether commercial or captive, is to uphold the quality of their product and meet client expectations while remaining profitable. Digitalization supports these efforts as it synthesizes and presents detailed, transparent, and accessible data that allows heat treaters to better manage their equipment, processes, and product quality. In addition, the collection of detailed information can serve as a database of knowledge to be used by the next generation of heat treaters, supporting future viability and advancement in the field.

There are necessary steps to take to establish a digital solution and essential components to look for when choosing a software platform that assists heat treaters in optimizing equipment and processes, effectively creating the digitalization of the heat treat operations. Let’s explore these now.

How Digitalization Optimizes Heat Treatment Processes

Digitalization in the heat treatment industry relies on the integration of industrial internet of things (IIoT) technologies with traditional and modern heat treatment processes. Using enabling devices such as sensors, modern connectivity methods, analytics, machine learning, and IIoT software platforms, it is possible for heat treaters to collect and process data that, after analysis, drives informed decisions to optimize equipment, processes, and product quality. To put a finer point on it, digitalization occurs when a manufacturing system is digitally integrated to capture and preserve human experience and knowledge, forming a holistic virtual representation of heat treat operations.

Figure 1. QMULUS Shop Layout enables visual inspection of the current production status, the location of goods and parts, as well as the real-time status of assets and their ongoing processes.
Source: Nitrex

While digitalization varies from industry to industry and plant to plant, there are some common ways in which heat treaters can employ digital technologies to build such a system. Firstly, digitally integrated solutions can optimize process management and control. For example, when a sensor detects a temperature anomaly during a heat treatment process, the integrated software platform picks up that reading, analyzes it in real time, recognizes it as an error based on historical data or programmed parameters, and alerts the operator.

This integration also facilitates predictive, condition-based maintenance. For example, if collected data and analysis suggests that a furnace is behaving abnormally, the system can automatically generate a work order along with a list of potential failure causes, so that a technician can troubleshoot, identify, and correct small issues — such as a failing thermocouple — before they impact quality or result in equipment failure. By addressing these proactively, heat treaters can avoid extended periods of costly unplanned downtime and ensure continuous operation.

Secondly, artificial intelligence through machine learning plays a crucial role in optimizing quality control in a digitalized system. By analyzing data collected during heat treating processes, it learns to detect patterns and identify anomalies. As in the examples above, this capability enables the system to identify deviations from the desired outcomes, allowing heat treaters to quickly rectify any issues before they impact quality.

Figure 2. The heart of the IIoT data platform needs to be thoughtfully planned and designed. Illustrated are 5 steps to follow to ensure the cloud data system properly engages with the data generated from your specific heat treat operations, ultimately delivering actionable insights. Step 1 depicts the various data sources; Step 2 shows the data transformation, integration, and processing stages; Step 3 highlights the central QMULUS database where data is indexed and organized; and Steps 4 and 5 demonstrate how data is further processed, distributed, and accessed by different end-users.
Source: Nitrex

Thirdly, algorithms can be programmed into a comprehensive management system to identify the most energy-efficient operating conditions for the heat treating process, helping heat treaters reduce their carbon footprint, minimize energy costs, and comply with sustainability goals.

In addition to these types of operational advantages, digitalization technologies can also be used to create a database of knowledge before experienced operators and experts leave the workforce. Traditionally, a handful of experts in the plant oversee the furnaces and equipment and understand how to best control and maintain them based on experience. However, passing down this knowledge to the next generation of heat treaters can take years, which may not be possible due to a company’s workflow demands and cost pressures. Digitalization addresses this challenge by creating a streamlined and accessible database of knowledge, offering less experienced operators and technicians immediate access to detailed information about what may be happening in the equipment or process for an issue at hand. This ensures that essential insights are not lost and enables quicker problem-solving and decision-making on the shop floor.

Making the Digitalization Transformation

While digitalization presents obvious advantages, the heat treatment industry, often conservative in its approach to technology, has some initial work and investment required before realizing the full benefits.

Going “paperless” in order to unlock the full potential of the available data is an important first step. All reports, histories, drawings, and other paperwork associated with equipment, processes, maintenance activities, product quality, and other relevant information should be digitized to provide a comprehensive view of both historical and current data.

Connectivity and integration between machine and higher-level systems are essential for effective data acquisition, monitoring, and remote control. SCADA systems, Manufacturing Execution Systems (MES), and other higher-level systems are rich sources of machine and process data. Gathering and analyzing this data can provide actionable insights that operators can use to make smarter decisions about the control and maintenance of equipment and processes.

Figure 3. A comprehensive overview displays all detected control loop anomalies, indicating possible root causes as well as recommended actions. Incorporating feedback from the responsible maintenance personnel further improves accuracy and delivers more effective recommendations for future occurrences.
Source: Nitrex

Finally, just having data is not enough. The data must be accessible, transparent, and relevant to be valuable. Achieving a complete picture of all the collected data, known as data consolidation, is necessary.

To build an IIoT platform with a well-architectured data engine, heat treaters should begin by identifying and understanding the different sources of data provided by sensors and high-level systems. This involves integrating the data through interfaces adapted to the data type and source, as well as documenting the integrated data sources, data fields, and data streams. Next, a “data lake” should be created to store the collected raw data. From this foundation, a data warehouse can be established to store enriched or analyzed data, derived values, data models, and forecasts in an organized way. For heat treaters, this type of contextualized data might be grouped by parts, loads, or orders.

Once the data engine is in place, the information stored in the data warehouse must be presented in a way that makes sense to operators and technicians for them to make informed decisions for heat treatment processes. To facilitate this, a universal data interface should be considered.

Building from this well-architectured data engine, the IIoT platform can then be expanded with statistical analytics, remote monitoring, KPI tracking, machine learning, artificial intelligence, and other applications to optimize processes and increase profitability.

What Heat Treaters Need in a Digitalization Solution

Harnessing modern technologies tomake digitalization a reality presents heat treaters with the opportunity to implement a solution based on a complete and well documented data system. It also means that the solution creates a holistic solution to data analysis, interpretation, reporting, and action that supports the real-world actions of heat treaters on the plant floor and in the office.

For this reason, a digitalization solution that has cloud and on-premises allows real-time access to analysis and alert messages for operators on the floor as well as managers who are away from the plant, ensuring quick problem-solving and maximum uptime in the event of process or machine issues.

Additionally, heat treaters should look for a solution that offers the freedom to integrate all the various platforms and equipment from which data are gathered from. These may include relevant machinery and production data from the shop floor as well as third-party and custom controllers. This flexibility to synthesize information from multiple sources will ensure the digitalization efforts lead to a comprehensive solution with actionable process overviews, recipe control, batch tracking, and other customization options.

To further this intent of a holistic solution, heat treaters should consider various data capabilities with different portal views, such as a manufacturer portal, a plant portal, and a client portal. However, considering the historic value of a comprehensive software solution, it may be worthwhile to consider how each user could transfer direct feedback and add new rules into the system, creating a repository of knowledge that bridges the knowledge of outgoing generations to future heat treaters.

Finally, any platform that directs the digitalization of a plant must prioritize robust security measures. Several features to look for are:

enhanced encryption standards to keep data confidential and tamper-proof during transmission and storage;
secure protocols based on industry best practices to safeguard data integrity;
a granular access control system (ACS) to allow IT administrators to define and manage user permissions of authorized personnel, thereby minimizing the risk of data breaches and unauthorized data manipulation; and
intrusion detection and prevention systems to continuously monitor network and system activities, enabling instant identification and mitigation of suspicious behavior. This serves as an additional layer of defense against potential cyber threats.

Beyond the software setup, be sure to use best practices by conducting regular security audits to assess the platform’s vulnerabilities and ensure compliance with evolving cybersecurity standards. While digitalization of heat treat operations may seem like a task for the next generation to complete, secure software options that integrate the hard work of digitizing plant activities can make this endeavor just a step away.

About the Author:

Mike Loepke
Head of Nitrex Software & Digitalization
Nitrex

Drawing from a background in Mathematics and Physics, coupled with extensive R&D experience and metallurgical modeling, Mike Loepke specializes in AI and process prediction. He has led Nitrex’s initiative in developing QMULUS, a pioneering IIoT cloud-based platform. Mike’s relentless pursuit of knowledge keeps him at the forefront of evolving technology.

For more information: Contact Mike at mike.loepke@nitrex.com.

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Heat Treat Radio #116: Basic Practices for Successful Leak Detection

December 19, 2024 / HEAT TREAT RADIO, Manufacturing Heat Treat Technical Content, VACUUM PUMPS GAUGES VALVES TECHNICAL CONTENT

In this Heat Treat Radio episode, Dave Deiwert, a seasoned expert in leak detection, shares key steps to locate leaks in a vacuum furnace. Host Doug Glenn and his guest specifically look at helium as a tracer gas. From Dave’s extensive experience starting as a field service engineer to founding his own company, Tracer Gas Technologies, listen as he identifies systematic approaches, the influence of air currents, and cost-effective strategies for effective leak detection.

Below, you can watch the video, listen to the podcast by clicking on the audio play button, or read an edited transcript.

HTT · Heat Treat Radio #116: Best Practices for Successful Leak Detection

The following transcript has been edited for your reading enjoyment.

Meet Dave Deiwert (01:10)

Doug Glenn: Welcome to another episode of Heat Treat Radio. We’re talking today about leak detection in vacuum, and we’re happy to have Dave Deiwert with us who is a leak detection expert.

Dave, would you give our listeners a little bit of background about you and your qualifications in the industry, and then we’ll jump into some questions about leak detection?

Dave Deiwert: I’ve been in leak detection since 1989. I started off my career as a field service engineer. I did that for about 10 years, then moved into sales engineering for probably the second third of my career. And for the last number of years, I’ve been a product manager and applications manager, working with several of the major vacuum and leak detection companies in the world. I thoroughly enjoy what I do and helping others with their leak testing applications.

Doug Glenn: And now you’ve got your own company. Could we hear a bit about that?

Dave Deiwert: Sure, Tracer Gas Technologies had its birth in September of this year. My focus will be on providing training and applications assistance to industrial clients, research and development labs, and government and university labs.

Doug Glenn: What’s the best way for people to reach you?

Doug Glenn and Dave Deiwert discuss his new position as president of Tracer Gas Technologies.

Dave Deiwert: We are new and still working on the website, but in the meantime, you can reach me at my phone at (765) 685-3360 or email me at DDeiwert@gmail.com.

Doug Glenn: Dave recently published an article in the November 2024 print issue of Heat Treat Today called, “Basics of Vacuum Furnace Leak Detection, Part One.” The article includes ten tips for vacuum leak detection using a helium leak detector.

Indicators of Leaks (03:45)

We’re going to cover some of those tips today. But before we get started, what are the most common symptoms that we have a leak when operating a vacuum furnace?

Dave Deiwert: I’ve been helping these clients for a number of years. And typically, one or two things happen: So, the client is following the furnace manufacturer’s recommendations to do a periodic “leak up test,” where they pump the furnace down towards base vacuum; they isolate the pumps to look for the pressure to rise after the pump’s been isolated, and if the pressure rises at a faster rate over a test period of time, which might be ten minutes, then they determine they have a leak that they should be looking for.

It’s either during that test that they discover they have a leak that they should be looking for before it impacts quality. Or the problem develops while they’re using the furnace, and it begins to affect the quality of the product. They start to see a difference in the appearance of the product because there’s some type of contaminant gas from atmosphere, water vapor, or maybe their product is sensitive to oxygen and such. It also could be as simple as they used to pump down to base pressure for the process in “x” amount of time, and it seems like it’s taking longer.

One of those two things will get their attention, and that’s okay. Let’s look for the leaks.

Isolating the Source of the Leak (05:11)

Doug Glenn: Most of the discussion we’re going to have today is going to be on using helium leak detectors. But let’s assume you don’t have a helium leak detector. What would be your checklist of things to run through to try to isolate the source of the leak?

Dave Deiwert: My perception is that end users that only have maybe one or two furnaces might not have their own leak detector, and calling for help might be quite a pricey option. They may try to do some things on their own without the leak detector or help from somebody outside the organization.

The first thing you’re going to do is consider where most leaks typically would be on a furnace. You’re going to think of things like the door is opened and closed on every cycle of the furnace, so the gasket or O-ring type material there can get worn over time.

Or maybe while the door was open, something came to rest on the O-ring: a piece of fuzz, hair, or slag metal. Something may be there that creates a leak path when they close the door. To look at that in greater detail, they get some extra light on it and see if they can determine something there. They may go ahead and remove that O-ring and just clean it up really well. Many might put a light coating with some vacuum grease or some type on it and then reinstall it.

Of course, we recommend that you try not to use vacuum grease. That could be a whole other discussion. But many will try that and see if it’s helpful to them.

The vent valve for the system also opens up after every test. So, there’s another gasket that can get worn or dirty.

Another thing would be process gases. If they filled their furnace with some back stream with argon or something, those process gas valves can leak past the seal.

So they think about each of these things and go through them one at a time and inspect them. And if they’re not quite sure what they’re seeing, they might replace the gasket or seal and then hope that they’re successful. And if they continue to not be successful, they ultimately end up calling for help.

Somebody could get very frustrated looking for leaks if you don’t know for sure that it’s only picking up helium. It’s not reacting to Dave Deiwert’s aftershave or cologne, or something else… the fork truck that went by, or something else. I can say with 100% certainty it’s reacting to helium.

Understanding Leak Detector Technology (07:14)

Doug Glenn: I want to ask for a further explanation on the first tip in this article.You say, “Understand how your leak detector works to the point that you can confirm it is working properly.” How does a company do that?

Dave Deiwert: If you’re going to go to the expense of having a leak detector — which many should — they should understand how it works properly and how to tell that it’s working properly or not before you start spraying helium to look for leaks.

Every manufacturer of leak detectors today, and for quite a number of years, has a leak detector that will let you know whether you’re in the test mode or in a standby mode. If you ever approach somebody that is leak testing and the leak detector is in standby mode and they’re spraying helium, you can suggest, “I bet you haven’t found any leaks yet, have you? Well then, you might want to put your leak detector in test mode.”

Understanding it’s in test mode and understanding how to calibrate the leak detector are good tools to help your success in finding leaks on the system. You have to at least be familiar enough with the leak detector to understand its operation and knowing that it’s sensitive to helium and the calibrating procedure increases and supports this understanding.

Doug Glenn: That makes a lot of sense: Make sure it’s turned on.

Dave Deiwert: Right, turned on and connected to your system. If you don’t have a hose going from the leak detector to the furnace and you’re spraying helium, that’s also going to be a problem.This might sound silly, but sometimes people think, “Hey, this sounds easy. You just spray helium and look for leaks.” They may ask some person who doesn’t really have much experience, “Hey, go over and test the furnace.” They may be embarrassed to say that they don’t know how to use the leak detector, so they may give it a go. Because they don’t understand the leak detector, they might not be successful.

Doug Glenn: That leads me to my next question because I would be that guy that doesn’t really know how they work. When you’re performing a leak detection using a helium leak detector, how does that process work? Where is the leak detector? Where are you spraying the helium?

Dave Deiwert: Sure. In my career I’ve seen people choose a few different points of connection to the furnace, but you’ll find our industry that we teach people that the best place would be to connect the hose from the leak detector to point in front of the blower if they’ve got a blower on their system. If they don’t have one, it’s going to go at a connection point near the inlet of the pump of gas pumping through this system. But you want to sample that flow of gases from the furnace towards the pumps. That way, you can get a sample to the leak detector as you’re spraying the helium.

When you talk about how the leak detectors work… at every class I teach, I think it’s important to at least give enough information so that you have confidence that the leak detector can help you. How’s it sensitive to helium and why? With these leak detectors, no matter who manufactures them, typically you’ll see that inside there’s a mass spectrometer that’s tuned to the gas mass weight of a helium molecule. And because it’s dependent on the mass weight of a helium molecule, not the mass weight of oxygen, nitrogen, argon, or whatever, you can be 100% sure that when the leak detector reacts, it’s getting helium from somewhere.

I stress that because somebody could get very frustrated looking for leaks if you don’t know for sure that it’s only picking up helium. It’s not reacting to Dave Deiwert’s aftershave or cologne, or something else… the fork truck that went by, or something else. I can say with 100% certainty it’s reacting to helium.

You might be surprised how often in my career somebody said, “Dave, the leak detector’s reacting, and I haven’t even started spraying helium yet.” I will tell them helium is coming from somewhere, and it could be the tank of helium that you’ve rolled up to the furnace is spraying helium and you didn’t realize it. Maybe the spray gun is still spraying helium even though the trigger is not pulled. Maybe the regulator’s leaking.

Leak detector hooked up to vacuum furnace
Source: Dave Deiwert

And if that furnace has got a leak, it’s the whole reason you brought the leak detector over. You’re not spraying helium yet, but helium is being sprayed by the tank or the regulator. The leak detector is going to react to the helium regardless of how it got into the system. So that can be very frustrating.

Let me back up: If you know beyond the shadow of a doubt the leak detector will only respond to helium and you haven’t sprayed helium yet, you know immediately it’s coming from somewhere.That is to say, I need to figure out what’s going on there. Otherwise I might spin my wheels looking for a leak while something else is a distraction for me.

Does that make sense?

Understanding Helium (11:53)

Doug Glenn: Yes, it does. Let me ask you this, though, because I’ve never done a helium leak detection as a publisher of a magazine — we don’t have a lot of helium in this business. You’ve got this box called the helium leak detector. It’s got a hose. You connect the hose near the blower or someplace close to the vacuum pump. I assume the leak detector is sampling the air as it’s coming towards the pump or towards the blower. Correct?

Dave Deiwert: Absolutely.

Doug Glenn: Then you’re spraying helium on the outside of the furnace somewhere to see if it’s being pulled into the furnace through some hole and therefore heading towards the pump. Correct?

Dave Deiwert: Yes.

Doug Glenn: I wasn’t ever sure how that worked — whether you spray the helium inside the furnace then you’re checking around the outside of the furnace with the leak detector; I know that sounds silly, but I thought that might be how it worked. But the truth is you’re sampling the air inside, and you’re spraying helium on the outside. If that’s the case, with a canister of helium on the outside of the furnace, won’t the detector be detecting the gas because it is going from that helium canister through and into the furnace, right?

Dave Deiwert: Yes, that’s correct.

When we get into the idea of spraying helium — where does the helium go when I spray it? When I started my career way back in 1989 as a field service engineer, I was taught that helium rises because it’s the lightest gas. And so I was taught, as were many other people, to start at the top of the furnace and work your way down.

The problem with teaching that is (remember, there’s five parts per million of helium naturally in the air we breathe) that if I start spraying helium, I can tell you with 100% confidence that the air currents in the room are going to impact that helium. If you can feel the air blowing from your right towards your left, and when someone’s got a floor fan on you can be sure of it, the predominant helium you’re spraying is going to move that way. It’s going to dissipate over time, but starting somewhere methodical to spray the helium is important and to not spray too much.

Be Patient with Leak Detection! (13:14)

Doug Glenn: I did want to ask a little bit about that because in your second and third tip in this article you expressed the need to be patient when doing a leak detection. Just exactly how patient do we need to be, and why do we need to be so patient?

Dave Deiwert: Frequently throughout my career, I’ve run into people who say, “I’m not sure if I’ve got a leak, so I’m going to spray a lot of helium so I can determine it pretty quickly.” But if you spray that helium like you’re trying to dust off the equipment, you will have so much helium in the air the leak detector will definitely react if there’s a leak. However, now you have to wait forever and a day; it could be quite a while until the helium that you just sprayed all over the system and in the room dissipates before you can continue looking for a leak.

I always ask this question when I’m teaching a class with people who have been doing leak testing: “How do you set your helium spray nozzle?” The ones that’ve been doing it for quite a while will say that they’ll get a glass of water, for example, and they’ll put the spray nozzle down in the water and adjust the flow to where they get one bubble every two to three seconds. I see some variation on that, one to ten seconds. But they’ll try to meter it down. Somebody might say, “I’ll put the nozzle up to my lip and spray so I can barely feel it.”

I’ve run into people who say, “I’m not sure if I’ve got a leak, so I’m going to spray a lot of helium so I can determine it pretty quickly.” But if you spray that helium like you’re trying to dust off the equipment, you will have so much helium in the air the leak detector will definitely react if there’s a leak. However, now you have to wait forever and a day.

To those people, I’ll say, “That’s a good start. If you put that nozzle in that glass of water and it looks like a Ken and Barbie jacuzzi, you’re spending way too much helium into that.” I would meter that down to a very small amount, whether it’s a bubble every three seconds or you can barely feel it on your lip is a good place to start.

And because I made the comment that helium doesn’t necessarily rise but can go different directions based on the wind, air currents in the room, and fresh air makeup, eventually somebody says, “Where should I start?” I’ll say, “I don’t have a problem with you starting at the top of the furnace and working your way down. Be methodical.”

Some people will start at the leak detector they just hooked up because they might have put a leak in the bellows connection from the leak detector. You might start there to make sure the assembly you just did is leak tight.

But start somewhere, be methodical as you move across the system, and remember that helium can go up, down, left, back, or forward depending on what the air currents are.

Doug Glenn: I was actually going to ask you about the air currents, because I thought that was an interesting tip that you had made. In fact, I think that’s like tip four and five in this article. I think we’re dealing with air currents and things of that sort. So, we’ll skip over that, because I think you’veaddressed that.

The Dead Stick Method (16:48)

Doug Glenn: You mention an interesting thing called a “dead stick method” in tip number six. Can you explain what that is?

Dave Deiwert: I’m glad you asked that because I looked back on that later and thought I don’t think I elaborated on that enough for somebody that’s never done the dead stick method. That is a term for when you spray just a little squirt of helium away from you and the furnace, and then stop spraying. Then you’re going to rely on the residual helium that’s coming out of the tip of the nozzle for some period of time.

In my training classes, I typically have a plastic bottle that has a little right-angle nozzle on it. You may have used them back in high school in chemistry; it might have had alcohol in it. I will squirt a little helium in that plastic bottle and then screw the cap on; that will last me for two or three days at a trade show or a training event. I don’t have to squeeze the bottle. There’s enough helium coming out of the nozzle that you can detect leaks.

To demonstrate, I’ll put hair on an O-ring on a test for the leak detector. (It’s the cause of my receding hairline.) I can take that nozzle without squeezing the bottle and move it near the hair that I put in there, and it will detect it very impressively every single time, at least over the course of two to three days.

Perspective looking up into the world’s largest vacuum chamber at NASA’s facility in Sandusky, Ohio
Source: Dave Deiwert

My point of demoing that is people tend to spray away too much helium. If there’s five parts per million naturally in the air we breathe, you only need enough delta difference so that as you go past where the leak’s at you can see a reaction from the leak detector and pinpoint it.

Backtrack to if somebody sprays a lot of helium to prove they have a leak. Now they have to wait a long time for the helium to dissipate. And by the way it’s not just dissipating from the room. You’ve sprayed a lot of helium that is now feeding that leak. And as it goes through the leak path in the furnace, it expands back out in front of you. It’s got to pump away from the furnace, too. It’s also got to clear the system and go out to the pumps before you get back to baseline so that you can continue leak checking.

Therefore, if you spray just very small amounts,, you have to get close to where the leak is before you start to get a response. This way you have less concern of helium drifting to the opposite side of the furnace and going through a leak path there — that can really distract. You may think you’re near the leak, but it’s really on the other side of the furnace because you’ve sprayed way too much helium.

Spraying little amounts might make you feel like it’s taking longer. But the fact is, when you start to get a reaction at the leak detector, you can be comfortable that you’re getting close to the where the leak is.

Doug Glenn: If you know you’re in a room with air currents in it (let’s just say there’s a flow of some sort from left to right), does it make sense to always start downwind, and then work your way back across the system?

Dave Deiwert: Yes. If I can feel a fan — Joe’s got his fan on because it’s keeping him cool, and it’s blowing over towards where I’m leak testing, I might say, “Hey Joe, could you turn your fan off a little bit while I’m testing?” He may say, “No, it’s making me comfortable.” All right, now I’ve got to work with that. I know that I can feel the air currents moving from my right towards my left. So, yes, starting downwind and working my way up could be helpful. You want to pay attention to what the air is doing if you can tell. It may be a very calm environment, and you’re not sure what the air currents are doing; just be methodical. Pick somewhere to start in the furnace.

Here’s something else about spraying helium: Once you think you know where the leak is at, every time you put the spray nozzle there you should get the same response. You spray the helium, you get a response, you stop spraying and wait until it drops back to baseline, and then you go back to where you think the leak is. If that’s where the leak is, every time you put the probe there, you should get the same response time at the leak detector. If even one time you put the spray gun there and don’t get a response or not nearly the same, then that’s not where the leak is at. Yeah, you should know beyond a shadow of a doubt when you pinpoint the leak.

Doug Glenn: How often do you see more than one leak at a time? Let’s say you isolate a leak, you think you got it, then say you take the gasket off or whatever you do, do the test again, and there’s still a leak.How often does that happen?

Dave Deiwert: It happens most of the time. When I was a field service engineer and somebody called me in to help, I almost never found one leak. That tells me they were working with one leak that maybe wasn’t large enough to affect their quality or the cycle time, and they were living with it. And the day comes where they have a leak that gets their attention or the leak got larger. It can be more challenging if you’ve got more than one leak. It’s a short-lived celebration when you think you found a leak and then you go to start the process, and, oh, it looks like you still have a leak. That wasn’t the one. So, you might make a case for looking to see if you can pinpoint another leak while you’re in the leak testing mode.

Doug Glenn displays the cover of the November 2024 issue of Heat Treat Today, in which Dave Deiwert’s article, “Basics of Vacuum Furnace Leak Detection, Pt 1,” is featured.

Saving on Helium Gas (21:35)

Doug Glenn: Besides the fact that a helium leak detector can save you all kinds of time because typically you can find a leak faster with a helium leak detector then in a process of elimination, you also mentioned a tip for saving money regarding the mixing of the gas. Could you elaborate on that and any other cost savings tips?

Dave Deiwert: I already mentioned that people tend to spray way too much helium at least until they’re sensitive to that concern and cut back. But when they buy the tanks of helium, they’re buying 100% helium. And remember my comment that you just need enough delta increase in the helium that you’re applying to where the leaks at to be able to pinpoint it. The possibility that you could buy your tanks of helium at a lesser percentage, maybe 25% helium and 75% nitrogen, would help you save on some helium and help your efforts to not be spraying too much.

People have not been saying that in this industry, and so that can make folks nervous. “I don’t know, Dave. We’ve never done that before. I’ve never heard anybody else say that before.” I suggest if you are going through a lot of helium, you could cut down how much helium you’re spraying. You could save some significant money, especially these larger facilities with many furnaces and so forth. Give it a try. Buy one tank of it with a mix gas and pick something that you’re comfortable trying, whether it be 25% or 50% helium and buy one bottle. And the next time you test your furnace and find a leak, then try to look at that leak with the lower percentage helium and prove to yourself whether using a lower percentage of helium is going to save you money.

Doug Glenn: You’re suggesting people get themselves comfortable with it, use their 100% until they find the leak, and then try the lower helium.

Dave Deiwert: When they show the proof to themselves, that they can still have the capability to find leaks like that, then they could save a little money. Plus, there’s the added benefit of not spraying so much helium and having to wait as long for the area to clear up before you can start spraying again to continue to pinpoint a leak.

Doug Glenn: And that would save you additional time. Dave, thank you very much. Is there anything else you’d like to add before we wrap up?

Dave Deiwert: Only that if you know you’ve got a leak in the system — it failed the leak up test or quality or whatever, you sprayed it around the entire system, and you can’t find any leaks — then you’re probably looking at an internal leak most likely past the seat of a valve. Or maybe you’ve got a vent valve that’s leaking past the seat, but your plumbing to that vent valve maybe goes out of the building, so you don’t really have an easy access to spray helium past that.

For example, with an argon valve, you may need to disconnect the argon supply from that valve so you can get access to that side of the valve to spray helium to see if you can detect a leak past the seat of that valve.

Doug Glenn: Dave, thanks very much, I appreciate it. I’m sure we’ll be talking again. I know vacuum leak detection is an important thing.

About The Guest

Dave Deiwert
President
Tracer Gas Technologies

Dave Deiwert has over 35 years of technical experience in industrial leak detection gained from his time at Vacuum Instruments Corp., Agilent Vacuum Technologies (Varian Vacuum), Edwards Vacuum, and Pfeiffer Vacuum. He leverages this experience by providing leak detection and vacuum technology training and consulting services as the owner and president of Tracer Gas Technologies.

Contact Dave at ddeiwert@gmail.com.

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Understanding Inductance in a Furnace Heating System

December 12, 2024 / CONTROLS TECHNICAL CONTENT, Manufacturing Heat Treat Technical Content, OP-ED, VACUUM FURNACES TECHNICAL CONTENT

In this installment of the Controls Corner, we are addressing inductance in a furnace heating system, and the critical role it plays in various industrial systems, including furnace load systems. Impedance acts as a measure of how much a circuit resists the flow of AC current. In this guest column, Brian Turner, sales applications engineer at RoMan Manufacturing, Inc., explains how impedance applies in electrical circuits.

This informative piece was first released in Heat Treat Today’s November 2024 Vacuum Heat Treat print edition.

Inductance is a fundamental concept in electrical engineering, and it plays a critical role in various industrial systems, including furnace load systems. In furnaces used for heating, inductance is a key factor influencing the system’s electrical performance, energy efficiency, and overall operational behavior.

To talk about inductance, let’s first address impedance and how it applies:

In electrical circuits, impedance refers to the total opposition to the flow of alternating current (AC), which is a combination of both resistance (from resistors) and reactance (from inductors), essentially acting as a measure of how much a circuit resists the flow of AC current, taking into account both the resistive component (like a resistor) and the reactive component (like an inductor at a specific frequency) within the circuit.

Load configuration, power source (IGBT, VRT, ERT) to the furnace feedthrough
Source: RoMan Manufacturing Inc.

Inductance

Inductance is the property of an electrical conductor that opposes a change in the current flowing through it. It arises from the magnetic field generated around the conductor when an electric current passes through it. The unit of inductance is the Henry (H).

In an AC circuit, inductance creates a phenomenon known as inductive reactance, which resists the flow of current. Inductive reactance (X_L) is given by the formula:

X_L = 2πƒL

Where:
• X_L is the inductive reactance (in ohms)
• f is the frequency of the AC supply (in hertz)
• L is the inductance (in Henrys)

This reactance influences how the current behaves in the system, which is particularly important in furnace load systems where high current flows are common.

Resistance

Electrical resistance is the opposition that a material offers to the flow of electric current. It is measured in ohms (Ω) and depends on factors such as the material’s properties, its temperature, and the geometry of the conductor (length, cross-sectional area). In heating systems like vacuum furnaces, resistance is harnessed to convert electrical energy into heat through Joule heating (also known as resistive heating).

The relationship between electrical power, voltage, current, and resistance is governed by Ohm’s law:

V = IR

Where:
• V is the voltage across the heating element(in volts)
• I is the current through the element (inamperes)
• R is the electrical resistance of theelement (in ohms)

The heat generated by the furnace’s heating elements is a function of the power dissipated in the resistance, given by the equation:

P = I² x R

This shows that the heat produced is directly proportional to the resistance and the square of the current flowing through the heating elements

Close Couple

Reducing the material in the secondary* reduces resistance (HEAT = I² x R)
Reducing the area in the secondary reduces inductive reactance increasing power factor

To be most efficient, use the shortest amount of conductor material from the electrical system secondary to the furnace feedthrough. Additionally, keep the distance between those conductors as small as possible.

Power Factor and Efficiency

Inductance in a furnace load system causes the current and voltage to be out of phase. This phase difference results in a lower power factor, which is a measure of how effectively the system converts electrical power into useful work. A lower power factor means that more apparent power (the combination of real power and reactive power) is required to achieve the same level of heating.

In practical terms, a furnace with a high inductive load will draw more current from the power supply for a given amount of heating, leading to increased energy losses and inefficiency.

In practical terms, a furnace with a high inductive load will draw more current from the power supply for a given amount of heating, leading to increased energy losses and inefficiency. Power factor correction techniques, such as the use of capacitors, are often employed to counteract the effects of inductance and improve system efficiency.

Conclusion

Inductance is a fundamental factor in the operation of furnace load systems, influencing everything from heating performance to energy efficiency and power quality. By understanding and managing inductance, furnace operators can optimize their systems for maximum performance while minimizing energy losses and operational costs. Controlling inductance is essential for ensuring that furnace load systems operate reliably and efficiently in demanding industrial environments.

*The connection from a vacuum power source to the furnace’s feedthroughs, this connection can be made using air-cooled cables, water-cooled cables, or copper bus.

About the Author:

Brian Turner
Sales Applications Engineer
RoMan Manufacturing, Inc.

Brian K. Turner has been with RoMan Manufacturing, Inc., for more than 12 years. Most of that time has been spent managing the R&D Lab. In recent years, he has taken on the role as applications engineer, working with customers and their applications.

For more information: Contact Brian at bturner@romanmfg.com.

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IIoT Connectivity — The Future of Technology Is Here Today

December 10, 2024 / CONTROLS TECHNICAL CONTENT, Manufacturing Heat Treat Technical Content, TECHNOLOGY

Maintaining clear communication for high precision processing, critical with medical component heat treating, requires sophisticated operations. In today’s Technical Tuesday, Mike Grande, vice president of Sales at Wisconsin Oven Corporation, provides an overview of how the industrial internet of things (IIoT) advances heat treat performance capabilities and ensures accurate, repeatable results.

This informative piece was first released in Heat Treat Today’s December 2024 Medical & Energy Heat Treat print edition.

Today’s technology is evolving at an exponential rate. Over the last several years, digital technology has provided more and more connectivity between devices and processes. One of the most impactful is IoT technology. From smartphones to virtual assistants, touchscreen refrigerators to thermostats and interconnected home management systems, these products are quickly changing the way people interact and connect.

In addition to consumer products, the industrial world is also seeing increased reliance on this technology to improve throughput, decrease energy use, and increase equipment longevity by capturing and analyzing the data generated by their machines.

What Is IoT and IIoT Technology?

IoT (internet of things) refers to everyday items that have been equipped with sensors that transfer data over a network. Refrigerators, lights, thermostats, smart speakers, and entire homes are now available with IoT technology. Devices equipped with IoT options provide conveniences like remote monitoring, advanced programming, and smart learning, which make daily and household tasks easier. What seemed like science fiction just a few years ago has become reality.

This impressive technology does not only apply to the consumer world. The application of IoT to the manufacturing sector is even more impactful. Industrial internet of things (IIoT) is the term used to describe the application of connected IoT technology to industrial machinery. These systems collect and analyze data, learn from that data (“machine learning”), perform predictive maintenance, and then share that information with personnel, manufacturers, including manufacturers of the machines being monitored, and even other devices. This type of data collection and analysis gives valuable insight into the facilities, processes, and equipment to ensure that everything from energy usage in a facility to equipment performance for a process is optimized.

Figure 1. The IoT gateway collects the data from oven-mounted sensors and wirelessly transmits it to the cloud.
Source: Wisconsin Oven Corporation

How Is IIoT Used in Industrial Ovens and Furnaces?

IIoT technology tracks the performance and health of the most critical components and conditions in the ovens and furnaces they are monitoring. The system utilizes an IoT gateway (Figure 1), which collects information from predictive maintenance sensors that gathers performance data and stores it over time. The gateway also wirelessly transmits the data to a cloud platform where it can be displayed in dashboards, designed for easy viewing and monitoring. Thresholds are set at warning or alarm conditions. When exceeded, the system alerts the user or the oven manufacturer that there is a problem. This type of system predicts component failures before they occur, allowing time to schedule maintenance and minimize unplanned downtime.

Figure 2: An example of a dashboard used on an oven IIoT system
Source: Wisconsin Oven Corporation

The data is displayed in a dashboard format (Figure 2) which permits visual analysis of the information, and intuitive understanding of the process being performed in the oven. In the example of an oven used to process parts in an inert atmosphere, the x-axis represents the elapsed time, which can be expanded or collapsed by the user in order to provide a more (or less) detailed view of the process. The y-axis tracks variables such as temperature, pressure, oxygen level, nitrogen flow rate, and humidity level.

A few examples of the oven data gathered and analyzed by an IIoT system are as follows:

The output of the temperature controller is monitored. If, for example, the controller output is normally running at 30% for a specific oven (meaning the oven is using 30% of its full heat capacity), and for no apparent reason it increases to 60% output, this indicates either an exhaust damper is stuck open and causing the oven to exhaust too much of its heat, there is a heater failure, or a door is not closing fully, or something else.
Vibration sensors installed on recirculation blowers can monitor the health of the oven. Since blowers are rotating machines, they have a predictable vibration frequency and amplitude. As the blower bearings wear over time, these vibration parameters change. The IIoT system uses proprietary algorithms to determine acceptable vibration levels at different temperatures and RPMs. As the vibration values change over time, the system can predict when blower failure is likely, prior to it occurring. This allows replacement parts to be ordered before a “hair on fire” situation where the equipment suddenly stops working, interrupting production and workflow.
In order to monitor the burners on gas-fired ovens, the flame safety system is wired to the IIoT system. This allows remote evaluation of the flame sensor, purge timer, and other components that are critical to safe and proper burner operation. On older ovens, nuisance shutdowns can occur due to a dirty combustion blower, dirty flame rod, faulty airflow switch, or other reasons. An IIoT system allows the oven manufacturer to remotely diagnose this type of issue without ever sending a service technician to the job site, saving time and money.
An oven IIoT system is often used to measure the oven chamber pressure. Ovens can be intentionally operated at a neutral pressure, a slightly negative, or slightly positive pressure, for various process-related reasons. A pressure sensor measures this value and, via the IIoT gateway, delivers it to the dashboard in real time. If the chamber pressure strays outside of a predetermined range, this indicates a failure such as an improper damper setting or a malfunctioning exhaust blower.

The Benefits of IIoT Technology

Predictive maintenance is one of the most important benefits of IIoT. The ability to prevent potential equipment breakdowns and resulting process bottlenecks is invaluable. Not only does IIoT allow plant managers and operators to schedule maintenance ahead of time, it also reduces maintenance hours by knowing exactly what the issue is that needs to be serviced. This reduction in unplanned downtime increases productivity, which translates to higher profits.

The quantity of detailed, relevant data available (real time and retroactive) via the IIoT system exceeds the information a service technician can gather oven side, especially if the oven has stopped working. Using IIoT to remotely gain information to service the equipment, the problem can often be resolved the same day.

Perhaps the most impressive benefit of IIoT is remote diagnostics. Whether a furnace or oven is experiencing occasional unexplained shutdowns, or is completely out of commission, it typically takes days or weeks to schedule a service technician to inspect the equipment and diagnose the problem. However, if the oven is equipped with IIoT, a call can be made to the oven manufacturer who can remotely log into the system dashboard. They will be able to view and analyze the data gathered by all the sensors going back over time, without sending a service technician to the job site. Also, the quantity of detailed, relevant data available (real time and retroactive) via the IIoT system exceeds the information a service technician can gather oven-side, especially if the oven has stopped working. Using IIoT to remotely gain information to service the equipment, the problem can often be resolved the same day. Further, the IIoT system gathers and records the data going back in time for months, which is invaluable when trying to diagnose a chronic or intermittent failure.

Another use of IIoT technology is energy management. Through IIoT monitoring, facilities and equipment can be set to optimize energy efficiency. By ensuring the oven uses only the amount of heat energy necessary, and no more, its energy consumption is minimized. The system can reveal, for example, that a second shift oven operator opens the oven doors for five minutes to unload the parts and then load the next batch, while the first shift operator takes ten minutes to do the same process, wasting a great deal of energy as heated air spills out of the oven for an extra five minutes with every batch.

Data Security

IIoT devices use encryption to protect against unauthorized access to the oven operational data. Data transmitted between IIoT devices and the cloud is encrypted using protocols like Transport Layer Security (TLS). This provides confidence that only approved parties can access the information, safeguarding it from those with malicious intent. This ensures that even if data is intercepted, it will appear as jumbled information that cannot be read without the decryption key.

Because the data collected relates to the oven or furnace being monitored, and is not descriptive of the parts being processed, it would be of limited use to anyone who gained unauthorized access. If a malicious actor discovered, for example, the vibration levels, temperature controller output, or the status of the burner system while the oven is processing a load, it would be of limited proprietary value and would not directly reveal information about the parts being processed since no information about the load is included in the data.

In considering the security risk of an IIoT system collecting and transmitting data to the cloud, it must be compared to the alternative, which is bringing a service technician to the job site to perform the required maintenance or troubleshooting. When a service technician is invited on site, they have the opportunity to view the parts being processed, which temperature profiles apply to which parts, material handling methods, ancillary processes performed before or after heating, and even unrelated proprietary processes performed in the facility. This level of intrusion is much greater than simply sending the oven IIoT data to the cloud and avoiding the service technician entirely.

The Future of IIoT

Since the introduction of IIoT to the industrial oven market, it has gained acceptance by a wide range of manufacturers, and it is expected to continue to grow. Artificial intelligence (AI) is becoming a part of IIoT, as it can optimize the algorithms used in predictive maintenance. Also, IIoT can incorporate AI’s cognitive capabilities to better be able to learn at what thresholds of vibration, pressure, etc., to send alert notifications.

To Summarize

Consider purchasing an IIoT system with your next industrial oven. The successful implementation and use of IIoT provides a competitive advantage to the owner of the equipment. In today’s world of “doing more with less,” IIoT can increase productivity, reduce maintenance costs and unplanned downtime, and decrease energy use, all at minimal cost, and with no additional personnel required.

About the Author:

Micke Grande Head Shot — Mike Grande
Vice President of Sales
Wisconsin Oven Corporation

Mike Grande has a 30+ year background in the heat processing industry, including ovens, furnaces, and infrared equipment. He has a BS in Mechanical Engineering from University of Wisconsin-Milwaukee and received his certification as an Energy Manager (CEM) from the Association of Energy Engineers in 2009. Mike is the vice president of Sales at Wisconsin Oven Corporation.

For more information: Contact sales@wisoven.com.

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Under Pressure? Here’s a Stress Relief Round Up

December 4, 2024 / Manufacturing Heat Treat Technical Content, STRESS RELIEVING TECHNICAL CONTENT

Did you know that November 6 was National Stress Awareness Day? It seems an appropriate designation to cover the days and weeks that follow Election Day as well as those leading up to the holidays. For many who are well aware of the stress of the events of the season, Heat Treat Today wants to help with a different kind of stress relief.

Today we’re highlighting technical content that we’ve published over the last couple of years about stress relieving processes. Read an overview about stress relieving stainless steel components, listen to a Lunch & Learn dialogue about this underrated process, and explore a mechanical testing method for measuring material strength.

Stainless Corrosion

It is critical to provide things like stainless steel appliances and the Tesla truck with proper maintenance to keep the corrosion resistance and appearance lasting as long as possible.

Stainless steel shines in our kitchens and is becoming more popular in auto showrooms, mostly because of the promise that it is corrosion resistant. What most people don’t realize is that stainless steel will rust in a lot of circumstances. Sarah Jordan explores how stainless steel can be compromised by improper heat treatment and the steps heat treaters can take to prevent corrosion:

“Improper heat treating can also contribute to stress corrosion cracking. When material is quenched, it can cause residual stresses that, if not relieved, can become an issue.

“Corrosion in stainless steel can often be traced to improper heat treatment. When stainless steel is heated between 842–1562°F (450–850°C), chromium carbides can form at the grain boundaries, depleting the surrounding areas of chromium and making them susceptible to corrosion.”

To read the article in full, click here.

Heat Treat Radio #88: Lunch & Learn — 3 Most Underrated Processes

Click on the image to hear this episode of Heat Treat Radio and read the transcript.

In this Lunch & Learn episode from Heat Treat Radio, Dave Mouilleseaux discusses the three most underrated heat treat processes, including stress relieving manufactured components. If a comprehensive analysis of a heat treat operation needs to be performed on a manufactured component, such as a gear or a shaft, it is necessary to take into consideration any prior existing stresses in the part and what effect that has on the part.

The detrimental effects of not having stress relieved
Source: pixabay

“Many times during the course of my career, I’ve had a customer come to me and say, ‘The part I gave you was correct, and you’ve given it back to me and then fill-in-the-blank. It’s warped, it’s changed size, it’s shrunk, all of those things.’

“What have you done in your heat treating process?” asked Mouilleseaux. “You have to back up all the way to the beginning of how this part was manufactured and deal with all of those component steps in order to answer that question properly. Stress relieving is one of the answers. It’s not the answer. It’s not the only answer, but it is one of them that has to be considered.”

To listen to this episode of Lunch & Learn, click here.

Indentation Plastometry

Photograph of the Hardox steel samples, with and without the WC insert attached, showing high levels of oxidation following from the brazing process.
Source: Plastometrex

Mechanical testing is a standard production step in heat treating operations, but conventional methods of testing don’t always yield stress values consistent with the testing calculations.

Indentation plastometry allows users to obtain material strength characteristics in a way that is faster, cheaper, and simpler than conventional mechanical testing procedures. James Dean explores this novel mechanical testing method developed to infuse efficiency and accuracy into the process.

“The testing process is fully automated and involves three simple steps. The first is the creation of an indent using the indentation plastometer which is a custom-built, macromechanical test machine. The second is measurement of the residual profile shape using an integrated stylus profilometer.

“The third is the analysis of the profile shape in a proprietary software package called SEMPID, which converts the indentation test data into stress-strain curves that are comparable to those that would be measured using conventional mechanical testing methods. The entire procedure takes just a few minutes, and the surface preparation requirements are minimal.”

To read this article in full, click here.

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Basics of Vacuum Furnace Leak Detection, Part 1

November 5, 2024 / Manufacturing Heat Treat Technical Content, VACUUM PUMPS GAUGES VALVES TECHNICAL CONTENT

If you have the right leak detection equipment, the process of detecting leaks can be more time efficient. In this Technical Tuesday installment, learn more about the practical side of leak detection, from potential sources of leaks to equipment and methods of effective leak detection. Guest columnist Dave Deiwert, president of Tracer Gas Technologies, also provides 10 tips for identifying the most common sources of leaks. Stay tuned for his follow-up article that will focus on operating and maintaining a helium leak detector and repairing the leaks that are found.

This informative piece can be found in Heat Treat Today’s November 2024 Vacuum print edition.

When leaks develop in a vacuum furnace, they can inhibit the furnace’s ability to achieve the desired process vacuum level. Without an appropriate leak detector, an operator and maintenance team are limited to guessing where the leak might be, a time-consuming process of elimination evaluating each component or possible leak point one at a time. Alternatively, if you have the right leak detection equipment, the process of detecting leaks can be more time efficient.

First, a team needs to know the possible sources for leaks — especially if they are troubleshooting without a leak detector. Then, selecting the appropriate equipment can speed up the leak detection process. Ultimately, that equipment is most useful if a team is informed on how to best use and maintain the equipment.

Troubleshooting Without a Leak Detector

If a team does not have a leak detector, they first must disassemble potentially leaking components to clean and replace gaskets and seals. For some products, like valves and pumps, they might use a supplier-provided repair kit.

After reassembling, if they discover they still have a leak in their furnace, they will continue to select possible leaking components for maintenance.

The team would then start with the components most likely to be leaking — for example, the door seal. The door to the furnace is opened and closed every cycle of the furnace as the operator removes products that were under process for the previous cycle and then places the next product, or batch of products, into the furnace. This opening and closing of the door creates wear on the gasket and also provides opportunity for foreign materials and debris to land on the seal and cause a leak. As this is just one possible source of a leak, continuing to troubleshoot can become a lengthy process. (See sidebar for more information on possible sources for leaks.)

Selecting Equipment To Support Vacuum Furnace Leak Detection

Having a leak detector on-site allows a team to identify the source of the leak more efficiently. Typically, major OEM furnace suppliers, their field service teams, and major end-users of vacuum furnaces have selected “fixed magnetic sector mass spectrometers” optimized for using helium as a tracer gas to look for leaks in vacuum furnaces. These are also the tool of choice for OEM companies and end-users in other vacuum applications such as glass coaters, solar panel manufacturing, automotive, medical, aerospace, and others. In industrial manufacturing plants and R&D, we commonly call these tools “helium leak detectors.”

Helium leak detectors are the well-established method for leak testing because helium — the second smallest molecule and a safe, inert gas that does not react with other gasses or material — is useful for finding the smallest of leaks.

Figure 1. Leak detector hooked up to vacuum furnace
Source: Dave Deiwert

10 Practical Tips for Leak Detection

The following tips for leak detection pertain to using helium leak detectors:

Understand how your leak detector works to the point that you can confirm it is working properly.
A common question is, “How long after I spray a point on the furnace should I wait for a reaction on the leak rate meter to ensure that point doesn’t leak?” The answer is to characterize your system so that you know what the longest time constant can be for a leak to be detected. For example, purposefully apply a leak at the furthest point on the furnace from where the leak detector is installed. Then, spray helium and count the seconds to when the leak detector reacts to helium from the leak. Now you will know that you never have to wait longer than that without a reaction before moving on to the next point of leak testing.
Avoid moving along too quickly around the furnace as you spray helium. If there is a reaction at the leak detector when you stop spraying, you may have passed the point of leakage. After the leak detector leak rate drops back to baseline, you will try respraying the point of concern. If there is no reaction, consider that you may have moved along too quickly, and retrace the area you had sprayed more slowly. If you do not get a reaction again, it is very possible that the air currents of the room had carried the helium towards a point that you have not even reached yet.
Remember: There are naturally five parts per million of helium in the air we breathe. Therefore, when you spray helium, it becomes the victim of the air currents in the air and the fresh air makeup of the room. Helium can go up, down, left, right, away from you, and towards you depending on the air currents of the room.
Because helium spreads so pervasively, it is better to spray very small amounts of helium so that when you get a reaction from the leak detector, you know you are getting closer to the leak. If you spray helium like you are trying to dust off the system at the same time, you will quickly confirm there is a leak but will be forced to wait forever and a day for the helium to clear up in the room to the point that you can continue looking for the leak.
If you have confirmed the location of the leak to a small area, but there are still several points of possibility within it and you are unable to pinpoint the leak, diminish the amount of helium you are spraying. You can try to further restrict the flow of helium by using the “dead stick” method. This is where you spray helium from the spray nozzle away from the area of interest, then you place the nozzle near the potential leak points one at a time, relying on the residual helium that is present at the nozzle. This can still work well because (if you remember that there are 5 parts per million of helium in the air we breathe) there could still be hundreds, if not thousands or more, parts per million of helium present at the tip of the nozzle — at least long enough for using the dead stick method.
If you are looking to minimize the costs of helium, consider buying your tanks of helium at a lower percentage using nitrogen as the balance gas in the cylinder. People already tend to spray too much helium when conducting leak detector tests, and we are not trying to measure the severity of the leaks. So, decreasing the percentage of helium will save money without negatively impacting leak detection. If you are not yet comfortable with this but interested in testing it, simply buy one tank with a lower percentage of helium. Next time you find a leak with your 100% tank of helium, roll the tank with a lower percentage of helium over, spray the same leak on your system, and determine the difference (if any) in the effectiveness of detecting any leaks found.
Learn the “wellness” checks from your leak detector’s manufacturer. This can help you establish preventative maintenance for your leak detector before it has a problem that makes it unavailable for use when your furnace needs a leak check. Your leak detector manufacturer should be able to recommend what points of interest on their leak detector need regular scrutiny.
Calibrate your leak detector when you start it up and check calibration when you are finished to confirm it is working properly.
If you are fortunate to not need your leak detector for many months, I recommend you schedule a few times per year to start it up and ensure it is still working well. Occasionally, I hear of someone who needed their leak detector after months to a year of disuse who found that it was not working well. Leak detectors, like pumps, should not be neglected indefinitely.

Figure 3. Blower mounted atop pump
Source: Dave Deiwert

The Value of Efficiency

While it is possible to identify and repair leaks without a helium leak detector, a team with one is likely to net significant time savings if they operate and maintain it intentionally. An operation with many furnaces typically will have their own leak detector — and probably a spare. Operations with just one or two furnaces may choose to hire a service company to find the leaks in their system; this works well if they rarely encounter leaks on their systems.

“Basics of Vacuum Furnace Leak Detection, Part 2” will cover advancements in helium leak detector technology, operating and maintaining a leak detector, and comparing whether it would make sense to repair vs. replace a leak detector.

About the Author:

Dave Deiwert
President
Tracer Gas Technologies
Source: Dave Deiwert

For more information: Contact Dave at ddeiwert@gmail.com.

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Ask the Heat Treat Doctor®: How Do Parts Fail?

October 22, 2024 / AEROSPACE HEAT TREAT TECHNICAL CONTENT, ATMOSPHERE AIR FURNACES TECHNICAL CONTENT, Manufacturing Heat Treat Technical Content

The Heat Treat Doctor® has returned to offer sage advice to Heat Treat Today readers and to answer your questions about heat treating, brazing, sintering, and other types of thermal treatments as well as questions on metallurgy, equipment, and process-related issues.

Product failures (Figure 1) can often be traced to deficiencies in design, materials, manufacturing, quality, maintenance, service-related factors, and human error to name a few. Examples of failures include misalignment, buckling, excessive distortion, cracking, fracture, creep, fatigue, shock, wear, corrosion, and literally hundreds of other mechanisms. Let’s learn more.

Figure 1. Image of damage to left fuselage and engine; fire damage to nacelle.
Source: National Transportation Safety Board

Figure 2.: Model of material science depicting— key interactions and /interrelationships
Source: The HERRING GROUP, Inc.

Whatever the source, it is important to recognize that it is next to impossible to separate the product from the process. Performance, design (properties and material), metallurgy (microstructure), heat treatment (process and equipment), and maintenance are all interconnected (Figure 2).

When considering ways to prevent failures from occurring, one must determine the factors involved and whether they acted alone or in combination with one another. Ask questions such as, “Which of the various failure modes were the most important contributors?” and “Was the design robust enough?” and “Were the safety factors properly chosen to meet the application rigors imposed in service?” Having a solid engineering design coupled with understanding the application, loading, and design requirements is key to avoiding failures. If failures do happen, we must know what contributed to them.

Let’s review a few of the more common failure modes.

Fracture Types on a Macroscopic Scale

Applied loads may be unidirectional or multi-directional in nature and occur singularly or in combination. The result is a macroscopic stress state comprised of normal stress (perpendicular to the surface) and/or shear stress (parallel to the surface). In combination with the other load conditions, the result is one of four primary modes of fracture: dimpled rupture (aka microvoid coalescence), cleavage, decohesive rupture, and fatigue.

Virtually all engineering metals are polycrystalline. As a result, the two basic modes of deformation/fracture (under single loading) are shear and cleavage (Table 1). The shear mechanism, which occurs by sliding along specific crystallographic planes, is the basis for the macroscopic modes of elastic and plastic deformation. The cleavage mechanism occurs very suddenly via a splitting action of the planes with very little deformation involved. Both of these micro mechanisms primarily result in transgranular (through the grains) fracture.

Fracture Types — Ductile and Brittle

Numerous factors influence whether a fracture will behave in a ductile or brittle manner (Table 2). In ductile materials, plastic deformation occurs when the shear stress exceeds the shear strength before another mode of fracture can occur, with necking typically observed before final fracture. Brittle fractures occur suddenly and exhibit very little, if any, deformation before final fracture. (The following is based on information found in Wulpi, 1985.)

Ductile fractures typically have the following characteristics:

Considerable plastic or permanent deformation in the failure region
Dull and fibrous fracture appearance

Brittle fractures typically have the following characteristics:

Lack of plastic or permanent deformation in the region of the fracture
Principal stress (or tensile stress) is perpendicular to the surface of the brittle fracture
Characteristic markings on the fracture surface pointing back to where the fracture originated

When examined under a scanning electron microscope, fracture surfaces seldom exhibit entirely dimpled rupture (i.e. ductile fracture) or entirely cleavage (i.e. brittle fracture), although one or the other may be more prevalent. Other fracture modes include intergranular fractures, combination (quasi-cleavage) fractures and fatigue fractures.

Fracture Types — Wear

Wear (Table 3) is a type of surface destruction that involves the removal of material from the surface of a component part under some form of contact produced by a form of mechanical action. Wear and corrosion are closely linked, and it is important not only to evaluate the failure but to take into consideration design and environment and have a good understanding of the service history of a component.

Fracture Types — Corrosion

Corrosion is the destruction of a component by the actions of chemical or electrochemical reactions with the service environment. The major types of corrosion include galvanic action, uniform corrosion, crevice corrosion, stress-corrosion cracking, and corrosion fatigue. The mechanisms and effects created by each of these are well documented in the literature, as in Fontana and Greene’s Corrosion Engineering (1985) and Uhlig’s Corrosion and Corrosion Control (1985). It is critical to understand that the effects of corrosion are present to some degree in every failure analysis, which is one of the reasons why protecting fracture surfaces is so critical when sending parts for failure analysis.

Table 1. Differences between shear and cleavage fracture (Data referenced from page 23 of Wulpi, see References.)
Source: The HERRING GROUP, Inc.

Table 2. Typical characteristics of ductile and brittle fractures
Source: The HERRING GROUP, Inc.

Table 3. General categories of wear
Source: The HERRING GROUP, Inc.

Final Thoughts

To avoid failures or their reoccurrence, it is important to document each step in the design and manufacture process (including heat treatment). In addition, careful documentation of failures if/when they occur is of critical importance as is assembling a team of individuals from different disciplines to perform a comprehensive investigation. This includes a thorough failure analysis to assist in determining the root cause (there is only one) and to avoid it from happening in the future.

References

Airline Safety. www.AirlineSafety.com. Accessed September 2024.

Fontana, M. G., and N. D. Greene. Corrosion Engineering, 3e. McGraw-Hill Book Company, 1985.

Herring, Daniel H. Atmosphere Heat Treatment, Volume Nos. 1 & 2. BNP Media, 2014/2015.

Lawn, B.R. and T. R. Wilshaw. Fracture of Brittle Solids. Cambridge University Press, 1975.

Shipley, R. J. and W. T. Becker (Eds.). ASM Handbook, Volume 11: Failure Analysis and Prevention. ASM International, 2002.

Uhlig, H. H. Corrosion and Corrosion Control. John Wiley & Sons, 1963.

Wulpi, Donald J. Understanding How Components Fail. ASM International, 1985.

About the Author

Dan Herring
“The Heat Treat Doctor”
The HERRING GROUP, Inc.

Dan Herring has been in the industry for over 50 years and has gained vast experience in fields that include materials science, engineering, metallurgy, new product research, and many other areas. He is the author of six books and over 700 technical articles.

For more information: Contact Dan at dherring@heat-treat-doctor.com.

For more information about Dan’s books: see his page at the Heat Treat Store.

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Parts Distortion: How To Predict It and How To Account for It

September 25, 2024 / Manufacturing Heat Treat Technical Content

Source: Paulo

No matter the craft, disappointment is inevitable when the end result doesn’t turn out as planned. But in heat treatment, distortion is more than just a disappointment, it could contribute to weakness in a component, putting lives at risk. The industry can be credited for its commitment to determining the causes and manners in which parts distort and how to eliminate the risk.

Today’s best of the web article examines the inevitability of distortion in heat treating and demonstrates how to predict changes in size and shape of parts during processing, acknowledging that “maintaining dimensional accuracy is essential, especially for mission-critical and safety-critical components with the tightest tolerances.”

An Excerpt:

“Every part you heat treat will have some degree of ‘ballooning’ and distortion, but there are ways to predict how much your parts will deform. Knowing how your parts will change during heat treatment allows you to account for that change in the design of the part and, in a perfect world, avoid an additional round of machining after heat treatment.”

Read the entire article from Paulo by clicking here: “How Much Distortion To Expect in Heat Treating”

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Dual Chamber Vacuum Furnaces vs. Single Chamber Vacuum Furnaces — An Energy Perspective

July 23, 2024 / FEATURED NEWS, GUEST COLUMN, Manufacturing Heat Treat Technical Content, OP-ED, VACUUM FURNACES TECHNICAL CONTENT

The need to understand how certain furnace designs operate comes at a time when heat treaters are weighing each energy cost and benefit of their systems and processes. Read on for a quick summary on how dual chamber furnaces preserve energy.

On April 17-19, 2024, TAV VACUUM FURNACES provided a speaker at the 4th MCHTSE (Mediterranean Conference on Heat Treatment and Surface Engineering). The speech focused on the energy aspects of vacuum heat treatment, a subject towards which all of us within the industry need to pay attention for reducing the carbon emissions aiming at a zero net emissions future.

We have already analyzed the essential role that vacuum furnaces will play in this transition, with a focus on the optimization of energy consumption in our previous article. With this new presentation, we wanted to emphasize how selecting the right vacuum furnace configuration for specific processes may impact the energy required to perform such process. For doing so, we compared two different furnace designs — single chamber vs. dual chamber vacuum furnaces — detailing all of the components’ energy consumption for a specific process.

TAV DC4, dual chamber vacuum furnace for low pressure carburizing and gas quenching
Source: TAV VACUUM FURNACES

As a sneak peek into our presentation, we will summarize below how the main features of the two vacuum furnaces design are affecting their energy performance.

Let’s start by introducing the protagonist of our comparison: a single chamber, graphite insulated vacuum furnace, model TAV H4, and a dual chamber furnace TAV DC4, both having useful volume 400 x 400 x 600 mm (16” x 16” x 24”) (w x h x d).

In a single chamber vacuum furnace, like the TAV H4, the entire process is carried out with the load inside the furnace hot zone. This represents a highly flexible configuration that can perform complex heat treatment recipes with a multiple sequence of heating and cooling stages and to precisely control the temperature gradients at each stage.

Configuration of the TAV DC4 dual chamber vacuum furnace
Source: TAV VACUUM FURNACES

Alternatively, a dual chamber vacuum furnace, like the TAV DC4, is equipped with a cold chamber, separated from the hot zone, dedicated for quenching. Despite the greater complexity of this type of vacuum furnace, the dual chamber configuration allows for several benefits.

First, in dual chamber furnaces, the graphite insulated hot chamber is never exposed to ambient air during loading and unloading of the furnace; for this reason, the hot chamber may be pre-heated at the treatment temperature (or at a lower temperature, to control the heating gradient). But in single chamber vacuum furnaces, the hot zone must always be loaded and unloaded at room temperature to avoid damages due to heat exposure of graphite to oxygen.

Because dual chamber furnaces have more controlled heating, this will result in both faster heating cycles and lower energy consumption, as a substantial amount of energy is required to heat up the furnace hot zone. This advantage obviously will be more relevant in terms of energy savings the shorter the time is between subsequent heat treatments.

View of the cold chamber of the TAV DC4 dual chamber vacuum furnace
Source: TAV VACUUM FURNACES

Secondly, since the quenching phase is performed in a separated chamber, the hot zone insulation can be improved in dual chamber vacuum furnaces by increasing the thickness of the graphite board without compromising cooling performance. This translates into a significantly lower heat dissipation, to the extent that at 2012°F (1100°C) the power dissipation per surface unit (kW/m2) is reduced by 25% compared to an equivalent single chamber vacuum furnace.

Additionally, quenching in a dedicated cold chamber allows to obtain higher heat transfer coefficients and higher cooling rates compared to a single chamber vacuum furnace. Since the cold chamber is dedicated solely to the quenching phase, it can be designed for optimizing the cooling gas flow only without the need to accommodate all the components required for heating. All things considered, the heat transfer coefficient achievable in the TAV DC4 can be, all other things being equal, even 50% higher compared to a single chamber vacuum furnace. Secondly, since the cold chamber remains at room temperature throughout the whole process, only the load and loading fixtures need to be cooled down; as a result, the amount of heat that needs to be dissipated is significantly less compared to the single chamber counterpart.

CFD simulation showing a study on the cooling gas speed in a section of the cooling chamber for the TAV DC4 dual chamber vacuum furnace
Source: TAV VACUUM FURNACES

For heat treatments requiring high cooling rates, it is possible to process significantly higher loads on the dual chamber furnace compared to the single chamber model; translated into numbers, the dual chamber model can effectively quench as much as double processable in a single chamber furnace, depending on the alloy grade, load configuration and overall process. The savings in terms of energy consumption per unit load (kWh/kg) achievable in the dual chamber furnace for such processes can be as high as 50% compared to the single chamber furnace.

In the end, the aim of the speech was to highlight how the energy efficiency of vacuum furnaces is highly dependent on the machine-process combination. Choosing the right vacuum furnace configuration for a specific application, instead of relying solely on standardised solutions, will improve significantly the energy efficiency of the heat treatment process and drive the return on investment.

About the Author

Giorgio Valseccchi
R&D Manager
TAV VACUUM FURNACES

Giogio Valsecchi has been with the company TAV VACUUM FURNACES for nearly 4 years, after having studied mechanical engineering at Politecnico di Milano.

For more information: Contact Giorgio at info@tav-vacuumfurnaces.com.

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Manufacturing Heat Treat Technical Content

Industry Automation

Manufacturing Concepts

Heat Treatment & Robotics

Batch Loading with Robotics

Networked Hardening

Vacuum Advantages

Conclusion

References

About the Author:

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The Future of Heat Treatment Relies on Digitalization

How Digitalization Optimizes Heat Treatment Processes

Making the Digitalization Transformation

What Heat Treaters Need in a Digitalization Solution

About the Author:

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Meet Dave Deiwert (01:10)

Indicators of Leaks (03:45)

Isolating the Source of the Leak (05:11)

Understanding Leak Detector Technology (07:14)

Understanding Helium (11:53)

Be Patient with Leak Detection! (13:14)

The Dead Stick Method (16:48)

Saving on Helium Gas (21:35)

About The Guest

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Inductance

Resistance

Close Couple

Power Factor and Efficiency

Conclusion

About the Author:

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What Is IoT and IIoT Technology?

How Is IIoT Used in Industrial Ovens and Furnaces?

The Benefits of IIoT Technology

Data Security

The Future of IIoT

To Summarize

About the Author:

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Find heat treating products and services when you search on Heat Treat Buyers Guide.Com

Troubleshooting Without a Leak Detector

Selecting Equipment To Support Vacuum Furnace Leak Detection

10 Practical Tips for Leak Detection

The Value of Efficiency

About the Author:

Find heat treating products and services when you search on Heat Treat Buyers Guide.Com

Fracture Types on a Macroscopic Scale

Fracture Types — Ductile and Brittle

Fracture Types — Wear

Fracture Types — Corrosion

Final Thoughts

References

About the Author

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About the Author

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