How does coin production benefit from vacuum heat treating? Is hardening, tempering, and machining required?
In this Best of the Web, take a look at what it takes to create “the master die” and the importance of vacuum heat treating in the minting process. The article offers a few contextualizing points around the topics of green energy and maintaining a safe workplace.
An excerpt:
[blockquote author=”TAV VACUUM FURNACES” style=”1″]The master die is then hardened and tempered to produce a positive tool called hob. Note that the master die is not used to produce coins. What do we need to produce our first coin?[/blockquote]
So your vacuum furnace is dangerous. You know that. But what do you need to know about hazardous materials and confined spaces when you’re on the plant floor?
This Best of the Web feature article is filled with important case studies that demonstrate how a lot of harm can happen due to negligence, assumed safe environments, and ill-informed habits. The writers go to great lengths to discuss why heat treaters should isolate the instances of danger in order to mitigate the effects, should any unfortunate event occur.
An Excerpt
[blockquote author=”Vac Aero International” style=”1″]Remember that all confined spaces are potentially hazardous to enter. Potential hazards within a vacuum furnace involve such items as…[/blockquote]
Medical devices, medical tools, and prosthetics all have a long history with heat treating. As we look to the future, the materials industry and the advancement of AM into the heat treat industry is moving at lightning speed.
In this article by Trevor Jones, CEO, Solar Manufacturing Inc., see why vacuum furnaces are excellent choices for accurately providing the necessary process parameters for this incredible medical technology that can provide people with mobility, function and independence to improve their quality of life.
This original content column was originally published in Heat Treat Today's Medical and Energy magazine, December 2020.
Trevor Jones CEO Solar Manufacturing, Inc. Source: Solar Manufacturing, Inc.
Thermal processing of metallic alloys is the backbone of the heat treating industry. Speaking of backbones, the human spine, a critical part of the human body, can now be replaced with an additively manufactured and heat treated prosthetic metallic alloy spine. Medical devices, medical tools, and prosthetics all have a long history with heat treatment. As we look to the future, the materials industry and the advancement of AM into the heat treat industry is moving at lightning speed.
AM parts require precise heat treating especially, when it comes to atmosphere control, temperature uniformity, and flexibility. Vacuum furnaces are ideal for accurately providing each of these process parameters. Let’s take a look at each of these heating treat parameters a little more closely.
Atmosphere Control
Vacuum, by nature, is a neutral atmosphere which, in part, means it has no carburizing or decarburizing potential. Therefore, the surface of the parts that is directly exposed to the vacuum atmosphere cannot gain or lose the base carbon content of the alloy. Additionally, vacuum is practically void of oxygen. If the parts were exposed to oxygen at the elevated processing temperatures, the surface of the parts would become oxidized. In minor cases, a superficial oxidation layer would be the result. In more severe cases, the surface could experience alloy depletion and diffused oxygen.
This is particularly important when processing titanium alloys, which are inherently more sensitive to carbon, oxygen, and nitrogen. When titanium is exposed to any of these elements, a metallurgical phase called “alpha case” can develop on the surface of the titanium and diffuse inwards towards the core of the part.
In most applications, the alpha case is undesirable, and precautions should be taken to prevent it.
Vacuum processing can also provide an atmosphere where an elemental substance, like nitrogen, can be kept in balance with the parts being processed. For example, if an AM part intentionally contains nitrogen, processing this part in a deep vacuum may remove some of the nitrogen base content in the part. To prevent this from occurring, partial pressure nitrogen in the vacuum furnace keeps the nitrogen in equilibrium. The surface condition of these parts is extremely important especially if the AM parts will be implanted into the human body.
The medical processing room at Solar Atmospheres. Source: Solar Manufacturing, Inc.
Temperature Control
The working zone of the furnace encompasses the parts being processed. It is critical that this entire working zone volume be thermally uniform to achieve predictable and consistent results. If any area of a working zone is cooler or hotter than the temperature of another area, it may negatively impact the heat treatment results including difference in mechanical properties and dimensional changes of the parts. For example, if the process is stress relieving and the parts were not subjected to high enough temperature for the requisite time, the parts may still contain some residual stresses.
Residual stresses can have various negative consequences during manufacturing, including cracking and part distortion – during build and finish machining. Tensile residual stresses in finished parts can also reduce fatigue and corrosion performance.1 A failure of a medical implant in the human body would be disastrous if it could have been avoided with proper heat treating!
Medical Instruments Source: ??
With proper design, vacuum furnaces can provide very tight temperature uniformity of ±5°F with direct part temperature monitoring throughout an entire working zone over a broad temperature range.
Flexibility
The vacuum furnace is extremely versatile in the infinite amount of process variables that are available to be adjusted, including heating rates, soaking temperatures, soaking times, atmospheric conditions, and cooling rates. All these variables can be adjusted to provide precisely what is required for a given alloy to optimize the heat treatment needs for the part being processed. To meet the need of the modulus and the strength and fatigue characteristics of a medical implant, AM technology can adjust the mechanical properties of the implant by changing some of the parameters in the processing.2
One of the many steps in the AM process is heat treating, and vacuum furnaces provide the flexibility that can be tailored to the alloy and heat treatment required. Having an AM prosthetic custom vacuum heat treated to fit the human body, could be the key to its success.
Vacuum furnaces and their unique heat treatment processes are ideal for providing the atmosphere control, temperature control, and flexibility that are essential for AM medical devices, tools, and prosthetics. As the AM market expands and the technology advances, vacuum furnace technology will continue to be integral in fostering that growth.
About the Author:
Trevor Jones began his career as the project engineer at Solar Atmospheres commercial heat treating on their Research and Development Team, concentrating on the improvement of vacuum thermal processing equipment and the development of new processes. He is currently the CEO of the Solar Manufacturing, Inc., a division of the Solar Atmospheres Family of Companies.
We hear the term “preventative maintenance” often used in the industry. Setting up procedures in advance to avoid unplanned downtime and other avoidable costs is certainly a hot topic. But this Heat Treat Today Best of the Web feature highlights a maintenance strategy that has become increasingly popular in creating better industrial efficiency: predictive maintenance. Read today’s feature article to learn about what predictive maintenance is, how it is implemented in a vacuum furnace system, and how this strategy saves you money.
An excerpt: “Predictive maintenance (PdM) evaluates the condition of equipment by performing periodic or on-line asset condition monitoring. Most PdM is performed while vacuum furnace is operating normally to minimize disruption of everyday operations. This maintenance strategy leverages the principles of statistical process control.”
The Furnaces North America 2020 was a virtual session, giving presenters the opportunity to create pre-recorded videos as a tool for future learning. The information for today's Heat Treat TodayTechnical Tuesday is pulled from a session delivered by Matt Clinite, customer service (aftermarket) sales manager at Ipsen USA.
As the sales manager of aftermarket sales at Ipsen USA, Clinite is familiar with what makes and breaks the lifetime of a vacuum furnace. In his presentation titled, "Vacuum Furnace Best Practices for Greater Reliability and Efficiency," Clinite presents a technical overview of the "five fundamental steps to keep your vacuum furnace running at peak performance."
An excerpt: Four of the five principles to assess your vacuum furnace's present condition right now are:
Start with the Hot Zone
Review Your Temperature Monitoring Systems
Assess Your Water Cooling System
Check Your Pumping System
And..[watch the video!]
Additionally, Clinite guarantees that viewers will learn three things: identify and correct common furnace problems; establish a maintenance plan; and improve reliability, efficiency, and overall capability of your furnace. If anything else, walking through how to build a preventative maintenance checklist will be a helpful review for any heat treater!
What is debinding in metal additive manufacturing (AM)? How do you debind after 3D printing? How do you avoid contamination during metal debinding? Heat Treat Today’s Technical Tuesday article features this Best of the Web piece to answer your questions.
There are several changes that have made new technologies of AM and 3D printing increasingly implemented in the heat treating process. Some of these reasons include: falling costs of 3D printers; increasing geometric abilities; constant rate of the costs of production; and a “drastic reduction” in process waste. Read on to learn how to properly “debind” as you implement these new technologies in the heat treatment process.
An excerpt: “The working temperatures in the debinding phase are in the range between 70 °C (158 °F) and the 450 °C (842 °F), corresponding to the melting temperatures of the various organic compounds.”
Jim Grann, Technical Director, Ipsen (photo source: www.ipsenharold.com)
We all like to make savvy commercial decisions, in fact, Heat Treat Today’s 101 Heat Treat Tips on page 20 of this digital magazine is a great example of tips that can save you time and money. But will it pay off to use your conventional vacuum furnace for aluminum brazing?
Questions involving safety, effectiveness, and quality might come to mind with this proposal. Before implementing such a strategy, head over to Heat Treat Today’s best of the web Technical Tuesday article by Jim Grann, technical director at Ipsen. He tackles the components of aluminum brazing versus the capabilities of conventional vacuum furnace as well as detailing some of risks that can happen if you do try to use your conventional vacuum furnace for aluminum brazing.
An excerpt: “By nature, vapor pressure aids in the depletion of magnesium and parent aluminum alloys in high vacuum, depositing magnesium onto the hot zone and into the shielding… Proper vacuum aluminum brazing requires special components that standard vacuum furnaces generally do not have, including…”
Heat TreatTV pulls the best heat treat videos from the web for your viewing, and today Heat Treat TV highlights Solar Atmospheres.
As a commercial heat treater, Solar Atmospheres is dedicated to providing vacuum heat treating and brazing services of the highest possible quality and meeting the expectations of their customers. They seek to educate their customers and will design a heat treating process that fits their needs.
This video demonstrates what a commercial heat treater considers when processing parts, including explaining why a heat treater chooses some methods over others. Topics mentioned in the presentation are brazing, carburizing, and nitriding as well as post-heat treat processing, vacuum brazing, vacuum carburizing, and vacuum gas nitriding.
Click here for more information on Solar Atmospheres.
If you have a video you’d like included on Heat TreatTV, please send an email to editor@HeatTreatToday.com and include a link to the video.
Discover how to keep your furnace in prime working order as Fred Hamizadeh, director of Global Manufacturing Services- Heat Treat & Facilities Equipment, of American Axle & Manufacturing and keynote speaker at Furnaces North America 2020 (Virtual) Trade Show, outlines the essential attributes of effective maintenance practices for industrial heat treating equipment.
This article will be featured in Heat Treat Today’s upcoming FNA Trade Show issue in early September.
Fred Hamizadeh, Director of Global Manufacturing Services- Heat Treat & Facilities Equipment, American Axle & Manufacturing
I recall great advice from my first boss, Bob Williams, of Williams Industrial Service: He said to me early on that if the maintenance people are happy with your equipment, you’ve designed a good furnace. Combining many years of my OEM furnace manufacturing experience with my current position allows for a perspective that is useful to both American Axle & Manufacturing (AAM) and our OEM suppliers.
American Axle & Manufacturing can trace its history to the early 20th century and was comprised of the five General Motors plants, purchased by an investment team led by our co-founder, Richard E. Dauch, in 1994. Heat treating has been a core competency of the AAM manufacturing system since the inception of the company. AAM uses conventional gas carburizing and tempering as well as various induction processes in the manufacturing of all drive-train components. These components include: case hardening of gears and pinions; induction hardening of shafts, CV joint and balance shafts; and sintering of powder metal. Our metal-forming product business unit uses induction heating to forge and manufacture a large variety of automotive components. As one of the largest captive global heat treaters, AAM’s carburizing equipment varies in size and style, from batch to single and multirow pushers. Induction equipment cells also vary from single spindle to multi spindle, fully automated hardening and tempering lines.
“While we remain open to all new developments and advances in technology, it does not provide suppliers with an open checkbook. We must maintain a balance between high technology, reasonable CPU, component performance improvement, and reliability. “
(Photo source: American Axle and Manufacturing)
An integral part of AAM’s quality process is the maintenance and reliability of production equipment including the heat treat equipment. To remain current with latest CQI-9 requirements, all maintenance intervals are scheduled, followed, and monitored by the company leadership. All AAM facilities have an advanced maintenance team that performs most of the day-to-day requirements and responds to all emergency cases.
Maintenance requirements must be considered early on during equipment selection, procurement, design, and manufacturing. AAM has specifications that heat treat manufacturers must follow to allow safe and fast maintenance to occur regularly without requiring equipment to be removed from production. As a minimum, sufficient access points within the equipment are essential. A preferred location would be to have access from the plant floor; otherwise, safe platforms must be provided. All hazards such as heat, electricity, and stored energy must be eliminated or locked out. A detailed LockOut TagOut (LOTO) system diagram allows maintenance to be performed safely. Use of our recommended parts list ensures that we have common components for speedy repairs within our stores.
(Photo source: American Axle and Manufacturing)
Today, we look for equipment that has the following features to allow extended mean time between failures (MTBF), provided regular scheduled maintenance is completed:
Equipment built to AAM’s specifications for heat treat equipment. These specifications are designed based on our needs and best practices as well as supplier capabilities and regional presence.
Use of common components within company provided parts list
Use of domestically available and reliable material and components for equipment built in various regions of the world for ease of replacement. Otherwise, the use of U.S. or European brands with global presence is preferred.
Use of standard equipment design to allow common spare parts that can be shared between plants. This standard design will also provide equipment interchangeability and allow maximized equipment utilization based on plant loading.
Use of common control equipment and sensors. We utilize two brands of process controls. Our electrical systems use AAM Controls Architecture specifications that allow all plant control engineers the ability to troubleshoot, repair, and place equipment back into production rapidly.
Use of highest-grade cast or wrought nickel-chromium grade components to insure long MTBF. This is one area that must be observed closely during the bidding process.
Use of brick lining for all carburizing zones. This eliminates the carbon burnout issues associated with ceramic fiber lining.
Use of reliable, dependable, and global suppliers. Our need to maintain interchangeability and versatility to maintain high utilization rates require suppliers to have presence in North and South America, Europe, and Asia. Same is true for component suppliers. Rapid response to issues is critical for our operations and most of our suppliers have met this requirement.
Enforcing a maintenance schedule that allows for maximized production while allowing time for burnouts and maintenance. Maintenance and burnout schedules are established a year in advance. These schedules are communicated and balanced with production requirements. This period is not only required for performing needed maintenance but should be used to plan the next maintenance activities.
Detailed LOTO tags to pinpoint all sources of energy that need to be locked out to perform safe maintenance.
Detailed inspection of equipment for safety, maintenance, and function prior to shipment from supplier.
Provide training for engineers, technicians, and operators in safety operation and maintenance of the equipment by the manufacturer.
For large and complex equipment, monitor force and cycle time historically as early indicators of maintenance requirement.
While there are some new developments and advancements in the maintainability of equipment using the latest digital technologies such as Mobile Maintenance Assistance by Aichelin, more development needs to occur to allow integrated maintenance, record keeping, spare parts ordering, and monitoring. Digital archives of system drawings and manuals must be available for a maintenance technician at point of use. Additionally, video recordings of training sessions can be maintained at the equipment for training new associates.
(Photo source: American Axle and Manufacturing)
The future of heat treat will include more advances in induction processing, austempering, and further development of liquid quench capable LPC equipment. Over the last 30 years, many new processes have been introduced into the market but were unable to justify eliminating conventional gas carburizing and induction hardening. While we remain open to all new developments and advances in technology, it does not provide suppliers with an open checkbook. We must maintain a balance between high technology, reasonable CPU, component performance improvement, and reliability.
About the Author:
Fred Hamizadeh, a mechanical engineer and 32-year veteran of the heat treat industry, is the director of Global Manufacturing Services-Heat Treat & Facilities Equipment, at American Axle & Manufacturing. The majority of his experience has been focused on the OEM side of heat treating with Surface Combustion and Williams Industrial. For the last 14 years, Fred has worked on the consumer side of heat treating with AAM.
For more information, contact Fred at Fred.Hamizadeh@aam.com
As society begins to slowly reopen in the wake of the COVID-19 pandemic, equipment that has been sitting idle will need to be brought back online.
In this Heat Treat Today Original Content feature, Abbott Furnace gives us a few important considerations to ensure a successful return to operation.
1) Reference the manufacturer supplied manual for specific information regarding the re-starting of the equipment.
2) Be sure that water is flowing to all of the cooling chambers of the furnace.
3) Check that the belt is on and moving smoothly through the furnace. Watch for jerking or jumping of the belt that would indicate an issue with the drive or pathway through the furnace.
4) Enable the ramp mode in your controls to limit the heating rate of each zone to 55C (100F) per hour or less. If the furnace does not have a ramp mode, be sure to manually adjust the set-points of each zone so as not to exceed the suggested ramp rate.
5) Once the furnace reaches 150C (300F) , purge the furnace with nitrogen and allow the nitrogen to flow as the furnace continues to heat up.
6) When the zones of the high heat section of the furnace are above 760C (1400F), combustibles may be introduced and the furnace can continue to be ramped to the final processing set-points, once the pilots are ignited.
7) Allow the furnace atmosphere to re-condition the furnace, clean the belt, and stabilize.
Loading scrap metal that is free of oils, grease, and rust will help the furnace to “clean-up” and stabilize.
Source: TAV VACUUM FURNACES
