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This article takes a look at the options, process and questions that will help you make the decision to automate your induction heating process.
Accepting a part into a machine (part loading), presenting the part for induction heating (part placement), moving the part (or the coil) while it is being heated (induction heating process, Fig. 1), retrieving the part from the heating area (part displacement), and then releasing the part (unloading) is non-trivial. While there are companies that can handle material, and there are companies that can build power-supply/coil solutions, it is the combination of all these steps that will produce the optimum solution.
It’s All About the Part
At the heart of your automated induction heating production machine (AIHPM) is the part (Fig. 2). It is important to understand that not every part and process is suitable for full automation. High production and small and bulk-fed parts may add to the handling cost. Asymmetric parts or parts with complex geometries may require a coil that spins instead of the part. Semiautomatic (manually fed) machines may be the appropriate compromise (Fig. 3). If your production runs are short or your product mix changes a lot, it might not be feasible or economical to employ automation.
Evaluating the Part
Understanding how to work with the part geometry is particularly important. Automating an existing heating process may require a new coil design to accommodate automation. Understanding how to leverage multiple (coil/part) positions and the limitations for optimization is not straightforward.
There could be “off-the-shelf” solutions available for your application, and some may employ flexible automation. Repurposing capital equipment is an excellent way of reusing CAP-EX dollars. Pay close attention to how much customization needs to be added onto the off-the-shelf solution because the option can sometimes cost more than the base unit. If repurposing is critical, you may want to reconsider your strategic decision to automate (variability and operational value, previously discussed).
Outsource or In-House
A good place to start is to ask, “Should the induction heating production be outsourced or retained in-house?” There are two variables to consider in determining if you should outsource the production of your heat treating. One is the strategic importance to your business. The other is the effect on your operation’s performance. If it is determined that the heat-treating operation is a strategic value you offer (intellectual-property/process) and you need to keep tight control over the variability (production, delivery and quality), then retaining the heat-treating process in-house should be strongly considered. Other valuations of these two variables may drive you to other options. When you decide to automate in-house, the questions become more complex and you are assuming more of the risk (while gaining process control).
It’s All About the Partner
The four basic areas that drive consideration of automating your induction heating production are product throughput, traceability, cost reduction and repeatable quality (Fig. 4). Automation of induction heat-treating production will provide increased efficiency, labor reduction, shorter cycle times, higher (process) availability, reduction or independence from manual operations, and greater production rates.
As you get started, defining clear, unambiguous expectations is the most important responsibility of the customer. The specifications should include all the parts that need to be heated along with the post-process characteristics of the part(s). Ensure that the specifications of the AIHPM incorporate country, state, company and plant safety, operating standards and specifications. Your AIHPM builder may request exceptions to a small portion of one (or some) of these specifications.
Production rate will drive the size and complexity of the AIHPM. You can reach the limits of physics in heating a part using induction. The surface of the part may be melting while the interior of the part could still be at a much lower temperature. Moving a part will be limited by the technology you choose. It is critical to understand the nuances involved in moving the part in an AIHPM. When you are working with high-volume production, one or two seconds can have a significant impact on the production output. Optimizing the trade-offs between handling and heating will keep you ahead of the curve.
Evaluating the Partner
You will be evaluating your prospective AIHPM builder in three main categories: their induction heating expertise, their ability to build an automated material-handling machine and their ability to put both of those together. Finding one company that is proficient in all three is unique. This will, however, remove the burden (read: risk) of ensuring the organization building the machine manages the part flow, quench, cooling, etc. the way the induction heating company wants it. Managing a project of this complexity with two separate vendors assumes a great deal of risk.
Depending on the complexity, a company may be able to build their own AIHPM. Saving the cost of system integration up front is good until the project suffers unacceptable delays. This decision could put the market launch of your (or your customer’s) new product in jeopardy. If you’re spending hundreds of thousands of dollars on new automation, getting it up and running fast helps recoup your investment faster.
First Things First
Before you select an AIHPM builder, there are other operational considerations that should be discussed and resolved.
• Warranties and timing: Just as important as the duration is the breadth of, and exceptions to, the warranties.
• Repair and spares: Your AIHPM builder should provide guidance on what you can repair and recommend a spare-parts list. You should attempt to achieve as much commonality with the other OEM components in your factory as possible.
• Training and truck rolls: If you are lucky enough to be within driving distance of the AIHPM builder, the term “truck roll” may apply. Factory support will most likely arrive on an airplane. It is important to understand, within the context of the warranty, who pays for what and how much it will cost.
• Implementation and documentation: The facilities should be prepared well in advance and be ready when the AIHPM arrives. It becomes very expensive to change things after the design is approved (by you). The AIHPM will most likely need some final adjustments at your facility. This will be an exceptional hands-on training opportunity for your maintenance people.
Verifying the Process
Your AIHPM builder needs to guarantee process, not just handling and heating. Your acceptance criterion needs to be established before the purchase is consummated. Specify the AIHPM acceptance criteria by discussing this with your internal team. There should be at least two process-verification “run-offs.” The first run-off will be at the selected supplier (Fig. 5) and must have the customer present (or a designated representative). It should produce acceptable parts. If the customer feels confident that the AIHPM will produce acceptable parts on the factory floor there should be a sign-off to ship the AIHPM.
The second run-off will be at the customer’s factory where it is installed on the production floor. Your maintenance and production people should be trained during the installation. If possible, they should be part of the installation team, even as early as the first run-off. Do not allow the AIHPM to ship before a successful first-run. It is far less costly to fix “bugs” at the machine builder, where they have all the talent and tools, than from miles away on the factory floor.
Keeping a Record
Develop a common components list. Your AIHPMbuilder should be able to accommodate most of this list (within reason). Components like NCs/PLCs, HMIs, pumps, valves, etc. should be common with what you are currently using.
If the quality standard requires periodic destructive testing and analysis of the part, or if you need to collect data on the heating process, you will want to consider process monitoring. With a graphics package, the real-time heating performance of every part can be captured and stored. Synchronizing the data of each part’s heating cycle to the actual data will take high-level expertise. A supplier that is adept in understanding both the heating process parameters and material handling is essential. If you need to have this process monitoring system built into (or added to) your AIHPM, it will be a machine builder that is intimately familiar with the induction heating processes, automation and data collection that you select.
The complexity of an AIHPM cannot be overstated. The nuances involved in combining material handling with the induction heating process are not written anywhere. The AIHPM builder should be able to make suggestions based on their experience.
The most basic of considerations include: how the part temperature should be managed (time and power, temperature or other); integrating the communications between the heating subsystem and material-handling subsystem; whether the part or the coil rotates; what is the best variation and change to the rotational speed; how is the part fed into the material-handling subsystem; how to control the induction heating system; what are the trade-offs between the coil design and the most efficient method of handling the part; how will your AIHPM builder quench, cool and dry the part; and how to harden and temper two different zones on the same part (Fig. 6) or two parts. All of these need to be addressed.
To achieve higher production volumes while maintaining consistent quality, find an AIHPM builder that will mitigate risk in automating your process. Select a machine builder with experience and expertise in designing and automating the induction heating process.
The machine should be designed around part, process and production. This unique combination will prove to be invaluable in guiding you to achieve your objectives. IH
For more information: Contact Lance Dumigan, regional sales manager, GH Induction Atmospheres, LLC, 35 Industrial Park Circle, Rochester, NY 14624; tel: 585-368-2120; fax: 585-368-2123; e-mail: firstname.lastname@example.org; web: www.gh-ia.com