CMT Blog

CMT Field Notes: 2015 Hands-On Thin Gauge Thermoforming Seminar at Penn College

Posted by CMTUpdate on 12:36 PM on June 29, 2015

Peer references are often the most effective way of imparting credibility to something: a product, a service, a new hire, etc. In the case of the Penn College Thin-Gauge Thermoforming Seminar, the same holds true. With over 30 participants from 19 different companies, the 2015 workshop garnered some very positive reviews. Here are just a few:

“[The workshop] increased my knowledge on how to dial in molds to produce better quality parts and reduce cycle times. I also have better knowledge on how to modify tool and plug design to increase the quality on our parts.” (Design Engineer)

“This workshop was a great way to supplement the limited hands-on experience that I’ve obtained (being new to the industry) with direct classroom training. In addition, there was opportunity to benchmark techniques and issues with others.” (Process Engineer)

Penn_College_2015

What makes this seminar particularly valuable is the way it covers the various elements of thermoforming. It starts with an introduction to polymer science - understanding how and why plastic forms, why knowing if a material is amorphous or semi-crystalline is important, and what happens to certain polymers when they reach critical temperatures.

Extrusion is critical to thermoforming. Without good sheet, the thermoformer is already struggling to form good parts.  Dr. Kirk Cantor of PCT presented elements of the extrusion process including crystallizing and drying, venting, blending/feeding, what happens when you introduce regrind, and die design. From there, Dr. Joseph LeBlanc presented the physics of heating and cooling the sheet. Even though the thermoforming industry has made great strides in technology in recent years, the ability to accurately measure sheet temperature is still an area for improvement. There were several questions throughout the course about the surface sheet temperature vs. the core sheet temperature; how a slight change in oven temperature can result in significant changes in radiation; and what happens when you're dealing with multilayer films with different stress-strain curves for each layer. 

After a perfectly-weighted dose of physics, the program moved on to the more practical elements of thermoforming. Mark Strachan is well-known in the industry for his subject matter expertise and his library of detailed powerpoint slides are worth the price of admission. From the fundamentals of forming through to advanced techniques, Strachan pulls attendees into the conversation which allows for frank discussion of real-life challenges. He nicely tees up a section on plug assists for CMT which, combined with the previous discussions on heat transfer, allows us to zoom into the material properties of syntactics before zooming back out to the practical considerations of machining and polishing plugs for optimal performance.

In addition to showing attendees our new HD video, we also spent some time discussing how Design of Experiment can be applied to thermoforming. Even though we have worked with industry colleagues on this topic in the past (2006 ANTEC, to be precise), there seems to be renewed interest in taking a statistical approach to understanding the variables that go into the thermoforming process. In fact, during the T-Sim presentation on simulation, one of the case studies described in detail the impact that plug shape had on the final part. DoE is probably not for everyone in every situation, but to the extent that a processor can reduce or eliminate waste through the smart application of data, the bottom line is certain to improve.

Want to work with us on DoE for one of your projects? Let us know and we'll be glad to set up a review.

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