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SPE workshop to expose myths about thermoforming

By: Roger Renstrom

July 29, 2013

Better sensors, faster computers, new material grades and co-extrusion and lamination capabilities are among changes impacting the world of roll-fed thermoforming.

Those topics will be parts of the Mythcrushers workshop in Atlanta on Sept. 9, the first day of the Society of Plastics Engineers’ annual thermoforming conference.

Mark Strachan has presented a thin-gauge thermoforming workshop annually for five years at SPE conferences. For 2013, he has invited industry experts to join him in a daylong program explaining the science of thermoforming and debunking myths about the process. Strachan is president of uVu Technologies LLC of Boca Raton, Fla., and chairman of the SPE Thermoforming Division. He also heads the conference’s thin-gauge program.

The other presenters include his father, Ian Strachan, along with Terry Woldorf and Joseph LeBlanc.

Ian Strachan is president of MGA SA Pty. Ltd. in Gordon’s Bay, South Africa. MGA also has an office in England.

Woldorf is general manager of syntactic-foams developer CMT Materials Inc. in Attleboro, Mass. LeBlanc is a physics instructor at Pennsylvania College of Technology in Williamsport, Pa., and an experienced aerospace engineer specializing in hypersonic fluid dynamics for propulsion systems.

Mark Strachan points to some myths: “Surface friction is primarily determined by the choice of plug-and-sheet material. Control of the sheet or material is not important. The shape of the plug assist is not important.”

None of those things are true, Strachan said.

Speakers will address trends involving down-gauging of material, the demand for high-transparency polypropylene and other plastics for aesthetics, and requirements for high-speed production.

The medical industry looks for ease-of-use packaging and the ability of material to stand up to sterilization. The food industry makes use of barrier and tamper-evident packaging and looks for light-gauging opportunities.

Thermoforming technology advances include precise oven controllers and heaters and more precise tooling-component actuators and control systems.

Ian Strachan will discuss why thermoforming for so long has been considered the black sheep among plastics conversion processes and how thermoforming is now shaping up against the most competitive processes such as injection molding.

LeBlanc will present a scientific approach on how to heat and cool the sheet and how processors can relate these functions to the heating components available on thermoforming machinery today.

Woldorf will explain how to understand elements of interaction and balance among plastic film choice, plug material choice, plug design, mold design, plug speed, vacuum, form air and “the numerous other factors that often separate true artists from lucky amateurs.”

In an advance abstract, Woldorf said he will use new empirical data from laboratory and field experiences and discuss the interplay of these factors as the plug meets the plastic and “the point where the action is most immediate in the thermoforming process.”