CMT Field Notes: 2014 Hands-On Heavy Gauge Thermoforming Seminar

CMT participated in the 5th annual National Hands-On Heavy Gauge Thermoforming Workshop at Pennsylvania College of Technology (Penn College) in Williamsport, PA.  As in previous years, CMT supported the workshop with presentations on syntactic foam plug assist materials and a product demo.    

Penn College is a national leader in applied technology and focuses on providing its students with practical hands-on experience that they can immediately apply in industry.  The graduates from its plastics engineering technology program are in high demand.  The workshop was sponsored by the college’s Plastics Innovation & Resource Center (PIRC) and drew participants from NY, MA, PA, TN and CA. 

The workshop combined technical presentations with numerous hands-on labs.  The workshop was coordinated by Christopher Gagliano, Program Manager of the Thermoforming Center of Excellence.  The keynote speaker was Jay Waddell of Plastic Concepts & Innovations.  Jay provided an introduction to thermoforming followed by information on controlling vacuum, process optimization and troubleshooting.

Several guest speakers assisted with presentations on their areas of expertise:

  • Roger Kipp of Roger C. Kipp & Associates – Tooling Performance: The Little Things Mean a Lot
  • Dr. Joseph LeBlanc of Penn College – Heating & Cooling the Sheet
  • Kathleen Boivin of CMT Materials – Optimizing the Cut Sheet Process with Syntactic Foam
  • Bud Foran of Heitronics – An Introduction to Infrared Thermometers

The syntactic foam presentation focused on the total cost of ownership for plug/pusher materials.  Wood may be cheap on a stricly material purchase basis, but it will mark off, crack, build heat and create problems with build-up (transfer of sheet material to plug surface).  All these issues lead to increased costs due to rejected parts, machine down-time and time-consuming maintenance.  Because syntactic foam has been specifically designed for thermoforming, it provides excellent material distribution, part cost reduction (through down-gauging), part consistency, minimal mark-off, plug durability and trouble-free plug maintenance. 

Participants obtained hands-on experience with following labs:

  • Thermoforming – Led by Christopher Gagliano
  • Physical Property Testing – Led by Dr. Tim Weston
  • Extrusion – Led by Jessica Fischer

In the lab, participants marked the sheet with gridlines so that they could see the material distribution.  They got to run with and without plugs to see the benefits of running with a forming assist. The starting sheet thickness was 0.250″ (6.35mm) acrylic PVC. The average sheet thickness on the bottom of the part increased from 0.072” (1.82mm) in to 0.171” (4.34mm) in by changing from vacuum only to plug-assist forming.  To illustrate the impact of plug material on results, one side of the mold used a “multimedia” plug made from wood, Bondo and felt while the other side used a highly-polished HYTAC-WF syntactic foam plug (see Figure 1).

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Figure 1Multimedia & HYTAC-WF plugs

As shown in Figure 2, the portion of the sheet formed with HYTAC-WF had significantly less mark-off compared to the side formed with the multimedia plug.  In addition, the sheet thickness at the bottom of the part was 0.186” (4.72mm) with the HYTAC-WF plug compared to 0.156” (3.96”) with the multimedia plug.  The lab demonstrated that syntactic foam can improve part visuals and material distribution.

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Figure 2Effect of plug type on mark-off and material distribution

The extrusion lab allowed participants to run the extruder, thread up the line and understand how challenging it is to make good sheet. The testing lab gave participants a better understanding of why sheet physical properties are important.  They got to see the effect of temperature on properties by testing the impact resistance of both room temperature and “frozen” sheet.

During the HYVAC demonstration, the benefit of being able to make a trim fixture quickly without machining was discussed.  The participants were instructed on how to use HYVAC and got to work first-hand with the material.

Surveys conducted by Penn College showed that the participants enjoyed the workshop and found the information extremely valuable (avg score of 4.6/5).  They especially appreciated the hands-on approach and the time spent in the labs.  Next week, CMT will be participating in the (sold out) National Hands-On Thin Gauge Workshop on June 24-26.

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