This is the second in our 2-part summary of the 2013 SPE Thermoforming Conference in Atlanta, GA. As we hinted at the end of our last post, CMT had many engaging conversations with heavy gauge thermoformers. The rapidly growing interest for syntactic foam plug assists in the heavy gauge world seems to stem from the following factors:
- a steady increase in the price of plastics
- an increase in quality demands from the market
- an industry-wide focus on reducing scrap, i.e. eliminating waste
- many, many companies looking to implement “Lean” or Continuous Improvement projects
Our work with Penn College and a number of processors has shown that HYTAC® can be used with great success in thick-sheet, deep-draw applications.
Because many heavy gauge projects have short runs (from a few dozen to several thousand parts) compared to thin-gauge or roll-fed applications, processors tend to be very cost-conscious when it comes to plug materials. Given that syntactic foam can range from $500-1000/ft3, this is not unreasonable. In many cases, a simple wooden plug can be slapped together and short runs can be achieved with minimal problems. When one stops to consider the total cost of ownership, however, the calculus changes. While wood offers low costs and easy manufacturability, it has limited temperature resistance which becomes problematic for longer dwell times associated with many heavy gauge projects. Wood also has a tendency to mark-off on the plastic which, if texturing and surface finish are important, can result in rejected parts. When used as a plug material, aluminum offers benefits beyond what you get with wood, but aluminum plugs must be heated and precisely controlled in order to achieve optimally formed parts. This adds a level of cost and complexity to the process.
As a result, syntactic foam is gaining acceptance as an option for large part plug assists. Low heat transfer, durability and minimal mark-off are three key reasons why some heavy gauge thermoformers will use syntactic foam. During the show in Atlanta, we had numerous conversations with processors about their positive results with HYTAC® materials. In some instances, they are using HYTAC® in limited fashion as pushers to eliminate webbing while improving material distribution. In other scenarios, syntactic foam can also be used on the clamp frame to minimize chilling of the sheet.
In July 2012, our senior materials engineer, Kathleen Boivin, published a paper that appeared in Plastics Technology. The following excerpt is taken from that piece as it neatly encapsulates much of what we talk about in heavy gauge thermoforming:
“Production volume is the main consideration when deciding whether to go with a full-size plug or localized pusher. For a 24/7 manufacturing operation, the cost of a full-size syntactic plug can be easily justified by the 15% to 20% cost savings per part. The bulk of this savings is achieved through better material distribution, allowing for down-gauging, which also leads to reduced cycle time and lower energy costs.”
If you weren’t at the show and want to learn more about how syntactic foam can work for you, give us a call at 508.226.3901 or fill out our application form.