The 2013 Thermoforming Conference has just ended in Atlanta, GA. While the final numbers are still being tallied, judging from the traffic at CMT’s booth, we would suggest that it was another successful event. In fact, we have so much good stuff to share that we’re going to split it into 2 separate blog posts.
Our GM, Terry Woldorf, played a leading role in Monday’s roll-fed thermoforming seminar dubbed, “Mythcrushers: Separating Black Art from Science”. The goal of the seminar was to bring a new level of scientific understanding to the thermoforming process. Dr. Joseph LeBlanc of Penn College presented information on heating and cooling the plastic sheet and mold, drawing from his knowledge as an aerospace engineer. Ian Strachan discussed the many factors that have led to a perception of thermoforming as a “Black Art” while Mark Strachan of uVu Technologies summed it all up with details relative to tooling and techniques to connect the science to the process.
CMT’s perspective on thermoforming is all about the plug assist materials, but we know that our HYTAC materials do not operate in a vacuum (they operate with vacuum, but that’s a bad joke). Because of the multiple variables involved, we stress that processors should appreciate the interplay of sheet temperature, tool design, friction and associated plug choices such as material and geometry.
Beyond the equations and hard science, however, we have seen how best practices can be standardized to give processors the ability to ramp up more efficiently without as much trial and error. As shown in our machining guidelines, we spent 12 months working with toolmakers and suppliers to develop these metrics. Based on the questions posed to Terry after his presentation, it is clear that many people still want guidance on how to mill, polish and clean HYTAC® plugs. Here is an abbreviated version of the Q + A session:
Q: Is centered turning the only way to make plugs from rods?
A: No, many people use centerless turning machines or even milling machines with cut pieces of rod. Our online turning and/or machining guides contain complete details for the best types of tools, feed and speeds and depths of cut for all types of equipment and sizes of material.
Q: What material do you use for turning?
A: As with milling, solid carbide inserts with positive rake provide the best results.
Q: Should we mill HYTAC materials dry?
A: Yes. Generally speaking, coolant doesn’t really help. In the case of the thermoplastic materials (B1X, XTL), the coolant will actually roughen and destroy the surface as it is machined. Many times, people run their feed rates too slowly or use dull cutting tools so they see overheating and use coolant. The use of sharp carbide tools and proper feed rates will result in a tool operating near room temperature. Following these steps will provide the best plug surface results.
Q: What’s the best way to clean the plug?
A: Isopropyl alcohol (pure, not those diluted with water) is typically a good option. A light touch with a very fine scuff pad generally works well.
In the next post, we’ll write about the many heavy-gauge projects we discussed where syntactic foam can provide a competitive edge. In the meantime, check out this post on using HYTAC® as a mold material.