This week Alfonso and Erik led the inflatable ultrasonic welding workshop. The ultrasonic welder has a kerf of 2mm, so the welding will be 4mm in total width by default. You can offset the lines in the 2D drawing if you want to thicken the line. The materials during the workshop available were TPU, PA-6, and nylon sheets. The welder end effector is attached to the Zund milling machine and it can read a dxf file (ideally 2018 version) for it to generate toolpath and be sent to machine. Make sure there are no duplicate lines in your drawing and joined as a continuous curve as needed so that the welder does not burn the material by going over the same path multiple times.
I was able to revist some of my tiny studies with inflatables by touching base with three tests that I've always wanted to try:
• Scaling Up Patterning - What happens if we apply the same unit of geometry across a large sheet? This pattern was inspired by smocking, a fabric manipulation technique that uses gathering to create texture. The inflation was a success and the material gathered as expected.
• Multi-layer Welding - Can we introduce multi-phase change with multi-layer welding? This sample confirmed that we can embed two or more phase actuation which provides opportunity for tailored inflation characteristics. Also out of curiosity, I also cut out the centers of the pattern so see if the result would be more dramatic.
• Stiffer Material - How will inflatables behave with a stiffer (PA-6) material? Is there opportunity for it to be structural? I closed the geometry for this design so that I can glue a valve to it. Quickly I realized the material was too stiff so I had to cut the centers of the pattern out in hopes it would take less effort to see inflation results.
Overall, the ultrasonic welder was a fun tool to experiment with and I can see myself using it for future projects involving inflatables. Thank you Alfonso for helping me run the machine!