Window: Process Optimization

After re-machining the thermoform mold window diameter to fit with the retainer ring, the thermoform process has been mostly optimized. We were planning on doing 6 optimization batches, all with different parameters. However, after batch 4 the air compressor stopped working. Of the batches we were able to do, batch 2 had the best definition with the fastest cycle time. Although we weren't able to continue after batch 4, we anticipate that batches 5 and 6 would not have improved the process enough to require us to use those parameters.

Thus, our optimized parameters are: 300 heat time, 75 form time, 175 open delay, 25 fan delay, 150 fan time, 5 hold time, 3 vacuum delay, 120 vacuum time, no air eject hold and 2.220" die cut. 

Below are pictures of our mold, optimized window, and some of the defects we came across during out optimization process.

Image of the thermoform window mold, after remachining the window diameter and redrilling vacuum holes.

Cut-out window made with optimized parameters.

Uncut window made with optimized parameters. The window corners are sharp and well-defined.

Window from batch 4b. The corners are clearly less defined and more rounded than those in the optimized windows.

Example of an inverted thermoform that was made when the air compressor was broken.

Example of a thermoform window that was made when the air compressor was broken. Notice the large dimple in the center of the window.