Thermoforming of PTFE tube - Designguidelines

[Hunskjaer]

Hi, are looking into introduction of PTFE tube thermoforming in volume production and wonder if anyone in this forum can share some designguidelines such as min bend radius and process parameters.

Have tested below setup:
- Materiar: PTFE pipes OD 8mm / ID 6mm
- Pipes are formed i an simple alu plate with grooves for the pipes as below picture.
- Process: 200C for 30 minutes with 2hours cooling in form at 25C

I can get a 24mm bend radius (3xOD) without kink problems. But would like to get smaller bend radius for which I am considering to test forming with mandrel insert but are concerned that the large deformation will create internal stress and cracks over time.

Hope you can help me with some designguidelines.

 

[Compositepro]

PTFE does not melt. When you get it hot enough (600F +) it goes from white to transparent and behaves as a soft gel/rubber. If you preheat the tubing it will be far more formable. Your process cycle is really long. I suggest you preheat your tubing straight and drop it into a cooler mold. Cooler might be 300-400F. You should be able to do this in less than a 1 minute cycle, although it will take longer to fill all the mold cavities.