Friday, April 4, 2008


Having a lot of trouble getting a reliable extrusion. I had two PTFE barrels, both of which are distorted too much to be useful. I had two extruder clamps (one quick-fit, one regular). Both have suffered heat damage.

See, here's the problem I'm running into. Plastic, when subjected to heat and pressure, tends to sag. This means that, under normal operation for extruding HDPE, the nozzle tends to edge downward. I've had a couple tests so far where everything started out fine but ended up with the nozzle grinding into the bed.

I'm beginning to think that the current extruder design just can't do HDPE reliably. It wasn't really designed to do it in the first place.

Current plan: Rebuild extruder using stronger components. I've got a 1" diameter piece of PTFE on order. I might end up making an extruder clamp out of MDF. I think I'm going to buy some CAPA to see if it's any easier to use.