Thursday, May 04, 2006


Attempt at extrusion over 3D axis #3

It was one of those evenings where everything turned to custard. Except custard, which turned to lumpy goo.

It started off OK. I made temperature measurements of the nozzle using a thermocouple, and slightly adjusted the parameters for the thermistor. At 120C it has a variance of +/- 8C using the chop-chop algorithm. Then I ran out of rod.

I ill-advisedly poked a second rod of CAPA down the extruder without taking the precaution of melting it to the first rod. The nozzle became blocked with a bit of red plastic (probably a piece of wire sleeve) and, aside from producing pink CAPA, caused the second rod to attempt to overtake the first rod. It all jammed up in the concrete holder, and I couldn't unscrew it.

I dismantled the thing, warmed it up to 120C with the extruder exerciser, removed the nozzle - a good case for removable nozzles - and pushed the whole lot out from the nozzle end using a blunt bamboo skewer.

I now have to make more rod, and run the thing with no nozzle to make sure I get all the crud out, then I have to clean the nozzle. That's probably what will happen this evening, so there may be a delay before attempt #4. Oh yeah, it's my turn for laundry duty too :(

I've added a couple of lugs to the poly-holder model in CVS, and that's going to be built by Adrian and Ed in Bath. This should allow easier and more stable mounting of the extruder assembly, which is currently held in place by a couple of the tensioning rods.

Still, now I know how to make pink CAPA.

Vik :v)

Comments: Post a Comment

<< Home

This page is powered by Blogger. Isn't yours?

Subscribe to
Posts [Atom]