The Inside Scoop

Posted by Rick Pollack on December 01, 2009 0 Comments

Well, the view from the inside of an extruder barrel, at least. I rigged up this little gizmo so that I can observe the behavior of plastic as it changes from solid filament into a viscous goo and works its way down the barrel.

The unit consists of a PTFE insulator, a piece of boro glass (aka Pyrex) and a modestly functional 0.4mm nozzle. The unit is compressed together using M3 rod. The problem with the nozzle is that it is held to the barrel by compression (the glass is not threaded) and ABS leaks from the barrel/nozzle seam. I need to figure out how to seal a 220C compression joint.

Here it is all wired up and ready to test.

And finally, after a couple of misfires trying to get the thermistor properly situated…action. I colored the filament tip before loading it. Here is a bit of orange filament slowly moving down the barrel. As you can see, some of the ABS came out of the nozzle and some came out between the barrel and nozzle. A higher rez version of this photo is available on the MakerGear Flickr page.

I’ll post photos, videos and results as they become available….