Thursday, January 11, 2007


Vik's polymer pump configuration works...

I found a piece of 1 x 1/4 inch steel bar and drilled a 1/4 inch hole through it. I then made a thrust collar out of two 1/4 nuts and a lock washer. An assembly of scraps from a z-axis thrust collar from the defunct Godzilla RepRap prototype served as an adequate mount for the bar and I was able to shift the torque application from the output side of the polymer pump lashup to the feed side.

I again used pliers to rotate the threaded rod. This configuration seems to require less torque that the previous experiment.

I am observing the tendency of this polymer pump to slowly rotate the 3 mm filament. It appears to complete a rotation every 1-1/2 inches. This is the same slippage that Vik Olivier has documented with his Mk II.

Most of the energy used in this pump seems to be employed cutting the threads into the filament. I tried to attach my electric screwdriver to the threaded rod with little success. My electric drill, on the other hand, proved far more of a success. Here you can see polypropylene filament being pumped. Please pardon the blurriness. I had to operate the drill with my right hand and the digital camera with my left. Sadly, my son has gone off to university again, so I'm down to two hands again.

Pretty neat.

By the way, is that Centipede I hear in the background?
I'm sure he meant this :
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