Archive for April 2nd, 2012
This slightly shrunken whosawhatsis Parametric Gyro Cube didn’t end well at all:
The print failed when the nozzle snagged one of the tines, which instantly jammed up against the bottom of the heater block and stalled the platform motion with a horrible crunch. Surprisingly, the motors didn’t lose all that many steps, but you can see extruded thread drooling off the top layers.
The 0.25 mm layer thickness contributes to the problem: any distortion while the plastic cools produces blobs on the top or poor adhesion, depending on whether the just-printed layer moves up or down.
This was with infill = 60 mm/s, perimeter = 20 mm/s, and moves = 250 mm/s.
That speed difference produces crap quality objects, because the high speed infill produces ragged edges that a single perimeter thread can’t convert into a smooth surface. Two perimeter threads work fine, but the top surface looks ragged from the mechanical wobbles induced at every direction reversal.
The root cause: my heavily modified Thing-O-Matic has too much moving mass and not enough rigidity, of course. Time to back off the speed for better results…