Wednesday, 20 April 2011


The temperature was not the only problem I had (though it may have played a small part). It seems that in my haste to get my printer working, I overlooked a key thing that I needed to calibrate, which I hope anyone after me will remember.

While the firmware on Gubbels' Gen6 electronics will turn the various stepper motors for axis control as far as they should do out of the box, the motor settings for the extruder drive need to be calibrated so that the plastic feeds out at the right speed. It seems that while the Mendel Parts kit was using Adrian's geared extruder, the firmware's step value for the extruder was way off.

This is what resulted in a test before a few people on the RepRap IRC helped me identify the problem:
I'm glad that's biodegradable.

The part I was trying to make is my Recycling Bin Key. The box-shape floating off the top, is due to the extruder head oozing when part of SkeinForge had programmed it to wait off to one side while small layers cooled. Funnily enough, the handle part wasn't so bad, even though it looks terrible, as it seems strong and stiff enough to be functional.

Calibration involved ordering the machine to run off 100mm of 3mm plastic rod, then measuring how much it actually did by lines marked on the feedstock beforehand. This produced some modern art in waste PLA, but at least got the extruder to do what it was being told.
Next I gave the part another shot, only to discover that some of the SkeinForge settings must be inappropriate, as the extruder was putting far too much plastic into the first layer, to the point that it filled in the handle string hole, and upon trying to start the second layer ran the extruder nozzle into solid plastic, before backing off to the wrong position.
Alas, this happened well over a day ago and I haven't had time to fix the problem yet, as I'm trying to get uni work done. I probably won't get round to solving this for a week, but we'll see.

No comments:

Post a Comment