Y Missing Steps ( Still... )

Ok, I haven't lost my mind yet but getting close. Every time I think I have this problem sorted it waits till I'm 2hrs into a 4hr print and rears its head.

Printrboard
Makerfarm i2 Prusa
GT2 belts and 36t Pulleys

I have tightened belt, swapped x & y motors (PITA), slowed down Accl and such in FW, added a fan to Printrboard, lubed rails. I checked for binding, motors cool to touch after 30min print. My thought is its skipping on small rapids/infills (I haven't caught it in the act so this is just a guess). most of my prints go well but they are mostly small items.

Does anyone have a torture test object for this problem that's quick-ish to print? I feel like on these bigger prints it would be easier to just take a blowtorch to 10ft of fresh filament, lol. I made a square spiral starting out with 4mm wide and working down to 2.5mm wide and it printed flawlessly and took about 20-30min if I remember correctly. I will post the object to thingiverse and add a link here shortly.

edit: added file

Edited 1 time(s). Last edit at 10/09/2012 08:38PM by 6of1.

Increase the voltage for the x and y motors by about turning the pot next to the x and y headers on the printrboard by about 10 degrees each clockwise. You will find the motors will run hotter after you do this but it will increase the torque of each motor and prevent skipping.

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Richmond, New Zealand
Thingiverse ~ YouTube

you can mark the belt, pulley and motor shaft inline with an ultra fine tip sharpie to check later after a shift to see if something mechanically slipped. otherwise, it is either a missed step, or software.

Well I didn't screw with the pots yet on my Printrboard but I did put a much bigger PC fan (80mm, the old one was a 40mm) on it this morning powered by a wall-wart. Started the 4hr print over again then left the house for the day. When I got home the object printed perfectly (minus some bridging issues). So either the fan helped, I got lucky or the printer knew I was at the hardware store buying a new sledge hammer... I guess we will find out on the next print...

Quote
6of1
or the printer knew I was at the hardware store buying a new sledge hammer...

I own a Printrboard as well. Gotta turn them pots up about a 5th of a turn to a quarter turn. Just turn on your motors, put your ear close to the motor, turn the pot until you hear the motor humming, then turn back the pot about a milimeter until it stops humming.

Had skipping issues (not board related) and thought it was the pulley, so I took the pulley apart like 4 times trying to tighten the screw and re-flat the shaft. Then the whole band around the base broke I tightened it so much. Finally just epoxied the thing on. I'll regret that later... Turns out the belt was loose. haha

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-Tom

It's definitely the pots. I had the same problem until I cranked up the output on the X & Y. I also did the extruder for good measure.
The Z axis motors do very little work and have bugger all load on them so leave them as is.
The motors will run a lot hotter and if you are doing a three hour print they will be getting too hot to touch almost. I designed these [www.thingiverse.com] to fix the problem and I wired the fans to run continuously. The motors now run cool again.

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Richmond, New Zealand
Thingiverse ~ YouTube