x axis slant

I have been finding that my print quality decreases as a print session goes on; in particular the x axis skips steps and creates a slanted print, in the x direction.

The print on the left was the first print, and although the angle of the photo isnt perfect, the 'side walls' are pretty much vertical.

The part on the right was printed second, about 2 minutes after the first print finished- the side walls have a much more exagerated slant to them.

It is also worth noting that the printer had been running pretty much continuously for 2 hrs before these prints.

Am I thinking along the right lines to suspect the stepper drivers are over heating, and causing the motors to skip/add steps?

The drivers have heatsinks and are uncovered, and in a cold (6°C) garage- is there anything else I can do to aid cooling/reduce heat build up?

Thank you in advance.

Will

what happens when you decrease your acceleration in firmware, or half the speed of the print?

at the very least slow down travel feedrate. this print has rapid travel moves. you will want to then see what is causing the travel rate to need to be slower. for example, for me it was a wire rubbing up against the rods on x axis. fixed it and generously applied 3-1 oil and it works better now.

Edited 1 time(s). Last edit at 12/28/2013 04:48PM by jamesdanielv.