Oil - the cause of, and solution to, all of life's problems.

Another week gone and there was not much to show for it. The extruder stopped working again, of course. No amount of fiddling with it would make it go for more than a layer or so of any print, which is really frustrating when one needs just one more print (ok, admittedly a pretty large one) to dump the extruder for good.

However I did solve some other niggling issues with the reprap. I figured out how to get a set square in between the X and Y axes and satisfactorily set them up perpendicular to each other; it worked really well until yesterday when there was a somewhat catastrophic failure and I had to go through the whole mess of disconnecting the X belts and realigning all over again. It *seems* to be robust now that it's back together, but I want to replace the bearing blocks that mount the X carriage onto the Y as they're extremely fiddly and will bind if they're done up too tight... or shed a bolt or two, go loose and bind anyway.

I also figured out a way of having the reprap itself tell me how much backlash there is in each axis. I modified the firmware so that it keeps track of how many steps it takes to move off an endstop - since there only needs to be one step's worth of actual movement away from an endstop to deactivate it, any extra must be backlash. I measured 5 steps of backlash on the X axis and 1 step on the Y axis, which seems to be about right; it comes out to 0.625mm on X and 0.125mm on Y. Plugging those values into Skeinforge's Lash module (well, half those values really) made a marked improvement... in the partial layers I could get out of the extruder, of course.

I noticed that the extruder seemed to have more trouble when the print head was in the middle of the bed as opposed to at the origin, which is closer to the spool and so the filament is pulled to the side less. I used a long bolt and a piece of acrylic with a couple of holes drilled in it to make a filament guide that sat a couple of inches above the extruder and ensured the filament was more vertical as it went into it. I also put some oil into a folded up Subway paper napkin and put it above the guide to oil the filament as it passed by.

Still no good. Gaah! Screw it, I'm just going to squirt heaps of oil (well, a few drops) directly into the top of the extruder. I don't care any more, and I've tried everything else.

Wait a second, that worked?

Two and a half hours later...

:D