Answered Print dimensions off.

Printed the leadscrew adapter https://www.thingiverse.com/thing:1147438 as a test.

The Z axis dimension came out pretty much spot on, which was a pleasant thing.

Oddly, X came out as expected, but Y was short by about .022 inches. The hex "nut" part came out a bit off as well, indicating X was fine, but Y was short.

Since I am certain my X and Y steps/mm are correct I wonder what the problem is?

I know about the jumpers for steps on the control board at least in theory. IF I read the information correctly, the jumpers appear to be the same for both. I'm not sure any difference in jumpers would result in that small an error in any case.

I do, occasionally, while printing hear what I might term "stepper stress" that I think I recall from years past as trying to step "too fast" or accellerate "too fast" under some conditions. However, if it lost steps, I would expect the print to be "offset" from there as the print progressed.

Sigh.

 

I'll give that a try.

 

Is there a part number or other identification for the stepper driver?

 

Thanks.

Have you used these specific ones, or just pointing to the type? I guess I also need to look for the "adjustment procedure" that is referred to in some reviews.

 

I'll turn on captioning and give that link a good look a bit later on. Also found a post, here somewhere, about methods of adjustment. May just try the "by ear" method (my term).

I did put the dial indicator on the bed and it seems to move and return, in 1mm increments at least, just as it should. Certainly not proof it is perfect under the stress of constant running.

Gave some thought to swapping the drivers around, but that is probably not really going to prove anything. Also gave some thought to tweaking the Y driver to max but paused. I suppose that can hurt nothing for a 25 minute print. To monitor motor temp I would have to rig up a monitor of some kind, or put the printer on a raised platform and monitor by feel. The potential for "shock and awe" notwithstanding. Hmm, I do have a IR "gun" thermometer around here somewhere.

By "steppers running hot", do you mean the drivers or the motors? If drivers, are there better heat sinks from those supplied?

 

They appear to mount on the sides of the motors?

So, to my thought of tweaking the existing Y driver and testing that way?

 

While waiting for Amazon to ship the drivers (and stop trying to get me to go Prime), I was poking about and noticed the Y Drive belt seems to be rubbing on the upper "guide" of the drive motor pulley.

There seems to be plenty of space on the lower (motor) side of the pulley, suggesting a slight mis alignment of that pulley as the belt appears to run centered on each of the idler bearing thingies. However to the extreme of motion it appear to ride up on the rear one as it nears the rear attachment point.

I guess the simple question is, could this be contributing to my dimensional difficulties and what is the proper way to get at the pulley set screws to adjust the distance. Hoping not to have to remove the bed.

 

View from front. Motor pulley is center, front idler to left. The set screws may be accessible via a cutout in the base.

 

Do I need to be concerned about wires, heater, sensor, etc when removing the bed?

I did manage to get the set screws loose and move the pulley, but it's turning out to be problem trying to tighten them.

 

Well, that was a lot easier than I feared. Test print may tell something, later on.

 

Not so easy after all. Turns out, I could not get the set screws tight enough. They would not bear on the shaft. Seems the pulley was on upside down, I guess since forever.

Took me a while to clean up the pulley bore so it would fit on the shaft. Had to completely release the belt to get they pulley off and on. I figured the belt tension was no big deal, and did it by feel.

Since then I've not been able to get a good print with the calibration circle. And now, got a printer shutdown, with

The extruder fans appeared to be running when I caught this error.