Front Calibration Points Unreachable
Hello - I've just finished my MK2S kit. While doing the XYZ calibration, I got an indication that the front calibration points were unreachable. I verified that the Y end stop was being triggered before the sensor reached the circle for the point on the bed. I went back and to adjust the rods on the Y axis stage to bring the frame forward. Unfortunately, I've run into a bit of a problem I'm not sure how to correct. If I bring the frame forward far enough to reach the calibration point, the PSU mounts are too far away from the frame for the PSU to be screwed into the frame. Doing this does allow the calibration to succeed, but the frame and PSU have about a 5mm gap between them. The corner to frame measurement is about 101.7mm with it this way. I did the slotted adjustment on the Y belt holder, but that seems to have maybe 1mm of total adjustment to it.
I've seen some other posts of this, but none that have any real discussion or resolution. Is there an adjustment I'm missing for this?
Re: Front Calibration Points Unreachable
Hard to tell for sure without pictures, but it sounds like you put the Y gantry on backwards. It is not symmetrical.
See Steps 13 and 26 here.
http://manual.prusa3d.com/Guide/2.+Y-axis+assembly/298
If you have the dot away from the stepper, it will not reach the calibration points.
If this is not it, please try to post some photos.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: Front Calibration Points Unreachable
Pretty sure that isn't it, the bearings are on the right sides of the axis and such. What pictures would help here?
Re: Front Calibration Points Unreachable
A photo of the bottom might help.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: Front Calibration Points Unreachable
Tricky without aiming for anything specific on the bottom. Can confirm that the countersink mark is not on the bottom, and the bearings are on the proper side, so the orientation there has to be correct.
Re: Front Calibration Points Unreachable
Yup. You have it on correctly, and 101.7m is about right.
Not sure what is going on with your PSU mount, but if it can do the XYZ Cal, I think you are good to proceed with it as is.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: Front Calibration Points Unreachable
OK - that's good to know. It seems that maybe my issue is that the PS casing itself is a bit warped/bent. I noticed that it was quite a bit closer at the bottom than the top, and not because it was sitting unevenly on the PS mount. I used some longer M4 screws I had in my parts bin and pulled it together. After tightening it down with the longer screws (they were about 20mm) I was able to back them out and use the provided M4 screws to tighten it up. There's still some uneven gap along the PS/Frame seam, but I guess that doesn't matter for the printing at all.
In case someone goes searching for this in the future like I did: I slid the Y axis all the way until it clicked on the end stop. Once you're in that position, if you look straight down from the top at the PINDA sensor - the housing for it is curved to match the sensor. You can look straight down and see where the apex of the curve is compared to the edge of the sensor position mark on the heat bed. In my case when I started it was very obviously about 1.5mm short. The first thing I did was as described in troubleshooting, which was to turn the machine over and adjust the Y belt holder - it is slightly slotted, but this only got me about .4 to .5 mm of movement from where it was tightened. You want to push the holder towards the front of the machine and the bed towards the back, the goal being to move the holder away from the end stop as far as possible. You might have to wiggle it a bit, it's possible there's actually some more movement in mine that is held up by the unclean edges of the slot.
If that isn't enough like me and you need another 1mm, - I went ahead and completely loosened the 2 M4 screws that hold the PSU to the frame and let the PS sit loose, held in by the bottom screws. Adjust the M10 nuts on the bottom Y axis threaded rods to move the frame towards the front of the machine. It takes very little to move it, you'll get 1mm out of about 1 full turn of the nuts, so don't go crazy or you'll be moving them back. As you set them, you'll have to constantly flip the machine over and measure the squareness with the X axis rods and do that whole thing again. Since the PSU is loose, you need to be careful and support it as you do the flipping. There are no longer M4 screws in the set, so you'll have to source those on your own if you end up with the PSU being slightly too far away from the frame.
Re: Front Calibration Points Unreachable
Also, looks like I'm not alone:
Just couldn't find any references in the Prusa docs/etc to other people having this issue.