I have had a terrible time trying to get the printer to calibrate.
When trying to do anything with the printer it grinds up against the Z-rod and makes a terrible noise. I have been able to do some x-axis calibration, but everything I click "too far forward" it grinds up against the z-rod as it adjusts. I can make some small adjustments, but all the grinding eventually puts it out of calibration again.
I used to be able to still get good prints sometimes. However, the Z-axis calibration is now totally off and I cannot correct it at all. When I try to calibrate, the print head pushes down hard against the build plate. When I click "too low" absolutely nothing happens. I have tried clicking "too low" dozens of times, and no calibration change ever seems to happen. Every so often, the printer will seem to try and home again (and grind), but no Z-axis calibration ever happens.
The printer is now completely unusable, and I have bunches of elementary school kids waiting to get their prints done.
I have upgraded to the latest firmware. I have lubricated all the rods.
After most recent software update, my first generation Polar 3Ds aren't calibrating correctly. Calibration keys are a wreck...not sticking on the ends, blobby, you name it. Can still get one of them to print so-so if lands on the correct side of the plate. The instructions for reading the calibration key don't go into enough detail about the corrections.
Out of nowhere, I am having the same issue. Printed many successful jobs the night before. The very next morning the print head rams in to the plate and wants to keep screwing downward. I have tried everything I know to try. Cannot keep the print head from driving in to the plate and then not raising. I have to pull the power cord for it to stop screwing in to the plate. HELP!!
As for the grinding against the rod of the z-axis, check if there is a magnet on the part of the printing table.This passes over a sensor on the side. If the small magnet is not there, it can be replaced by a small neodynium one, this should stop the printbed from ramming into the Z-axis.
As for the Z-axis calibration, open the front part with the fan , and check if the cable isn't between the calibrationPCB of the nozzle/extruder-hinge construction.
I have the magnet on my turntable and I get the same grinding.
Wow...this sounds just like what I am dealing with our printers.
Just last night the print failed 1 hour into the build. All of a sudden the the nozzle was stuck and not moving. I paused the print and tried to raise the head and it just would moved. Then upon careful observation I noticed that the silicone tube coupler and bearing had completely come off and were not on the pin. Not sure how to get it back on....ughhh
I think with the later firmware versions, "home and center" became the calibration sequence vs the older versions which had you do it manually. With our 7 Polar3Ds having issues, I appreciate the older version where I knew it would be calibrated.
Regardless of which version, sometimes we run it through the calibration process but then when it prints, it clearly has lost where "z=0" and the printer becomes useless
Michele, in your case, did you have a good solid layer (or 2 or 3) of hairspray that was dried in between? We found that even one spot of not good first layer adhesion can throw the job out of order and cause the solid globs of plastic to form.
I know there is a switch that is supposed to be activated when the nozzle hits the plate, indicating it has reached z=0. Maybe something is preventing the switch to be activated?
The following is a diagram from one of the support agents from May on a related issue.
Printer will not calibrate properly. Will not allow z axis adjustment.
When trying to print, nozzle is directly on the mirror and will never raise up, which clogs the nozzle.
At one time the silicone tube coupler had rotated up the motor shaft and was in a bend.