Checking Z-axis: nozzle hits bed with whatever probe height
I'm struggling with probe height.
I restarted the wizard several times.
Fan tests and bed test are fine, so are X- and Y-axis tests. Then the Z-axis test starts lowering the extruder towards the bed.
1) First, I had set the PINDA probe at zip-tie height above the nozzle, as described in section 9 of the online assembly manual. After OK checks for X and Y movement, the nozzle just crashes into the heatbed and I have to abort. Several retries led to the same outcome.
2) I lowered the PINDA probe a bit, to about six sheets of paper above the nozzle. This time, at least the Z-axis lowering stops and some X-Y movement begins ("Calibrating home"). When the nozzle is moved up to start the 12 minute XYZ calibration, I notice the X-Y movement has actually scratched the heatbed.
I decided to let it continue. I put a paper sheet on the heatbed as instructed, but the nozzle never catches the piece of paper. I played a bit with Z-values during first layer calibration, but I'll need some more practice at that. I started a Benchy print, the first layer could be better but, again, I let the print continue. I went well up to about 80% of the print, when the first layer is printed that would connect the door posts.
I didn't see what happened but when I looked the print was no longer attached to the bed and had rotated 90 degrees. Not sure if this was "just" bad bed adhesion or because the PINDA probe hit the print.
3) I restarted the wizard from scratch to see if, when I lowered the PINDA probe to nozzle height, at least the nozzle would not hit the heatbed this time. I put a single piece of paper on the bed just to be safe (even though use of a piece of paper is only required during XYZ calibrarion), but the nozzle catches the piece of paper.
What is going on? 🙁
Re: Checking Z-axis: nozzle hits bed with whatever probe height
Against better knowledge/experience, I tried again, using the zip-tie to measure the spacing. Nozzle keeps on pushing into the bed during Z-axis check.
Here's a picture taken with my cellphone at the right Z-axis, aligned with the bottom part of the part cooling fan.
Re: Checking Z-axis: nozzle hits bed with whatever probe height
The best way will be to go back to xyz calibration (btw to do that you do not have to go thru all wizard procedure, just use xyz calibration from calibration menu.) SInce you have already printed 80% of your object, we can assume that you are good.
First layer procedure is good for testing adhesion but for correct first layer surface test it is better to do another test. Let's do it Prusa way. If you had bought assembled printer, you will find Prusa logo printed on your printer. There are 2 purposes, first there is line all around the bed surface which proofs that your bed is correctly leveled and in the middle there is Prusa logo print. That object serve to test couple of things . Let's just concentrate on first layer calibration.
First clean the bed surface with kitchen paper and alcool. This is important step.
The test print is on your SD card. Start to print it. On the menu go to First layer adjustment. When fist third of the Prusa logo is printed, increase for 50 microns, I.e if value is 0.300 dial to 0.350. On the end of second third dial again 50 microns more. Let it start the second layer and stop the print. Cool and carefully detach prusa logo.
Let's examine the first third. Can you detach the filament easily ? That's not good. We are looking the part where filament is sticking together. If even the third part is not ok, repeat the whole process.
Let's assume that you find that the settings where the filament is sticking together. Write down this height. Repeat again and use it for the first third. Increase for 50 microns for other steps. We are looking now for value for where you first layer surface is completely smooth.
Note that value. The best value is somewhere in between.
When you find the correct value, print complete Prusa logo and keep it. Keep that filament. Whenever you got in any kind of trouble again, print Prusa logo again and compare. Happy printing.
Cheers,
NB0