First Layer Not Sticking and Maybe Other Printing Problems
I'm new to 3D printing and if this topic has been previously addressed I apologize for bringing it up again. Below is my story and problem.
I purchased the MK3S from Prusa about two months ago. I have printed approximately three dozen objects without a problem. Now I can't get the first layer to stick to the printbed. I may also have other problems, but until I can get passed the first layer issue I won't know. When I try to print, the initial test strip that is laid down in the front left corner of the printbed seems to be fine and holds well to the printbed. When the printhead starts to lay down the skirt it is obvious there is an issue. The filament will not stick and starts to build around the nozzle, and any of the layer that was on the print bed quickly comes loose because it is dragged by the filament stuck to the nozzle. Here is what I have tried so far.
1. I cleaned the printbed numerous times with 90 percent alcohol, acetone, and soap and water. That did not solve the problem. In fact I used my printbed another Prusa MK3S and the object adhered just fine. Thus, I don't think a dirty printbed is the problem.
2. Even though filament seems to freely flow from the nozzle, I did a "cold pull" in case the nozzle had a partial blockage.
3. I re-calibrated the XYZ axis.
4. I tried adjusting the Z value in the First Layer calibration, and regardless of how I adjusted the Z axis I can't successfully complete a first layer test. The test seems to start fine, but eventually the filament will get stuck to the nozzle and get pulled off the bed, even after changing the Z value.
5. I have installed the latest firmware.
6. I have been using the same roll of PLA filament from the start. As I mentioned I had several successful prints and now with the same roll of filament I'm having a problem. I even tried a different roll of PLA, but still have the problem.
7. I have not knowingly changed any system settings, nor made any mechanical adjustments to the printer. I bought the fully assembled MK3S, and had to only do a minimum amount of setup when I first got the printer.
8. I am mostly using the Prusa slicer, but did notice the problem started after the fourth print job using the Cura slicer. I did notice after the fourth print job using the Cura slicer that Cura defaulted the hotend temperature to 200 degree C. I didn't catch this until after I started having problems, but this seems a lot lower than Prusa's default setting of 215 degrees. Because of this I thought I may have clogged, at least partially, the nozzle which is why I did a "cold pull". After the problem showed up with Cura sliced object I then went back to testing the printed using Prusa sliced objects that I had previously printed successfully.
9. I am thinking of re-flashing the firmware, and have even considered doing a system reset in case I unknowingly changed a system setting, or Cura changed one unknown to me.
10. I have reached out to Prusa directly, but they have not responded.
Any thoughts/ideas would be greatly appreciated.
Thank you in advance.
Keith
RE: First Layer Not Sticking and Maybe Other Printing Problems
Your problem may have two causes, dirty bed or wrong z-level on the nozzle.
Since you have washed the bed thoroughly with detergent and water (do not use acetone!) We can exclude dirty bed.
Then the wrong height of the nozzle remains, that you have to lower the nozzle slightly.
If the filament does not get stuck but rolls up to the underside of the nozzle, this is because the distance between the bed and nozzle is too large.
There are probably 1000 posts about this, but this post is the best for you.
Bear MK3 with Bondtech extruder
RE: First Layer Not Sticking and Maybe Other Printing Problems
rhdreambox,
Thank you for your response. I ruled out the print bed when I used it on another Prusa and the object stuck just fine. I'm now playing with the Z-level and seem to be making some progress, but still have to do more work. I am also drying my filament. I didn't realize until today that the moisture PLA can absorb could also lead to problems.
I know Z values vary across printers, but do you know what the normal range of values might be? I bought the printer fully assembled and calibrated, and never put any thought into Z values until my filament stopped sticking. In retrospect, I should have checked the Z value when I first got the printer. It would have given a starting point. After playing around I have my Z value now set to -0.725, but as I said I still need to work on it.
Also, do you have any ideas what might have changed in the printer that now requires me to adjust the Z value. I never intentionally changed any settings, but one day after several successful prints the filament stopped sticking. The only thing that did change is that the problem started on the first print job I did where I sliced the object with Cura. Prior to that I had only been using the Prusa slicer.
Thanks for your suggestions. I'm going to use the test object attached to the link you gave me to do further testing.
Keith
RE: First Layer Not Sticking and Maybe Other Printing Problems
Hi Keith
As you mention, the Z value varies between different printers and it depends on the height of the PINDA sensor. But if you bought your printer fully assembled, the Z level should be between -0.600 and -1.000. When measuring the distance between the bed and the nozzle and the distance between the bed and the PINDA sensor, the position of the PINDA should be 1 mm higher than the nozzle.
If you have access to a digital caliper and measure the thickness of the first layer, it should be 0.2 to 0.25 mm thick. It is about as thick as two A4 sheets.
The printer is very sensitive, so moving the printer may be enough to change the z level. And every time you remove and replace the bed's steel sheet, the z-level can vary slightly from time to time.
It is also important that you use the correct printer and material profile in your slicer. For that reason, I only use Prusa slicer because it is calibrated for my printer.
Bear MK3 with Bondtech extruder
RE: First Layer Not Sticking and Maybe Other Printing Problems
rhdreambox,
Once again thanks for responding. After a lot of attempts I believe I have the Z level dialed in. Mine is -0.750. When I first noticed the problem, I probably was not that far off from its original setting. When I started to calibrate the Z level, I didn't realize I could start from its current setting and instead I started at Z= 0.000. If I had started from its original position I would have reached the new correct setting much quicker. I'll do some more testing today, but at least I can print again.
Thanks,
Keith