Nothing is sticking & bad first layer
I just upgraded my i3 MK3 to the MK3S and had to re-calibrate, etc. For some reason I cannot get my first layer to stick!!! I've cleaned my smooth PEI sheet with Windex, etc. and adjusted my Z down to -1.35. It never used to be this high for me. Was around -8. Why such a change? I've readjusted the PINDA and re calibrated again and same results. The first "wipe" line gets a good "squish" on the PLA, but the first later rim and print is more of a bead. I'm not sure just how much more to lower the Z without scratching the plate. I'm using a silicone sock, which I used to use and had great prints, but not sure if it could be an issue with the new upgrade? I've also verified I'm using the correct firmware for MK3S.
I'm not very experienced with 3D printing, so any tips and help would be greatly appreciated!
Kind Regards,
Nelson
Re: Nothing is sticking & bad first layer
A photo would help. Plus, Windex is't used to clean the bed, rather, it is used to reduce adhesion for plastics like PETG.
Hot Water wash: as needed
Handle the bed only by the edges.
Wash the bed in hot water, use a fresh paper towel as a wash cloth, with a few drops of plain dish soap (Dawn, unscented, no anti-bacterial, etc.). Rinse well in hot water - if you have very soft water, rinse a bit longer.
Dry the bed with a fresh paper towel.
Handle the bed only by the edges.
Place bed on printer.
Alcohol rinse: every few prints
Once in a while, an alcohol rinse is helpful.
Pour a 5 cm puddle of 91%+ alcohol in the middle of the bed, use a fresh paper towel to scrub the bed. Wipe up all the alcohol.
Streak test: when contamination is suspected and after a wash
With a fresh piece of paper towel, and very clean fingers, dampen the towel with 91%+ alcohol, and wipe the bed side to side moving back to front, like you're painting it with alcohol. The alcohol should be thin enough on the towel it quickly evaporates. If you see any streaks, the bed is dirty and needs a wash.
Acetone wash: infrequent
Pour a 2 cm puddle of acetone on the bed, scrub it around with a fresh paper towel. It will evaporate fast as you clean. This step removes PEI oxides that form over time and with heat, and improves PLA adhesion to a like new state.
Re: Nothing is sticking & bad first layer
I've cleaned my smooth PEI sheet with Windex,
Windex should not be used for cleaning the bed. It is used for PETG not to attach too hard to the bed.
Windex means that PLA comes off more easily from the bed.
PLA requires a completely cleaned surface, use detergent and water.
Bear MK3 with Bondtech extruder
Re: Nothing is sticking & bad first layer
Have you tried slowing the speed to 50% for the first 2 layers, I do this and hardly even clean the bed, everything sticks like glue is used, but nothing is used, simple Prusa PEI sheet stock from them, just go to Tune and reduce to 50% try it you will surely see a difference, after the first 2 layers, you can go back to tune and bump it up to the speed you wish 75% or 100%.
Re: Nothing is sticking & bad first layer
Thank you very much everyone! I will stop using Windex - not sure why I had read to clean with that for PLA. I washed the smooth PEI sheet in warm water and dish detergent and re-adjusted the PINDA once again with a complete re-calibration. This time my Z offset is -.73. Much better! The manual says it's not supposed to be over 1 and before I was up over -1.5. I also removed the silicon sock thinking that may be interfering with the print if it falls down a little bit and touches the print. Anyone here use those? I just wanted to keep the nozzle as clean as possible.
Printing now @ 60% speed (was using 75% before) and first layer looks great! Before the print was about 80% completed before the entire print became unstuck and trashed. I've raised the bed temp to 70 for the first layer and 65 for the rest instead of having it at 60 to see if that helps as well. I'll let you know how it goes. Only issue I have now with this Prusa black PLA is I occasionally get some stringing (like a tiny fine spider web line) while printing @ 215 degrees. Any easy setting or Slicer PE config to get rid of that?
Thanks again!
Re: Nothing is sticking & bad first layer
70c is useful when printing large items subject to warp (> 120 mm base); otherwise not really needed.
I use the sock once in a while, but they wear out very quickly when using GRID infill. I've resorted to trimming the sock so it fits near the bottom of the nozzle cone (nearer the HEX) rather than nozzle tip. It still helps with temps, yet reduces the chance of it dragging on and pulling up plastic. Next time around I'll be buying the "open" variety (top), not the closed variety (bottom).
Re: Nothing is sticking & bad first layer
@tim.m30 - Great idea on the sock! I did see the open version when I purchased a few of these, but figured I'd try to protect as much of the nozzle as I could. I just cut that tip away to make it fit around the hex nut and it fits & holds much better. I'll give it a shot and if I ever need to order more, I'll go with the open ones too. Thank you!