Recently I noticed that my print’s first layer looked horrible. Didn’t stick to the plate well and didn’t attach to the next layer up either. I changed the nozzle a few months ago and noticed this after that time. I don’t know if the nozzle change should make any difference to the z offset. I had to lower it from -1.15 to -1.20 then got a good first layer and adhesion to the next layer.
Could the nozzle change cause this or am I overly aggressively cleaning the PEI sheet and increasing the distance from the washers over time?
If you’re using the washers, nozzle height doesn’t matter, that’s one of the good features of the washer-based system.
You’d have to be sanding through the sheet to glass to make a difference.
When I was using the washers, Z offset was -1.32. By spec, the washers are 1.25mm thick, so anything above -1.25 is going to eliminate any squish on the 1st layer, while anything below that is cutting into your 1st layer. If there’s any plastic on the nozzle, it’s going to delay sensing the washer, requiring the offset above -1.25 to compensate.
After destroying a PEI sheet a couple of years ago due to plastic on the nozzle I became a stickler for being certain the nozzle is super clean before starting a print and leveling. I guess I’m not sure what caused the change when it used to print correctly at -1.15 but needs it closer to the bed now.