First layer issue  

RE: First layer issue

I have been experience the exact same issue for the past few months. It comes and goes, randomly, even when re-printing the same gcode in succession with the same filament on the same sheet (e.g., when printing a batch of five, two of them will start with the first layer too high). But it happens much more frequently with the textured sheet (PETG) than the smooth sheet (PLA).

I have tried going through the whole recalibration routine, thoroughly cleaning the nozzle, swapping sheets, using different (brands of) filament, tweaking filament settings and some other stuff I'm forgetting. IIRC it started happening around the 5.1.0 FW; I'm currently on the 6.0.0 FW.

The only solution I have found is to watch when it puts down the first layer and, if it looks too high, use the live Z adjust to lower it by 0.055. (You can switch to live Z adjust by depressing and holding the knob as soon as it says "Printing" on the LCD screen.) After I set Z height to -0.055 the first layer is perfect.

RE: First layer issue

I disassembled the printer head, cleaned it, put together and did the calibration. Now it's working.

We will see for how long 🙂

RE: First layer issue

I have the exact same problem.  I am printing with PETG and textured build plate.  It was working perfectly, and I tried to print parts for the openable enclosure that had something like 8 perimeters, and it has not worked since.  Nothing works.  First layer failures even with older models.  I've upgraded the firmware, did a factory reset with 6.0.0 firmware, reset defaults in PrusaSlicer to no avail.  I'll try thoroughly cleaning the nozzle and see if that helps.  The live Z adjustment is creative; maybe that will work.

RE: First layer issue

The nozzle needs to be cleaned between every print, especially with petg which notoriously sticks to the nozzle. 

If your nozzle is dirty it will mess up the bed probing because it'll be probing on the plastic build up on the nozzle and not on the nozzle itself, creating your first layer issues. 

Preheat the nozzle to printing temperature and lightly brush it clean with a brass brush.  I have a good first layer every time by doing this.

RE: First layer issue

Posted by: @brian-12

The nozzle needs to be cleaned between every print, especially with petg which notoriously sticks to the nozzle. 

If your nozzle is dirty it will mess up the bed probing because it'll be probing on the plastic build up on the nozzle and not on the nozzle itself, creating your first layer issues. 

Preheat the nozzle to printing temperature and lightly brush it clean with a brass brush.  I have a good first layer every time by doing this.

I see this theory put forth pretty much every time someone brings up the first layer issue. And it very well may be a problem for printers with dirty nozzles. But I keep my print head clean and it does not matter. Sometimes filament will ooze before the bed leveling and get stuck between the nozzle and the bed during leveling and the first layer will be perfect. Other times a sparkling clean nozzle will produce an absolutely terrible first layer.

Whatever the cause, the first-layer problem has nothing to do with the nozzle making clean contact to the bed during leveling. It comes and goes and the only reliable solution I have found is lowering the nozzle via live Z adjust right before the first layer. I do, however, think it is related to the load cell since I never, ever have a problem with the first layer on my MK3.

RE: First layer issue

Just reporting my experience.  When I first got the MK4 I had a few bad first layers.  Now probably 500+ prints later making sure the nozzle is clean I've had zero first layer issues.  You can't really compare it to the MK3 because your nozzle could be dirty and it wouldn't matter.  It's a different mindset when your probing. with the nozzle. 

Maybe you have a bad load cell, but I'm guessing 95% of the time people have problems is because they didn't clean the nozzle. 

RE:

Hi again!

Now the problem is back again..! And I also starting to get the same problem on my other MK4 !!

Tried contact the Prusa support. But The help I get from them is so time consumin my mind explodes. Both printers are standing in a closed heated Cabinet and haven't been used more than some hours. 

II really miss my old MK3 printers. 

Tried cleaning nozzles of course and I think lower the printer head by 0.055 every time the printer starts is a hassel.

/M

RE: First layer issue

I've a similar problem with PETG and the textured sheet and I assume this isn't really a cleaning issue. My nozzles are always clean on the tip and the cone. I use a silicone sock but I don't thinks that this is the problem when I read this thread. Is it possible that the cable to the heater will influence the result? Due to the fact that I often switch the whole head I don't lay the cable careful in the cable slot. But this don't explain why PETG/textured sheet often affected and not PLA.

RE: First layer issue

I have the same first layer issues with the MK4 printing PETG. I also tried contacting support, but the only thing they suggested is making sure the nozzle is clean, and making sure the nozzle is pushed all the way through.

Sometimes cleaning it well does help, but usually the layer is still too high. I was hoping a firmware update would help, but it didn't.

The only way I found to get a perfect first layer is by adjusting it manually on every print (by about -0.1)

I was really hoping the Mk4 automatic first layer calibration would finally rid of the need to do the z offset adjustment, but it's actually a worse experience than the Mk3...

RE:

Hmm I have the exact same issue. I'm trying to print PETG on the textured sheet and the issue arose just a few prints ago. I was printing in the same exact setup from the beginning without a problem. Yes I'm cleaning the nozzle / sheet. I don't know if the issue started with updating my firmware / configuration templates in the slicer.