RE: what would cause this ripply look in first layer?
Disregard the extrusion multiplier and temperature fix. It helps with the first layer but then it causes a different problem altogether of under extruding on the other layers.
RE: what would cause this ripply look in first layer?
I usually like to check my first layer to avoid printing a lot of spaghetti. I've had really good luck with the original PEI sheet that came with the Mk4 kit 8 months ago. I just noticed that I'm getting the same issue here but I have to wonder if it might not be heat related.
This is the rippling I saw in my last print:
However, this was the second item's first layer. The first one to print was fine:
So I have imagine that if it were the filament, the printer, or the sheet, which were all the same, how could this be? My theory is heat.
At the time of this picture:
These was what the control panel showed:
The hot end fan was running as usual, but I have the cooling fan set per normal specs, to not run during first layer.
I've only once or twice in 8 months had a bed adhesion issue printing PLA, so I just continue to clean with an alcohol wipe between prints. But now this.
I do have to admit that I have not done any "maintenance": cleaning the nozzle and whatever else one is supposed to do on a regular basis. So perhaps I should try that. When I was much younger and unable to afford auto mechanics I found that sometimes the thing just needed a good cleaning. If that works, I'll let you know.
But I'm also willing to try other things if anyone has any suggestions.
I should add, I have just upgraded Prusa Slicer to the latest 2.8.0 and the firmware to 6.0.3 and I'd be interested to know if others only noticed these issues after upgrading.
I'm hoping this or subsequent information helps us figure this out and find a solution for everyone.
Thanks
Mike
RE: what would cause this ripply look in first layer?
Well... now I think I need to formulate a new theory. The next 2 items I started printing together decided to start printing the right piece first, then the left. This is the opposite of the example above. But note that still it is the right side that is wavy and not the left. So it is not about a build up of heat as I was theorizing. This is very odd.
RE: what would cause this ripply look in first layer?
I have 2 Mk4's. one has a diamondback nozzle, the other the standard brass. Both sliced with Prusa Slicer using the profile for Jessie PLA, both with Jessie PLA in machines. Ripples show up on diamondback nozzle, not on brass. Diamondback conducts heat more efficiently than brass so lowering the temperature on the diamondback one works and makes sense.
Also Satin sheets that have to be perfectly clean.
RE: what would cause this ripply look in first layer?
Diamondbacks are made mainly from brass and just a small diamond tip. To practical effects, the difference in thermal conductivity is negligible, if compared to regular brass units. If diamond nozzles seem to ooze more than brass is not because of better thermal conductivity but due to the fact that diamond has an extremely low friction coefficient, so the filament drips faster from the tip. Lowering the temperature helps to minimize this issue. Increasing a bit the retractions would help too.
Concerning the ripples, I don't see how the type of nozzle can have nothing to do with that. In all likelihood, if you have ripples on the MK4 with a diamond nozzle and not on the one with the brass nozzle it's because of the bed being a bit irregular and/or the automatic Z-offset calibration being a bit off. Have you tried to swap nozzles on both printers to check if the ripples still appear on the same MK4 ?.
RE: what would cause this ripply look in first layer?
I'm 99.9% sure that the ripples you are getting are from the nozzle being too close to the bed. I've had very inconsistent results with the homing of my MK4 machines, but that exact look (the ripples of raised filament) has occurred on many different machines of mine (prusa, ender, bambu, etc), and always when the first layer was too close, so there wasn't enough room for the filament, and it started pushing up.
This is something you can easily test. Start a print, and when you see this happening, long press the control knob, which will allow you to adjust the Z-offset for that print. raise it up by 0.05mm, and let it go for a minute. Repeat this a few times. At some point, you should see the ripples magically disappear.
It's always possible that I'm wrong about this, but I'd wager money that I'm not.
As for fixing the homing on the MK4, I found that on one of my machines, loosening the screws attaching the nextruder to the gantry, and tightening things back up, helped a ton for some reason. Maybe there was some sort of tension tightened in there affecting the load sensor. In one of my machines I had to replace the load sensor completely, it never was able to home correctly, and that solved the problem. Each of my MK4 printers seems to have a different level of squish when they home, and I desperately wish they would allow you to fine tune the Z-offset for each machine and save that to the specific machine.
Well... now I think I need to formulate a new theory. The next 2 items I started printing together decided to start printing the right piece first, then the left. This is the opposite of the example above. But note that still it is the right side that is wavy and not the left. So it is not about a build up of heat as I was theorizing. This is very odd.
RE: what would cause this ripply look in first layer?
Thanks Mark. That makes sense. It wasn't too long after I made the post that the hot end slipped down and buried itself in the print bed. I had taken the nozzle out and when I put it back in had pinched one of the thermistor wires under the thumb screw, and it was working it's way out. Very consistent with what you said. Funny thing, I ordered a .4 nozzle to replace and before it arrived my 4S kit arrived, which includes a .4 high flow nozzle.