First Layer issues when using 'Complete Individual Objects'
Looking for suggestions. The parts that I am printing have a very tight tolerance and the parts come out different sizes when printing as an individual vs. printing a group of them. I have narrowed the issue down to the fact that the amount of cooling time between layers is much greater when printing multiple parts vs. a single part.
In order to solve my issue I have started using the Complete Individual Objects feature in PS which completes a single object before printing the next. This has solved my tolerance issue, however I often get first layer issues on some of the parts printed after the first one. I believe the issue is related to the fact that the shape of the bed changes over time as it heat soaks, and possibly from the adjacent completed objects possibly changing the shape of the bed. The issue I believe is that the bed mesh is made under 1 condition and therefore when it prints the sequential parts the bed is a different shape. I have tried glue stick, and preheating the printer for 60 minutes prior to starting the job, but nothing has been consistent up to this point.
I'm printing PETG on the Satin sheet. I am going to try printing on the textured sheet, hoping it might be a little more forgiving.
FYI I don't get the first layer issues when all of the parts are printed together as a group, only when printed sequentially.
Any other ideas?
RE: First Layer issues when using 'Complete Individual Objects'
Update. The textured sheet was successful, however I don't care for the textured surface on these parts.
I also was able to solve it for the Satin sheet as well by lowering the live Z after the print started. Not ideal, because I'll have to do this every print, and the first part printed has a bit of an elephants foot, but it'll work for now. It would be nice if we could save the Live Z, or compensate somehow in the g-code and only apply it on the sequential parts. I'll do some more research.
RE: First Layer issues when using 'Complete Individual Objects'
This was buggy when I tried it in march when I got my printer. Possibly the Z offsets were not carrying over after completing the first object, in my case it was printing every object after the first in air (about 0.5-1mm above the bed). All at the same (wrong) height though. I gave up eventually, apparently still not solved.
You have other options, e.g. play with the cooling settings, minimal layer time or max volumetric flow. Make sure your filament is calibrated properly, temp as low as possible and compensate for part shrinkage and filament thickness. You can also reduce extrusion width if you need better detail resolution.
RE: First Layer issues when using 'Complete Individual Objects'
This was buggy when I tried it in march when I got my printer. Possibly the Z offsets were not carrying over after completing the first object, in my case it was printing every object after the first in air (about 0.5-1mm above the bed). All at the same (wrong) height though. I gave up eventually, apparently still not solved.
You have other options, e.g. play with the cooling settings, minimal layer time or max volumetric flow. Make sure your filament is calibrated properly, temp as low as possible and compensate for part shrinkage and filament thickness. You can also reduce extrusion width if you need better detail resolution.
I wish there was a better way of getting these issues addressed. Prusa support is great, but I'm not sure they take this kind of stuff seriously unless you get the right person.
I've posted on GitHub before but I feel like that pretty much gets ignored. I've never had anything I've put there have any response or action other than when it expires and has to be closed. I usually end up having to come up with my own fix, which is not usually ideal.
Maybe I'll try posting this if I get some time since you've had issues too. Maybe it is not carrying over the bed mesh.
RE: First Layer issues when using 'Complete Individual Objects'
What you need adding to PS is the suggestion from the bottom of this github issue https://github.com/prusa3d/PrusaSlicer/issues/877#issuecomment-1107787123
RE: First Layer issues when using 'Complete Individual Objects'
Thanks for pointing me that direction. I personally don't think it's a bed temperature issue, at least not in my case, it's only 5°C difference between first layer and the rest, I think it's more to do with the bed mesh.
I'll add my 2¢ to that.
RE: First Layer issues when using 'Complete Individual Objects'
Yeah from your description I'd agree with you that its probably not applying the mesh adjustment to the other objects, just the first one. Which to be honest probably 'should' be fixed in the printer firmware properly.
The suggestion to print all the objects first layers though might be a sufficient workaround.
I also kind of liked the suggestion as for me once I know the first layer is good I'm pretty much confident that the print will go fine. If it puts the fist layers for all down then that means I don't have to check for each one in turn lol.
It might be worth opening an issue in the Buddy firmware repo asking about this too. I couldn't find an existing one when I looked. I think that to fix properly its going to need a firmware change and also possible a code that the slicer outputs between objects to tell the printer to use the mesh data for each one.
RE: First Layer issues when using 'Complete Individual Objects'
@Neophyl was on to something. The changing of the bed and nozzle temperature appear to be the culprit.
I have been successfully printing now by making the first layer and other layers bed temperatures the same as well as for the nozzle temperatures.
In the default PETG profile the first layer bed temperature is 85 and other layers are 90. I suspect that the bed mesh is different at 90 vs. 85 due to thermal expansion. So now I have both set to 85 and have the nozzle temp the same for both.
The nozzle temperature may not be much if any influence, but in my case printing in an enclosure, I've not seen any benefit in running a higher temperature for the nozzle on other layers. So I just left then the same.