PrusaSlicer 2.5.0 - Interference between print and SuperPINDA?
Noob here, hoping this isn't a dumb question.
1:40 into a 2:10 print w/Prusament PLA on an MK3S+, all had gone perfectly when suddenly the object was no longer stuck to the bed. Earlier in the print, I'd been noticing very close clearance (maybe 1mm, possibly less) between the SuperPINDA and the print. Didn't witness the event, but I'm thinking the sensor might have hit the print and knocked it over. First layer calibration is at -1.6mm which yields the test looking as it should.
Not clear to me whether Slicer is "smart" enough (i.e. has sufficient data upon which to base a conclusion) to avoid interference. I've now rotated the object 90deg to minimize the potential for this issue to occur, but for future prints, I'm wondering if what I've described is a real thing, and if it is, whether there's some action or combination of actions to prevent it ... e.g. maybe move the SuperPINDA up, recalibrate, etc.?
RE: PrusaSlicer 2.5.0 - Interference between print and SuperPINDA?
Unlikely to have been the SuperPINDA as that is always higher than the nozzle.
Much more likely is that your print warped and lifted somewhere on its perimeter, was caught by the nozzle which detached it from the bed. Check the underside of the failed print for flatness - it is usually pretty obvious if it is warped.
Cheers,
Tim
RE: PrusaSlicer 2.5.0 - Interference between print and SuperPINDA?
No its not a real thing. As its printed layer by layer it will be above the level on every layer. It not a question of slicer smarts, its the nature of the printing itself. Just watch a normal print from the side next time you do one. The pinda is close but it has to be to work. Its always the same height above the previously printeed layer below. Normally. However depending on your design and the way plastic and cooling works it is possible for parts to cool in thinner areas and 'curl up' above the height they were laid down at.
This is most likely on sloping areas that slope upwards gradually. With this type of geometry the plastic as the edge is connected to the perimeters next to it but is largely printed over nothing. So when it cools and contracts it can raise upwards slightly.
In this scenario though the nozzle is always lower than the pinda sensor so the nozzle is more likely to hit the previously curled section of the printed layer. A part only gets knocked off the print bed when your bed adhesion is not dialled in though. If you have z set properly and your bed is clean then very little will knock a print off. Normally with slight curling the hot nozzle will remelt the area and push it back down. You will often hear a knocking sound as it does so. Its not ideal as you are introducing stress into not only the part but sideways into your extruder, and the heatbreak is only thin and can be bent.
If it happens to me then that is an indication that the part should be re-oriented if possible or redesigned in that area to make it more printable.
RE: PrusaSlicer 2.5.0 - Interference between print and SuperPINDA?
The only situation in which the hotend hitting the model seriously is when sequential printing is on and there's not enough clearance for the hotend and/or x-axis.
But as explained before, under normal circumstances the nozzle will always hit the model before the PINDA. In addition to the curling described by Neophyl, infill patterns with lines crossing in the same layer (such as grid) can lead to little "pileups" at the intersection points, which can lead to layer shifts when hit by the nozzle at high speed. But in no case should the PINDA interact with the model.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: PrusaSlicer 2.5.0 - Interference between print and SuperPINDA?
Thanks to all for the detailed explanations. Much to learn, and these insights do definitely help me get there.
FWIW, and with what you've said it's likely just the luck of the draw, but turning the object 90deg did result in a successful print. (Yippee!)
In the short term I'm going to increase the lighting in the space, my observing of the process, and my post-print inspections in an effort to get this resolved.
Again, thx for your input.