The photo shows serious warping (or curling) of my print from my old PEI sheet which was printed on my MK4 with my old heatbed. All four of the corners warped (only the worst corner is shown).
This has been a persistent problem for the last couple of years. Smaller models printed closer to the center of the bed are fine. Only bigger prints which approach the edges of the bed curl up.
I recently upgraded my MK4 to the MK4S. While I was at it, I replaced the heatbed and I bought a new PEI sheet. And even though the sheet was brand new, I did wash it thoroughly with warm water and Dawn dish soap before using it.
After running through the full calibration and reslicing my model for the new high-flow nozzle using the latest stable release of PrusaSlicer, I reprinted it with high expectations.
Unfortunately, I was disappointed. One of the corners warped. It wasn’t quite as severe as before, so that’s a slight improvement. The corner that did warp happens to be the same one shown in the pic.
Print Settings: Prusa MK4S printer (no enclosure) 0.4 mm high-flow nozzle 0.2 mm resolution 15% infill Prusament Army Green PLA
– Edit –
Wow, there are lots of good ideas here. Thanks everyone!
The things I’m going to try (in no paticular order).
- Covering the printer with a cardboard box or insulation sheets to see if an enclosure would help.
- Cutting a tiny relief across the sides on the first layer.
- Adding a brim.
- Slow down the first layer.
- Spraying 3DLac on the corners
I’m not convinced this is helpful. These tests even suggest it’s harmful
Not trying to be combative here but the tests you linked further support what I was saying. A small chamfer and I really mean small will have a similar effect once rendered in gcode to a fillet. If you have access to software to generate a fillet easily that is good too. That being said I would only do it for the outer rim.
Either way the print looks like it is warping on the lowest layers and has elephants foot which is what I suspect is the biggest issue here.
The steps I proposed are
I might have misunderstood you, sorry. Do you mean a fillet or chamfer on the corners? (ie rounding as viewed from the top?) Or do you mean a chamfer such that the part’s second layer is slightly wider than the first layer?