Concave warping of a large rectangular print
Hi,
I have been trying to print a large rectangular tray (345 mm x 100 mm) on a Prusa XL printer. For weight, we decided to print it at 100% infill. Every print has turned out well except for a defect toward the bottom of the print. There is a concavity that keeps forming on the walls on the first few couple of layers. The walls should all be straight because it is a strictly rectangular part. The tray has four 13-mm-deep blind holes on the bottom, the inner diameters of which seem to be affected by the concavity. Has anyone encountered a similar issue, or might anyone know the root cause? I would greatly appreciate some insight.
Thank you
100% fill is usually a mistake and leaves the printer no room to accommodate variations ...
but the curves are typical thermal contraction artifacts. As each layer cools and contracts it first bows in so the next layer is printed overlapping slightly - then cools and contracts in its turn. As the part grows the accumulated layers resist further contraction and the walls straighten.
Reducing the fill to 75% cubic or gyroid should give the part some resilience and reduce the effect - it it's still too much then incorporating some stress relieving slots in the structure is always worth trying.
Cheerio,
RE: Concave warping of a large rectangular print
Thank you,
I had a feeling the 100% infill may have had something to do with it. I tried again, printing a smaller test piece at an infill of 20%, and found that it came out way better although there is still an ever so slight curve at the bottom. I suppose the geometry of the part has something to do with it.