Calibration v08 - B9creator

thingiverse

This calibration thingi can be printed really quickly because it stands 100 layers tall (sliced at 50.8 microns, so it is about 5 mm tall). The STL for printing is inside the ZIP file (the unzipped STL is only for visualization: do not download it). The base layer is divided in two, to minimise the potential shrinkage (during printing): you can easily fill that gap in the B9C editor if so you prefer. There is only one base layer but it is easy to add more base layers in the B9C editor. There is a wall around the perimeter to ensure that, even in case of printing just one base layer, the print retains its shape (after detachment). There are 4 towers at the corners: they are there for calibration: to make sure that you can print "equally" well in all areas of the surface. In other words, this design helps you to make sure that the projector focus is uniformly good and that the z-calibration is parallel to the shallow coating surface. The towers have got indentations every 1 mm. There are various items, with small and curved shapes. there is also a hollowed item to test resin escape (with one, 3 mm hole). I also added two B9J files: they contain a depth-map butterfly. There are two versions because one is rotated by 180 degrees on the z axis. Printing both calibration items (rotated and not) helps understanding the issues. The first photo (on the glass) is perfect. The other photos contain print problems and I explain in the section "Instruction" a few more details on debugging with this calibration model. Instructions I printed at 50xy and 50.8 z with only 1 base layer. If you experience problems with your prints, you have to print this calibration model twice: once as it is and then print it again rotated by 180 degrees on the z axis: then compare the differences. Debugging exercise: this calibration design highlighted one flaw in a corner of the print (see the photo with the red build table): the flaw shows that the base layer partially detached in that corner during printing, causing the voxels printed above it to be imprecise. Possible causes are: resin shrinkage during printing (to prove those type of problems, you should rotate on the z axis by 180 and print again), incorrect z-calibration (should cause the base layer to be thicker on side than the other: this is a very likely cause) build table cleaned incorrectly (quite rare as a cause of that defect) incorrect projector calibration (quite rare for this type of defect) incorrect coating which leaves it non-planar (rare)