This occurs due to material shrinkage and is difficult to eliminate in this technology if one edge is parallel to the base of the workspace. In order to avoid this, turn the model at least 20 degrees in the X axis. If the problem persists, also rotate the model in the Y axis.
FAQ (Frequently Asked Questions)
The powder behaves like damp dust (is not as loose as it should) which makes spreading the first layer difficult. Will the prints be ok?
Do not get discouraged. The printout will most definitely come out fine, as any dampness that may be contained in the powder because of its hygroscopicity will be immediately vaporised during the warm-up and printing of the machine. Spreading of the first layer will simply be slightly more onerous and take more time.
The recoater roller has probably stopped rotating. In order to fix this, apply two drops of oil to each of the recoater bearings (at both sides). Another reason that may have caused this: the recoater transmission rope (responsible for its rotation) may have broken. This is easy to ascertain as one of the strands that is always located by the recoater will simply be broken in such case. This will be visible to the naked eye, in which case replace the strand.
The powder has not been refreshed properly and has aged. Use new powder or add at least 50% of the so-called ‘fresh powder’.
The gaps between the pins and the rotating elements have been too narrow. Increase the gaps in the model.
The pyrometer sight glasses have probably not been cleaned properly. Use a cloth saturated with spirit to wipe them thoroughly. This should remove the problem.