Issues with 3D models

Hello, my name is Angela and I work for an orthodontist. We have 2 Moonray S100 printers and we 3D print dental models of patients teeth and use them to make retainers. We purchased our first one about 3 years ago so I've been working with them since them. One of the printers has started to distort the models so that they are wider by the molars when printing horizontally. The model looks fine but when compared with a reprint you can notice the difference. I have done the Fit and Tolerance and the Dimensional Accuracy calibrations since it started happening and they have not fixed the issue. I've attached some pictures for reference.

Hello. I have a problem with printing on a 3D printer. As you can see in the photo, the printing is uneven and wavy. The first figure is normal, the rest with a partak. I print PLA plastic. However, the temperature and speed were the same on all figures. Belts on axes "X" and "Y" are OK. I changed the nozzle, it didn't help. Upon close inspection during printing, I found that the first layer is printed well (the nozzle is above the table as expected), in the subsequent layers the nozzle seems to rise by half a millimeter (maybe 1mm) from the printed part (figure) and because of this, the layers do not stick together normally between themselves. Is it in the "Z" axis ?? or something else.How will I solve this problem? help me please. Thank you in advance!

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