I’m in the process of cutting several identical relief carvings. The first three went fine, no problems. Then, on number four I noticed changes in z height as the carving progressed.
Design worked up in VCarve Pro. Part is 32” wide and 4” tall, just fits in my XL. Relief is a maximum 3/4” deep.
3D roughing toolpath is a raster on the x-axis, .25 doc, .25 inch ballnose. As I said, first three ran fine. Now, about a third of the way thru the job the z depth decreases about 0.1 inch. Then, about 2/3 of the through the job it decreases another 0.1 inch. So, a stair step from the bottom to the top. Fortunately the 3D finish toolpath with .125 ball nose works ok, cleans up all the leftovers.
On the last piece I changed the roughing toolpath to raster on the y-axis, and…got the same stair steps except right to left rather then bottom to top! What the heck?