Inaccuracy

Just wondering if anyone else is having problems with the accuracy of the machine/software. I am using the machine to make skis. When cutting out base material, two at a time, they do not come out symmetrical despite being mirrored with Solidworks. Also when profiling cores, I cannot get them to come out as drawn in Solidworks. So instead of being 2.5-12-2.7mm (tip-waist-tail) it will be more like 5-12-5. I guess potentially I can try to make the model to compensate for this but it kind of defeats the purpose of trying to make something accurate. I am using Vectric 2d/3d software to create the gcode.
My computer has been acting up a bit and I want to replace it but before I spend a few hundred on that I wanted to see if anyone else was having these same problems.
Also sometime I seem to get pulsing through the motors and the move slowly with out any reason. Today I reset my computer and this seemed to help but other times I have had the machine move all axis about 1/4" away from the home position over about 20 min.
Basically just wondering if anyone else is having trouble with the machine cutting accurately.

Thanks
Happy building

Have you worked this out yet? Things that jump to mind are the flatness of your spoilboard and your zeroing accuracy. Probably not zeroing though since your middle dimension is correct. You can tell if it is your cut path that is the problem by watching the coordinates on the computer and seeing if the comp is telling the machine to go to the right place. Make sure all the set screws are tight on the z axis pulleys.

Let me know if you have a solution as we would like to improve the accuracy of our profiling.
thanks,
Morgan