We are using an Akira seiki V4. Cutting graphite. When we cut the perimeter (on a rectangle). Length will be oversized while width will be undersized. This problem occurs randomly, the machine will be running fine and next thing you know this problem will pop up and we start seeing parts with variation on the length and width. What are some possible causes for this problem? Is it a worn out ball screw, cutting tool or something else? Anyfeedback is appreciated.