Job accident with weird movement

[WillAdams (William Adams (Carbide 3D))]

This was probably caused by lost steps — you seem to be cutting a slot just as narrow as the endmill? That results in near constant 100% tooling engagement which is rough on the machine to do — best practice is to add geometry and cut as a pocket down to tab depth or the penultimate pass:

Adding geometry to cut as a pocket with a finishing pass

One technique which is often suggested to avoid slotting is to add geometry around a part which one wishes to cut out and cut as a pocket down to tab depth — here’s one technique for that. In this case, the project is a bevel gauge which will be cut out of 0.0625" (~1.5mm) thick aluminum: [bevelgauge] Due to the narrowness of the angles, an 0.03125" endmill has to be used, so after importing and scaling the file (we will be cutting out one which is 3") we select the perimeter and offset it tw…