malfunction in toolpath

[grandpa]

 I have a problem when running a 3d tool path, it goes just fine then for no reason it will move the starting point. And then the project is just a scrap of lumber, has anyone else had this problem?

[Hood]

Can you attach our xml and also the code you are having issues with and say roughly the line number in the code where the problem appears.
Hood

[ger21]

Sounds like your machine is losing steps and losing position. Try lowering the acceleration by 50%.