Help with FEM drilling model

Hi All,

I am trying to simulate the drilling process of Aluminium using JC model, the thrust force diagram Fz I get back from the simulations are not correct, I keep getting sudden drops in cutting force down to zero or below zero, its like every time the cutting tool drills through a layer of elements, once elements get deleted the cutting tool does not interact any more with the next layers for a period of time and this produces zero cutting force on my graphs, any idea of what could be the problem?

I have attached some images for my results.

Thank you

It sounds like you explained the problem by the element removal process.
If that is a problem, perhaps you can use a finer mesh?

-Jorgen