Additive-Manufacturing

Additive manufacturing is changing how we think about deep hole drilling. Instead of drilling a solid bar to create a hole, additive processes can build the part with the hole already partially formed. But the as-printed surfaces are not suitable for most engineering applications, so post-process drilling is still needed. I have worked with hybrid manufacturing processes that combine additive deposition with subtractive machining in the same machine. The deep hole drilling step comes after the additive build, and it presents unique challenges compared to drilling from wrought material. The approach to selecting a machine for the application becomes more complex when the machine must serve both additive and subtractive functions. ...

I started drilling additively manufactured metal parts expecting them to be harder than wrought. The porous, layered structure looked like it would eat tools. The data surprised me. AM metals — specifically laser powder bed fusion Inconel 718 — machine differently than wrought. Tool wear is lower, cutting forces are lower, and the wear mechanism shifts from adhesive to abrasive. Understanding these differences changes how you set up parameters and select tooling. ...