Rotary broaches manufactured with a proprietary hardening process can cut material as hard as 50 HRC with minimal tool wear, improving the production process for medical screws and other components.
High-production CNC machining environments often rely on small process improvements to save a lot of money on a given job. The economies of scale simply mean that shaving a few seconds off a cycle will lead to shaving hours off the total time needed to machine all the parts. However, just as savings can add up in a high-production environment, so can costs. This is often a major hurdle in the production of medical-grade screws.
Rotary broaches – also known as wobble or hex broaches – need to be ground to fit each specific application, as the shape of the cutting tool needs to mirror the desired geometry of the hole. They are designed with a 1-degree offset along the longitudinal axis, which creates the “wobble” that enables the tool to cut hexagonal and square holes.
Medical screws can provide a challenge to manufacturers, as they join the scale of high-production jobs with the challenges of working with difficult materials. Using metals such as titanium and high-strength, low-nickel alloys like BioDur 108, medical screws often demand robust cutting tools in order to make any cuts at all, and even then tool life can suffer. When production volumes are high, the added tooling costs can rocket to tens of thousands of dollars per year, if not more. For screws requiring rotary broaching, the costs are especially prohibitive.