Modern high speed machining centers should not mix with conventional tooling and methodology. Doing a machining process on a new or newer machine should not necessarily use traditional, proven machining techniques. These processes may work; however, they may not be optimizing the capabilities of your machining center. As the industry has progressed, Cutting Tools Chicago aka General Cutting Tools has kept up with current technology.
One of our customers has a re-occurring job of machining a fairly large piece for Boeing that is cut from a solid block of titanium. In order to maintain competitive in the market, General Cutting Tools was invited to come in and examine their processes.
Titanium is normally classified as a difficult to machine. This is due to the physical, chemical and mechanical properties of the metal. Titanium’s low thermal conductivity does not allow the heat generated by the cutting action to dissipate quickly. Consequently, most of the heat is concentrated on the cutting edge and the tool face. Titanium has a high chemical reactivity or strong alloying tendency with materials in the cutting tools at tool operating temperatures. Galling, welding and smearing can be found along with rapid destruction of the cutting tool.
Titanium is more “springy” than steel. The work piece has a tendency to shift away from the cutting tool unless heavy cuts are maintained or strong support us used. Chatter, tool rubbing and tolerance issues occur as a result of tool pressure’s tendency to deflect slender parts. Usage of sharp, properly shaped tooling and rigidity of the complete system is extremely important.
A total of seven operations are required to make a finished part. We elected to focus on the first milling operation. This operation alone had required over five hours of machining time. Given the speed capability of the machining center, General Cutting Tools along with Ingersoll Cutting Tools were confident we could improve the process with a helical interpolation method using Ingersoll’s high feed milling cutters.
With this switch, we were able to condense the first milling operation from well over five hours to only 42 minutes. With this singular improvement, the customer has been able to not only maintain the orders coming from Boeing, but also increase profit margin.