The U.S. Army’s Armament Research, Development and Engineering Center (ARDEC) at Picatinny Arsenal was commissioned to reduce the weight of the base for the 120mm mortar by replacing an approximately 5.5″-diameter steel base support with one made of titanium 6AL-4V.
Titanium weighs 45 percent less than steel, is stronger and more resilient, and doesn’t rust. However, its unique properties also make it difficult to machine productively.
NCDMM was tasked by ARDEC to reduce the machining time and, thereby, the cost of the process. Working with its partners, COM 1 and Kennametal, NCDMM created a “proof-of-concept” simulation of new tooling for both turning and drilling processes for machining the base. Machining upgrades included introducing high-performance PVD-coated carbide cutting insert material for the profile turning operation and upgrading indexable insert drills for roughing out the bore. The new process was then proved out on ARDEC’s CNC lathe at Picatinny Arsenal.
As a result of the process changes determined by NCDMM and its partners, both turning speed and depth of cut increased, producing a metal removal rate 10 times greater than achieved previously. Drilling speeds also increased by 40 percent. These turning and drilling improvements translated into an 800 percent increase in turning and drilling productivity, representing an 89 percent decrease in machining time. No additional capital investment was required, because existing equipment was employed.