By Richard Ward
(Job Shop Technology, March 1999)
The ability to hold parts tolerances to 0.005 inch while circumventing the issues of heat-affected zones, local hardening, and burring continues to launch new opportunities for waterjet cutting, according to Richel. Inc., a waterjet consulting firm based in Tallmadge, Ohio. The firm recently reported that waterjet cutting helped save time and costs for Miamisburg, Ohio-based CAM Manufacturing, which produces high-tolerance parts for the aerospace and aircraft industries.
After retrofitting a used, water-only cutting system to a multiple-abrasive-head cutting system, CAM Manufacturing was able to achieve near net-shape cutting on a "fan" made of Hastalloy X, Richel reported. The fan, 0.75-inch thick, has an OD of 5.3 inches and an ID of 4.25 inches. The firm also eliminated some costly steps associated with traditional machining.
When the parts were manufactured on traditional machining centers, burring was severe. As a result, the entire part needed to be re-machined after all the teeth of the fan had been cut. But by using a simple, 2 axis waterjet with manual Z, CAM cut the teeth to tolerances of +0.015 inch. Use of the waterjet caused virtually no burring, thus eliminating the second machining phase of removing burrs. It also freed the milling machine, previously used to "hog out" the material, to be used only for final shaving of the teeth.
In addition, because the waterjet placed no stress on the thin support ring, it caused no distortion and eliminated the need to machine any part of the teeth, Richel reported. Use of the waterjet is said to have reduced total cost of machining from $272 on a 4-axis machining center, to $110 with the waterjet. Similarly, time of machining dropped from four hours and ten minutes, to two hours and five minutes.
