Page 31 - MetalForming January 2013

otherwise develop on both workpieces. The savings in time that waterjet cutting delivers to a fabricator becomes most impressive when a high-pressure cutting system is integrated with a mod- ern cutting table on which cutting and milling operations can be performed under precise computer control. It is that control, with the fine adjustment of cutting angles, which allows cuts with an edge alignment of 0.001 in. in thick
plate at commercially viable rates. With this capability, plate-nesting programs become more cost effective, as traverse time between cuts and the travel distances are minimized, reduc-
ing cutting time.
University Research on Cutting Nozzles
Although it might appear that a waterjet-cutting machine at a univer- sity research center might not get much use, many years ago student design teams at the Missouri University of Science & Technology (MS&T) discovered mul-
Fig. 2—Using a waterjet at 40,000 PSI and a cutting speed of 1.25 in./min., researchers performed nozzle-life tests by cutting triangular-shaped test pieces of 1⁄4-in.-thick mild steel right down the middle, starting at the sharp end of the triangle and cutting to the thick end. The goal was to gauge how far along the triangle the waterjet would cut before it stopped cutting all the way through. Then they sectioned the cut plates to measure cut quality and average depth.
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MetalForming/January 2013 29
tiple applications for the process. Their applications revolve around fabricating components for national and interna- tional design competitions—a solar car, concrete canoe, etc. Waterjet cutting, they have discovered, allows them to design and fabricate parts to the most efficient size to carry the loads needed. As a result, the vehicles they build gen-
Forming Systems
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Pressure Systems
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erally are smaller and lighter than those of their competitors. This has not been lost on the competition, as several other universities have since acquired their own waterjet-cutting machines.
As MS&T’s use of waterjet cutting has expanded, researchers have focused growing attention on cutting-nozzle life. To compare various nozzles on the