Page 32 - MetalForming January 2013

Waterjet Technology
market, and learn how they wear and cut, we prepared test samples of triangular pieces of 1⁄4-in. mild-steel plate, set on edge. Using a waterjet at 40,000 PSI and a cutting speed of 1.25 in./min., we cut the samples 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 we sectioned the cut plates to measure cut quality and average depth (Fig. 2).
We set a performance requirement for each cut so that when a cut fell below a certain depth, we would con- sider the nozzle to have worn out. Results varied among nozzles, with operational life ranging from 10 to 40 hr. So while we do not necessarily recommend that fabricators perform the exact same test that we did, we do recommend you test various nozzle types to see how they perform for the range of materials and thicknesses typically processed.
Lastly, a point of emphasis when
working with our research teams is teaching them to conserve materials, starting with an understanding of opti- mum sheet nesting. Another way to conserve material is to repurpose the next skeleton for cutting small parts from what otherwise would be tossed aside as scrap. Here we find yet anoth- er advantage of waterjet cutting over conventional milling, since milling turns the workpiece skeleton into chips to be sold as scrap.
More than Metal
As a final note, metalformers and fabricators must fully understand the capabilities of the waterjet process to cut other types of materials, including glass, and even to create art forms. To do so, take a look at Vanessa Cutler’s new book, “New Technologies in Glass,” available on Amazon. Here you’ll find several fascinating designs that can be achieved using, among other tools, abrasive waterjet cutting.
Another trend we see is growing
use of waterjets to micro-etch metallic surfaces. Micro-etching, using plain water at around 20,000 PSI and per- formed using one to three passes, can impart unique and interesting surface finishes on bronze, steel and alu- minum surfaces.
There are, in short, a variety of dif- ferent ways metalformers and fabrica- tors can apply a high-pressure waterjet cutting machine. Some of these ideas are well known, and others less so. There- fore, to shed more light on the possible applications of waterjet technology, I encourage the readers of MetalForming magazine to visit my new Waterjet Technology Blog, launched in January 2013 on the website of KMT Waterjet Systems (www.kmtwaterjet.com). There you’ll find posts providing detailed information explaining why some things work and others don’t, as well as thoughts on where the waterjet indus- try can grow. I look forward to seeing you there, and to fielding any ques- tions that you might have. MF
30 MetalForming/January 2013
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