Modern Machine Shop

NOV 2018

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MMS NOVEMBER 2018 74 mmsonline.com FABRICATING Meeting Mold Shop Needs The expansion that made waterjet necessary also made waterjet feasible by freeing room for the system in the first place. With a total footprint of 35 by 17 feet, the Wardjet Z-2543 and its auxiliary equip- ment occupy most of the space in plant 3 vacated by the move of blow-mold personnel and equipment to plant 4. Given the advantages of cutting multiple parts from a single, large plate (typically 4 by 8 feet) and the ability to reuse the scrap later, Mr. Meldrum says the system has been worth every square inch. The focus of plant 3 is prototype/low-volume injection molds, many of which are destined for operation, or at least try-outs, on the presses in plants 2 and 6. The waterjet was installed there largely to machine manifolds for this tooling. Built to house the mold's plastic-delivery system, manifolds are forgiving, but they are made of steel, and they trend large. Without a waterjet, these components would occupy valuable time on CNC machining centers that are better suited for more difficult jobs. They also would require carbide cutting tools that are generally more costly than the high-speed steel cutters used for the rest of the aluminum molds. Manifolds were once outsourced, but they still required cleanup on a machining center due to a hardened scale left by the outside supplier's f lame-cutting process. Relying entirely on the pressure of the stream and the garnet particles carried within, waterjet came to mind as a way to make these simple cuts in-house and without the heat. Before long, waterjet had proven equally useful for supporting blow-mold production in plant 4, just a short walk away. This tooling is too com- plex and customer specifications are too varied for in-house manifold production, Mr. Meldrum says. However, unlike injection tools, making blow molds often involves fabricating a number of 2D components, such as brackets and other fixtures. From there, the waterjet's work expanded to ejector plates, wear plates, shims used to adjust a mold's fit in the press, and even various compo- nents for its own custom machinery, such as the hot-plate welding unit used in plant 6 for plastic assembly operations. However, expanding the waterjet's share of work at IMC required config- uring the machine to suit the needs of mold man- ufacturing. Here are a few key elements: • A Precision Platform. Employed to cut every- thing from f loor tiles to food, waterjet is known more for its versatility than its preci- sion. One relatively easy means of improving the machine's precision—and, by extension, expanding its stable of work—was leveling the four sections of grate that constitute the table. This was accomplished by milling grates f lat, then putting them back together, using shims to ensure a level surface for workpieces. These improvements enabled the machine to achieve tolerances of ±0.005 inch. Mr. Meldrum adds that the same oper- ations can be repeated as table sections wear from heavy use. • Powered Pressure. Water pressure and cutting speed are directly correlated, but high pres- This vacuum loader enables operator Aaron Bazydlo to easily load large plate onto the waterjet grates. A chief advantage of water- jet over a process like laser is lack of heat. But what happens when a laser beam travels within a stream of water? Learn more at gbm. media/waterlaser . HOT MEETS COLD

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