Production Machining

AUG 2018

Production Machining - Your access to the precision machining industrial buyer.

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:: Figure 3: Dogs: These parts are precision cast alloy, pre-hardened steel chain links. The finished chain is used to move logs in a saw mill. Hanging onto these parts in me- chanical fixtures is somewhat slow and prone to parts moving when taking heavy cuts. For Op. 10, the part is supported by self- shimming pole extensions in the Z axis, with no issues with the casting not being perfect—the moving poles will conform. For good measure, these contact faces have been "friction coated" to increase sliding force. In the Y axis, the dog is held against a magnetic side-rail—the locator rail is magnetic and is pulling the part in Y. For the X axis, a simple plate that engages the finger protrusion on the top of the part contacts the logs. Loading involves placing the part on top of the self-shimming pole extensions (Z), sliding it against the side rail (Y) and along the side rail to the stop (X). Then, the magnet is switched on. Holding forces gen- erated are ~2 tons in Z and ~1 ton to pull it away from the side rail in Y. The part doesn't move. Workholding is not a limitation to the metal removal rate in this application. The chips do not stick to the part, and for Op. 20 with the dogs flipped and uses the two pins technique. with AlNiCo with north polarity against the base of the steel pole, and the steel pole becomes a north pole. To switch off the magnetic circuit, the AlNiCo needs to be reversed magnetized to present a south polarity against the base of the steel pole. If the two sets of magnets are "matched" to be equal, then all of the north polarity energy of the rare-earths is absorbed by the south polarity of the AlNiCo and the working face becomes non-magnetic. is design is able to saturate the workpiece with maximum clamping force. e on/off switching is fast— less than 1 second. Power is consumed only during the switching phase. Once magnetized, the device stays magnetized until switched off. Holding Force With magnetic workholding, the workpiece forms half of the magnetic circuit. e magnetic chuck is the engine, but the part is what closes the magnetic circuit and creates the clamping force. However, different materials have different magnetic saturation levels, resulting in different maximum holding forces. For mild steel, ultimate pull force potential is about 210 to 220 psi. For alloy steel and soft tool steel, the holding Introducing new helical chamfer mills with 30º, 45º, and 60º included angles www.sct-usa.com sales@sct-usa.com 1.805.584.9495 1.800.383.2244 Single Point - Thread Mills - Port Tools - Indexable Tools - Specialty See it first At IMTS BOOTH# 432013 Scientific Cutting Tools Magnetic Workholding productionmachining.com :: 39

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