ShopSolutions Case Histories of Manufacturing Problem Solving Breathing New Life into Old CDCF Iron T
he forte at Lakes Precision (Three Lakes, WI) is creep- feed grinding, specifically continuous dress creep feed (CDCF) grinding to precise tolerances of 0.0002– 0.0005” (0.005–0.01-mm) with surface finishes of at least 8 Ra. Materials range from the very tough, including A2, M2, S7 tool steels to the odd lots of customer-requested aluminum and cold rolled steel.
Lakes Precision, which started some 25 years ago, cur- rently occupies 25,000 ft2
(2322.5 m2 ) and runs two shifts,
five days a week. CDCF technology is provided by three Mägerle and three Blohm creep-feed grind- ers from United Grinding Technologies (UGT; Miamisburg, OH). Several horizontal CNC machining centers, a couple of belt- driven vertical through-feed grinders, some surface grinding, and EDM machines round out Lakes’ machining capabilities. Lakes Precision’s core business is manufacturing perishable tooling for wire stripping and wire crimping (termination) machines. Its market is everywhere wire stripping or crimping is needed, including automotive, aerospace, “white goods,” electronics, and medical. Creep-feed or profile/form grinding is a process that allows a high rate of stock removal in a single pass. This grinding tech- nique is often applied to high-performance alloys or hardened materials. Each CDCF machine is capable of either single- pass or reciprocating processing, yielding extremely consistent tolerances to 0.0002" (0.005 mm).
rates of speed and grinding pressure for precise stock re- moval. This process yields high production, single-pass flat grinding for, but not exclusive to, stampings, fine blanked parts, or bar stock material removal. Stock removal to 0.100" (2.5 mm) and ±0.0005" (0.01-mm) tolerances are possible for finished parts.
CDCF technology uses a constantly in-feeding rotary diamond dresser that dresses the wheel continuously during the grinding cycle at a pre-programmed infeed rate. The initial CDCF process relied on heavy dressing rates up to 40 mils/per
Mägerle continuous dress creep feed grinders retrofit with Siemens 840 D controls and Blohm creep-feed grinders are used to machine wire stripping/ crimping blades at Lakes Precision.
wheel revolution (0.000040"/0.001 mm) that resulted in high wheel consumption, measured as G ratio (volume of material removed in cubic inch per volume of grinding wheel consump- tion in cubic inch).
You can’t buy a creep-feed machine for $250,000 that’s rigid, reliable, repeatable with highly precise accuracy. Plus, you’ll not get the kind of support you get from a supplier like UGT.
Through-feed grinding is a flat production machining process using a belt-feed system. Parts in hardened or soft state are passed under a vertical spindle wheel at varying
Designed for high stock removal of difficult-to-grind mate- rial, CDCF provides productivity improvements of 20 times that of conventional grinding and EDM processes.
April 2013 |
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