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IMPCO.MACHINE.TOOLS |
Centerless Microfinishing Improves Compressor Reliability When Visteon (Dearborn, Michigan USA) was assigned production of scroll compressors for automotive climate control systems, it turned to IMPCO Machine Tool's Cimtec Centerless Microfinishers (superfinisher). At the heart of every new high rpm scroll-type compressor in a climate control system is an eccentric crankshaft and bushing. Visteon, the only North American source of these parts for Ford Motor Co. (Dearborn, Michigan USA), has eight classes of shaft and bushing assembly size in four micron increments. Scroll compressors are a new product for the Connersville, Iindiana plant. Visteon wanted a high-production process that could economically handle millions of parts. Visteon decided to invest in two Cimtec Model 50 Centerless Microfinishing (Superfinishing) Machines equipped with a patented GBQ microfinishing (superfinishing) process from IMPCO Machine Tools (Lansing, MI). Specifications for the eccentric bushing required improving surface finish to 8uinch Ra from incoming measurements up to 16uinch on the journal; roundness was to improve at least 30%, while maintaining straightness and taper. Stock removal is expected to be less than 0.0002" (0.005mm) on diameter for the bushings. The shaft must have a seal surface, with a no-lead (straight-line) microscrath specification, 0.8-0.32 Ra DIN. The spec allows shafts to rotate without lubricant being pushed or pulled into the compressor body by turning or grinding lines created by previous operations. The GBQ process uses a non-compressive, coated abrasive film backed by nonresilient tooling ensuring full, consistent part/abrasive contact. Film indexes automatically after each cycle, presenting fresh abrasive to each workpiece. In operation, the scroll compressor shafts go into the Cimtec on a small pallet, and are pushed onto rollers that rotate the parts. As the parts turn, abrasive film is pressed onto the diameters at a consistent pressure. A transfer mechanism rotates the parts out of the work area and onto unload automation. Total cycle is 16 sec., including finishing, gauging, washing, and final assembly. Visteon completes two bushings at a time in one machine, and two shafts at a time in the second machine. |
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Worldstar Machines | Worldflex Machines | Microstar Attachments | Cimtec Centerless | What is Microfinishing? | What is GBQ? | What is GBQ-SC? | What's New? | About Us | FAQ | Contact Us | Customer Feedback Surveys | Home Page IMPCO Machine Tools 3417 West St. Joseph Street, Lansing, Michigan USA 48917 Phone: (517)484-9411 Fax: (517)484-0502 Email: Sales @IMPCO.com |