Flexcrankfinish

IMPCO.MACHINE.TOOLS

Flexible Crankshaft Finishing

Tooling and Production Magazine

A major diesel engine parts manufacturing plant in Indiana handles some very large jobs. It products core commodities for heavy diesel engines - crankshafts, connecting rods, and cylinder heads and blocks. And when the company plans a capital purchase, it carefully qualifies the need for the equipment.

The plant was confronted with the need to add flexibility and capacity to its production of V-8, V-12, V-16, and V-20 diesel crankshafts used in engines for vehicles and stationary power applications. These enormous parts weigh between 700 lb (318 kg) and 2,800 lb (1273 kg) yet each crankshaft pin and bearing journal surface finish must be microfinished to just 0.125 Ra with a process capability of 1.66 Cpk.

Plant management had decided that its existing microfinishers would not provide the flexibility and ease of changeover it required for future production and decided that IMPCO Machine Tools, Lansing, Michigan USA, provided the optimum solution in its Model 1240HD CNC microfinishing system.

According to IMPCO, the Model 1240HD CNC microfinisher was designed just for large shaft-type parts can process various combinations of parts up to 3,500 mm in length and bearing diameters up to 200 mm.

Independent microfinishing arms allow either a single bearing journal or a combination of journals to be microfinished. The workpiece is shuttled to present a journal to a microfinishing arm, the arms close on the specified journal, and the part rotates and oscillates for a predetermined cycle. Approximately 0.002 to 0.005 mm of stock is removed from diameters during microfinishing. Crankshafts come to the machine ground.

The microfinishing machine is designed to semi-finish and finish main bearing journals and pin journals at a a production rate of about 3 parts per hour for the V16 crankshaft. On the V16 crankshaft, microfinishing arms open, close, and are indexed 33 times to complete the part.

A manual changeover, requiring less than 50 minutes to replace the microfinishing tooling or "shoes" and the microfinishing film, allows the plant to process a family of crankshafts, including a split-pin V-8. Part programs, stored in the CNC, are operator selectable. The machine may be manually or gantry-loaded.

The new IMPCO replaced an existing machine. According to a manufacturing engineer on the project, the IMPCO 1240HD can handle longer part lengths and offers greater flexibility and the potential for significant process quality improvements compared to the previous machine.

The Model 1240HD also helps the plant capacity. "We have future products to come online and the IMPCO microfinisher will be able to accommodate that increase in our plant's production," the engineer points out. "One of them is a new commodity and one is an existing part currently finished to our specifications. We can now do that part in-house, saving time and cost and improving our ability to respond to our customer's needs."

The flexible microfinishing capability now at the diesel components plant represents a successful strategy for controlling part quality as well as cost, and for meeting the need to produce variable volumes within a family of critical components. "It's the type of capability manufacturers of any part must have to be competitive today," says Norm Judge, IMPCO vice president.

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IMPCO Machine Tools

3417 West St. Joseph Street, Lansing, Michigan USA 48917

Phone: (517)484-9411 Fax: (517)484-0502

Email: Sales @IMPCO.com