Tools improve gear turning productivity at Saturn - WIP - advertisement - Brief Article

Automotive Design & Production, July, 2002

Consider these results being achieved in gear turning operations at Saturn's Spring Hill operations:

* 23% greater average throughput on 26 different parts

* 50 to 100% increase in insert life

* 33% reduction in insert types (due to standardization)

* 50% reduction in insert inventory

* 50% reduction in scrap on setup

* $63,000 savings per year.

Reportedly, these gains were realized as Saturn engineers worked with those from cutting tool supplier Sandvik Coromant (Fair Lawn, NJ).

Saturn's powertrain plant uses 16 CNC lathes to turn 28 transmission gear blanks that range in size from 50 to 11.0 mm in diameter. The workpieces are low-carbon steel forgings, 150 to 160 Brinell hardness. "It's a tough metal to machine because it's so soft and gummy," explains Saturn engineering support technician, Craig Fincher. One failure mechanism for the inserts that had been used is the built-up-edge that results from the stringy chips that are generated. Sandvik recommended a grade GC2015 coated cemented carbide for the task; its coating Tesists the built-up-edge.

For example, one manual transmission gear had a cumulative cycle time of 0.402 minutes. Using the new inserts and making adjustments to the feedrate (a wiper geometry helps assure good surface quality) cutting time was reduced to 0.322 minutes. Tool life increased from 350 to 600 pieces per edge. Taking into account the 20% reduction in cycle time and a 71% improvement in tool life, that translates into an additional 298 parts per shift, or 25% greater productivity.

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