Yesterday
Results - Impact of Tooling:
- PCD tooling proved best. CVD Diamond coatings successful in some finishing applications
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- Higher Productivity may justify higher tool costs
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- Abrasive wear is the tool failure mechanism.
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- Feed rate has a MUCH greater effect on successful machining then does cutting speed.
Most Research Was Done in the Early 90’s Machining AlSiC MMCs -
Notes:
- It was found that PCD tooling preformed best. Others were tried; HHS, Carbide CVD, CVDD - none of these were able to remove as much material (Vol./time) as the PCD at that time.
- Wear is the failure mechanism. Each test reviewed showed a similar scenario to failure; initial break-in where a “hone” of apx. .001” developed, optimum run characteristics with forces sliding gently up a slope, failure. Note that depending on the type of machining and the test, End of Life (E.O.L.) criteria was used and this was not always catastrophic.
- The conclusions in the tests reviewed, felt that the reason that feed had more of an effect on failure then speed was that at a slower feed and given speed, the edge was encountering the particulate more frequently and therefore chipping more often. At a higher feed with the same speed, a larger chip is produced and fewer Matrix particles need to be broken through.