Project ForgeManufacturing Engineering
Machining Processes
GATE 2008
Hard
For the same CNC feed drive (BLU=5 microns via gear ratio U=1/4 and pulse frequency f=10,000 pulses/min), a customer wants to change the BLU to 10 microns WITHOUT changing the table speed. This can be accomplished by
- changing U to 1/2 and reducing f to f/2
- Bchanging U to 1/8 and increasing f to 2f
- Cchanging U to 1/2 and keeping f unchanged
- Dkeeping U unchanged and increasing f to 2f
Explanation
BLU∝U, and table speed=BLU×f. To double BLU (5→10 microns), U must double (1/4→1/2). To keep table speed constant despite BLU doubling, f must simultaneously be halved (f→f/2).
Source: GATE ME 2008 (2008)
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