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GATE 2021 ME (ME2) – Question 49

Machining and Machine Tool Operations · Abrasive and non-traditional machining processes · 2 marks · Numerical answer

A surface grinding operation has been performed on a Cast Iron plate having dimensions 300 mm (length) × 10 mm (width) × 50 mm (height). The grinding was performed using an alumina wheel having a wheel diameter of 150 mm and wheel width of 12 mm. The grinding velocity used is 40 m/s, table speed is 5 m/min, depth of cut per pass is 50 μm and the number of grinding passes is 20. The average tangential and average normal force for each pass is found to be 40 N and 60 N respectively. The value of the specific grinding energy under the aforesaid grinding conditions is _____ J/mm³ (round off to one decimal place).

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Correct answer: 38.21 to 38.59

Explanation

Grinding power uses tangential force: P=40×40=1600 W. Material removal rate is work width×depth×table speed, $10(0.05)(5000/60)=41.6667$ mm³/s.

Specific energy=P/MRR=1600/41.6667=**38.4 J/mm³**. Normal force does no cutting work, and number of passes cancels from the energy-to-volume ratio.