Machining Time Calculation

Q. In a shaping process, the number of double strokes per minute is $30$ and the quick return ratio is $0.6$. If the length of the stroke is $250mm$ the average cutting velocity in $mm/min$.

1. $3.0$
2. $4.5$
3. $7.5$
4. $12.0$

Q. A $600mm\times 30mm$ flat surface of a plate is to be finish machined on a shaper. The plate has been fixed with the $600mm$ side along the tool travel direction. If the tool over-travel at each end of the plate is $20mm$, average cutting speed is $8m/min$, feed rate is $0.3mm/stroke$ and the ratio of return time to cutting time of the tool is $1:2$, the time required for machining will be

1. $8min$
2. $12min$
3. $16min$
4. $20min$

Q. If the number of double strokes per minute in a shaper is calculated by ($0.643\times$cutting speed in mm/min)/length of the stroke in m. Then the return speed is faster than the cutting speed by

1. $40$%
2. $60$%
3. $80$%
4. $100$%

Q. The quick return mechanism used in the shaper has rocker arm drive of length $200mm$. If the crank radius is $50mm$ and the offset between crank centre and rocker arm pivot is $20mm$, length of the stroke (in meters) is

1. $0.5$
2. $1.0$
3. $1.5$
4. $2.0$