Answer:
26.7 min
Explanation:
First, we will find the <u>time required to drill each hole</u>:
- N = 300 x 12/0.75
= 1527.7 rev/min
- fr = 1527.7 (0.015) = 22.916 in/min
Formula for <u>distance per hole</u>: 0.5 + A + 1.75
- A = 0.5 (0.75) tan (90-100 / 2) = 0.315 in
- Tm = (0.5 + 0.315 + 1.75) / 22.916 = 0.112 min
Now, we will calculate the <u>time required to draw back the drill form hole</u>:
= 0.112 / 2 = 0.056 min
Time to move between holes = 1.5 / 15 = 0.1 min
For 100 holes, the number of moves between holes = 99
Total time required to drill 100 holes (t):
t = 100 (0.112 + 0.056) + 99 (0.1) = 26.7 min