Answer:
a) metal removal rate is 1915.37 mm³/min
b) the time required to etch to the specified depth is 500 min or 8.333 hrs
Explanation:
Given the data in the question;
starting thickness of one work part of interest = 20 mm
depth of series of rectangular-shaped pockets = 12 mm
dimension of pocket = 200 mm by 400 mm
radius of corners of each rectangle = 15 mm
penetration rate = 0.024 mm/minute
etch factor = 1.75
a)
To get the metal removal rate MRR;
The initial area will be smaller compare to the given dimensions of 200mm by 400mm and the metal removal rate would increase during the cut as area is increased. so'
A = 200 × 400 - ( 30 × 30 - ( π × 15² ) )
= 80000 - ( 900 - 707 )
= 80000 - 193
A = 79807 mm²
Hence, metal removal rate MRR = penetration rate × A
MRR = 0.024 mm/minute × 79807 mm²
MRR = 1915.37 mm³/min
Therefore, metal removal rate is 1915.37 mm³/min
b) To get the time required to etch to the specified depth;
Time to machine ( etch ) = depth of series of rectangular-shaped pockets / penetration rate
we substitute
Time to machine ( etch ) = 12 mm / 0.024 mm/minute
Time to machine ( etch ) = 500 min or 8.333 hrs
Therefore, the time required to etch to the specified depth is 500 min or 8.333 hrs
