Donner Company Case Solution

1. The process flow diagram of the production system at Donner.
Preparation Stage

Imagine Transfer

Fabrication

2. What size orders would you schedule on the CNC drill? On the CNC router?
Time taken to process the orders depends on the selected drilling method either
a) Manual drilling or CNC OR b) Using CNC Drill
Assumption 1: Manual Drilling is not done on all the available Manual Drill Presses in parallel.
Calculating time taken for Manual drilling and CNC Drilling:
= Setup Time + Run Time (Per Hole) * No. of Holes drilled on each circuit board * No. of boards
Time taken for Manual drilling =15 + 0.08*500*x where x= number of circuit boards
Time taken for CNC drilling = 240 + 0.004*500*x where x= number of circuit boards
To figure out whether CNC drill to be used,
15 + 0.08*500*x ≥ 240 + 0.004*500*x
Hence x ≥ 5.92. This indicates that whenever 6 or more boards are needed to be drilled, manual drilling will take more time than CNC Drilling
Assumption 2: Manual Drilling is done on all the available Manual Drill Presses in parallel. Total no. of available manual drill presses = 7 (1 Panel per Manual Drill Press)
Total no. of Circuit Boards on Each 12”X18” Panel = 8
Hence total No. of Circuit Boards can be operated in parallel = 7*8=56 Circuit Boards
Time taken for Manual drilling on 1 Drill Press = Time taken for Manual drilling on All Drill Press = 15 + 0.08*500*8 =335 min.
Time taken for CNC drilling for 56 Circuit Boards = 240 + 0.004*500*56=352 min
335 Mins < 352 Mins, so let’s try adding one more Unit of Board and calculate time taken
Time for Manual drilling = Existing time for 56 Boards + Time taken for 1 new Board = 335 + 0.08*500*1= 375 min for 57 Boards
Time taken with CNC drilling for 57 Circuit Boards = 240+ 57*500*0.004=354 min.
Hence when total no. of Boards exceeds 56, the time taken for manual drilling is more than that of CNC Drilling. Therefore, up to an order size of 56 circuit boards,