Donner Case

Order Size for drilling: * The Manual press needs 15 min for set up, in addition to 0.08 min for every hole. Knowing that the typical circuit board has 500 drilled holes, then run time will be 0.08*500 = 40 min / board. Therefore, time taken to drill N boards manually will be equal to : 15 + 40(N) * On the other hand the CNC drill needs 240 min for set up, in addition to 0.004 min for every hole. So run time will be 0.004*500 = 2 min / board. Then the time taken to drill N boards by CNC drill will be equivalent to : 240 + 2(N) * It is then logic to conclude that we will use CNC drill only in order sizes that will provide timing benefit over manual press. i.e. when 240 + 2N < 15 + 40N which means N 6 * However the shop floor policy dictates that only orders for more than 100 boards be drilled by CNC drill !!!!! Surely this must be changed * This means that they used the CNC drill in only 12 orders of the 60 orders received in September, while actually they should have used it in 35 orders ( all orders 6) !!
Order Size for Profiling: * Set up time for Punch press is 50 min, while run time is 1 min / board. So Time taken to profile N orders will be 50 + N * While set up time for CNC routers reaches 150 min, in addition to 0.5 min / board run time. So the time needed to complete profiling of N boards equals 150 + 0.5(N) * Thus CNC reuters will produce time benefit if used only in orders more than 200 boards
Capacity of Dry Film Photo Resist area: * Assuming order size equals 8 boards
Then the panel preparation will take 5 + 0.2 = 5.2 min
Lamination & Exposure will take 20 + 2 = 22 min
Development will take 20 + 0.2 = 20.2 min * This means that Lamination and exposure are the bottle neck of the process, and the cycle time for this step will be 22 min / panel. Which means that the capacity will be 2.7 panels / hour * If we increased order size to 2 panels (16 boards)
Panel preparation will take 5 + 0.4 =