Donner Case

a. Critically analyse the notion capacity by analysing the questions :

I. How much Donner make choices for use of alternative technologies ? Using this logic decide what orders should Donner schedule on the CNC drill and on the CNC router.

The alternate technology to the use of CNC Drill is Manual drill. The company has 7 manual drills, but we can use only one at a time for a given circuit board.

Let us assume we have an order of N circuit boards,

Process Setup Time (min)

Run Time (Min) Total Time (Min)

Manual (using only 1 drill)

15 0.08×500× N=40 N 15 + 40N

CNC Drill 240 0.004×500× N=2 N 240 + 2N

If we are allowed to use only 1 manual drill for all the circuit boards, then we must revert to a CNC Drill if the time taken in it is less,

240 + 2N ≤15 + 40N => 38N ≥ 225i.e. N ≥ 5.92 ~ 6

In case we are allowed to use 7 parallel manual drills, for an order of N circuit boards (Assuming N= 7*k + c)

Process Setup Time (min)

Run Time (Min) Total Time (Min)

Manual (using only 7 parallel drill)*

15 0.08×500×k + 0.08×500 =40k + 40 15 + 40k + 40

CNC Drill 240 0.004×500× N=2 N 240 + 14k + 2c

* Suppose there 51 circuit boards, 49 of them would be processed by 7 drills in parallel, andthe final 2 would be done by 2 drills. Hence the effective time would be

Time to manually drill 7 boards * Time per hole in a board*Total holes per board + Time to manually drill 1 board* Time per hole in a board*Total holes per board

If we switch from this setup to CNC Drill,

15 + 40k + 40 ≥ 240 + 14k + 2c => 26k ≥ 185 + 2c, k>7 (Anything above 56 boards i.e. k=8 we need to do a CNC)

At N = 56 (7*7+7) , Time Manual Drill = 335 , Time CNC = 352At N = 57 (7*8 + 1), Time Manual Drill = 375, Time CNC Drill = 354

Hence, if we need to drill more than 56 circuit boards, we must use the CNC Drill against manual drill.

The Alternate technology to using a CNC Router is a punch press. Suppose we need it do it for N circuit boards, the time required

Process Setup Time (min)

Run Time (Min) Total Time (Min)

Punch Press 50 1× N= N 50+ N

CNC Router 150 0.5× N= 0.5 N 150+ 0.5 N

To schedule on CNC router, total time for CNC router should be less than that of punch press. Thus, 150+ 0.5N ≤ 50+ N 0.5N ≥ 100 => N ≥200

II. What is the standard labour time for an order of 1 board? 8 boards ? 200 boards ?

Assuming we can change the shop floor policy, and orders for even less than 100 boards can also be drilled on the board.

Operation Setup Time Run Time UnitBoards: 1 Panels: 1

Boards: 8 Panels: 1

Boards: 200 Panels: 25

PREPARATION

Artwork Generation 29 0 29 29 29Inspect & Shear 20 0.5 /panel 20.5 20.5 32.5

Punch Tooling Holes 10 0.5 /panel 10.5 10.5 22.5

IMAGE TRANSFER

Drill Holes (Manual or CNC Drill)

1. Manual 15 40 /board 55 335 80152. CNC Drill 240 2 /board 242 256 640

Drill Time : min (1,2) 55 256 640

Metallization 10 0.75 /panel 10.8 10.8 28.8

Dry Film Photoresist1. Panel Prep 5 0.2 /panel 5.2 5.2 10

2. Laminate & Expose 20 2 /panel 22 22 703. Develop 20 0.2 /panel 20.2 20.2 25

Photoresist Time : sum(1,2,3) 47.4 47.4 105

Electroplate 25 8.5 /panel 33.5 33.5 237.5Strip DFPR 5 0.2 /panel 5.2 5.2 10

Etch & Tin Strip 10 0.2 /panel 10.2 10.2 15

FABRICATION

Soldermask 45 1.5 /panel 46.5 46.5 82.5 Solder Dip 30 0.5 /panel 30.5 30.5 42.5Profile (Punch press or CNC Router)

1.Punch Press 50 1 /board 51 58 2502.CNC Router* 150 0.5 /board 150.5 154 250

Profile Time : min(1,2) 51 58 250

Inspect and pack 45 1.5 /board 46.5 57 345

Total Time (minutes) 396.60 615.10 1840.30Total Time (hours) 6.61 10.25 30.67Time/board (mins) 396.60 76.89 9.20

So for the order size of 1 board, we use the manual drill and punch press, whereas for the order size of 8 boards, we use the CNC drill and punch press for the most optimum time. For the order size of 200 boards, we use the CNC drill and we can use either the punch press or CNC router as the time taken for both will be the same.