Donner Case Operations Management

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)

Manual (using only 1 drill)

15

CNC Drill

240

Run Time (Min) 0.08×500× N=40 N 0.004×500× N=2 N

Total Time (Min) 15 + 40N 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 i.e. N ≥ 5.92 ~ 6

=> 38N ≥ 225

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, and the 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 = 352 At 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

Unit

Boards: 1 Panels: 1

Boards: 8 Panels: 1

Boards: 200 Panels: 25

PREPARATION Artwork Generation Inspect & Shear

29 20

0 0.5 /panel

29 20.5

29 20.5

29 32.5

Punch Tooling Holes

10

0.5 /panel

10.5

10.5

22.5

15 240

40 /board 2 /board

55 242 55

335 256 256

8015 640 640

10

0.75 /panel

10.8

10.8

28.8

5

0.2 /panel

5.2

5.2

10

IMAGE TRANSFER Drill Holes (Manual or CNC Drill) 1. Manual 2. CNC Drill Drill Time : min (1,2) Metallization Dry Film Photoresist 1. Panel Prep

2. Laminate & Expose 3. Develop Photoresist Time : sum(1,2,3)

Electroplate Strip DFPR

Etch & Tin Strip

20

20

2 /panel 0.2 /panel

22 20.2

22 20.2

70 25

47.4

47.4

105

25 5 10

8.5 /panel 0.2 /panel 0.2 /panel

33.5 5.2 10.2

33.5 5.2 10.2

237.5 10 15

45 30

1.5 /panel 0.5 /panel

46.5 30.5

46.5 30.5

82.5 42.5

50 150

1 /board 0.5 /board

51 150.5 51

58 154 58

250 250 250

45

1.5 /board

46.5

57

345

615.10 10.25 76.89

1840.3 0 30.67 9.20

FABRICATION Soldermask

Solder Dip Profile (Punch press or CNC Router) 1.Punch Press 2.CNC Router* Profile Time : min(1,2)

Inspect and pack

Total Time (minutes) Total Time (hours) Time/board (mins)

396.60

6.61 396.60

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.