1. Operations Management
Feedback
for control
Transformation
Network of activities
Inputs
Outputs
Raw Materials
Requests for Service
Goods
Services
Flow Units
Resources
Labor & Capital

2. Process Flow Diagrams Activities: Material flows: Inventory / buffers:
Mix
Activities:
Material flows:
Inventory / buffers:
Information:
Work in
Process
Term 2, 2015
Joseph Milner, RSM 1340

3. Cook
Custard
Cool
Freeze
Work in
Process
Finished
Goods
Raw
Material
Pack
Freeze
Cool
Cook
Custard

4. Raw
Material
Cook
Custard
Pack
Cool
Freeze
Work in
Process
Finished
Goods

5. BREAK

6. Flow Unit: Batches are 100 liters ice cream packed
3/4 hr/b
1 hr/b
Raw
Material
Cook
Custard
Pack
Cool
Freeze
Work in
Process
Finished
Goods
24 sec./l
2/3 hr/b
24 s l × 100 l batch × 1min 60s × 1hr 60min. = 2 3 hr/batch

7. Capacity of a single resource:
Cook
Custard
Process Time:
3/4 hour per batch of 100 l-ice cream
Capacity =
4/3 batch/hr

8. Process Time (for each freezer):
Capacity of resources in parallel:
1 b/hr
Freeze (Machine 1)
Freeze (Machine 2)
Process Time (for each freezer):
1 hour/ batch
1 b/hr
Capacity =
1 b/hr + 1b/hr
= 2 batches/hr

9. Capacity of resources in series:
Cook
Custard
Cool
Freeze
Process Time:
3/4 hour/
100 l
Process Time:
3/4 hour/
100 l
Process Time:
1 hour/
100 l
4/3 b/hr
4/3 b/hr
1 b/hr
Capacity =
Minimum(4/3, 4/3, 1)
= 1 batch/hr

10. p = average service or process time per flow unit
m = average service or process rate (flow units per hour)
Observe p = 1/m

11. If service takes 15 minutes or p=1/4 hour, then you can serve m =4 customers per hour.

12. Flow Unit: Batches are 100 liters ice cream packed
3/4 hr/b
1 hr/b
4/3 b/hr
4/3 b/hr
1 b/hr
Raw
Material
Cook
Custard
Pack
Cool
Freeze
Work in
Process
Finished
Goods
2/3 hr/b
3/2 b/hr
4/3 b/hr
4/3 b/hr
1 b/hr

13. 2 b/hr 1 b/hr 4/3 b/h 4/3 b/hr 1 b/hr 3/2 b/hr 4/3 b/hr 4/3 b/hr
Raw
Material
Cook
Custard
Pack
Cool
Freeze
Work in
Process
Finished
Goods
3/2 b/hr
4/3 b/hr
4/3 b/hr
1 b/hr
1 b/hr
Minimum(2 b/hr, 3/2 b/hr)
3/2 b/hr

14. BREAK

15. 3/4 liter-cream 1 liter ice cream 4/3 b/hr 150 l−cream hr 2 b/hr
Cook
Custard
4/3 b/hr
150 l−cream hr
2 b/hr
Raw
Material
Prepare
Cream
3/4 liter-cream
1 liter ice cream
150 l−cream hr
× 1 l−ice cream 3 4 l−cream
= 200 l−ice cream hr
× 1 batch 100 l−ice cream
= 2 batches hr

16. 100 l- 95 l-packed ice cream × 100 l−ice cream batch
= 150 l−ice cream hr
3/2 b/hr
100 l-ice cream /hr
95 l-packed/hr
1 b/hr
Pack
Freeze
Work in
Process
Finished
Goods
142.5 l-packed /hr
150 l-ice cream /hr
3/2 b/hr
100 l-
ice cream
95 l-packed
100 l-ice cream /hr
95 l-packed/hr
1 b/hr
100 l−ice cream hr
150 l−ice cream hr
× 95 l−packed 100 l−ice cream
× 95 l−packed 100 l−ice cream
= l−packed hr
= 95 l−packed hr

17. BREAK

18. m = number of resources available at a workstation
Cook
Custard
Cool
Freeze
2/3 hr/b
3/4 hr/b
1 hr/b
4/3 b/hr
1 b/hr
3/2 b/hr
Work in
Process
Finished
Goods
Raw
Material
Pack
Cook
Custard
Cool
Freeze
Freeze
Cool
Cook
Custard x
2 cookers
2 coolers
2 freezers
1 packer
8/3 b/hr
2 b/hr
3/2 b/hr
m = number of resources available at a workstation
Capacity of a workstation
= # of resources x service rate = m m

19. Fundamental Parameters of a System
rB = Bottleneck and Process Capacity
Tmin = Minimum Flow or System Process Time

20. What is the bottleneck rate? (batches per hour)
Bottleneck = Packing
rB = 3/2 batch per hour

21. What is the system process time? (hours)

22. 3/4 hr/b 1 hr/b 2/3 hr/b Raw Material Cook Custard Pack Cool Freeze
Work in
Process
Finished
Goods
2/3 hr/b

23. What is the system process time? (hours)
TMin = 3/4 + 3/ /3 = hrs = 3:10 hrs

24. Process Utilization and Capacity Utilization
Throughput Rate
Process Capacity
Process Utilization =
(Resource) Throughput Rate
Process Capacity
Utilization of Resource =
Capacity Requested by Demand
Available Capacity
Implied Utilization =

25. Ice cream making process utilization at TH=1.5 batches/hr
1.5/1.5 = 100%
Cooking process utilization =
Cooling process utilization =
Freezing process utilization =
Packing process utilization =
1.5 / (2 x 4/3) = 57%
1.5 / (2 x 1) = 75%
1.5 / (1 x 3/2) = 100%
If the demand is 2 batches per hour,
Implied Utilization of Freezing =
Implied Utilization of Packing =
2 / 2 = 100%
2 / (3/2) = 133%

26. Define a “job” (flow unit) = Batch of 100 liters – ice cream
(3/2) / (8/3)
Cooker
3/4 hr
4/3 b/hr 2
8/3
57%
Cooler
3/4 hr
4/3 b/hr 2
8/3
57%
3/2 b/hr
Freezer
1 hr
1 b/hr 2
75%
Packer
2/3 hr
3/2 b/hr 1
3/2
100%
*assuming system is processing at full capacity

27. BREAK

28. Flow Unit = 1 batch of 50 croissants
RM:
Dough
Mix
Pack
WIP:
Finished
Goods
Bake
Proof
Roll &
Cut
Fill &
Fold
Filling
5 min/b
15min/b
10 min/b
5min/b
20min/b
10min/b
5 min/50
Croissants
15min/50
10 min/50
5min/50
20min/50
10min/50

29. ∞ RM: Dough Mix Pack WIP: Finished Goods Bake Proof Roll & Cut Fill &
Fold
Filling
5 min/b
15min/b
10 min/b
5min/b
20min/b
10min/b ∞

30. ∞ ∞ Define a “job” (flow unit) = 1 batch of 50 croissants 1 1/6 hr
Mix Filling 1
1/6 hr
10 min.
6 b/hr
6 b/hr
100%
Mix and Roll Dough 1
5 + 5 min.
1/6 hr
6 b/hr
6 b/hr
100%
6 b/hr
1/4 hr ∞ ∞
Proof
4 b/hr
Fill and Fold
1/12 hr
12 b/hr 1
12 b/hr
50%
1/3 hr
3 b/hr 2
6 b/hr
100%
Oven
1/6 hr
6 b/hr 1
6 b/hr
100%
Pack
*assuming system is processing at full capacity

31. What is the bottleneck rate? (batches per hour)
What is the system process time? (hours)
Bottleneck = All but Fill and Fold
rB = 6 batches per hour

32. Flow Unit = 1 batch of 50 croissants
RM:
Dough
Mix
Pack
WIP:
Finished
Goods
Bake
Proof
Roll &
Cut
Fill &
Fold
Filling
5 min/b
15min/b
10 min/b
5min/b
20min/b
10min/b

33. What is the bottleneck rate? (batches per hour)
What is the system process time? (hours)
Bottleneck = All but Fill and Fold
rB = 6 batches per hour
TMin = 5 min + 15 min + 5 min + 5 min + 20 min +10 min = 60 min = 1 hr

34. 5 min. / batch 60% 20 min. / batch 40% Average unit
Fill &
Fold
20 min. / batch
40%
Average unit
p = 5 min. x 60% + 20 min. 40%
= 11 min.
= hr.

35. ∞ ∞ Define a “job” (flow unit) = 1 batch of 50 croissants 60/40 mix
Mix Filling
1/6 hr
6 b/hr 1
6 b/hr
90.9%
100%
Mix and Roll Dough
1/6 hr
6 b/hr
90.9%
100%
6 b/hr 1
6 b/hr
5.45 b/hr
1/4 hr ∞ ∞
Proof
4 b/hr
5.45
b/hr
Fill and Fold hr
5.45b/hr 1
50%
100%
1/3 hr 2
90.9%
3 b/hr
6 b/hr
100%
Oven
1/6 hr
6 b/hr 1
6 b/hr
90.9%
100%
Pack
*assuming system is processing at full capacity

36. BREAK