Date post: | 03-Jun-2018 |
Category: |
Documents |
Upload: | shreeraj-pawar |
View: | 227 times |
Download: | 0 times |
of 14
8/12/2019 Hndt Mba s4 Shouldice
1/14
DISCLAIMER: Use of any portion of these materials toaid in the preparation of a case write-up for this, or anyother class; current or future, or sharing any portion ofthese materials with anyone who mustor might somedayhave toprepare a case write-up for this case constitutes a
serious violation of the Olin School Honor Code .
Session 4 HandoutPart 1
1
Cycle Time Management
Session 4
2OMM 5704 Session 4 Handout 1 of 14
8/12/2019 Hndt Mba s4 Shouldice
2/14
CYCLE TIME
C A P A C I T Y
INVENTORY
T HR O U GHP UT
THE OPS QUADRANGLE
3
OMM Chayet
Capacity Makespan, INV, !
Capacity Investment Capacity Constraints Product-Mix Decisions Levers for Increasing Capacity
Capacity and Bottlenecks
4OMM 5704 Session 4 Handout 2 of 14
8/12/2019 Hndt Mba s4 Shouldice
3/14
OMM Chayet
Make Sure not Wasting Bottleneck Capacity Idle during lunch breaks Bottleneck not making parts for nished goods inventory! Quality Control prior to Bottleneck
The Goal
BN QC
defects
pass
BNQC
defects
pass
5
OMM Chayet
Ofoad Must all parts ow through the BN? Sub-Contract?
Heat Treatment Across Town Price? Shadow Prices: (NCC, Merton)
The Goal
6OMM 5704 Session 4 Handout 3 of 14
8/12/2019 Hndt Mba s4 Shouldice
4/14
CYCLE TIME
C A P A C I T Y
INVENTORY
T HR O U GHP UT
THE OPS QUADRANGLE
7
OMM Chayet
Search for Clarity
Drive
Critical Paths Cycle Time
Bottlenecks Capacity
Drivedifferent paths ! critical path cycle time
throughput ! bottleneck capacity
8OMM 5704 Session 4 Handout 4 of 14
8/12/2019 Hndt Mba s4 Shouldice
5/14
OMM Chayet
Of Bottlenecks and Critical Paths
A B
C
D
E
F G
H
I
13 15
6
5
4 9
5
19 16
10 11
5
4
3 7
3
12 11
max = ?
Critical Path ?
9
10OMM 5704 Session 4 Handout 5 of 14
8/12/2019 Hndt Mba s4 Shouldice
6/14
OMM Chayet
Of Bottlenecks and Critical Paths
A B
C
D
E
F G
H
I
13 15
6
5
4 9
5
19 16
10 11
5
4
3 7
3
12 11
Critical Path Length = 53 min
11
OMM Chayet
Are Bottlenecks Always on the Critical Path?
12OMM 5704 Session 4 Handout 6 of 14
8/12/2019 Hndt Mba s4 Shouldice
7/14
Washington University Olin Business School
OMM 5704 Operations Management
Chayet
Bottlenecks and Critical Paths: An Example
1
1 2
W a i
t
1
0
1
2
3
4
5
6
7
8
T 1
T 2
T 3
B
I n B W O u t
1 t
1 t
1 t 2 t
2 t
2 t 3 t
3 t 3 t 4 t
4 t
1 b
2 b
3 b
4 b
1 b
T 1
T 2
T 3
2 b
3 t
1
2
3
4
1
2
3
1 b
1 t
2 b
2 t
3 b
3 t
4 b
4 t
C u t
OMM 5704 Session 4 Handout 7 of 14
8/12/2019 Hndt Mba s4 Shouldice
8/14
OMM Chayet
Are Bottlenecks Always on the Critical Path?
Top 1 Top 2 Top 3
Bottom
1 11
2
Wait
13
OMM Chayet
Are Bottlenecks Always on the Critical Path?
InTop 1Top 2Top 3
BottomWaitOut
0 1 2 3 4 5 6 7 8
1t
1t
1t
1b
1b
2t
2t
2t
2b
2b
3t
3t
3t
3b
3b
4t
4t
4b
1 2 3 4
2 3
=
CT =
1
2 min
I V =
m n
+ 1
2=
3
2
1
14OMM 5704 Session 4 Handout 8 of 14
8/12/2019 Hndt Mba s4 Shouldice
9/14
OMM Chayet
CT: Key Facts
Includes Waiting Times It is an Average
Determined by Critical Path
15
OMM Chayet
Customers Should Only See Value-Add!
Process Value-Add Non-Value-Add
Fire ghting Spraying water Testing the sirenProduct development Designing to meet specs Perfecting a new technology
Retail ordering Ordering hot-selling items Ordering slow-moving itemsHome mortgage approval Processing application Deciding lending policy
Order fulllment Assembly Credit checkingComplaint processing Phoning customer Management study
16OMM 5704 Session 4 Handout 9 of 14
8/12/2019 Hndt Mba s4 Shouldice
10/14
OMM Chayet
Focus promotes rapid learningand smooth ow (variance reduction)
through simplicity and repetition.
Focus
17
OMM Chayet
Riding the Learning Curve
time/cost
quality
Experience
P e r f o r m a n c e
18OMM 5704 Session 4 Handout 10 of 14
8/12/2019 Hndt Mba s4 Shouldice
11/14
DISCLAIMER: Use of any portion of these materials toaid in the preparation of a case write-up for this, or anyother class; current or future, or sharing any portion ofthese materials with anyone who mustor might somedayhave toprepare a case write-up for this case constitutes a
serious violation of the Olin School Honor Code .
Session 4 HandoutPart 2
19
OMM 5704 Session 4 Handout 11 of 14
8/12/2019 Hndt Mba s4 Shouldice
12/14
Washington University Olin Business SchoolOMM 5704 Operations ManagementChayet
Session 41. Assignment: Merton Truck Company Exercise II
Testing Constraint:12
X 101 + 14
X 102 1100
Or equivalently:2 X 101 + X 102 4400
The new decision variable graph:
0 500 1000 1500 2000 2500 30000
500
1000
1500
2000
2500
3000
3 0 0 0 X 1 0 1 + 5 0 0 0 X
1 0 2 = 5 , 0 0 0 , 0 0 0 X
101
X 102
M e t a l S t a m p i n g
E n g i n e As s e m b l y
Constraints Graph
T e s t i n g
The optimal solution is encircled. Using Excel Solver we conrm:
X 101 = 1600
X 102 = 1200
Contribution = $10 .8M .
1OMM 5704 Session 4 Handout 12 of 14
8/12/2019 Hndt Mba s4 Shouldice
13/14
2. Assignment: Shouldice Hospital Limited
Annual net prot
Hospital: $111 1patient day
(4 day)(6850 patient) $2.8M = $241, 400.
Clinic: ($450 + $60 + (0 .2) $75) 1patient (6850 patient) $2M = $1 , 596, 250.
Average number of beds occupied according to Littles Law
INV = CT = 6850/ year50wk/ year
4 day7 day/ wk
= 78.29.
Recall that there are 89 regular and 14 hostel beds for a total of 103, well above 78.29.Although not part of the assignment, notice that if beds were the only limitation,Shouldices capacity would be max = 1034 / 7wk = 180.25/ wk.
Please see the posted spreadsheet
Some available options and their associated costs:
Conguration Schedule Capacity I NV Revenue IncrementSu M T W Th F S (#/wk) (per wk) (per year)
Current 34 37 15 14 37 0 0 78.3 $132,753 CT=4 37 37 15 14 37 0 0 140 80.0 $135,660 $145,350CT=3 37 37 29 37 37 0 0 177 75.9 $151,866 $955,650S CT=4 35 33 21 14 35 33 0 171 97.7 $165,699 $1,647,300
S Su CT=4 26 26 26 25 26 26 25 180 102.9 $174,420 $2,083,35045 bed wing CT=4 37 37 37 37 37 0 0 185 105.7 $179,265 $2,325,600S,No W CT=4 37 37 0 29 37 23 0 163 93.1 $157,947 $1,259,700
2OMM 5704 Session 4 Handout 13 of 14
8/12/2019 Hndt Mba s4 Shouldice
14/14
Washington UniversityOlin Business SchoolOMM 5704 Operations ManagementFall B 2013, Chayet
Session 4: Lessons
1. Critical Path:
We learned that the critical path is the sequence of steps through which all jobs must pass,
having the longest total time, including wait time. If you want to reduce cycle-time, you
must focus on the critical path.
2. Bottlenecks and Critical Paths:
Using a simple example we saw how the critical path doesnt always include the bottleneck.
We used a Gantt chart to illustrate the progress of jobs through the system.
3. Focus Strategy:
By focusing, rm can reduce variability, simplify processes, and increase the rate of learning
through repetition. The effect is to more quickly ride the learning curve of improving Time,
Price, and Quality. We discussed in detail how Shouldice creates value through focus, as
well as other examples.
4. Revenue as a Function of the Operations Quadrangle:
We can use the Operations Quadrangle to understand how a rm makes money. In an INV-
business, such as the hospital side of Shouldice, customers pay more as their cycle-time, i.e.
length of stay, increases. In a -business customers pay for participation, such as the clinic
side of Shouldice where customers pay per operation. Viewed on the whole, Shouldice is
a mixture of both. We saw that because inventory is tightly held, i.e. INV INV max ,
Shouldice can increase revenue by reducing cycle-time to increase , which follows from
Littles Law. Shouldice can also increase INV max by adding a 45-bed wing, or increase
the weekly effective capacity by scheduling operations on Saturday.
5. Scheduling Constraints:
Unlike all other situations we have faced so far, assessing the capacity of Shouldice cannotbe done by looking at each resource pool in isolation. There are constraints that depend
on time, i.e. patients cannot be admitted on Friday or Saturday, which interact with
inventory constraints on the number of beds. We saw how Excel Solver can be used to
obtain a schedule that maximizes weekly throughput, i.e. yields weekly effective capacity.