The Job Shop Game

1
The Job Shop Game

• Developed by
• James R. Holt, Ph.D., PE
• Associate Professor Engineering Management
• Washington State University

2
Objective

• To understand how Drum-Buffer-Rope (DBR)
  scheduling applies to Job Shop environments.

3
Overview

• 36 Orders and 4 Workstations(A-D).
• Calculate flow days.
• Plot the data.
• Analysis the results.

4
Overview cont.

• 3 Scenarios
• 1st Orders are released at the rate of one per
  day in a random order.
• 2nd Using intuition sequence the orders for the
  best performance still release orders at the
  rate of one per shop day.
• 3rd Orders are released into the system based on
  how much work is in the buffer (using the same
  release order as the second scenario).

5
Roles

• Boss(one)
• Scheduler(one)
• Work Center Operator(four)
• Flow Control Monitor(one)

6
THE BOSS

• Controls the rate of play
• Call out shop day , write, and pass
• Keep everyone on track

7
SCHEDULER

• Release or not to release
• Writes the shop day on the order card
• Then passes the order card to the correct station

8
WORK CENTER OPERATOR

• Takes order card from Queue
• Writes
• Passes
• Capacity(FIFO)

9
FLOW CONTROL MONITOR

• Calculate flow days
• (Final Workstation Release Day)
• Total flow days
• Plots

10
Getting Started

• Organize yourselves into groups of seven
• Prepare your workstations
• 36 order cards
• FIFO
• Plots

11
Example Run
Order Card Product 1 Release Day
__1___ Day Operation Complete
A B C D Total Flow Days___ ____
Workstation Setup
2
3
Write
Write
Write
4
Write
Write
Write
Workstation B
5
4
Scheduler
Workstation A
Workstation D
Flow Control Monitor
Workstation C
12
Plot number 1
X
Number of flow days
X
X
X
X
Orders
13
Plot number 2
Number of Orders
X
X
X
Flow Days
14
Scenario 1

• Schedulershuffle the order cards
• Bossget the job shop operating

15
Discussion Topics

• Ability to promise Customer Delivery
• Ability to predict Order Completion
• Whats holding you back?
• Flow Days (Lead Times)
• --Variability--Growth
• Capacity vs. Load
• Inventory in the System

16
Scenario 2

• Take 6 to 8 minutes and develop a strategy for
  getting the order cards through the workstations
  especially B.
• SchedulerRelease the orders at a rate of one per
  shop day.

17
Discussion Topics

• What was the amount (insignificant or lack of)
  improvement when using intuitive scheduling?

18
Scenario 3

• The third scenario is run using the DBR
  scheduling theory, below are the definition of
  the terms for DBR.
• Drum System constraint or critical resource that
  sets the pace of the schedule
• Buffer Extra materials before critical
  operations
• Rope Schedules that tie the release of raw
  materials and customer promise dates to
  production at the drum

19
Scenario 3 cont.

• Use the same order as scenario 2.
• Limit the amount of B order cards that are in
  the system (4 to 6).
• BossAsk for Buffer count at the beginning of
  the shop day
• SchedulerCount fingers that the workstation
  operators show.
• Release or not to Release

20
Discussion Topics

• Compare the results of the third scenario to
  the first two scenarios with the same topics used
  in Scenario 1.

21
Assignment

• Turn in a typed memo answering the questions
  and your discussion at the end of each scenario.
  Write down whether or not the lab helped
  introduce DBR scheduling. The memo should be
  single-spaced and at least one page, but no
  longer then two.