1. Operations Management Short-Term Scheduling Chapter 15
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

2. Learning Objectives
When you complete this chapter, you should be able to :
Identify or Define:
Gantt charts
Assignment method
Sequencing rules
Johnson’s rules
Bottlenecks
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

3. Learning Objectives - continued
When you complete this chapter, you should be able to :
Describe or Explain:
Scheduling
Sequencing
Shop loading
Theory of constraints
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

4. Strategic Implications of Short-Term Scheduling
By scheduling effectively, companies use assets more effectively and create greater capacity per dollar invested, which, in turn, lowers cost
This added capacity and related flexibility provides faster delivery and therefore better customer service
Good scheduling is a competitive advantage which contributes to dependable delivery
You might stress to students that scheduling is what the end-customer actually sees.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

5. Short-Term Scheduling
Deals with timing of operations
Short run focus: Hourly, daily, weekly
Types
Today
Due Date B E
Forward Scheduling
Backward Scheduling
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

6. Short-Term Scheduling Examples
© T/Maker Co.
Hospital
Outpatient treatments
Operating rooms
University
Instructors
Classrooms
Factory
Production
Purchases
Students should be asked to provide additional examples. They should also be asked to identify any “unusual circumstances” which might pertain to their examples.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

7. Scheduling Decisions Organization Managers Must Schedule
Operating room use
Patient admission
Nursing, security, maintenance staffs
Outpatient treatments
Classrooms and audiovisual equipment
Student and instructor schedules
Graduate and undergraduate courses
Production of goods
Purchase of materials
Workers
Mount Sinai Hospital
Indiana University
Lockheed-Martin Factory
Here you might ask students to identify the scheduling decisions for a business with which they are familiar. McDonalds, grocery store, and doctor’s office are useful examples.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

8. Scheduling Decisions Organization Managers Must Schedule
Chefs, waiters,bartenders
Delivery of fresh foods
Entertainers
Opening of dining areas
Maintenance of aircraft
Departure timetables
Flight crews, catering, gate, and ticketing personnel
Hard Rock Cafe
Delta Airlines
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

9. Capacity Planning, Aggregate Scheduling, Master Schedule, and Short-Term Scheduling
1. Facility size
2. Equipment procurement
Long-term
Aggregate Scheduling
1. Facility utilization
2. Personnel needs
3. Subcontracting
Intermediate-term
Master Schedule
1. MRP
2. Disaggregation of master plan
Intermediate-term
Students should be asked to identify three decisions at each level.
Short-term Scheduling
1. Work center loading
2. Job sequencing
Short-term
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

10. Forward and Backward Scheduling
Forward scheduling: begins the schedule as soon as the requirements are known
jobs performed to customer order
schedule can be accomplished even if due date is missed
often causes buildup of WIP
Backward scheduling: begins with the due date of the final operation; schedules jobs in reverse order
used in many manufacturing environments, catering, scheduling surgery
Students should be asked to consider how, using either process, they would modify the schedule when (a) an order is cancelled, (b) a priority, rush order is accepted, or (c) a delay is encountered.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

11. The Goals of Short-Term Scheduling
Minimize completion time
Maximize utilization (make effective use of personnel and equipment)
Minimize WIP inventory (keep inventory levels low)
Minimize customer wait time
While we would like to minimize customer wait time, an alternate goal might be to make customer wait time consistent - we could always ask them to come later.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

12. Choosing a Scheduling Method
Qualitative factors
Number and variety of jobs
Complexity of jobs
Nature of operations
Quantitative criteria
Average completion time
Utilization (% of time facility is used)
WIP inventory (average # jobs in system)
Customer waiting time (average lateness)
Ask students to identify at least one example of a scheduling based on qualitative factors, and one one quantitative factors.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

13. Process-Focused Work Centers
High variety, low volume systems
Products made to order
Products need different materials and processing
Complex production planning and control
Production planning aspects
Shop loading
Job sequencing
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

14. Types of Planning Files
Item master file - contains information about each component the firm produces or purchases
Routing file - indicates each component’s flow through the shop
Work-center master file - contains information about the work center such as capacity and efficiency
It is helpful to discuss the purpose of each of the planning files. What is the data used for?
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

15. Process-Focused Planning System
Aggregate
Forecast &
Resource
Production
Firm Orders
Availability
Planning
Material
Master
Requirements
Production
Planning
Scheduling
No, modify CRP, MRP, or MPS
It is helpful to actually walk the students through the steps illustrated in this slide.
Capacity
Shop
Requirements
Realistic?
Floor
Yes
Planning
Schedules
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

16. Input-Output Control Week Ending 6/6 6/13 6/20 6/27 7/4 7/11
Planned input
280
Actual input
270
250
285
Cumulative Deviation
-10
-40
-35
Planned Output
320
Actual Output
-50
-100
-150
-200
Cumulative Change in Backlog
-20
-+5
Explanation: 270 input, 270 output, implies 0 change
Explanation: 250 input, 270 output implies –20 change (20 standard hours less in the work center)
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

17. Gantt Load Chart Shows relative workload in facility Disadvantages
Does not account for unexpected events
Must be updated regularly
Work Center M T W Th F
Metal Works
Job 349
Job 350
Mechanical
Job D
Job G
Electronics
Job B
Job H
Painting
Job C
Job E
Job I
A characteristic of most of our project management and schedule management tools is that they require management attention for updating on a regular basis.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

18. Gantt Load Chart for Week of March 6
Shows relative workload in facility
Disadvantages
Does not account for unexpected events
Must be updated regularly
Day
Work Center
Monday
Tuesday
Wednesday
Thursday
Friday
Metalworks
Job 349
Job 350
Mechanical
Job 406
Electronics
Job 408
Painting
Job 295
Center not available (for example, maintenance time, repairs, shortages)
Processing
Unscheduled
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

19. Gantt Scheduling Chart
Start of an activity
Scheduled activity time allowed
Point in time when chart is reviewed S T W F
Day
Job
Job A
Job B
Job C
Maintenance
Now
End of an activity
Actual work progress
Non-production time
Day 1
Day 2
Day 3
Day 4
Day 5
Day 6
Day 7
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

20. Assignment Method Assigns tasks or jobs to resources
Type of linear programming model
Objective
Minimize total cost, time etc.
Constraints
1 job per resource (e.g., machine)
1 resource (e.g., machine) per job
Students should be asked to consider what other assumptions must be made when using the assignment model for job scheduling.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

21. Assignment Method – Type Setter Example
Job A B C
R-34
$11
$14
$ 6
S-66
$ 8
$10
T-50 $9
$12 $7
Initial set-up
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

22. Empat Langkah Assignment
Kurangi setiap angka pada satu baris dengan angka yg terkecil, dan demikian juga untuk kolom. Hasil yg diperoleh adalah opportunity cost.
Buat garis lurus vertikal dan horisontal untuk menutup angka nol dalam tabel. Jika jumlah garis lurus tsb telah sama dengan jumlah baris/kolom, maka penugasan telah optimal (lanjutkan ke langkah 4). Namun, jika belum (lanjutkan ke langkah 3).
Kurangkan dg angka paling kecil untuk angka yg tidak tertutup garis sampai diperoleh nol. Kemudian kembali ke langkah 2 untuk memperoleh penugasan optimal. Tambahkan dengan angka yang sama pada angka pada perpotongan garis.
Penugasan optimal akan berada pada lokasi nol.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

23. Step 1a & 1b Step 1a Step 1b Typesetter Job A B C R-34 5 8 S-66 2 3
S-66 2 3
T-50
Typesetter
Job A B C
R-34 5 6
S-66 3
T-50 2
Step 1a
Step 1b
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

24. Step 2 Smallest uncovered number Typesetter Job A B C R-34 5 6 S-66 3
S-66 3
T-50 2
Smallest uncovered number
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

25. Step 3 Make assignments Typesetter Job A B C R-34 3 4 S-66 5 T-50 1
S-66 5
T-50 1
Make assignments
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

26. Sequencing Challenge Order release Job Packet Job XYZ
Which job do I run next?
Dispatch List
Order Part Due Qty
XYZ
ABC
Production Control
Production
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

27. Sequencing Specifies order jobs will be worked Sequencing rules
First come, first served (FCFS)
Shortest processing time (SPT)
Earliest due date (EDD)
Longest processing time (LPT)
Critical ratio (CR)
Johnson’s rule
The next seven slides provide additional discussion of these rules.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

28. Priority Rules for Dispatching Jobs
First come, first served
The first job to arrive at a work center is processed first
Earliest due date
The job with the earliest due date is processed first
Shortest processing time
The job with the shortest processing time is processed first
Longest processing time
The job with the longest processing time is processed first
Critical ratio
The ratio of time remaining to required work time remaining is calculated, and jobs are scheduled in order of increasing ratio.
FCFS
EDD
SPT
LPT CR
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

29. First Come, First Served Rule
Process first job to arrive at a work center first
Average performance on most scheduling criteria
Appears ‘fair’ & reasonable to customers
Important for service organizations
Example: Restaurants
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

30. Shortest Processing Time Rule
Process job with shortest processing time first.
Usually best at minimizing job flow and minimizing the number of jobs in the system
Major disadvantage is that long jobs may be continuously pushed back in the queue.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

31. Longest Processing Time Rule
Process job with longest processing time first.
Usually the least effective method of sequencing.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

32. Earliest Due Date Rule Process job with earliest due date first
Widely used by many companies
If due dates important
If MRP used
Due dates updated by each MRP run
Performs poorly on many scheduling criteria
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

33. Critical Ratio (CR) Ratio of time remaining to work time remaining=
Work days
remaining
Due date -
Today'
s date =
Work (lead
) time remaining
Process job with smallest CR first
Performs well on average lateness
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

34. Advantages of the Critical Ratio Scheduling Rule
Use of the critical ratio can help to:
determine the status of a specific job
establish a relative priority among jobs on a common basis
relate both stock and make-to-order jobs on a common basis
adjust priorities and revise schedules automatically for changes in both demand and job progress
dynamically track job progress and location
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

35. Criteria to Evaluate Priority Rules
You might point out (even though you have probably noted it before) that ratings or rankings of the different scheduling rules will differ depending upon the criteria used.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

36. Job Sequencing Example
Job Work
Processing time in days
Job Due Date (day) A 6 8 B 2 C 18 D 3 15 E 9 23
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

37. FCFS Parameter Value Average completion time 15.4 days Utilization
36.4%
Average number of jobs in the system
2.75 jobs
Average job lateness
2.2 days
Sequence A B C D E
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

38. SPT Parameter Value Average completion time 13 days Utilization 43.1%
Average number of jobs in the system
2.32 jobs
Average job lateness
1.8 days
Sequence B D A C E
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

39. EDD Parameter Value Average completion time 13.6 days Utilization
41.2%
Average number of jobs in the system
2.43 jobs
Average job lateness
1.2 days
Sequence B A D C E
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

40. LPT Parameter Value Average completion time 20.6 days Utilization
27.2%
Average number of jobs in the system
3.68 jobs
Average job lateness
9.6 days
Sequence E C A D B
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

41. Summary Rule Average Completion Time (days) Utilization (%)
Average Number of Jobs in the System
Average Lateness (Days)
FCFS
15.4
36.4
2.75
2.2
SPT
13.0
43.1
2.32
1.8
EDD
13.6
41.2
2.43
1.2
LPT
20.6
27.2
3.68
9.6
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

42. Processing time in days
Critical Ratio (CR)
Job
Job Work
Processing time in days
Job Due Date (day)
Critical Ratio A 6 8
0.75 B 2
0.33 C 18
0.44 D 3 15
0.20 E 9 23
0.39
Sequence A C E B D
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

43. Johnson’s Rule
Used to sequence N jobs through 2 machines in the same order
© 1995 Corel Corp.
Saw
Drill
Job A
Job B
Job C
Jobs (N = 3)
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

44. Johnson's Rule - Scheduling N Jobs on Two Machines
All jobs are to be listed, and the time each requires on a machine shown.
Select the job with the shortest activity time. If the shortest time lies with the first machine, the job is scheduled first; if with the second machine, the job is scheduled last.
Once a job is scheduled, eliminate it.
Apply steps 2-3 to the remaining jobs, working toward the center of the sequence.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

45. Johnson’s Rule Steps 2 1 List jobs & activity times Select job with
shortest time
Machine?
Schedule
FIRST
LAST
Eliminate job
from list
Jobs left?
Break
arbitrarily
Ties?
Yes 1 2
Stop No
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

46. Johnson’s Rule - Example
Job
Work Center 1
(Drill Press)
Work Center 2
(Lathe) A 5 2 B 3 6 C 8 4 D 10 7 E 12
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

47. Johnson’s Rule - Example
Step 1 A
Step 2 B A
Step 3 B C A
Step 4 B D C A
Step 5 B E D C A
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

48. Graphical Depiction of Job Flow
Work center 1
Work center 2
Time => B E D C A B E D C A
= Idle
= Job completed
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

49. Limitations of Rule-Based Dispatching Systems
Scheduling is dynamic; therefore, rules need to be revised to adjust to changes in process, equipment, product mix, etc.
Rules do not look upstream or downstream; idle resources and bottleneck resources in other departments may not be recognized
Rules do not look beyond due dates
You might point out to students that this is another case of models which are insufficiently robust to handle all factors.
Ask students to consider how these limitations might be overcome. (Finite scheduling?) What is the role of information technology?
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

50. Finite Scheduling System
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

51. Theory of Constraints
Deals with factors limiting company’s ability to achieve goals
Types of constraints
Physical
Example: Machines, raw materials
Non-physical
Example: Morale, training
Limits throughput in operations
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

52. Theory of Constraints A Five Step Process
Identify the constraints
Develop a plan for overcoming the identified constraints
Focus resources on accomplishing the constraints identified in step 2
Reduce the effects of the constraints by off-loading work or by expanding capability
Once one set of constraints is overcome, return to the first step and identify new constraints
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

53. Bottleneck Work Centers
Bottleneck work centers have less capacity than prior or following work centers
They limit production output
© 1995 Corel Corp.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

54. Techniques for Dealing With Bottlenecks
Increase the capacity of the constraint
Ensure well-trained and cross-trained employees are available to operate and maintain the work center causing the constraint
Develop alternate routings, processing procedures, or subcontractors
Move inspections and tests to a position just before the constraint
Schedule throughput to match the capacity of the bottleneck
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

55. The 10 Commandments for Correct Scheduling
Utilization of a non-bottleneck resource is determined not by its own capacity but by some other constraint in the system
Activating a resource is not synonymous with utilizing a resource
An hour lost at a bottleneck is an hour lost of the whole system
An hour saved at a non-bottleneck is a mirage
The transfer batch may not, and many times should not, be equal to the process batch
Discussion should include not only a definition of the commandment but an explanation of how it impacts the production system.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

56. The 10 Commandments for Correct Scheduling
The amount processed should be verifiable and not fixed
Capacity and priority need to be considered simultaneously, not sequentially
Damage from unforeseen problems can be isolated and minimized
Plant capacity should not be balanced
The sum of the local optimums is not equal to the global optimum
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

57. Repetitive Manufacturing - Advantages of Level Material Use
Lower inventory levels, releasing capital for other uses
Faster product throughput
Improved component quality and hence improved product quality
Reduced floor space requirements
Improved communication among employees because they are closer together
Smoother production process because large lots have not “hidden” the problems
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

58. Scheduling for Services
Appointment systems - doctor’s office
Reservations systems - restaurant, car rental
First come, first served - deli
Most critical first - hospital trauma room
Students should be asked to consider what special problems arise in scheduling services.
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

59. Cyclical Scheduling
Plan a schedule equal in weeks to the number of people being scheduled
Determine how many of each of the least desirable off-shifts must be covered each week
Begin the schedule for one worker by scheduling the days off during the planning cycle (at a rate of 2 days per week on average)
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J

60. Cyclical Scheduling - Continued
Assign off-shifts for the first worker
Repeat this pattern for each other worker, but offset by one week from the previous
Allow each worker to pick his/her “slot” or “line” in order of seniority
Mandate that any changes from the chosen schedule are strictly between the personnel wanting to switch
Transparency Masters to accompany Heizer/Render – Principles of Operations Management, 5e, and Operations Management, 7e
© 2004 by Prentice Hall, Inc., Upper Saddle River, N.J