1. Production Activity Control
“The time comes when plans must be put into action”

2. Production Activity Control
Responsible for executing the:
Master Production Schedule (MPS)
Materials Requirements Plan (MRP)
At the same time:
Make good use of labor, machines and materials
Minimize work-in-process inventory
Maintain customer service

3. Production Activity Control
Release work orders to the shop for manufacturing
Control work orders to complete on time
Control detailed the flow of orders through
manufacturing
Carrying out the plan
Controlling the work as it progresses to completion
Manage day-to-day activity and provide support

4. Priority planning and production activity control
Master
Production
Scheduling
Planning
Material
Requirements
Planning
Input/
Output
Control
Implement
and
Control
Production
Activity
Control
Purchasing
Operation
Sequencing
Figure 6.1
Priority planning and production activity control

5. Planning To meet delivery dates Ensure: Schedule:
The required materials, tooling, personnel and information
Schedule:
Start and completion times for each shop order
Develop load profiles for the work centres`

6. Implementation Gather information needed to make the product
Release orders to the shop floor
MRP authorized
“Dispatching”

7. Control The production order has been released
Is corrective action necessary?
Rank the orders by priority
Establish a dispatch list
Track performance to planned schedule
Replan, reschedule, adjust capacity
Monitor and control WIP, lead times, queues
Report work center effciency, scrap, times

8. PRODUCTION ACTIVITY CONTROL
PLAN
Schedule
Replan
EXECUTE
Work
Authorization
CONTROL
Compare
Decide
Dispatch
Feedback
MANUFACTURING OPERATIONS
Figure 6.2 Production control system

9. Manufacturing Systems
Flow manufacturing
Intermittent manufacturing
Project manufacturing

10. Flow Manufacturing High volume Standard products Repetitive or
Continuous
(production of high volume standard product) = repetitive manufacturing eg. Cars and appliances, if the goods are made in a continuous flow (eg. Gasoline) : continuous manufacturing

11. Flow Manufacturing Routings are fixed
Work centers arranged according to the routing
Dedicated to a limited range of products
specifically designed equipment
Use of mechanical transfer devices
Low WIP and throughput times
Capacity is fixed by the line

12. Flow Manufacturing Production Activity Control Plans the flow of work
Planned schedule of materials to the line
Implementation and control are relatively simple

13. Intermittent Manufacturing
Many variations in:
product design
process requirements
order quantities

14. Intermittent Manufacturing
Flow of work is varied - work flow not balanced
Machinery and workers must be flexible
Usually grouped according to function
Throughput times are generally long
Capacity required depends on product mix

15. Intermittent Manufacturing
Production Activity Control is complex:
number of products made
variety of routings
scheduling problems
PAC is a major activity
Controlled through shop orders for each batch

16. Project Manufacturing
One or a small number of units
Usually in one place
Close coordination between:
Manufacturing, Marketing, Purchasing, Engineering
Examples:
Shipbuilding
House construction

17. Data Requirements Need to know: Organized into databases:
What and how much to produce
When parts are needed
What operations and times are required
Work center capacities
Organized into databases:
Planning or Control

18. Planning Files Item master file Product structure file Routing file
Work center master file

19. Item Master File Part number Part description Manufacturing lead time
Lot size quantity
Quantity on hand
Quantity available
Allocated quantity
already assigned to other work orders
On-order quantities

20. Product Structure File
Bill of material file
A listing of single-level components to make an assembly
Forms a basis for a ‘pick list’

21. Routing File Step-by-step instructions on how to make the product
Operations and their sequence
Operation descriptions (brief)
Equipment tools and accessories
Operation setup times
Operation run times
Lead times for each operation

22. Work Center Master File
Details on each work center
Work center number
Capacity
Shifts, machine hours and labor hours per week
Efficiency
Utilization
Average queue time
Alternative work centers

23. Control Files Shop order master file Shop order detail file
Summarized data on each shop order
Shop order detail file
Current record of each operation

24. Shop Order Master File Shop order number Order quantity
Quantity completed
Quantity scrapped
Quantity of material issued to the order
Due date
Priority
Balance due
Cost information

25. Shop Order Detail File Operation number Setup hours planned and actual
Run hours planned and actual
Quantity complete (at this operation)
Quantity scrapped (at this operation)
Lead time remaining

26. Order Preparation A check for available: Tooling Materials
Capacity - when it is needed

27. Scheduling To meet delivery dates Make the best use of resources
Need information on:
Routing
Capacity
Competing jobs
manufacturing lead times

28. Manufacturing Lead Time
Queue - time spent waiting before operation
Setup - time to prepare the work center
Run - time to make the product
Wait - time spent after the operation
Move - transit time between work centers

29. Manufacturing Lead Time
Queue
Setup
Run
Wait
Need a lift truck here
Move
Queue
Setup
Run
Wait
Move

30. Cycle Time
“The length of time from when material enters a production facility until it exits”
APICS Dictionary 11th Edition
Synonym - throughput time

31. Example Problem

32. Scheduling Techniques
Forward Scheduling
Start when the order is received
May finish early
Used to determine the earliest completion date
Determine promise dates
Builds inventory
Backward Scheduling
Uses MRP logic
Schedule last operation to be complete on the due date
Schedule previous operations back from the last operation
Reduces inventory

33. Forward and Backward Scheduling: Infinite Load
Order Recieved
Due Date 1 2 3 4 5 6 7 8 9
Forward Scheduling
Material
Ordered
3rd
Operation
1st
2nd
Backward Scheduling
Material
Ordered
3rd
Operation
1st
2nd
Figire 6.4 Infinite load profile

34. Infinite Load Profile Capacity Overload Capacity Capacity Underload
Figure 6.5 Infinite load profile

35. Forward and Backward Scheduling: Finite Load
Order Recieved
Due Date 1 2 3 4 5 6 7 8 9
Forward Scheduling
Material
Ordered
1st
Operation
2nd
Operation
3rd
Operation
Backward Scheduling
Material
Ordered
1st
Operation
2nd
Operation
3rd
Operation
Figure 6.6 Forward and Backward scheduling: finite load

36. Finite Load Profile Capacity Smoothed Load
Figure 6.7 Finite load profile

37. Example Problem Backward Scheduling
A company has an order for 50 brand X to be delivered on day 100
Only one machine is available for each operation
The factory works one 8 hour shift 5 days a week
The parts move in one lot of 50 X A B

38. Example Problem Answer
Part A
OP 10
OP 20 X
Assembly
Part B
OP 10 85 90 95
100
Working Days

39. Operation Overlapping
The next operation is allowed to begin before the entire lot is completed
Reduces the manufacturing lead time
Order is divided into at least two transfer lots SU
Lot 1
Lot 2
Operartion A T T
Transfer Time SU
Lot 1
Lot 2
Operation B

40. Operation Overlapping
Costs involved:
Handling costs between work centers
May increase queue and wait for other orders
Idle time if the second batch doesn’t arrive in time

41. Size of the Transfer Batch
SUA = Set up time operation A
SUB = Set up time operation B
RTA = Run time per piece operation A
RTB = Run time per piece operation B
QT = Total order size
T1 = size of the first transfer batch
T1 = QT x RTA - SUB T2 = QT - T1
RTA + RTB

42. Size of the Transfer Batch
If the second operation is slower than the first make the first transfer batch small
i.e. get the slower machine started early
If the second machine is faster than the first make the first transfer batch large
i.e. the second machine will be able to catch up

43. Example Problem Operation A 70 x 10 = 700 30 x 10 = 300 70 x 5 = 35030
730
1,000 (Minutes) 30
70 x 10 = 700
30 x 10 = 300 T
Transfer Time
1,010 50
70 x 5 = 350
30x5 = 150
740
790
1140
1290
Operation B
Stores 1305

44. Operation Splitting Reduces manufacturing lead time
The order is split into at least two lots
Similar machines are run simultaneously
Setup time is low compared to run time
Operators can run more than one machine

45. Operation Splitting Run Run Run Figure 6.9 Operation splitting
One Machine SU
Run
Two Machine Operation Splitting SU
Run
Reduction in
Lead Time SU
Run
Figure 6.9 Operation splitting

46. Load Leveling Load Report
Tells PAC the current and upcoming load on a work center
Based on standard hours of operation for each order

47. Load Report
Figure 6.10 Work centre load report

48. Scheduling Bottlenecks
Some workstations are overloaded and some are underloaded
Bottlenecks
“a facility, function, department, or resource whose capacityis equal to or less than the demand put upon it.”
APICs Dictionary 11th Edition

49. Throughput The total volume of product passing through a facility
Bottlenecks control the throughput
If Work centers feeding bottlenecks produce more than the bottleneck can process, excess WIP inventory is built up. Therefore, work should be scheduled through the bottleneck at the rate it can process the work
Work Centers fed by bottlenecks have their throughput controlled by the bottleneck, and their schedules should be determined by that of bottleneck

50. Example Problem - Bottlenecks
Wagon Wheel Assembly sets (2) per week
Handle Assembly per week
Final Assembly wagons per week
a. What is the capacity of the factory?
b. What limits the throughput of the factory?
c. How many wheel assemblies should be made each week?
d. What is the utilization of the wheel assembly?
e. What happens if utilization is 100%

51. Example Problem - Bottlenecks
a. 450 units per week
b. Throughput is limited by the handle assembly operation
c. 900 wheel assemblies per week
d. Utilization of the wheel assemblies =
900 ÷ 1200 = 75%
e. Excess inventory of wheel assemblies

52. Bottleneck Principles (7)
1. Utilization of a non-bottleneck resource is not determined by its potential, but by another constraint in the system.
2. Utilization of a non-bottleneck 100% of the time does not produce 100% utilization.
3. The capacity of the system depends on the capacity of the bottleneck.
4. Time saved at a non-bottleneck saves the system nothing.
5. Capacity and priority must be considered together.
6. Loads can and should be split.
7. Focus should be on balancing the flow in the shop.

53. Managing Bottlenecks
1. Establish a time buffer before each bottleneck.
2. Control the rate of material feeding the bottleneck.
3. Do everything to provide the bottleneck with capacity.
4. Adjust loads.
5. Change the schedule.
Back schedule before the bottleneck; forward schedule after the bottleneck.

54. Theory of Constraints 1. Identify the constraint Figure 6.11 Process 1
5 per hour
Process 2
7 per hour
Process 3
4 per hour
Process 4
9 per hour
Marketing sells
5 per hour?
Figure 6.11

55. Theory of Constraints continued
2. Exploit the constraint. (idle time?)
3. Subordinate everything to the constraint.
4. Elevate the constraint.
5. Once the constraint is a constraint no-longer, find the new one and repeat the steps.

56. Drum-Buffer-Rope Drum - pace of production set by the constraint
Buffer - inventory established before the constraint
Rope - coordinated release of material

57. Example Problem Work Center 20: Capacity = 40 hours per weekZ
Work Center 20: Capacity = 40 hours per week
Y: Setup = 1 hour, Run Time = .3 hours per piece
Z: Setup = 2 hours, Run Time = .2 hours per piece
Let x = the number of Y’s and Z’s to produce
x x = 40 hours
0.5x = 37 hours
x = (you can produce 74 Y’s and 74 Z’s)

58. Implementation Issuing shop orders to manufacturing
Which have a good chance of being completed on time
Orders which have the:
tooling
material
capacity

59. Shop Order Information
Order number, description
Engineering Drawings
Bills of Material
Route Sheets
Material Issue Tickets
Tool Requisitions
Job Tickets
Move Tickets

60. Review Order Figure 6.12 Order Release Process Check Tooling
and Material
Availability
Okay? No
Resolve
Yes
Check Capacity
Requirements
and Availability
Okay? No
Resolve or
Reschedule
Yes
Release
Order

61. Control
Control the work going into and out of a work center: Input/output control
Set the priority of orders to run at each work center

62. Input / Output Control Input Rate Control Queue (Load, WIP)
Output Rate
Control
Figure 6.13
Input/output control

63. Figure 6.14 Input/output report

64. Cumulative Variance
The difference between the total planned for a given period and the actual total for that period
Cumulative variance
= previous cumulative variance + actual
- planned

65. Cumulative variance week 2 = -4 + 32 -32 = -4
Figure 6.14 Input/output report

66. Example Problem: Input/Output

67. Operations Sequencing
“a technique for short term planning of actual jobs to be run in each work center based on capacities and priorities.”
APICS Dictionary 11th Edition
Priority: The sequence in which jobs should run at a work center

68. Dispatching Selecting and sequencing jobs to be run at a work center
Dispatch list
Plant, department, work center
Part number, shop order number, operation number and description
Standard hours
Priority information
Jobs coming to the work center

69. Dispatching Rules FCFS - First come, first served
EDD - Earliest job due date
ODD - Earliest operation due date
SPT - Shortest processing time
CR - Critical ratio

70. Critical Ratio CR= due date - present date lead time remaining
= actual time remaining
CR<1 Behind
Schedule
CR=1 On Schedule
CR>1 Ahead of
CR<0 Already late

71. Sequencing Rules
Figure 6.16 Application of sequencing rules

72. Production Reporting
Feedback of what is actually happening on the shop floor
Needed for management decisions
on-hand on-order
job status shortages
scrap material shortages

73. Production Activity Control Summary
Converting MRP plans into action
Reporting results
Revising plans
Need:
detailed and current schedules and priorities
Results:
on-time deliveries, well utilized labor, and equipment, minimum inventory levels