ITEC 477 Chapter 6

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Production Activity Control (PAC)
Responsible for executing the master production schedule and the material requirements plan (MRP)
The MRP authorizes PAC to _____:
1) Release work orders to manufacturing
2) Control work orders & make sure they are completed on time
3) Responsible for flow of orders thru manufacturing
Flow of work must be planned to meet delivery dates, meaning PAC must:
1) ensure materials, labor, tools, and information are available
2) schedule start and completion dates for each shop order
Once plans are made, PAC puts them into action by advising the shop floor on what must be done, usually by issuing a ______:
Shop order
Control
Once planning and shop orders are released, the process must be monitored to learn what is actually happening
PAC's are organized into:
Flow manufacturing
Intermittent manufacturing
Project manufacturing
Flow manufacturing:
Concerned with production of high-volume standard products

Repetitive manufacturing and
Continuous manufacturing

PAC focuses on flow of work
• Repetitive manufacturing
If units are discrete, I.e. appliances
• Continuous manufacturing
Continuous flow goods, I.e. gasoline
Intermittent manufacturing
Many variations in product design, process requirements, & order quantities
Project manufacturing
Involves creation of one unit, ex. shipbuilding. Design of product is carried out as project develops
Data requirements
PAC must have data or an information system from which to work. This data is organized into databases. The files within the databases are planning files and control files
Control files: two basic kinds
Shop order master file
shop order detail file
• Shop order master file:
Contains each active manufacturing order record. Provides summarized data on each shop order

Ex: order number, quantity, due date, priority, cost, quantity completed, quantity scrapped
• shop order detail file:
Record for each operation needed to make item and contains: operation number, set up hours, run hours, quantity reported complete, quantity reported scraps, and due date or lead time
Order Prep.
PAC is responsible for planning and preparing its order release to the shop floor

Review order for availability. If not available, order should not be released
Scheduling
Objective is to meet delivery dates & make best use of manufacturing resources
What do reliable schedules require?
Information on lead times, available capacity, & competing jobs
Time required to produce an item consists of what 5 elements?
Queue time
Setup time
Run time
Wait time
Move time
- Queue time
waiting time before operation begins
- Setup time
prepping the work center for operation
- Run time
run the operation
- Wait time
time at this work center before it moves to the next work center
- Move time
transit time between work centers
Forward scheduling
Assumes scheduling & material start when order is received

Used to calculate how long to complete task
Backward scheduling
Last operation is scheduled 1st

Used to determine when an order must be started
Infinite loading
Work stations are assumed to have capacity available when required

Assumes infinite capacity will be available
Finite loading
Assumes a defined limit to available capacity at any workstation
Operation overlapping
Next operation begins before the entire lot is completed on the previous operation, reducing total manufacturing lead times
Operation splitting
Order is split into two or more lots & run on two or more machines simultaneously
When is Operation Splitting practical?
Setup time is low compared to run time

Suitable work center is idle

Possible for operator to run more than one machine at a time
Bottleneck
when required capacity is greater than available capacity
Throughput
the total volume of production passing through a facility
What is the result of bottlenecks?
Excess WIP inventory is built up
Bottleneck principles
Utilization of a bottleneck resource is not determined by its potential but by another constraint in the system

Using a non-bottleneck 100% of the time does not produce 100% utilization
Bottleneck Principles (Continued)
Capacity of the system depends on capacity of the bottleneck

Time saved at a bottleneck saves the system nothing

Loads can & should be split
Theory of constraints
Every operation producing a product or service is a series of linked processes. There is always one process that limits or constrains the thruput from the entire operation
Steps to managing constraints by improving the process
Identify the constraint

Exploit the constraint

Subordinate everything to the constraint

Elevate the constraint

After eliminating the
constraint, find the new one & repeat steps
Implementation
Arrived at by issuing a shop order to manufacturing, authorizing them to proceed with making the items
Control
to control progress, performance has to be measured & compared to what is planned
The objectives of PAC are to meet _____ _____ & make best use of _____ _____.
delivery dates

company resources
Dispatching
The function of selecting & sequencing available jobs to be run at individual work centers
Dispatching rules
First come, first served
Earliest job due date
Earliest operation due date
Shortest process time
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