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PAC Definitions


By Anonymous - Posted on 15 January 2012

Order Processing
APICS defines order processing as the activity required to administratively process a customers’ order and make it ready for shipment or production.

Order Promising
APICS defines order promising as the process of making a delivery commitment, I.e. answering the question, when can you ship? For make-to-order products, this usually involves a check of uncommitted material and availability of capacity, often as represented by the master schedule available to promise.

Pull System
APICS defines Pull System as a system that In production, produces items only as demanded for use or to replace those taken for use
In material control, withdraws inventory as demanded by using operation. Material is not issued until a signal comes from the user In distribution, replenishes field warehouse inventories where replenishment decisions are made at the field warehouse itself, not at a central warehouse or plant.

Push System
APICS defines Push system as a system that In production, produces items at times required by a given schedule planned in advance
In material control, issues the material according to a given schedule or issues material to a job order at its start time. In distribution, replenishes field warehouse inventories where replenishment decision making is centralized, usually at the manufacturing site or central supply facility.

Planning files
PAC must have a data or information system from which to work. The files contained in the databases are of 2 types: planning and control.
4 planning files are needed: item master file, product structure file, routing file and work center master file.

Item master file
There is one record in it for each part number. The file contains all of the pertinent data related to the part. For PAC, this includes the
following:
- Part number, a unique number assigned to a component;
- Part description;
- Manufacturing lead time;
- Quantity on hand;
- Quantity available;
- Allocated quantity;
- On-order quantities, the balance due on all outstanding orders;
- Lot-size quantity.

Product structure file (bill of material file) It contains a list of single-level components and quantities needed to assemble a parent.

Routing file It contains a record for each part manufactured. For each product, this file contains a step-by-step set of instructions describing how the product is made. It gives details of the following:
- The operations required to make the product and the sequence in which those operation are performed;
- A brief description of each operation;
- Equipment, tools and accessories needed for each operation;
- Setup times;
- Run times;
- Lead times for each operation.

Work center master file It collects all of the relevant data on a work center.For each work center, it gives details on the following:
- Work center number,
- Capacity,
- Number of shifts worked per week,
- Number of machine hours per shift,
- Number of labor hours per shift
- Queue time,
- Alternate work centers, work centers that may be used as alternatives.

Control files
Control in intermittent manufacturing is exercised through shop orders and control files that contain data on these orders. There are generally 2 kinds of files: the shop order master file and the shop order detailed file.

Shop order master file
Each active manufacturing order has a record in it.The purpose is to provide summarized data on each shop order such as the following:
- Shop order number, a unique number identifying the shop order;
- Order quantity;
- Quantity completed;
- Quantity scrapped;
- Quantity of material issued to the order;
- Due date, the date the order is expected to be finished;
- Priority, a value used to rank the order in relation to others;
- Balance due, the quantity not yet completed;
- Cost information.

Shop order detail file
Each shop order has a detail file that contains a record for each operation needed to make the item. Each record contains the following:
- Operation number;
- Setup hours, planned and actual;
- Run hours, planned and actual;
- Quantity reported complete at that operation;
- Quantity reported scrapped at that operation;
- Due date or lead time remaining.

Manufacturing lead time (MLT)
MLT is the time normally required to produce an item in a typical lot quantity.
Typically, MLT consists of 5 elements:

- Queue time, amount of time the job is waiting before operation begins;
- Setup time, time required to prepare the work center for operation;
- Run time, time needed to run the order through the operation;
- Wait time, amount of time the job is before being moved to the next work center;
- Move time, transit time between work centers.


The total MLT
will be the sum of order preparation and release plus the MLTs for each operation. Setup time and run time are straightforward and determining them is the responsibility of the industrial engineering department. Queue, wait and moves times are under the control of manufacturing and PAC.
The largest of the 5 elements is queue time. In an intermittent manufacturing operation, it accounts for 85%-95% of the total lead time. If the number of orders waiting to be worked on (load) is reduced, so is the queue time, the lead time and work-in-process. Increasing capacity also reduces queue. PAC must manage both the input of orders to the production process and the available capacity to control queue
and work-in-process.

Cycle time is the length of time from when material enters a production facility until it exits. A synonym is throughput time.

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