This chapter contains the following topics:
Section 12.1, "Understanding Process Manufacturing Planning"
Section 12.2, "Understanding Repetitive Manufacturing Planning"
Section 12.3, "Generating a Master Planning Schedule for Batch Bills"
Section 12.4, "Generating a Master Planning Schedule for Processes"
Section 12.5, "Generating a Master Planning Schedule for Repetitive Items"
Process manufacturing results in products such as liquids, fibers, powders, and gases. Pharmaceuticals, foodstuffs, and beverages are typical examples of process products. Products such as these are usually manufactured by a two-step process:
Mixing or blending
Filling or packaging
These kinds of products might involve intermediate steps, such as curing, baking, or preparation.
Process manufacturing uses ingredients and bills of material. Ingredients can be either consumed or produced during the manufacturing process. In a process bill of material, the quantity of a component can vary, according to its grade or potency.
Unique features of process manufacturing are:
Pacing co-products.
Planned co-products (by-products are unplanned).
Additional processing options in MPS/MRP.
Process manufacturing produces co-products and by-products. A co-product is a saleable end item that results from a process. A by-product is a material of value that is produced incidental to or as a residual of the process.
The different types of process manufacturing are:
Batch
Continuous
In batch processing, you usually produce a product in a standard run or lot size that is determined by vessel size, line rates, or standard run length. Because of the life cycle of the product after its completion, you typically schedule items that are made this way in short production runs. Co-products and by-products can be generated during batch processing. Typical items that are produced with batch processing include:
Pharmaceuticals
Foods
Inks and paints
Glues
Oil or chemical products
In the continuous flow environment, production runs typically continue for an extended duration. Equipment is dedicated to one product or product line. This method of manufacturing is characterized by difficulty in matching output volume with demand and varying yield from process operations. Examples are petroleum-based products and water purification. Co-products and by-products are generally more prevalent in continuous processing than in batch processing.
Master Production Scheduling (MPS) calculates the time series for co-products. Demand for the co-product generates MPS order messages to drive the production process. Co-products that are fully satisfied by the process do not receive order messages. Processes might also make a by-product that has value but is not the central purpose of the process. For example, the lubricant process has co-products of household lubricant and graphite lubricant, and a by-product of sludge. The lubricant would not be processed primarily to obtain sludge.
Usually, both batch and continuous processing methods require extensive record keeping, such as recording quality and tolerance values during the process, and strict adherence to lot tracing and tracking.
With batch manufacturing, a product is made from a bill of material in a standard run. The run is determined by vessel size or standard run length. Typical products that use batch manufacturing include:
Pharmaceuticals
Foods
Glues
Fermented beverages
Paints
The objective for batch manufacturing is to process work orders with a batch quantity that corresponds to a batch bill of material and to use these orders for Material Requirements Planning (MRP) processing. Just as the bill type uniquely defines a bill of material, you can use the batch quantity with bill type to further define a unique bill.
With this manufacturing method, some restrictions on capacity determine the size of the batch that is produced. For example, you might need to fill the vats to a certain level for the process to perform properly.
In addition, the system specifically defines the component quantities for the batch. For example, a 50-gallon vat requires a given quantity of one component, but the system does not necessarily double the component for a 100-gallon vat. Such components are often enzymes or catalysts.
Vats are often physically located close to a more repetitive downstream process. For example, in the manufacture of bread, dough is mixed and left to rise in a vat before being formed into individual loaves and sent for baking and packaging.
You often express units of measure for batches in terms of volume or weight, such as liters or kilograms.
After you create a batch bill of material and batch routing for the work order header, you process the batch work order to attach the parts list and routing instructions to the work order header. Then you generate a master schedule of batch work orders and review the output.
Use repetitive manufacturing for highly repetitive production that relies on a production rate. Repetitive manufacturing enables you to specify a rate schedule by effective date in daily, weekly, or monthly quantities.
Repetitive manufacturing has these characteristics:
Production volume is stable and predictable.
Lead time is short.
Factory layout is product-oriented and often characterized as cellular manufacturing in which dissimilar operations are physically grouped so that the product flows rapidly from one operation to the next.
Setups are short so that switching between products does not significantly affect the time that is available for production.
Group technology is often incorporated into the design engineering and manufacturing engineering to accommodate some variety with little effect on cost or production speed.
Unit of measure is often each.
However, it can also be volume- or weight-related when it is used in an environment that is similar to process manufacturing (as opposed to discrete).
Examples of repetitive products are:
Electronic goods.
Automobiles.
Durable consumer goods (washing machines, refrigerators, and so on).
This section provides an overview of MPS generation for batch bills and discusses how to generate MPS for batch bills.
Use the MPS - Gross Regeneration version of the MRP/MPS Requirements Planning program (R3482) to generate a master schedule for all items or for selected items. This program functions in different ways, depending on whether more than one batch bill exists.
If only one batch bill exists, MPS uses the batch quantity:
As a multiple, if the net requirements are greater than the batch quantity.
As a minimum, if the net requirements are less than the batch quantity.
In either case, the program generates a separate planned order for each batch quantity.
For example:
| Batch Quantity | MPS Requirement | Resulting MPS Planned Order |
|---|---|---|
| 1000 | 1500 | 1000
1000 |
| 1000 | 967 | 1000 |
If the batch quantity is 1000 and the MPS requirement is:
1500, the program generates two planned orders for 1000 each.
967, the program generates a planned order for 1000.
If one batch bill is greater than all of the batch quantities, the program uses the largest batch quantity in combination with any of the other quantities to most accurately satisfy the requirement.
For example:
| Batch Quantity | MPS Requirement | Resulting MPS Planned Order |
|---|---|---|
| 400
600 800 1000 |
1500 | 1000
600 |
| 400
600 800 1000 |
3000 | 1000
1000 1000 |
Assume the batch quantities are as shown in the following list and the MPS requirement is for 1500:
400
600
800
1000
The program generates a planned order for 1000 and a planned order for 600. Using the batch quantities, 1600 is the quantity that most accurately satisfies the requirement.
If multiple batch bills exist and the net requirement is less than the largest batch quantity, the program uses the next highest batch quantity to satisfy the requirement.
For example:
| Batch Quantity | MPS Requirement | Resulting MPS Planned Order |
|---|---|---|
| 400
600 800 1000 |
780 | 800 |
Assume the batch quantities are as shown in the following list and the MPS requirement is for 780:
400
600
800
1000
The program generates a planned order for 800.
After you generate a master schedule, use MPS Time Series (P3413) and MRP/MPS Detail Message Revisions (P3411) to review the time series and messages from the MPS generation.
The time series is a record of time-phased supply-and-demand netting for selected items. The messages reflect how the system uses batches to generate order quantities for net requirements for each time period.
Select Single Site Periodic Planning Operations (G3422), MPS Regeneration.
This section provides on overview of MPS Generation for processes, lists prerequisites, and discusses how to generate a master planning schedule for processes.
After you generate a master schedule, use the Time Series - MPS version of MPS Time Series and the Message Detail - MPS version of MRP/MPS Detail Message Revisions to review the time series and messages that the system generates.
Many processes produce multiple co-products. In each time period, whichever co-product has the greater demand is the pacing co-product. For example, a process might produce both plastic and ethylene glycol (antifreeze). If greater demand for plastic in a time period exists, the system plans for the process based on the demand for plastic, which might result in excess antifreeze production.
The time series is a record of time-phased supply-and-demand netting for selected co-products and by-products. Co-products that are fully satisfied by the process do not receive order messages. Instead, the system creates warning messages for co-products that are planned by a process.
|
Note: Process item numbers do not have a time series. |
After you have defined the stocking types and co-products and by-products for the process, you can generate and review a master schedule of all process work orders and output. This output consists of time series and messages for the co-products and by-products.
Before you complete the tasks in this section:
Define co-products and by-products for the process.
Set up stocking type for process.
| Form Name | FormID | Navigation | Usage |
|---|---|---|---|
| Work With Time Series | W3413A | MPS Daily Operations (G3412), MPS Time Series/ATP Inquiry | Review time-phased supply-and-demand quantities. |
| Work With Detail Messages | W3411D | MPS Daily Operations (G3412), MPS Detail Message Review | Review detail messages that were generated by this version of the Requirements Planning Regeneration program (R3482). |
Select Single Site Periodic Planning Operations (G3422), MPS Regeneration.
This section provides an overview of MPS generation for repetitive items, lists prerequisites, and lists the forms used to generate master planning schedules for repetitive items.
When you run the MPS - Net Change version or the MPS - Gross Regeneration version of the MRP/MPS Requirements Planning program (P3482), the system:
Evaluates selected information.
Performs calculations.
Generates a time series and messages for the selected items.
To generate the master production schedule for repetitive items:
Set the processing options to generate the master production schedule.
Enter the type of rate schedule that you want to use for processing.
Set the appropriate processing option to extend rate adjustments to lower-level items.
After you generate a master production schedule, use MPS Time Series and MRP/MPS Detail Message Revisions to review the time series and messages that the system has generated.
The time series is a record of time-phased supply-and-demand netting for selected items. The system links the planned order releases for the parent item to the gross requirements of component items.
If a component does not have its own rate schedule, the system applies the demand from the parent item. The demand from the rate-scheduled parent follows the same logic as regular work orders. When a rate schedule is added for a component of a rate-based parent, the calculation includes the information for the component in both the rate schedule (+RS) and unadjusted rate schedule (+RSU) data lines. The component is processed as supply, and regular MRP logic applies.
The messages reflect how the system uses rate-scheduled items to generate quantities for net requirements for each time period. The MPS/MRP program produces three main action messages that pertain to repetitive items:
| Message | Description |
|---|---|
| I = Increase rate to | Updates an existing rate to the increased quantity. |
| H = Decrease rate to | Updates an existing rate to the decreased quantity. |
| N = Create rate | Treats messages as a group from the MPS/MRP Detail Message Review form. You can answer more than one message at a time.
Instead of creating a single rate for a given schedule period type over a date range, the system creates a series of rates to cover the entire period. For instance, instead of having one weekly rate in effect for four weeks, the system creates four weekly rates, each in effect for a week. When you process a Create Rate message, the system can attach the parts list and routing automatically. |
When the system processes messages to update rates (I and H messages), it does not validate the dates that are received. The MPS/MRP regeneration produces messages with valid dates. However, you can change these dates before processing the message. To avoid updating invalid rates, ensure the validity of the dates that you enter whenever you change message dates before processing.
|
Note: Non-repetitive items use lead time to backschedule the start date of an order. A repetitive item does not use this logic. Repetitive items use the rates that are effective from and thru dates for backscheduling. |
Before you complete the tasks in this section:
Set Stocking Type to M for manufactured item.
Set Order Policy Code to 5 (Rate Scheduled Item).
Set Order Policy Value to define the length of the rate schedule.
Ensure that all routings are set up.
Ensure that all production lines are identified.
Ensure that all rate schedules are set up.
| Form Name | FormID | Navigation | Usage |
|---|---|---|---|
| Work With Time Series | W3413A | MPS Daily Operations (G3412), MPS Time Series/ATP Inquiry | Review time-phased supply and demand quantities. |
| Work With Detail Messages | W3411D | MPS Daily Operations (G3412), MPS Detail Message Review | Review detail messages that were generated by this version of Requirements Planning Regeneration (R3482). |