Concepts

The following topics discuss concepts you should understand before you schedule co-/by-products within the workbenches.

When scheduling co-/by-products in the workbenches, it is important to know that the workbenches work with base processes. A base process is a manufacturing operation that creates more than one product, that is, the co-products or by-products.

Co-products and by-products of a base process do not have their own product structures or routings. These are defined in the base process. Base processes are items containing formulas for co/by-product operations, and are defined in the same way as regular items. A base process has an item record, a product structure with co-/by-products, a formula, routing, and BOM code.

There are some important distinctions between base process items and regular items:

• Base process items are never regarded as items to be stocked. Item status codes are used to restrict inventory transactions related to base process items and to ensure that these items never appear on sales or purchase orders. Should base process items end up in inventory, or on sales or purchase orders, they are ignored by MRP.

• Demand for co-products drives the planning of base processes, and the co-product that has the most demand is the one planned for.

MRP plans orders for a by-product as a result of creating planned orders for a base process. By-product demand is not considered when planning a base process, but MRP creates a joint order set for demand records from the unsatisfied demand for a co-product. An item is a co-product when:

• It is manufactured, that is, the Pur/Mfg code is set to Manufactured, Routable, or blank.

• The BOM or formula code is a base process that has the item as a co-product.

MRP plans for a base process by determining the unsatisfied co-product demand for all co-products that reference the base process as their BOM or formula code. MRP creates planned orders to fill the unsatisfied co-product demand without regard to projected quantities on hand for the base process. MRP does not consider base process inventory.

MRP uses the order policy and order modifiers for the base process, except safety stock, when creating planned orders. When the order policy is not period order quantity (POQ) or fixed order quantity (FOQ), MRP uses an order policy of POQ. If no order period is specified, MRP uses an order period of seven days.

When MRP plans a base process, it searches for the first unsatisfied demand record for a co-product. Then, depending on whether the order policy is POQ or FOQ, MRP evaluates unsatisfied demand records for all co-products of the base process:

POQ: MRP searches from the first unsatisfied demand record through the end of the order period.

FOQ: MRP looks at all unsatisfied demand records for all co-products that fall on the same date as the first unsatisfied demand record.

MRP creates one or more planned joint order sets to satisfy demand for the co-product that presents the greatest demand for the base process for a specific date or date range. As a result, planned orders for the other co-products of the base process are also created. MRP also creates action messages for base processes and co-products, but not for by-products.

The workbenches provides the ability to manage and monitor joint order sets—two or more production orders that are dependent upon each other. Managing orders for co-/by-product functionality is an example of production order set management.

A joint order set must have only one base process order and at least one co-product order. If you delete the base process order or the only co-product order, the entire set is deleted.

A joint order set consists of the following production orders or order attributes:

Joint orders can be added to or deleted from a joint set when the status is Exploded, Allocated, or Released. Since a joint order set must have only one base process order, when you delete the base process order or the only co-product order, the entire set is deleted.

For workbenches considerations:

• Only the base process order is sequenced and has a sequence value, so, only the base-process is shown in the PSW for sequencing.