Batch Balancing

Batch balancing is a method of coordinating lot sizes so that the total quantity of components produced matches the quantity needed for the planned end products. It is required when one component is used for more than one end product. You must create shop orders for each level. 

Alternative Structures and Batch Balancing

When you create a shop order requisition, the system uses the standard alternative (*). However, you can select another alternative. Doing so affects the following elements:

• Components: A product or recipe structure can have different components, depending on the alternative.
• Quantity per Assembly: A product or recipe structure can have different quantities, depending on the alternative.
• Batch Size kg: A recipe structure can have different standard batch sizes, depending on the alternative.

The system uses the revision that is valid for the product on the date on which you create the requisition.

Conditions for Shop Order Requisitions

The shop order requisitions must fulfill all of the following conditions:

• They must be requisitions for parent parts with a component that equals the selected part.
• The requisition number in the Header Req No field either must be equal to the Requisition No displayed in the upper portion number of the window or must have no value.
• The status of the requisition must be Proposal Created. This is because you cannot balance or create new shop orders for requisitions for which shop orders have already been created.

Scrapping Factors in Batch Balancing

If the component that is being balanced exists more than once in a structure at the same level as a parent part, a formula can be used to decide the required quantity of the component to produce the parent. The following is an example of that formula, which assumes the component is used twice.

Qty Required = { [Parent Qty * First Qty per Assembly] / [1 - (First Scrap Factor / 100) + First Fixed Scrap] }
+{ [Parent Qty * Second Qty per Assembly] / [1 - (Second Scrap Factor / 100) + Second Fixed Scrap] }

The values used for Qty per Assembly and Fixed Scrap are sums, whereas the value used for Scrap Factor is a weighted average. This means that the scrap factor will be:

Scrap Factor = [ (First Qty per Assembly * First Scrap Factor) + (Second Qty per Assembly * Second Scrap Factor) ] / (First Qty per Assembly + Second Qty per Assembly)

Using a batch-balanced component more than once in a structure might cause slight discrepancies in the displayed values and calculations.

Scheduling Batch Balanced Shop Orders

Once the balance id is released, APB or CBS clients can be used to schedule them as a collection of shop orders grouped under the given balance id.

Inside CBS and APB clients, all the shop orders created upon releasing a balance id is grouped together under one object. This helps planners to schedule shop orders belong to one balance id as a group of shop orders (shop order structure).

Shop orders under one balance id, maintain their preceding and succeeding relationships based on the header requisition number that are there in each requisition. Therefore, the shop orders under one balance id is scheduled together and the desired relationship is taken when they are scheduled (First the component shop orders, then sub-assemblies and then the final products and so on).