This chapter explains how to use the bill of manufacturing for batch style manufacturing where products are made using a batch formula or recipe.
What is batch manufacturing?
Products such as food, chemicals, plastics, and liquids are made using a batch formula or recipe. This style of manufacturing is called “batch manufacturing.”
The BOM is defined against a fixed batch size
Instead of defining BOM specifications against a parent quantity of ‘1’, BOM specifications are defined against a fixed batch size that does not vary from job to job.
Use the ‘Batch’ BOM type
If you wish to define a BOM for batch manufacturing, assign the parent to the ‘Batch BOM type on the List tab in the Bills of Manufacturing screen.
Specify the Batch Size against the current revision
On the Revisions tab, specify the Batch Size against the current revision.
The Batch Size is the default Items/Process against routing sequences
The Batch Size is inserted by default into the Items/Process field when the first routing sequence is created, which is then used as the default value when subsequent sequences get created.
NOTE: The Hours/Process is divided by the Items/Process to determine the cycle time required to make one unit of the parent item.
Enter the batch formula or recipe on the Components tab
Enter the batch formula or recipe on the Components tab. The Batch Size is displayed in the upper panel. Each component’s Usage Qty is the total amount required by each batch.
The order Multiple is made equal to the Batch Size
In the MRP Settings screen, the parent item is automatically assigned an order Multiple equal to the Batch Size so that MRP always generates planned jobs in a multiple of the batch size.
Using the Review Note for MRP generation
Entering a Review Note against the parent item in the MRP Settings screen can be used to prompt for manual intervention during MRP generation.
•If demand causes MRP to generates a job quantity multiple that is two or three times the batch size, the review note can instruct the planner to use the Split Job function to split the planned job into two or three jobs, each equal to the fixed batch size amount.
•If a component is subject to a custom quantity that can vary with each job, the review note can be used to specify the calculation formula that is to be applied to the component job quantity after the job is generated.
Avoid the ‘Batch’ type and use the ‘BOM’ type when possible
If you can define your item recipes or formulas against a parent quantity of ‘1’ instead of the batch size, we advise doing so by using the ‘BOM’ BOM type in conjunction with the order Multiple and Review Note instead of using the ‘Batch’ BOM type. This will still result in jobs being generated in batch size multiples and is more compatible with the unit cost basis used by the estimated cost rollup, unit job cost, and item inventory cost.
