If you use the assembly replenishment system in Business Central, you set the behaviour through a few fields on the item card. The replenishment system “Assembly” means you build the top-level item from a bill of material instead of running a production order. You then choose between two assembly policies: Assemble-to-Stock and Assemble-to-Order. Assemble-to-Stock creates assembly orders during planning, and you post consumption manually to put the finished item on inventory. Assemble-to-Order creates the assembly order automatically when you enter a quantity on a sales order line, then draws the components and posts the finished item when you post the sales order.
You can also set the assembly policy on stock-keeping units per location. You cannot change the assembly BOM on a stock-keeping unit. The bill of material can only be changed on the item card.
Setting the assembly replenishment system on the item card
When you want to build an item from components rather than run it through a production order, you set the replenishment system to Assembly on the item card. In the demo data this applies to an item like the mixed energy snack box, which is a finished item put together from underlying parts.
On the Replenishment tab you select the replenishment system Assembly. This tells Business Central that you will draw from a bill of material and create the top-level item from those components, instead of using a production order.
The assembly BOM and how to add components and resources
An assembly item has an assembly BOM. You can open the assembly BOM directly from the item card, from the menu, or by searching for it. In the example the BOM is made up of two parts.
On the assembly BOM you can change the items and define the quantity per. You can also add resources instead of items. Resources look into the standard resource table, so you can add an hourly cost to the build. That cost is then calculated into the standard cost of the finished item.
Assemble-to-Stock: creating assembly orders during planning
When an item is set up as Assemble-to-Stock, planning creates assembly orders. You then open the assembly order and post the consumption yourself. When you post the consumption, you draw the components and put the finished item on inventory. This gives you a stock of the finished item ready for sale.
Assemble-to-Order: creating assembly orders from the sales order
If you choose Assemble-to-Order instead, Business Central creates the assembly order automatically. When you enter the quantity of the item on a sales order line, an assembly order is created in the background. When you post the sales order, it automatically draws the components, puts the top-level item on stock, and posts the item to the customer.
This means Assemble-to-Order lets you pick the underlying components automatically straight from a sales order, without keeping the finished item in stock.
Assembly settings on stock-keeping units per location
The assembly information is also available on stock-keeping units, so you can control assembly behaviour per location. On the Replenishment tab of the stock-keeping unit you can define that it is an assembly order on that specific location, and you can change the Assemble-to-Stock policy there.
You cannot change the bill of material on a stock-keeping unit. The assembly BOM can only be changed on the item card.
Q&A
What does the Assembly replenishment system do in Business Central?
It tells Business Central to build the top-level item from a bill of material instead of running a production order. You draw the components from the assembly BOM and create the finished item.
What is the difference between Assemble-to-Stock and Assemble-to-Order?
Assemble-to-Stock creates assembly orders during planning, and you post consumption manually to put the finished item on inventory. Assemble-to-Order creates the assembly order automatically when you enter a quantity on a sales order line, then draws the components and posts the finished item when you post the sales order.
Can I add resources and labour cost to an assembly item?
Yes. On the assembly BOM you can add resources from the standard resource table and assign an hourly cost. That cost is calculated into the standard cost of the finished item.
Can I change the assembly policy and the BOM per location using stock-keeping units?
You can change the Assemble-to-Stock policy on the stock-keeping unit for a specific location. You cannot change the bill of material there. The assembly BOM can only be changed on the item card.