How You Gather Components for Assembly Depends on Business Central Setup

Assembly orders in Business Central look simple: you have a finished item, a list of components (the assembly BOM), and you post the order to build it. But one question trips people up constantly: how exactly do the components get gathered and consumed? The answer is not the same for every company, because it depends on how your warehouse is set up.

Get this right and assembly flows smoothly. Get it wrong and you either post consumption you did not intend, or you cannot ship because a pick step is missing. This guide explains, in plain English, how component gathering changes with your warehouse configuration and your assembly policy, so you can pick the flow that fits your business.

Assembly Basics: BOM, Order, Consumption, Output

Before the “how”, a quick refresher on the parts. An assembly item is a finished product built from other items, defined by its assembly BOM (the list of components and any resources). An assembly order is the document to build a quantity of that item. When you post the assembly order, two things happen:

• Consumption: the components are taken out of inventory (used up).
• Output: the finished assembly item is put into inventory.

Assembly is simpler than full production: there is no routing with multiple operations, and posting is a single completion step rather than separate consumption and output postings over time. The one thing that varies is how the components get gathered before that consumption is posted, and that is driven by your warehouse setup.

Production BOM Explained: Concepts and Functionality

Why “It Depends” on Your Warehouse Setup

Every location (warehouse) in Business Central has warehouse handling settings on its Location Card. These settings decide how much warehouse process sits between “components in stock” and “components consumed by the assembly”. There are three broad levels:

The same assembly order behaves differently depending on which of these applies at its location. Let us look at each.

No Warehouse Handling (Automatic)

This is the simplest flow, and the most common for smaller businesses. The location has no pick requirement, so when you post the assembly order, Business Central automatically consumes the components (per the Quantity to Consume on the lines) and outputs the finished item. There is no separate gathering step; posting does everything.

Use this when you do not need to direct warehouse staff with pick documents, and trust that the physical components are on hand. It is quick and needs the least setup.

Basic Warehouse: Inventory Pick vs Movement

When a location requires basic warehouse handling (for example Require Pick, and often bins), you gather components using one of two documents. The difference between them is important, because it decides when consumption is posted.

Inventory Pick (posts consumption)

An inventory pick records the picking of components to the assembly, and when you register it, the consumption of the picked components is posted at the same time. For an assemble-to-order line ready to ship, posting the inventory pick does several things at once: it creates the movement of the components, posts the assembly output, and posts the sales shipment. One action, several results.

Inventory Movement (does not post consumption)

An inventory movement moves the components (for example to the assembly bin) but does not post consumption. You then post consumption separately by posting the source document (the assembly order). Use a movement when you want to physically stage components first and post the build as a distinct step.

💡 The key distinction: inventory pick = gather and consume in one step. Inventory movement = gather only, consume later when you post. Choosing the wrong one is a common reason people are surprised that consumption did (or did not) post.

Advanced Warehouse: Warehouse Pick

In an advanced warehouse configuration (directed put-away and pick), component gathering is part of a fuller warehouse process using a warehouse pick document. For assemble-to-order items in the outbound flow, warehouse pick documents move the assembly components to the assembly area as part of picking the sales shipment. This suits larger operations with formal warehouse control, bin-level tracking, and dedicated warehouse staff.

This is more powerful but heavier to run. You only want it where the warehouse genuinely needs that level of control.

Assembly Policy: Assemble-to-Order vs Assemble-to-Stock

Alongside the warehouse setup, one field on the item card shapes the whole flow: the Assembly Policy. It decides when the assembly order is created and how components relate to demand.

You set this in the Assembly Policy field on the Item Card. There is useful flexibility too: even for an assemble-to-stock item, if stock runs short on a sales line you can fill the Qty. to Assemble to Order field to build the shortfall to order. So the two policies can work together on one order.

Why this matters for gathering components: with ATO, component gathering is tied to the sales shipment (often one pick posts consumption, output, and shipment together). With ATS, you gather and consume components when you build to stock, and the later sale just picks the finished item.

Which Setup Should You Use?

Bringing it together, here is the practical guidance:

• Small or light kitting, parts on hand: No warehouse handling. Components consume automatically on posting. Simplest.
• You need to record picking and want consumption posted with it: Basic warehouse with an inventory pick.
• You want to stage components first, post the build separately: Basic warehouse with an inventory movement.
• Large, formal warehouse with bins and directed picking: Advanced warehouse with warehouse picks.
• Customized items built per sale: Assemble-to-Order policy.
• Standard kits built ahead and stocked: Assemble-to-Stock policy.

The golden rule: match the warehouse level to how much physical control you actually need, and no more. Extra pick steps that nobody uses just slow the process down.

FAQ, Gathering Components for Assembly

How are components consumed on an assembly order?

It depends on the location’s warehouse setup. With no warehouse handling, components consume automatically when you post the assembly order. In a basic warehouse, an inventory pick posts consumption when registered, while an inventory movement only stages components and consumption posts later.

What is the difference between an inventory pick and an inventory movement?

An inventory pick records the pick and posts consumption of the components at the same time. An inventory movement moves components without posting consumption; you post consumption separately by posting the source document.

When do I use a warehouse pick for assembly?

In advanced warehouse configurations (directed put-away and pick). Warehouse pick documents move assembly components to the assembly area as part of a fuller, bin-controlled warehouse process, typical of larger operations.

What is the difference between assemble-to-order and assemble-to-stock?

Assemble-to-order builds the item in response to a sales order (a linked assembly order is created automatically). Assemble-to-stock builds ahead of demand and stores the item, which is then sold from inventory like any stocked item. You set this in the Assembly Policy field on the item card.

Can I sell stock and assemble-to-order on the same sales order?

Yes. Even for an assemble-to-stock item, if inventory is short you can use the Qty. to Assemble to Order field to build the shortfall to order, combining stock and made-to-order quantities on one line.

Does posting an assembly order always post consumption and output together?

In simple (no warehouse handling) setups, yes: posting consumes components and outputs the finished item in one step. In warehouse-controlled setups, the gathering step (pick or movement) affects exactly when consumption posts.

Final Thoughts

The reason assembly component gathering confuses people is that there is no single answer: it genuinely depends on your Business Central setup. The location’s warehouse handling decides whether components consume automatically on posting, through an inventory pick or movement, or through a warehouse pick. The item’s assembly policy decides whether you build to order or to stock. Once you see those two dials, the whole process becomes predictable.

Choose the lightest setup that gives you the control you need. For many businesses that is no warehouse handling with automatic consumption; for larger, bin-controlled operations it is full warehouse picks. Match it to reality and assembly runs smoothly.

Stay tuned to NavisionPlanet for more practical Business Central manufacturing and inventory guides drawn from real project experience.

Note: Warehouse and assembly behaviour can vary with location settings and Business Central version. This guide reflects current Business Central. Confirm specifics for your version on Microsoft Learn or with your partner before changing a live location’s warehouse configuration.