An assembly is a stock item built from other stock items. Its bill of materials (BOM) lists the components and the quantity of each needed for one assembly. An assembly's cost is the sum of each component's cost multiplied by its BOM quantity. See Stock costing and valuation. This article covers creating an assembly, managing its BOM, building assemblies for the shelf, customising the BOM on a quote or order, and the BOM picking lists.

Compared with a stock item, an assembly has no Cost Price, Purchase Analysis, Minimum Order Quantity, Can Sell or Dual Description field, and no Suppliers action. When you copy an assembly, Copy BOM replaces Copy Suppliers. See Stock items and stock types.

Open the assembly and click BOM. The form lists each component with its quantity, cost and location.

Start typing in Part # or Name and choose the item. Enter the Qty needed for one assembly (up to 4 decimal places) and click the tick.

Only items with Can Buy are offered: stock and never-diminishing items, not assemblies or archived items. To nest an assembly, add its components instead. Each component can appear once.

Click the pencil at the end of the row to load the component into the entry row. Change Qty and click the tick, or click the pencil again to cancel. To remove a component, click its pencil, then the bin, then Delete BOM Stock Item to confirm. This cannot be undone.

Each row shows the component's Cost Price and its Cost Price Source: the purchase order it came from, or the item's own Cost Price. See Stock costing and valuation. A component with no cost is shown in red. Click a component's Name to open its stock page.

The BOM form does not warn you about short stock. Use Assemblies Possible on the assembly page, or the component table in Untracked Build, where short rows are highlighted.

The assembly page shows Assemblies Possible in place of On Order. For each counted component Omono divides its In Stock by the quantity per assembly and rounds down. The lowest result is the number you could build now. Components with a quantity of 0 are ignored.

The figure uses In Stock only, so it ignores stock already allocated to other dispatches. Open a component and compare In Stock with Allocated to see what is reserved.

A never-diminishing item, for example labour or packaging, can go on a bill of materials. It adds to the assembly's cost but is never counted: Assemblies Possible ignores it, it shows - under Available, and it is not consumed when the assembly is picked or built.

When a dispatch containing an assembly is allocated and picked, Omono uses built assemblies from the shelf first. If there are not enough, it builds the rest from components, and each component's In Stock goes down by the quantity needed. A line with a custom BOM is always built from its components, even if built assemblies are in stock. See The Workflow board.

To build assemblies ahead of demand, open the assembly and click Untracked Build.

Each counted component's In Stock goes down and the assembly's In Stock goes up. The form refreshes its stock figures every 2 seconds, so if another user uses the stock while it is open, Assemblies Possible drops and the tick refuses a Build Quantity above it. If the stock goes in the instant before you click the tick, the form closes with no message and nothing changes; check In Stock before you try again. The build writes a system note on the assembly and appears as Built and Consumed by Build in the Stock Movement report. See Stock reports.

An assembly with no components cannot be built: Build Quantity is disabled. Add the bill of materials first.

No. To put the components back:

Add a note on the assembly with the reason so the Stock Movement report makes sense later. See Stock levels, stocktakes and reordering.

When you add an assembly to a quote or sales order, Omono copies its BOM onto that line. Later changes to the stock BOM do not affect the document, and you can change the copy for that document only.

A line whose BOM differs from the copy taken when the item was added is marked as a custom BOM and shows N/A under Available. Custom BOMs carry across when a quote is won and are used when the dispatch is picked and costed. An assembly with zero-cost components shows a warning icon.

You cannot change a BOM on a quote once it is won or lost: the form still opens, but Omono does not save the change and shows no message. On a sales order, you cannot change it once the line is on a dispatch that has moved past Unallocated, or once the order is cancelled.

Open a sales order, click BOM and click the print icon in the form. The icon is not shown on quotes. Omono downloads a list headed BOM / Picking List with the order details.

Each order line is a row with a tick box. Assemblies show their components underneath:

In the Untracked Assembly Build form, click the print icon before you click the tick. The list shows the assembly, the reference, build quantity, who raised it and the date, and each counted component with the quantity for the whole build. Never-diminishing components are left out.

Both lists print your standard header but no footer. See What prints on your PDF documents.

Assemblies cannot be bought. Raise Linked PO on a sales order expands each assembly into its components and buys those. See Linked purchase orders and drop shipping.