Bills of Materials, Recipes and Kits

A structure says what something is made of. Manufacturing calls it a bill of materials, food production calls it a recipe, and distribution calls it a kit — but they are the same shape, and the platform models them once.

One graph, any depth

A structure is a parent with children, and a child can itself be a parent. An assembly contains sub-assemblies which contain components, to whatever depth your product genuinely has. There is no fixed number of levels.

What each component line carries

• Quantity — how many of the child go into one of the parent.
• Scrap — expected loss, so requirements reflect what you must buy rather than what ends up in the product. A component with 5% scrap needs more purchased than consumed.
• Sequence — the order components are consumed or assembled, which drives works instructions.
• Revision — which version of the structure this line belongs to.
• Effectivity dates — when this line applies. See the next article; this is not optional.

Kits versus assemblies

The distinction is what happens to stock. A kit is picked and shipped as its components — the parent may never exist as stock. An assembly is built: components are consumed and the parent is received into stock as a new item. Decide which you are modelling before configuring, because they produce different movements.

Scrap is not a rounding fudge

Use scrap for genuine, predictable loss — offcuts, evaporation, test failures. Do not use it to compensate for inaccurate quantities, because it will disguise the inaccuracy in exactly the reporting that would otherwise reveal it.

Getting structures in

Import them rather than keying them, and import the deepest level first so a parent never references a child that does not yet exist. Verify a sample by exploding it and comparing against your existing system before trusting the whole set.