Lesson 5 · Bills of materials

• Time 18 min
• Level Intermediate
• Before Lesson 4

Goal of this lessonTo tell the engineering, production and spare-part trees apart, find where a part is used and compare two trees.

The engineering BoM (EBOM) is the structure as designed, usually from the CAD client. The normal BoM is the structure production uses; it may carry items the design does not (here the drive and the cable). The spare BoM lists the parts sold as spares. A revision copies all three; the new revision's tree is edited independently of the old one.

Step by step

1. Read the engineering BoM

   The Component Relations menu lists the three kinds of tree separately. An EBOM's type is “Engineering BoM”, and the lines show each component's revision and state.

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2. Look at the normal BoM

   Production uses the normal BoM. To make a normal BoM from the EBOM the part screen's action menu has Create Normal Bom; for the spare tree, Create Spare Bom.

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3. Open the multi-level tree

   The BoM Overview button on the BoM form shows the tree at every level; Unfold opens every sub-assembly.

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Where-used

1. One level: Used In

   One of the counters on the part form lists the trees the part is a direct component of (under More when it does not fit).

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2. Every level: Check Product Change Impact

   Check Product Change Impact in the part form's action menu (⚙) reports every parent assembly level by level. If the part is in several trees of one assembly (normal, engineering, spare) each is its own row.

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3. Compare two trees

   Select two trees in the BoM list and choose Compare BoMs in the action menu; the wizard shows the differences line by line. That is how you see what a revision changed, or how the EBOM differs from the normal BoM.

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4. Freeze the structure: a baseline

   Take Baseline in a released part's blue box freezes the structure as it is: every part at its revision, every document at its revision, every quantity. Later changes never move it; it answers “what exactly did we build in March?”. Every applied change order takes its own baseline too. Baselines are under Changes › Baselines.

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Products with variants (150% BoM)

One bill of materials can hold every option of a configurable product (a 150% BoM): each line says for which attribute values it is used. In the blue box on the product form's variants tab, Configure shows the BoM of any selection before a variant exists; when the selection obeys the rules, Create Variant creates it. Check All Combinations scans every combination for rule breaches and empty BoMs. Rules that say one value requires another carry an engineering reason and are applied on sale order lines too.

Check yourself