A bill of materials is a table that contains information about the parts within an assembly. The table includes quantities, names, costs, vendors, or any other information someone building the assembly needs. Quantities on the bill of materials are updated when a part is added or removed from the assembly.
Bill of materials information is automatically collected fromin the Properties dialog box, such as the Title and Part Number from the Project tab. Using the Bill of Materials command in the Manage panel of the Assemble tab, you can view and edit properties for the bill of materials. The exported file can be used in an application such as a spreadsheet or text editor. You can also export a bill of materials (partial or full) to an Engineer's Notebook note.
You can modify values on the bill of materials by changing the design properties in the Properties dialog box or in the Bill of Materials dialog box.
Within a drawing, you can create a similar document called a parts list. The parts list derives data generated by the assembly and the Properties dialog box (as reflected by the bill of materials). The placed parts list can then be edited, with changes to its structure and content. Data in the parts list derived from the Properties dialog box can be edited in the property dialog box. The data can be overridden in the Edit Parts list dialog box. You canparts list to the DWF format.
Thedisplays item numbers in the bill of materials. Every item is automatically assigned an item number. The item number can be edited as needed. Changes to item numbers update automatically in the parts list and balloons.
Quantity is a calculated property that describes how many or how much of a component is used in an assembly. Three distinct properties define Quantity property: Item Quantity, Unit Quantity, and Total Quantity.
Item Quantity (Item QTY) is the number of instances of a component. It is a read-only property.
Unit Quantity (Unit QTY) is the amount which each discrete instance of a component adds to the total quantity. Components that are quantified by the number of instances of the component have a Unit Quantity of Each. Some components are quantified based on some physical aspect of the component. These physical aspects, such as wires, grease, cut-length steel, tubes and pipes, and so on, have a Unit Quantity derived from a parameter.
Unit Quantity is composed of two properties: Base Quantity and Base Unit. Base Quantity is the parameter that is the raw value for Unit Quantity. By default the Base Quantity of a component is Each. Base Unit is the unit that Unit Quantity is expressed in.
Total Quantity (QTY) is the Unit Quantity multiplied by the Item Quantity.
Bill of materials structure and total quantity
Every instance of a component that has a bill of materials Structure of Normal, Inseparable, or Purchased adds 1 to its Item QTY. Components that are children of Reference parents are "hidden" in the bill of materials and are not added to Item QTY. Children of Inseparable and Purchased components are hidden in a Parts Only Bill of Materials. There is one exception. Purchased components that are children of Inseparable assemblies are promoted outside Inseparable assemblies in a Parts Only bill of materials.
In the BOM Editor, an arrow icon flags components that have been promoted to a higher level in the BOM. Components are promoted for one of the following reasons:
Item QTYs of promoted components reflect how many times they actually occur in the assembly. For instance, if you have two Phantom assemblies that have four nuts each, the nuts are promoted and the total quantity is eight.
A virtual component is a component that requires no modeling of geometry and no file. It is the equivalent to a custom part in a parts list. Virtual components are considered and treated as real components for all practical purposes: They have a browser representation, have properties such as quantity, bill of materials Structure, Part Number, and so on.
Virtual Components have the following characteristics:
Examples of standard virtual components are:
You use the Create In-Place Component command to create a virtual component in an assembly. Virtual components can be deleted in the same manner as other components. When all instances of a virtual component are deleted from the browser, the virtual component must be recreated using the Create In-Place Component command.
Virtual Components can have multiple instances inside of an assembly. All virtual components have a node in the assembly browser and can be reordered. You can copy and paste, or pattern a virtual component in an assembly. If you select the Reuse option for virtual components, you can include them in a Mirror or Copy operation.
If two or more components have the same part number, the assembly considers them to be the same component. Two or more equivalent components can end up at the same level in the bill of materials because of modeling, promotion due to a Phantom parent, or promotion in a Parts Only list. Those components are rolled up into a single line item. Their quantities are summed together, and properties that do not match are reported as *Varies* in the bill of materials.
Sometimes multiple components have the same Part Number, but require treatment as separate components. This occurrence is common for cut-length items such as tube and pipe, flexible hose, wires, tape, and so on. A new iProperty, Stock Number, is added to all components to accommodate this intention.
Stock Number can be substituted by for the Part Number column for parts lists to support the workflows of cut length items. This is done by default for Part List styles provided with Autodesk Inventor. You can change the substitution setting in the Format Column dialog box.