BOM (Bill of Materials) tab

The BOM tab displays the list of parts (with quantities) that are required to build that assembly.

The BOM tab is shown only if Show BOM tab is marked on the current Part Types collection member.

If a part iteration has not yet been released, then the Current list will remain hidden until it's been formally released on a change form.

The BOM is changed by specifying the desired result on the Markup list. Releasing the part iteration resolves the changes into a final part list.

After an assembly has been released, the Current list will always display the latest released iteration of each BOM component. Therefore, when a BOM component is revised, it will automatically appear on the BOM as soon as it's approved and released.

Since a part's most recently released iteration is always displayed in the BOM, you must follow this best practice rule: parts with the same identifying number are interchangeable, and non-interchangeability cannot be controlled using only a revision. If a part is not interchangeable with its previous iteration, the modified part must be assigned a new identifying number - not a new revision.

Assemblies and their BOM components are typically owned by the home organization.

Some organizations adopt vendors' proprietary part numbers for their internal manufacturing/purchasing system (ERP) and reference them directly on their product BOMs. While this approach may appear simplest in the short-term, it limits your purchasing department to exactly one source for each part, and may cause some assemblies to carry one vendor part while other assemblies carry a different but equivalent part. In addition, changing a vendor part requires changing each assembly where it's used.

The better method is to create an internal part with your own part number, list the various sources that meet your requirements, and use this internal part on BOMs.

When an assembly iteration is canceled, the Current list will display the child part iteration that was valid at the time the parent was canceled. If a child part is subsequently revised, that later iteration does not appear on the canceled assembly's BOM.

Markup list

This is the initial set of parts that will be approved for use on the iteration. The BOM mark-up identifies changes to the assembly's components. A component may be designed or purchased, or may be a subassembly with its own bill of materials.

While the current assembly iteration is pending, a component part's most recent pending or released iteration is displayed.

To create or modify the contents of the BOM list:

  • Add a new part to the list by dragging it from the Search tab or Previous tab of the Item Explorer, and then dropping it onto the Markup list. Add quantity and other details as needed.

  • Change an existing item by selecting the component, displaying the context menu, and selecting the Modify Item command. A new row is created, and the row details can be edited.

  • Replace an existing reference by dragging an item from the Item Explorer and dropping it onto an existing Markup row. The details are copied to the replacement row, and can be edited.

  • Remove an existing reference by selecting the reference, displaying the context menu, and selecting the Remove Item From List command (or pressing your keyboard's Delete key). The row doesn't disappear, but is marked to be removed upon release.

If you're working with the parent assembly's first pending iteration, you can freely arrange the parts on the markup list by editing their Find numbers.

Releasing the part iteration on a change form copies the Markup list (excluding removed components) to the Current list. The current child iteration is permanently shown as the starting point on the Markup tab. No further modifications can be made to the current iteration's Markup list.

Current list

This is the most recent set of parts that are approved for use on the iteration. While an assembly's iteration remains pending, its Current list of references remains hidden.

After the assembly iteration is released, its Current list always shows the latest released iteration of each component part. That is, every time a child part is revised and released, the parent assembly's Current list is automatically updated to the new child's iteration.

When the assembly's iteration is canceled, the Current list is "frozen" to show the component part iterations that were valid at the time of cancelation. If a child part is subsequently revised, the canceled assembly's Current list won't be updated.

You can see all of the parts that have been formally approved for use on the assembly. Drill down to deeper levels by clicking on the expansion icons ( and ) on the left edge of each panel.

Markup and Current data fields

These fields are locked on the released ("current") list, and can be edited on a parent assembly pending iteration ("markup").

Find
This column contains the child part's find-item number. (These may also be called "bubble" numbers or "call-outs", since the part row is often tied to the circled number that calls out a component on an assembly drawing).
Find numbers are stable for the life of the parent assembly, and are not re-assigned as the BOM changes. A specific row's find-item number is locked once the parent has been released.
A BOM's find-item value is 1 or greater, and unique for each row on a released assembly.
Quantity (value, units of measure)
Indicate the quantity of child parts that are required to build the parent assembly.
A system rule setting determines whether the part's default unit of measure is locked on a BOM. If it's unlocked, then another measure in the same unit of measure category (count, length, mass, etc.) can be applied. See the System Rules reference > Lock part default unit of measure on BOM help topic.
Whenever the component part's default unit of measure is modified, review the part's quantity and unit on each affected BOM.
To indicate an "as required" amount, enter a typical or expected value and select As needed for the BOM quantity category. If you don't have a reasonable estimate, use 1.
BOM quantity category
BOM quantity categories are used in roll-up and pick list calculations.
  • A part quantity is typically specified Per assembly. The quantity is summed into its higher-level parent, then multiplied by that parent's quantity, continuing to the highest level assembly.
  • Parts specified as Per setup (such as a disposable fixture) and As needed (lubricants, fasteners, or floor stock) are included in roll-up and picklist reports, but are always treated as having zero quantity.

    You can use the Per setup or As needed setting to apply custom calculation rules for your manufacturing system in your Data Transformations and Views.

RefDes
A reference designator ("RefDes") specifies a part's logical location on a diagram and its physical location in an assembly.

While editing the Markup list, RefDes values are counted and compared to the Quantity value according to these rules:

  • A RefDes has a prefix of at least one alphabetic (A-Z, a-z) character. The prefix is immediately followed by at least one numeric (0-9) character; for example S2 or R0012, but not FA or J 7. Different prefixes are allowed: D8,VR2. A RefDes can have a suffix, like U43C.

  • Individual RefDes values are separated by a comma ,, semicolon ; or vertical line |; for example U1A, U1B or LED7;LED9. Spaces can be used between each RefDes but are not required.

  • A hyphen - or colon : identifies a range of RefDes values, starting with the lowest value; for example R6-R12 or C036:104. This starting value's format is applied to the entire range (only the numeric value of the upper limit is used). The upper value doesn't need a prefix, but if it's included then it must match the lower value's prefix. A range value cannot have a suffix.

  • RefDes data is stored as entered. However, characters in a valid RefDes are converted to upper case for comparison, counting and exporting to a PDX package.

  • A RefDes is one unit of the Quantity unit of measure. Fractional Quantity values can't be compared.

A count or format error (such as missing or duplicate values, or invalid range endpoints) changes the text background color, and is described in the RefDes tooltip. After changing the RefDes or Quantity value, press the keyboard TAB key to save the value and update the calculation.

These rules are used to separate RefDes into PDX package ReferenceDesignator elements. Use the Notes field for normal text.

The content of the RefDes field is not indexed for search.
Notes
This text may contain information for any purpose, such as processing instructions for the current row.
The content of the Notes field is indexed for search.

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