Project Lifecycle Management Glossary

Talked about PLM in previuous post, this post will focus on some PLM glossary in order to define confused term and to provide an easy-to-remember reference.It will contain definition and explanation of distinction.

Alternate parts

Alternate parts are different parts in inventory that fill the same function

  • Alternate parts are interchangeable components
    in a
    post-release production phase.
  • For example, a factory might have two different windshield wipers in inventory that fill the same function, and for a given car they must decide which one to use. Both of these parts are released and have different part numbers.


  • Sometimes alternate parts are confused  with …

–Design alternatives (concept for functional or detail   design phases)

–Substitute parts

–Configured assemblies

  • Also referred to as …

Interchangeable parts

Design alternatives

Evaluate several, choose one.  Only one.  “Design alternatives”

When Julie plans her wedding, she may consider different alternatives for her hairdo.  But come the wedding day, only one hairdo is possible; she must make a choice.  These are design alternatives.

  • Design alternatives are competing solution scenarios for a given part.
  • With respect to a given part, there are times when a designer wants to explore several different alternatives in parallel.
  • This is during the design phase when he (or the design office) is not yet sure what an optimal part would look like.
  • Ultimately, he will retain only one alternative and abandon the others.

Part vs. design alternatives

  • Although some design alternatives never see the light of day, there are times when the designer wants to publish two or more design alternatives for the same part.
  • Yet, even if there are several design alternatives, there is still only one part (and by extension, only one part number) in the BOM.
  • With respect to this one part, the designer delivers different variations of the part geometry in order to allow the downstream actors to choose the best one (e.g., as a result of CAE analysis, manufacturing feasibility, etc.).
  • In pre-release design phases, the designer delivers a collection of suggestions without yet committing himself to one particular design.
  • Simply speaking, he is essentially sharing his ideas and asking the others which one they like best.
  • Yet, it is important to understand that these suggestions all concern the same part.


Promotion of design alternatives

Different companies have different approaches to the management and maturation of part design alternatives. These fall roughly into two distinct schools of thought: one, where a group of related alternatives is managed together, and another where alternatives evolve independently one from the other. These two approaches might be called:

  • School class paradigm
  • Company paradigm

Design iterations

With respect to non-released (or “under construction”) parts, any change that the designer considers worthy of saving for posterity constitutes a new design iteration.

1.Part design iterations are changes to part geometry and placement which need to be recorded and tracked.

  1. When a designer is finished with a given geometry, he will publish it (promote its maturity status) in order that others may now take this geometry into account for their own needs.

Preserving distinct iterations of a part’s design allows other actors in the product design process to work on an official or “published” iteration of that part.  In the meantime, the part owner continues to refine his design on a private “in-work” iteration of the same part.


  • Design iterations are used to help converge on a part’s ultimate shape and characteristics. In simple terms, they are the photographs taken as the part is growing up. They record primarily updates to part geometry.
  • Ultimately, one design iteration is selected as the one to be released and go into production.
  • Published iterations go into the “public domain” of a development project and are used or referenced by others for several purposes, including:

ØThe design of other parts (“design in contextand “contextual design”)

ØIntegration and consolidation (interference with surrounding parts, assembly feasibility in the vehicle context, etc.)

ØDownstream analysis and assessment (e.g., structural, thermal and/or assoustic analysis, 2D drawing creation, etc.)

  • New iterations are created most naturally:

1.When the previous iteration is published

2.When a part is checked out for modification


  • Sometimes Design iterations is confused with …


–Document iterations

–“Standard save” (in some DS documents)

–“Ready for release” (in some DS documents)

  • Also referred to as …

–Drawing index (BMW)

–Minor index

Part versions

Same product, only better.  Still works as before

Part versions are recorded changes made to released parts. New part versions must preserve the “form, fit, and function” of their predecessor. When you see words on product packaging like “longer lasting,” “lower calories,” or “less fat,” ….. these are analogous to promotions for new “versions” of existing “parts.”

  • Part versions record minor updates to part characteristics such as:

ØMaterial (which can in turn influence weight)



ØShape (light modifications only)


  • New part versions are usually requested through an engineering change.

Warning !

  • Sometimes confused with …

–Design iterations

  • Also referred to as …


–Change index

–Release index

–“Major modification” (in some DS documents)

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