Lesson 2 · Part and engineering code

The engineering code never changes, the revision grows with each change; new code or new revision.

Goal of this lessonTo know the difference between the engineering code and the revision, and to decide whether a change needs a new code or a new revision.

Code and revision

The engineering code is the part's number and never changes. A new version of the part keeps the code and its revision number goes up by one: 0, 1, 2… Code and revision together name one exact design: PW-BRK-80 rev 1 is the bracket's second version. A released revision is never edited; a change means a new revision.

New code or new revisionPW-BRK-80Rev 1Engineering code: the part's number, never changes.Revision: 0, 1, 2… Code + revision name one exact design.The part must changeIs the part released?Draft / Confirmed → nonoCorrect the same revisionIf confirmed, Correct Componentsends it back to draftyesIs it interchangeable?same form · fit · functionyesNew revisionsame code, rev + 1 (ECR → ECO)noNew engineering codea new part; the old one is made obsolete
The decision tree. The test is not the part itself but its users: a part that replaces the old one in place keeps the code.

Step by step

  1. Find the code and revision on the part form

    The part number field shows the code and the revision together (PW-KIT-750 - Rev_ 0). A new revision opens as a separate record under the same code; the old revision's record stays as history.

    A released part12345
    1. State: Released.
    2. The guide box says which revision a change will make (here revision 1).
    3. Request a Change: the one door to a new revision.
    4. Code + revision.
    5. Take Baseline: a snapshot of the structure as it is now.

  2. See every revision of a part

    Remove the Latest filter in the part list: old and new revisions of the same code come side by side. The bracket's rev 0 is Under Modify (rev 1 in work), the plate's rev 0 is Obsoleted (rev 1 released).

    The part list without filters1234
    1. Search bar: the Latest filter removed.
    2. Revision column.
    3. PW-BRK-80 rev 0: Under Modify — valid until the new one is released.
    4. PW-PLT-80 rev 0: Obsoleted — replaced by rev 1.

The rule: form, fit, function

If the new part fits in place of the old one with no other change — same outer dimensions and interfaces (form, fit) and the same job (function) — it is a new revision. If it does not, if an assembly must change with it, it is a new engineering code; the old code is made obsolete when needed. The users of the part decide, not the part: if old and new can be mixed in stock, the code stays the same.

Caution: one code per physical part
Two codes for the same part make two “parts” in stock and in the bills of materials and split the where-used answer in two. Search the part list before you open a code.

Mini case: the plate from 8 mm to 10 mm

Change
The adapter plate bends under load; thickness 8 → 10 mm.
Question
Does the new plate fit in place of the old? Holes and outline unchanged, the screws are long enough: yes.
Decision
New revision: PW-PLT-80 rev 1 (released by ECO-2026-0002).

Check yourself

Code or revision: the bracket's weld grows from a5 to a6, dimensions unchanged.
Revision: the part fits in place of the old one (PW-BRK-80 rev 1).
Code or revision: the new plate fits a different gearbox, the hole pattern changes.
A new code: it does not fit in place of the old one; the assembly changes too.
Is the old revision's record deleted when the new revision opens?
No. It stays as its own record; when the new one is released it becomes Obsoleted and the history is kept.