Direct Answer
When a design revision arrives mid-fabrication, immediately identify all affected piece marks, assess which have been cut, partially assembled, or completed, and issue a fabrication hold on any in-progress members until you've confirmed the new requirements. Never continue fabricating a member you know has been revised without understanding the full scope of the change.
Full Explanation
The revision triage process: (1) Receive revised drawing. (2) Identify all changed elements (revision clouds). (3) Query your production tracking system for the fabrication status of each changed piece mark. (4) For any member still in raw material stage: simply update the drawing on file and proceed. (5) For any member in-process: issue a hold, assess whether partial work is salvageable, and determine the cost of rework vs. replacement. (6) For any completed member: issue a rework order or replacement order and document for change order submission.
What This Means for Your Shop
Mid-fabrication revisions are a major source of cost and schedule disruption. The faster you triage, the smaller the financial impact. A revision discovered at the raw material stage is a minor inconvenience; the same revision discovered after welding and priming can mean scrapping an expensive assembly.
Common Mistakes
Continuing to fabricate a revised member because 'the shop is busy and we'll figure it out later.' Every hour of labor added to a member that must be scrapped is 100% unrecoverable cost.
Recommended Process
Implement a production status board (physical or digital) showing every piece mark and its fabrication stage. When a revision arrives, the project manager can triage the impact within an hour. This information also supports your change order documentation.