Why single efficiency factors fail
Deposition efficiency changes by process, position, welder profile, and pass sequence. One blanket factor for all welds can materially understate consumption on complex joints.
Segment by weld class
Create separate classes for fillet, groove, and overlay work, then apply process-specific consumption factors and contingency values.
- Separate shop welds and field welds for better realism.
- Apply higher contingency to out-of-position and repair-prone joints.
- Convert to per-joint and per-spool metrics for procurement clarity.
Feedback from production
Update factors monthly from actual issue and return records. The fastest way to improve estimates is to close the loop with consumable store data.