Planning illustration: a changeover divided into preparation, stopped-machine activity and validation. It is not customer data, a machine specification or an operating instruction.

Define the start and finish first

Before measuring a changeover, agree when it starts and when it ends. A useful evaluation normally distinguishes preparation that can happen while production is running, work that requires the machine to be stopped, and validation through the first accepted piece. This CBOXTEC checklist is purchasing guidance, not a safety procedure and does not establish time savings.

Changeover activity record

  • Previous and new part or product family; drawing and program revisions; fixture removal and installation; torch, contact-tip or consumable checks where relevant; program and parameter selection; sensing setup checks; first-piece loading; agreed inspection result; manual correction or rework; responsible person; start and finish reference.

Keep the three periods separate

Record preparation, stopped-machine activity and first-piece validation as separate lines. Otherwise a short program selection can hide time spent moving fixtures, checking consumables, adjusting sensing conditions or repeating the first piece. Record actual observations; do not insert a standard duration or savings percentage before the intended parts and process have been evaluated.

Link every change to the result

Note what changed between the last accepted piece of the previous run and the first accepted piece of the new run. Keep manual corrections and rejected or repeated first pieces visible. If different parts, fixtures, operators or revisions are involved, identify them rather than combining the results into one unsupported average.

Does the checklist qualify the welding procedure?

No. TWI explains that a welding procedure specification records welding variables and is supported by separate qualification records. A changeover activity sheet does not replace those documents, engineering review, safety controls or required validation. Source: TWI, Welding procedure — Job Knowledge 39, accessed 16 September 2026. It supports the document distinction only; the changeover checklist is CBOXTEC purchasing guidance. TWI. Discuss your changeover scope.