Releasing a Job with an Unapproved Alternate Boring Bar
Ridgeline Pumps has a released job for 500 stainless pump housings due in six working days. The boring operation requires tool assembly BOR-62-A, which is at an external grind shop and is promised back in three days. The job starts tomorrow on one horizontal machining center. An alternate assembly, BOR-62-B, exists with the same nominal diameter but a different insert grade and a 0.15 mm shorter gauge length; engineering has verbally said it should run but has not signed a deviation. The alternate has 260 pieces of remaining life at the standard feed, while the job needs 500 pieces and one tool change is allowed. The planner is considering releasing the job now and letting the operator decide at the machine. The customer requires full tool traceability by serial number on the certificate of conformance.
1. Should the planner release the job with the alternate assembly now? Justify by identifying the checks that must happen first.
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Do not release on a verbal should run. The alternate has a different insert grade and a 0.15 mm shorter gauge length, so it can change offsets, surface finish, and hole size. Before release, engineering must approve the alternate for this operation and material, quality must confirm the control plan and traceability, and the tool room must preset the assembly and prove the offset.
Capacity also fails: the job needs 500 pieces and the alternate has only 260 pieces of remaining life, with one tool change allowed. That is not enough unless a second qualified assembly or a verified life extension is available. Only after approval, preset, and sufficient tool life should the planner update the operation tool list and reserve the assembly. Releasing early pushes an unapproved decision to the operator.
2. How should the substitution be recorded so the certificate of conformance and job costing remain correct? What planning control would reduce recurrence?
Read the worked answer
Record the substitution at the operation, not in a note. Put the approved alternate tool ID and effective date on the job operation or tool list; attach the engineering deviation to the job; record the serial numbers of every assembly used, including the second assembly if life is split; capture actual usage and any reset; and keep the original and alternate linked for traceability. For the certificate of conformance, the serial record must show what actually cut the part. For costing, charge actual tool consumption and any regrind or expedite cost to the job rather than the standard assembly.
To prevent recurrence, add the alternate as a qualified alternate in the routing or tool requirement and add a tool-availability check at job release. The planner should see outside-regrind status and remaining life before releasing the operation.