Most small shops send most of their calibration out. That is sound practice, and it makes the laboratory an external provider: it is selected, approved and monitored like any other supplier (8.4). In-house calibration is also sound for many instruments, if it is done to a written method, with traceable standards, by trained people, and recorded the same way.
Choosing and approving a laboratory
- We prefer laboratories accredited to ISO/IEC 17025 by a recognized accreditation body, and we check that the accredited scope covers the instrument types and ranges we send. Accreditation for torque says nothing about dimensional work.
- We put our requirements on the purchase order: as-found and as-left data, the measurement uncertainty, traceability, notification of any out-of-tolerance result, and any customer requirement that flows down.
- Where a customer specifies laboratories or methods, the customer's requirement comes first.
Checking a certificate when it comes back
A certificate is checked before the instrument goes back into service, not when the auditor asks for it. Our checklist:
- The instrument ID and serial number match the instrument returned7.1.5.2
- As-found data is reported, not only as-left7.1.5.2
- Every as-found result is within the instrument's limits (if not, open an assessment today)7.1.5.2
- The standards used and their traceability are stated7.1.5.2
- The measurement uncertainty is stated and small enough for the instrument's use7.1.5.1
- The conditions (temperature) are stated7.1.5.1
- The laboratory's accreditation covers this work, or our approval of the lab does8.4.2
- The due date on the label matches the interval on the register7.1.5.2
Answer each: Yes / No / N/A, with your notes and evidence. The Word and fillable PDF handbook have the check boxes.
Your suppliers' measuring equipment
Much of what you ship was measured by someone else: a machining subcontractor, the anodizer's thickness gauge, the heat treater's hardness tester. Their measuring equipment is part of your product's acceptance even though it never enters your building.
- Flow it down. The purchase order or quality clauses require calibrated, traceable equipment, records that name the instrument used, and notification to you when an instrument that accepted your product is found out of tolerance.
- Check it at the source. Supplier audits sample the supplier's register, a certificate with as-found data, and one of their out-of-tolerance events: did they trace it, and did they tell their customers?
- Check it at receiving. Where a supplier's measurement accepts a key characteristic, a periodic re-measurement at receiving shows whether their numbers agree with yours.
- Act on their failures. A supplier's out-of-tolerance notice starts your own assessment: which of your lots did their instrument accept, and where are those parts now?
Need more than one resource, or not sure where to start? Book a complimentary 30-minute Aegis Quality Guidance Call. We'll find the tools that fit your situation and a sensible place to start. No sales pressure, no obligation.
A management aid, not certification or a registrar audit. Using it does not by itself show conformity to AS9100D or any other standard, and your customers' requirements may add to it.
Clause numbers refer to AS9100D (SAE AS9100 Rev D) unless another document is named. The standards' text is not reproduced here: use your own licensed copy.
Aegis Insights are our own guidance, labeled wherever they appear: how we approach this work, not a requirement of any standard or customer.