How to audit a manufacturing supplier

01Prepare

Define the objective (qualification, process, for-cause), the product family and the criteria. Request the certificate scope, organisation chart, machine list, process flow and control plan in advance. Prepare a checklist, but leave room for what you find.

02Walk the process

Start at goods receipt and follow a real order to shipping. At each step ask: what are the inputs, who does it, with what equipment, to which instruction, how is it checked, what happens when it is wrong? Look at actual parts, records and gauges.

03Evidence to look for

• Incoming inspection records and supplier ratings
• Set-up approvals and first-off records
• Control charts and inspection records at stations
• Calibration status of gauges in use
• Nonconforming product area and records
• Customer complaints and 8D reports
• Maintenance records of critical machines
• Training and qualification records for special processes

04Special processes deserve extra time

Welding, heat treatment, casting, plating, painting and moulding cannot be fully verified afterwards. Check qualification, parameter control, monitoring and outsourced control. Many critical findings are in processes the supplier outsources.

05Score and report

Rate each area against defined criteria, record findings with objective evidence and photographs, and give a clear recommendation. A report that the supplier can act on is more valuable than a long one.