How to conduct a manufacturing process audit

ITVC GLOBAL · BUSINESS SERVICES

How to conduct a manufacturing process audit

Auditing a manufacturing process

A manufacturing process audit is a comprehensive evaluation to verify whether a process is operating as intended. Processes produce results; the audit determines whether those results are correct and whether they are produced by an effectively managed process. The audit should verify that procedures are followed, that the process is consistent, and that continual improvement and corrective action take place where necessary.

To conduct the audit, prepare the Control Plan, PFMEA, and the procedures and work instructions relevant to the manufacturing stages being assessed. An audit checksheet should also be prepared to make the assessment and recording of findings easier.

Questions to guide a manufacturing process audit

Are materials purchased from approved suppliers?
Have materials been inspected and found to meet requirements?
Are materials stored, preserved and labelled appropriately?
Are all operations performed in the required sequence and controlled in accordance with the Control Plan?
Are quality inspection requirements followed?
Have measuring devices undergone the required verification?
Are instructions followed for transporting and using materials issued from the warehouse?
Are products manufactured using the type of equipment specified in the Control Plan?
Is SPC performed in accordance with the Control Plan?
Does output at each process stage meet requirements?
Does product quality on the production line meet requirements, such as PPM and scrap-rate targets?
Are nonconforming products detected, labelled, segregated, stored and handled in accordance with the procedure?
Are changes made by the factory, customers and suppliers reflected in the Control Plan, PFMEA and work instructions?
Is the operating process effective, as assessed using process, final-inspection and customer PPM, Cp/Cpk indices, and process control parameters?

8 steps for a manufacturing process audit

1. Select a process to audit

Select the process to be audited. Prioritize processes according to their importance and the risks they pose to overall operations. Begin with the areas presenting the highest risks.

2. Select the manufacturing process audit team

Choose an audit team that understands the process being assessed. Team members should also be proficient in audit techniques, including sampling and analysis of results, and have the expertise needed to identify issues and the corrective actions required.

3. Determine the audit frequency

Decide how frequently the process should be audited. Where serious problems or nonconformities exist, audit the process more frequently until the situation is under control.

4. Announce the manufacturing process audit

Give advance notice of the audit so that it does not come as a surprise. The objective is to improve the process, which requires cooperation from everyone involved.

5. Schedule the manufacturing process audit

Establish an audit schedule covering the full work shift and follow it. The checks should use samples representative of the work performed during that shift. Define the schedule in advance and make the selection of representative samples as random as practicable. Following the established schedule supports results based on random sampling.

6. Document the issues identified during the audit

Document all issues identified and inform everyone affected. The aim is to find solutions together, rather than assign blame. The issues identified form the basis for corrective action and follow-up. Inform affected personnel so that they understand the issues and can contribute to resolving them. Also consider how the process being audited may affect other processes across the factory.

7. Define and implement corrective actions

Invite employees to suggest corrective actions and select appropriate options. Management should make the final decision on which corrective actions to implement.

8. Perform follow-up monitoring

Monitor the results of corrective actions. Determine whether the actions have actually eliminated the problem or whether further action is needed. Also verify that no new problems have developed or been introduced into the process.