Supplier audits for preventative quality assurance
Manufacturing companies are constantly exposed – due to irregularities and downtime on the part of their suppliers – to the risks of disruptions in their own production processes, such as delays or even production stoppages and quality defects. Against this backdrop, every manufacturing company should take preventative measures to ensure their suppliers’ quality and ability to supply, and to minimise the risks. One important instrument in this respect is the regular audit of suppliers’ processes and products by the manufacturing company.
The right choice is essential
Supplier audits can be carried out by the manufacturing company at the supplier’s location or take place by means of a self-assessment by the supplier at the bidding of the manufacturing company. A supplier audit which is carried out on location by an auditor is particularly time-consuming and resource intensive. In light of the resources required, there is a bigger picture to consider in choosing the scope to be audited and deciding on the type of audit. The following questions must be answered in advance: How many audits are necessary? At what intervals should the audits take place? For which suppliers does an on-site visit make sense and where can a supplier carry out a self-assessment?
Different indicators can play a part in this context. Suppliers of critical components should, for example, be evaluated in the course of an audit visit. Further indicators for an on-site visit could be, for example, if parts have already been supplied with quality defects, there have been delivery delays or if large volumes are being supplied. For less critical parts, on the other hand, a self-assessment can be carried out by the supplier, which can, as needed, be verified using random plausibility checks carried out by the manufacturing company.
Carrying out supplier audits
Every supplier should be contractually obliged to subject every part (or family of parts) to audit at regular intervals. Whether this is carried out by an auditor or the supplier themselves – it should first be initiated using a self-assessment from the supplier. Different questions in regard to product requirements, production planning, measurements and assurance, auditing, targets and control loops, subcontractor management, shopfloor, maintenance and testing equipment will be evaluated by the supplier in this connection.
In the case of a self-assessment by the supplier, the manufacturing company can carry out a random plausibility check of the results. For parts on which there is a particular focus, following the self-assessment an auditor from the manufacturing company will carry out an on-site visit. In the course of a two-day audit, the questions will be validated again together with the supplier.
Identification and halting of risks
The goal of the audit is to identify potential risks. In the case of discrepancies, counter-measures will be drawn up and their implementation agreed with the supplier. In order to halt the risk permanently, the implementation of the measures will be examined by the auditor. The effectiveness can subsequently be measured using quality indicators, such as the number of faulty parts or reworking minutes.
The results of the audit can also be used as an index for evaluating suppliers and, for example, serve as key performance indicators in the supplier selection process.