When a supplier sends you defective product, your first reaction is to send it back and issue a Supplier Corrective Action Request (SCAR). Not so fast…
You might get egg on your face if you don’t do a thorough investigation first. Often the actual root cause is that your own supplier controls are inadequate.
“Inadequate supplier controls” can include a variety of sins, such as:
- You have no supplier quality agreement to communicate customer requirements
- You didn’t send the latest drawing revision to the supplier
- Your suppliers were qualified based upon self-surveys and certificates that appear to have expired
- You have no historical trend data for supplier capability
- You are less confident of your own inspection results than your supplier’s inspection results
- You have never actually audited a supplier (hopefully they exist)
Medical Device Academy performed a Pareto Analysis of the FDA inspection observations report for FY2013. Supplier controls, 21 CFR 820.50, was one of the most frequently issued FDA 483s. The methods described below will help you prevent supplier quality issues that could result in a 483.
Communicating Material & Process Specifications
Drawings for machined metal components typically will identify the type of material that is supposed to be used to machine the component. However, it is often necessary to add notes to drawings and specifications for an assembly. For example, if a supplier assembles an instrument, and all screws require adhesive to prevent loosening, then drawings need to include a prominent note explaining this requirement. In the past, manufacturers relied upon a Certificate of Conformity to ensure compliance with a specification. Unfortunately, most Certificates of Conformity and Certificates of Analysis do not provide sufficient detail to ensure that every drawing specification was met.
Communicating Changes to Suppliers
When you implement a corrective action or make a revision to the design of a component, you need to communicate these changes to suppliers. Most companies communicate revisions at the time of the next purchase order, upon approval of the change or at both times. Seldom is this communication verified with a confirmation from the supplier, and often there is no plan for product that has already been ordered but has not yet been delivered.
If you make a design change, the change may result in component inventory becoming obsolete, work in-progress could become obsolete and any inventory that is waiting for a purchase order may need to be scrapped. Therefore, it is important to communicate design changes to suppliers and develop transition plans—prior to approval and implementation of the change.
The first step to effective supplier controls is the qualification of suppliers. Most companies rely on the same four tools for supplier qualification:
- ISO Certification
- Quality Manual
- Supplier Questionnaire
- Certificate of Conformity
I refer to these four tools as “antiques,” because they are slow and ineffective. You need effective supplier qualification tools. Suppliers can be qualified by verifying ISO certificates and reviewing supplier surveys, but there are modern tools for supplier qualification such as A3 Reports, Process Validation, SPC and PPAP reports. The “antique” tools for supplier qualification can also be modified slightly to improve the value you get from reviewing certificates and surveys. For example, the expiration date of supplier ISO Certificates should be tracked.
The most powerful modern tool for qualifying suppliers is statistical analysis of initial production lots to verify that the supplier’s process is capable of consistently producing conforming product for each dimension and specification. Until you have collected an adequate amount of information to meet your acceptance criteria for the supplier, you may want to keep the supplier on a “provisional” status. You can also use this data to determine which dimensions require routine monitoring and measurement, while other dimensions may require no monitoring and measurement, because the supplier’s process demonstrates a high degree of capability.
Trend Analysis of Supplier Data
Once a supplier is qualified, your company still needs to monitor the supplier on an ongoing basis. The simplest approach is to monitor the percent of lots that are accepted and rejected. This approach may tell you which suppliers require immediate attention and may warrant a supplier audit in the next quarter. However, this approach will not proactively identify problems. If you maintain a Statistical Process Control (SPC) run chart for each of the critical dimensions identified during your supplier qualification process, then you can identify process changes—even when your supplier doesn’t notify you. An example of an SPC run chart is provided below.