Six Ways to Prevent Supplier Quality Problems

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.

Supplier Qualification
The first step to effective supplier controls is the qualification of suppliers. Most companies rely on the same four tools for supplier qualification:

  1. ISO Certification
  2. Quality Manual
  3. Supplier Questionnaire
  4. 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.

SPC-Chart web

Validation of Inspection Methods
When you are monitoring and measuring critical dimensions for a purchased component, it is critical to ensure that your own inspection methods are valid. Even if a calibrated device can measure to a precision of 0.0001 inches, the method of measurement may be inconsistent. Two inspectors may get different results for the same part, or the same inspector may not get the same result twice when re-measuring parts. Therefore, you need to validate your inspection methods prior to approving inspection work instructions.

One of the most common tools for validating inspection methods is to perform a gauge R&R (repeatability and reproducibility) study. Repeatability is determined by having an inspector measure multiple parts of a known dimension. Typically, ten parts are used and the person repeats the measurements three times. This provides a total of 30 measurements, and the variation from the known dimensions is used to quantify repeatability. Reproducibility is then assessed by repeating the study with two other inspectors. This demonstrates the effect upon measurement results due to minor variations in technique. Gauge R&R studies are time consuming, but if your measurement process is not consistent, any trend analysis will be a waste of time.

Supplier Auditing and Remote Auditing
The most time-intensive tool for evaluating suppliers is the supplier audit. However, most supplier audits are limited in three ways:

  1. The audit is typically only one day in duration
  2. Auditors focus too little time on production process controls
  3. Companies do not use remote auditing techniques enough

The first limitation to supplier audits is due to the limited availability of resources for both companies—you and your supplier. However, if you are going to conduct one-day audits of suppliers, you need to make every effort to schedule multiple supplier audits near the same airport in order to minimize the travel costs associated with each audit.

Your supplier quality team might consider auditing potential new suppliers that are near existing suppliers during auditing trips, as well. Two suppliers per trip should be the minimum, unless no other suppliers can be identified in the same region.

Most medical device suppliers are ISO 13485 certified and therefore, these companies are routinely audited to that standard. However, contract manufacturers are not inspected by FDA routinely. Therefore, the weaknesses in a supplier often lie in the area of compliance with 21 CFR 820 that are slightly different from ISO 13485.

Suppliers are also accustomed to auditors spending much of their time in a conference room requesting a predictable list of procedures. In order to get the most from your limited time at a supplier, you may want to spend most of your time in production areas and request a list of quality records to be sent to you to review remotely after the on-site portion of the audit is completed.

Remote auditing techniques are relatively new, and few auditors have formal training on remote auditing. In fact, the ISO 19011:2011 guidance document only mentions remote auditing in a table in Annex B.

If your company wants to make greater use of remote auditing, emphasize that any activity that you can do in the supplier’s conference room can also be performed using interactive web-based tools, such as Skype, WebEx and GoToMeeting. Even a simple conference call and emails can replace 99 percent of the auditing activities that occur in your supplier’s conference room. What you can’t see remotely is how many people are actually doing what their paperwork says.

How will you know if your controls are working?
You can implement all of the above ideas, but the goal of supplier quality management is problem prevention—not problem correction. In order to prevent problems, you must be able to predict future supplier performance. Therefore, integrate statistical analysis into your supplier qualification process and use the quantitative results to direct continuous improvement of your supplier controls. If your supplier controls are effective, you will identify potential quality problems before you receive any nonconformity product.


Robert Packard is a regulatory consultant with 20 years of experience in the medical device, pharmaceutical and biotechnology industries. Robert served in senior management at several medical device companies, including President and CEO of a laparoscopic imaging company. His Quality Management System expertise covers all aspects of developing, training, implementing and maintaining ISO 13485 and ISO 14971 certification. From 2009 to 2012, he was a lead auditor and instructor for one of the largest Notified Bodies. Robert’s specialty is regulatory submissions for high-risk medical devices, such as implants and drug/device combination products for CE Marking applications, Canadian medical device applications and 510(k) submissions. The most favorite part of his job is training others. He can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

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