Meeting OEM’s New Standards for Quality

The word “quality” has been applied so ubiquitously in the medical device industry that some argue the term has lost its influence to differentiate one company from another. The reality, however, is that as compliance requirements have increased and “preferred suppliers” lists have shrunk, the ways in which medical device original equipment manufacturers (OEMs) evaluate their contract manufacturing (CM) partners for quality also has changed.

In order for contract manufacturers to set their capabilities apart, they must be able to demonstrate that their quality systems are structured to help their OEM partners mitigate risk and cost-effectively produce devices that are verified and validated to be safe, reliable and effective. This requires medical device CMs to have more advanced quality controls in place throughout all aspects of their organization—particularly with regard to their product controls, process controls and supplier controls.

Product Controls
The process of taking an OEM customer’s device from drawing to production is much more robust than it was just a decade ago. The status quo used to be that if an OEM’s audit concluded that a CM’s quality system was adequate, the project would progress through design, development and manufacturing.

Today, if a satisfactory OEM audit is followed by drawings and control dimensions, the standard expectation is that the CM will provide specific detail for how every design specification and dimension will be measured and evaluated.

For example, if an OEM provides a CM with 300 control dimensions for 35 drawings, it’s likely that the OEM will want the official control plan to include:

• How the CM will measure each one of those dimensions;
• What instrument the CM will use to measure the dimensions;
• The number of parts to be measured;
• If a Gauge Repeatability and Reproducibility study will be performed;
• If the CM plans to do a 100 percent inspection or statistical process control (SPC); and
• If installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ) validation was done, what equipment it was done on, and when.

In today’s medical device manufacturing world, these are just a few of the delineations that OEMs might see in their CM’s control plan. As the pressure increases on OEMs to be fully engaged with what their suppliers are doing, a thorough control plan establishes that the CM has put sufficient controls in place to safely and effectively meet their OEM’s requirements.

Figure 1 illustrates the comprehensive quality system that medical device OEMs require of the CM partners.

Process Controls
Once the OEM has signed off on the design and the control plan, process controls manage the quality of the product once it advances to manufacturing. Through a variety of measurements and inspections, process controls help manufacturers verify and validate that their production processes are predictable, stable, and consistently operating at the specified level of performance.

Capability Studies and SPC
Meticulous medical device CMs will conduct capability studies and apply statistical process control (SPC) methods to improve their processes.

A capability study determines the extent to which a manufacturer’s process is capable of meeting their customer’s requirements, specifications, or product tolerances. This usually is expressed as a single number using a process capability index (Cpk). Cpk measures the actual capability of a process (e.g., if it’s operating off-center, etc.).

SPC goes hand-in-hand with a process capability study. SPC collects, organizes, analyzes, and interprets data to ensure that the production process is operating at its full potential to produce a conforming product.

If the capability study exposed an off-center manufacturing process, SPC can be applied to monitor and control the process and keep it from drifting even further (e.g., significant drop in t° and/or pressure; excessive vibration due to incorrect setup, etc.). This provides a manufacturer the opportunity to do something about non-conformances earlier in production, thereby reducing inspection, rework, and scrap costs. In addition, using SPC to monitor performance over time enables a manufacturer to catch “out of control” processes even before non-conformances arise, leading to further reduction in the cost and time required to produce the device.

GR&R
To sufficiently demonstrate to an OEM customer that measurement equipment and methods are accurate, a medical device CM should perform a gage repeatability and reproducibility (GR&R) study.
A GR&R study attempts to determine if the right gage (measurement equipment) was selected to accurately measure a specific part or feature. This determination is ascertained by analyzing the variation produced from both the gage/test equipment (repeatability) and the operators using the equipment (reproducibility). For a measurement system to be capable and stable, the variation contributed by the gage and the operator must be minimal.

For example, consider that you, Operator A, measure 10 individual sample parts (e.g., a shaft) three times using the same piece of equipment (e.g., optical comparator, etc.). If the measurement is so delicate that you can’t get the same reading three times in a row, it might be that you’re using the wrong gage.

And if Operators B and C measure the same 10 parts three times using the same measuring equipment that you did, and their data set reveals widely varying measurements, then it’s statistically proven that an alternative gage is needed—perhaps one that is table mounted or isn’t touched by the operator.

While most engineers and quality managers understand the principles behind GR&R studies, the reality is that most haven’t performed them to the degree that OEM’s rely on. With parts being designed with tighter tolerances (+/- .0001 inches), OEMs no longer can assume that their CM’s gages are accurate. By performing a GR&R study, CMs demonstrate to their OEM partners that they have the quality systems in place to statistically verify and validate that they are using the right gage to capably measure what they need to.

IQ, OQ & PQ
Once a copious control plan has been developed, capability studies and SPC methods have been implemented, and GR&R studies have been performed, a CM needs to ensure that its machines are capable of precisely and consistently making a part at specified dimensions. This is done through
installation qualification, operational qualification and performance qualification.

Five years ago, IQ, OQ and PQ validation processes were relatively uncommon, as capability studies were considered adequate enough to prove production quality. Today, leading medical device OEMs conduct more thorough machine validation using IQ, OQ and PQ, and expect their contract manufacturing partners to do the same.

Installation Qualification confirms that a machine has been installed correctly and is ready for use. This generally involves test reports describing wiring verification and tests of emergency stop and interlock features. If deviations are found during execution of the IQ protocol, the CM details the deviation and documents recommended correction action and preventative action. After IQ, the machine may need to be revalidated every two to three years.

Operational Qualification stresses the machine’s limits to determine the optimum process. The OQ reporting explains what constitutes proper documentation of test results and the actions to be taken in the event of deviations. OQ tests for machine functions typically include cycle-mode and run-empty tests, assessment of start-up, shut down, and power failure, and calibration of sensor functions for all sensors that could influence product quality.

Performance Qualification can be initiated when IQ and OQ are finished. Because PQ stresses the optimal process over longer trial runs, significant amounts of information and documentation involving the production process is required. This might include descriptions of in-process controls, the number of validation lots and runs, the number of validation lots produced under normal and worst-case process conditions, and specific manufacturing instructions. PQ documentation is used to generate the evidence that the machine can consistently produce a product that meets all predetermined specifications.

If a machine is moved, becomes unbalance or misaligned over time, has a major repair, or is changed in any way, it can affect how the machine operates. To verify that a change in the machine or assembly process does not impact product quality, the machine may need to be revalidated. Revalidation includes documenting what change was made and performing a failure modes and effects analysis to identify any risks to product quality and human safety caused by the change(s).

Although IQ/OQ/PQ validations take more time and cost more money, overall it gives both the OEM customer and contract manufacturing supplier a much higher degree of confidence in the quality of the end product.

Supplier Controls
Just as medical device OEMs must audit their CMs to ensure their standards for validation and process controls are being met, a CM must have controls in place to objectively confirm that their supplier can capably and consistently deliver high-quality parts. Suppliers also should be evaluated and monitored depending on their classification or “risk” related to final product.

By reviewing a supplier’s control plan, process flow, process capability and/or measurement system, a CM can gain a clearer understanding of its process capability to assure that purchased products conform to requirements. If the process capability does not satisfactorily meet the CM’s minimum expectations, the supplier might need to improve its process(es), increase inspection frequencies, increase inspection sample size, or implement controlled-shipment by sending smaller lots so the potential risk of receiving non-conformance products can be eliminated.

It’s also important for CMs to establish an adequate acceptance quality level (AQL) sampling plan at incoming inspection for products from its suppliers. Based upon the type of products, how they fit and function with their mating parts, and, of course, supplier’s capability, a specific inspection plan needs to be established for each component, and the appropriate AQL set for each critical feature.

Once the sample lot size has been determined, a CM’s supplier should submit a pre-production sample (first article) for the CM to verify to confirm that it meets quality requirements. First article samples gives the CM objective evidence that the engineering, design and specification requirements are correctly understood, accounted for, verified, and recorded by the supplier. If the CM’s first article inspection substantiates that the supplier prescribes to acceptable production methods, then the sample is considered the product indicator.

It’s recommended that CMs retain their supplier’s first article samples to help maintain consistent quality. In the event that the supplier’s product ever deviates from the approved first article sample, the CM will have the evidence to confirm that the product it is receiving is different than what originally was approved.

With every new supplier and every new part, it’s important to request a new first article. Just because a supplier is qualified to anodize parts, for example, doesn’t guarantee that it is qualified to nickel-plate them. Each supplier should be evaluated at the part and process level and prove its capability and repeatability.

Last, but certainly not least, maintaining supplier control also means clearly stipulating in the supplier quality agreement that if the supplier changes anything, or deviates from its process in any way, it is contractually obligated to notify the CM. As an example, if the supplier makes any change to material or transfers the product to a different facility or sub-contractor, it needs to inform the CM before sending them any parts. This provides the CM the opportunity to conduct the same approval process again and re-verify the supplier’s quality, capability, repeatability, and reproducibility.

Controlling Quality Advantage
Traditional quality systems have been based upon inspection as the basis for quality control, supported by standard gage calibration systems. Over time, gage repeatability and reproducibility studies have proven to enhance overall measurement systems and validation requirements have become essential to accurate process controls through final process validation of the product. In addition, fully documenting each of these steps in a formal control plan offers an OEM more rigorous supporting evidence of the CM’s approach.

With medical device regulations placing a greater emphasis on quality, OEMs will continue to seek CMs that enhance their control plans, elevate their process controls, and stringently control their supply chain. In doing so, CMs not only minimize the risk of an U.S. Food and Drug Administration warning letter—or worse, a product failure—they become a better, more transparent partner to their OEM customer.

Vu Doan is quality engineer, Angel Domingo is quality systems manager, and Joe Rotino is vice president of regulatory affairs and quality assurance at Pro-Dex Inc., an Irvine, Calif.-based company that designs, develops and manufactures surgical devices, motors, metal components, and sub-assemblies for world-class medical device OEMs.