Risk can be a threat or an opportunity, but as a threat it can be understood as the combination of the probability of occurrence of harm and the severity of said harm. For medical device manufacturers the risk levels in which they can categorize their products ranges from low to high based on the level of injury or even death a possible malfunction can cause.
Medical device manufacturing is one of the most highly regulated manufacturing segments and manufacturers risk more than litigation if their products fail. As these products directly or indirectly affect the well-being of their end-user consumers, quality errors can lead to the complete destruction of brand identity and cost the business everything. The constant need to deliver a near zero-defect production for every single lot produced is a challenge and requires the most modern tools possible to make quality management both precise and cost-effective.
Regulatory authorities, like the FDA, or the EMEA, lay out clear guidelines for the validation of the manufacturing process and the product based on the risk assessment of the given product category. This translates into measurement, control, and mitigation of risk through the validation process and application of statistical tools which allow for produced lots to be sampled in a verifiable, repeatable, and effective fashion.
According to the FDA’s Quality System Regulation (QSR) for medical devices, Code 21 CFR 820 Subpart A-§ 820.3 “Process validation means establishing by objective evidence that a process consistently produces a result or product meeting its predetermined specifications.”
The QSR also mandates the application of appropriate statistical tools for establishing, controlling, and verifying the acceptability of process capability and product characteristics, this is where sampling plans, statistical tools and AQL comes in.
Sampling needs to be performed throughout the process for individual production lots to ensure that production-related measurements, both variable, and attribute, are within acceptable norms and within the specification and validation. FDA regulation 21 CFR 820.250(b) mandates “Sampling plans, when used, shall be written and based on a valid statistical rationale. Each manufacturer shall establish and maintain procedures to ensure that sampling methods are adequate for their intended use and to ensure that when changes occur the sampling plans are reviewed. These activities shall be documented.”
AQL Defined: ISO 2859-1 establishes AQL (Acceptance Quality Limit), as a sampling-based method for determining quality through inspection of attributes. In simpler terms, AQL is the maximum number of defects allowed in a given lot above which the entire lot would be rejected, or the lowest level of acceptable quality.
AQL is an accepted standard across multiple manufacturing industries. For medical devices, AQL operations become critical because of the overarching regulatory requirements associated with the validation of the manufacturing process and the recording of metrics.
AQL levels may vary depending on the risk acceptance, regulatory requirements, and industry best practices. These levels are represented in percentages and can be better understood from the depiction below.
The chart represents acceptable AQL risk levels, and depending on the product type, it may be subject to general and/or special inspection requirements. The sample size and acceptable minimum quality levels are determined based on these underlying factors.
The example above demonstrates that even a critical single defect will lead to the rejection of an entire lot. However, that rejection might not necessarily indicate scrapping, but instead may call for rework or increased measurements to ascertain the specific defect and determine the root causes to implement improvements.
The details of determining and establishing AQL standards for medical devices in any given process would need a deeper explanation. However, for the purpose of this post, we will focus on how AQL can be established, sampling related metrics captured, reports versioned and validated based on guidelines through the aid of an MES application.
Where the MES fits in
Industry 4.0 means a lot of things for manufacturers, but what it means for medical device manufacturers is the ability to execute their manufacturing process while ensuring they are fully compliant from a regulatory standpoint and are able to produce the best quality product possible using the data in their own process in a faster and more cost-effective manner.
This is where the MES can play an essential function in operations. We have visited the role an MES plays in automated validation for medical device manufacturing, we will now focus on how it can improve sampling and implement verifiable AQL standards across the process. Bear in mind, MES is supposed to be the single source of truth when it comes to manufacturing, it is connected to all the process equipment either via IoT or through automation applications and allows users the ability to capture and report data directly from the shop-floor while storing it in the right format and controlling the versions.
An MES application, configured for the medical device industry, allows for the creation of sampling plans, based on risk and for those plans to be enforced either on a time or counter basis. The application supports AQL and allows the definition of measurement tools, along with their calibration status and switches severity automatically which is an advantage for high mix production facilities. It measures both variable and attribute data points based either on time or counter and can be integrated with material logistics to give users a complete view of the quality as materials move across the production line and are converted into the end product.
The MES, with its ability to capture and report real time quality data, does not only help implement AQL and create records which validate its implementation, it also triggers an action when any OOS (out of spec) event occurs. Based on the severity of error and set containment and corrective action protocols, the MES may trigger immediate re-inspection or re-work of a given lot. Using AI the application may also prompt other instances of similar failures which may help determine root cause of the error faster and record steps taken to ensure similar errors aren’t repeated.
Medical device manufacturers deal with high criticality and high-risk products, so a modern MES is a true ‘life-saver’, as it ensures the process is validated per FDA and EMEA regulations and helps improve the process simultaneously. The application automatically adjusts sample size and helps implement the sampling strategy based on pre-set protocols to alleviate dependence on manual enforcement of quality-related parameters.
Even metrology itself can be automated where possible, else, users can simply upload measurements on their mobile device (see figure 2 above). All this translates to a more predictable, more controlled, and more precise quality management paradigm, which is absolutely critical for medical device manufacturers.
So if you are looking to implement and automate AQL within your manufacturing process, think MES!