Supply chain quality challenges in low volume manufacturing for medical device manufacturers include analysis of the data measuring supplier performance in relation to product risk. Under ISO 13485:2016, section 7.4, purchasing has a higher profile and more stringent requirements for documented purchasing process and supplier management.

Standard industry metrics such as lot acceptance rates (LAR), yield percentages and DPPM (defect parts per million) can be significantly skewed by the lower volumes typically encountered by small manufacturers. This criteria is essential to understanding supplier performance, yet a single non-conforming part in a small lot receipt can result in an unacceptable LAR and yield, when in reality the issue may be minor and not have the same proportionate effect on the product. In this manner, standard metrics do not paint an accurate picture of supplier performance.

So what can small manufacturers do to ensure that their suppliers are performing to an acceptable level proportionate to the risk failure would have on their manufactured products? Here are a few tips for tackling supply chain quality challenges in low volume manufacturing:

1. Ensure you have a clear process for establishing supplier controls. This process should include establishing criteria for evaluating, selecting, monitoring and reevaluating suppliers. Inputs to these criteria should also be well established and include processes for non-conformance (NCR), incoming inspection criteria to be met, expected performance metrics to specification via Supplier Quality agreements, and supplier feedback and communications such as formal supplier corrective actions process (SCAR)
2. Keep your Approved Vendor List as small as possible and ensure the suppliers on that list have good reputations, ISO certifications and capabilities suitable to the types of products you are manufacturing. This allows you to leverage your spend and partner with your key suppliers, while having a larger pool of data to use for assessing their performance.
3. Classify your suppliers based on the parts they supply and their relative risk to product. Suppliers who provide critical parts require more frequent and stringent monitoring to ensure that they are continuing to provide high quality and reliable parts for your medical device. These suppliers should have clear supplier agreements in place outlining exactly what is expected of the parts they supply and the conditions under which the parts are manufactured.
4. Push inspection criteria up the supply chain to your supplier. If your supplier can take measurements or perform testing prior to shipment, they are more likely to troubleshoot and correct fabrication errors prior to shipment and ensure that you only get good parts through the door. Remember to ensure that the evidence of conformance accompanies the shipment. This can be detailed measurements or test results and be backed up by a certificate of conformance. This may add cost to the parts, but it is usually less significant than the cost of poor quality discovered at incoming inspection or on the manufacturing floor.
5. Review supplier performance data in detail and don’t rely on performance metrics that can be skewed by low volume. When you are only getting a few shipments per year of a few parts from your suppliers, it’s important to look beyond the metric to review and further justify use of the supplier for your manufacturing needs based on objective evidence.

Small manufacturers don’t have the luxury of large data sets for measuring performance, but with attention to the details and strong supplier relationships, these tips can help you more fully understand what the statistics aren’t telling you when tackling supply chain quality challenges in low volume manufacturing.