The art of design validation and verification
Medical device design operates on a similar concept, layering smaller components together to form one machine, each component tailored to the needs of the original equipment manufacturer (OEM).
Design verification and validation are akin to the finishing gloss, and aren’t reserved for the largest doll – or completed product; each component gets the same gloss
The words verification and validation are a little overused, and it can be easy to confuse the two processes or even to think they are one and the same. However, they are distinct and important practices that OEMs can’t afford to take for granted, especially in the field of medical device manufacture. The possible repercussions of failing to ensure that your new device is effective, safe and fit-for-purpose in medical and healthcare applications can be severe.
So what’s the difference between the two? Design verification establishes whether you designed the device right to the specification, design validation ascertains whether you designed the right device to meet customer expectations and requirements. The distinction may be subtle, but it is significant.
There’s no room for error when supplying medical devices, so verifying and validating your design proves that you’ve developed the best possible solution to a specific need and that it is safe to use. However, did you know that OEMs designing the machine are not the only ones going through this process? Often, the smaller components within a device are bespoke designs created by another OEM, such as the all important battery.
At Accutronics we understand how important it is to design the right batteries for our customers that are both effective and safe. That’s why the team places such a high premium on the two Vs. Not only does this prove our own products are up to scratch, it helps OEMs using our batteries to verify and validate their own devices.
Plan for success
Much like lining up your Russian nesting dolls in height order before tucking them away, successful design validation and verification requires order and planning. Treating this process as an afterthought will, at best, cause you a headache, at worst it could mean your device fails the procedure.
When we first sit with any customer to establish a brief for battery design we set up both a design verification plan and a design validation plan. These documents, which are reviewed regularly throughout development, mean we stay on target and develop the very best product for our clients’ needs.
A design validation plan should include a validation strategy that covers life cycle and risk assessment, validation deliverables including design specification, operational support, and continuity plans, acceptance criteria; standard operating procedure, training, documentation management, and guidelines on maintaining the validated state.
By comparison, a design verification plan should describe in detail the tests and trials that the device needs to be put through.
Testing the waters
For medical devices to pass validation and verification, they have to be built in the long term production environment as well as put through testing – in other words on the production line and by the people that will actually manufacture the product.
The US Food and Drug Administration (FDA) guidelines on the topic stipulate that medical device verification activities must be "conducted at all stages and levels of device design" and say that the "basis of verification is a three-pronged approach involving tests, inspections, and analyses". In addition, the guidelines state that devices should be "tested in the actual or simulated use environment as a part of validation".
To ensure our customers’ devices meet all necessary regulatory requirements, we test all of our batteries in simulated conditions, and to make sure we can do this effectively, we recently upgraded our test facility. Automated testing cabinets linked to climatic chambers tirelessly test cells and batteries for applications ranging from portable instrumentation and medical devices to robotics and defence.
Having these resources in-house allows our battery evaluation department to test the performance of rechargeable cells at different rates and temperatures, and as everything is fully programmable we can accurately replicate customer application discharge-profiles.
Cell manufacturers rarely provide useful cell test data, and when they do it is often data from performance under benign conditions. Our new test equipment allows us to really put cells through their paces based on real world usage. For instance, in the field of medical devices accurate power gauging, reliable charging and storage performance are vital. We are able to accurately replicate the demands the device will place on the battery so we know the cells will perform as needed.
Testing at various stages of production becomes easy when all the tools are on your doorstep, so we know that by the time we get to validation and verification our batteries will pass with flying colours.
When making Russian nesting dolls you start with the smallest one first and work out. She has to be perfectly formed and solid, or the rest simply doesn’t fit. Your medical device battery is that tiny figurine; if it is not formed properly the rest of your device will fail. Choosing a battery OEM that can guarantee the two Vs is the first step in getting your device verified and validated.
About the author:
Gareth Hancox is engineering and commercial support manager at Accutronics –www.accutronics.blogspot.com
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