While modern electronic manufacturing and design are more conscious of the environmental impacts on biological systems for e-waste, medical devices have to operate while performing vital care safely. This heightened requirement can affect anything from material selection for components or the board to limits on circuit parameters. People rely on medical devices for everything from routine diagnostics to daily monitoring of conditions; as such, medical device prototype development uses the most stringent industry demands for safety and reliability as a baseline expectation.
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The Shifting Requirements of Medical Device Prototype Development
Medical prototype governance falls under ISO 13485, an international standard for quality management systems (QMS) that covers documentation, approval/review, and version control. ISO 13485 operates under a Plan-Do-Check-Act format that controls for design variation while seeking continuous improvement. Since the use and concerns of devices incorporate a vast number of different organizations, the standard defers to specific requirements; it is the responsibility of the designers to personalize their QMS to support these needs.
Any serious prototype begins with modeling, and because medical devices may be responsible for interacting chemically or biologically with the user, these factors require consideration. In general, any medical device will contend with the same basic design constraints as any other prototype, yet safety concerns may increase the difficulty of implementing them:
- Durability – Shock, vibration, deformation, and other results of instantaneous and long-term forces can become more prevalent with human interaction, especially in the case of wearables. Board failure due to mechanical action will likely occur at the solder joints joining components or connectors to the board, across the board due to flexure action, or between the PCBA and its enclosure. The best preparation, therefore, is a rigorous check of a production’s QMS to ensure that all design factors meet the minimum level of operational ruggedness.
- Wireless communication – Most notably, antenna function will depend heavily on location and normal device orientation for proper transceiving. Other electromechanical structures within the prototype will also affect the strength and reliability of the signal. Medical devices must incorporate a human body model to determine how electromagnetic waves propagate to prevent interference from or to other nearby devices; this wrinkle is critical as Internet of Things (IoT) devices continue to grow in prevalence.
- Power management – Low power consumption is ideal for portables, but this may be relative depending on the device’s functionality and features – in general, the more dense and complex the circuitry, the higher the power draw. On the reverse end, in more powerful prototypes that prioritize robustness (say for designs that significantly utilize actuators), the primary concern is thermal dissipation for manageable heat flux that prevents early aging of the devices.
There is no one-size-fits-all for medical prototyping due to the broad nature of the industry. Like with the QMS, designers will want to meet their specific industry and manufacturing needs while optimizing performance.
Incorporating ISO 13485 Practices Into Design
As alluded to above, proper documentation, including component and material traceability, is equally necessary in the design of medical devices. Document and product control is an essential part of any device DFM PCB, the difference being that safety takes on an even greater importance for devices that users rely on for their health. To that end, requirements for documentation, quality control, purchase order history, and more permeate the entire design process:
- Traceability – Electronic device manufacturing will want to record order history in case of mischaracterization (think improperly or falsely labeled RoHS materials), poor service life, or other factors, but medical devices also rely on a rigorous tracking system to locate devices post-production. Whereas consumer-level devices can simply issue a warning and recall to users, medical device manufacturers have to head off failures to prevent injury or incorrectly rendered information. Tracking procedures must extend throughout a device’s service life; these processes must be extensive to support continued safe use as set by the manufacturer.
- Documentation – PCBA manufacturing is a highly technical industry that relies on intricate control of physical and chemical processes. Strong standardization techniques start with documentation quality to communicate the requirements of the product and establish the manufacturer’s expectations (where necessary–it’s fair to expect some deferral). Medical device prototyping includes a scanning system to tag components entering the premises and proceeding through the assembly. This database forms a subsection of the larger traceability needs, but handling that volume of data becomes a complex undertaking in its own right.
- Iteration – All prototype development sharpens the design over continual revisions. Whereas non-medical devices may only focus on how well the product realizes the design or any adjustments therein, medical device prototyping will want to gauge the QMS as well simultaneously. This way, the QMS and design remain synchronized despite alternations or updates.
Your Contract Manufacturer Has Medical Device Prototyping Sewn Up
For the safety of its users, medical device prototype development adds an extra layer of complexity to development, ensuring the design and any information related to the procurement and production of the device are well maintained. The additional requirements can be taxing, even to those with device experience, as the QMS shifts based on the relevant standards rather than remaining a fixed implementation. Fortunately, VSE has a wealth of experience in general electronic prototyping and medical devices: we’re a team of engineers committed to building our customer’s electronics. With our valued manufacturing partners, we’ve facilitated PCBA production for several life-saving and life-changing devices for over four decades.
