How to simplify the complexity of your medical device design

Mick Fry, engineer, Minnetronix Medical, shares how to simplify the complexity of your medical device design to make production more efficient.

The ultimate success of your medical device can be greatly affected at its inception – during the design phase. This early stage is the ideal opportunity to partner with others - especially those who will be responsible for producing and scaling up your device while keeping timelines and costs under control – for insight on how to achieve your goals for the device. 

Manufacturers can lend valuable recommendations during design, including ideas on ways to reduce the complexity of the device to increase success of the project, without affecting the device’s functionality.  

Take the number of parts, for example. At the design stage, consider having a manufacturer assess the number of parts that will be required to produce the device. There may be ways to combine or eliminate parts in various design and production scenarios. With fewer parts, development and manufacturing can be streamlined. With less parts to procure, there will be fewer supply chain issues, reduced risk of quality issues, and less time and cost needed for manufacturing, assembly, inspection, packaging, and shipping.  

Begin reducing complexity from the start 

The primary short-term goal when creating a med device is to prove its safety and efficacy – making sure it works. The long-term goal is to bring the device successfully to market – helping patients and driving revenue.  

And then there is the goal that should be ever-present: the ability to make the product efficient enough to meet clinician and patient demand while building the OEM’s business. Producing the product in the most efficient, cost-effective manner – from its first run to large volume scalability – should be on everyone’s minds and agenda, throughout the development of the device. 

At the design stage, device engineers are motivated by the short-term goal, and they design devices using what they have on hand, relying on their own experience with other devices they’ve designed. They typically build in a Lego-style format: take a part, add a part to it, add another part, and so on. As features are added to the device, the parts add up.  

Complexity begins to be baked into the device from the start. The farther they go down the design road, the more ensconced in design the multiple parts become, more tooling is built, more processes are created, and it gets increasingly difficult to change and/or correct the device later.  

At a basic design level, there is a part. That part is designed into a larger assembly. It's one part that must be controlled. There must be drawings, specifications, and manufacturing methods for that part.   

When the design grows to include 10 parts, that requires 10 different drawings, specifications, and manufacturing methods. For every addition and revision, there's a ripple effect -- a material non-conformance or a deviation that must be engineered, accounted for, and controlled. This leads to a systemic impact on the engineering workload required for the product. If you have fewer parts to control, revise, and track, the workload goes down. 

Design for manufacturability 

When a designer invites a manufacturing expert into the design process to discover opportunities to reduce complexity, such as by reducing parts, the result is a device that’s designed for an optimal development and manufacturing process. This process of collaboration between designer and manufacturer is called design for manufacturability (DFM).  

The design stage is the easiest place to reduce the number of components or parts. If a DFM process is not used as early as possible, there is still an opportunity to identify ways to use different methods of manufacturing the product, later down the line, to combine features of what would have been separate parts, into one part.  

An initial analysis at the design stage keeps score on a couple of things: the number of designed parts and the number of total parts. If a part is used multiple times, like a fastener or screw, there's an opportunity for one design. The specifications control that fastener screw but, if it's used 15 times in the design, then it's a component part that must be considered in the production system.   

In the analysis, you can keep count of the before- and after-concepts and compare and contrast DFM-driven improvements that can be made to the device. The analysis lets you quickly see the results on the system architecture and the complexity of the entire manufacturing and engineering systems that are required to build that device. 

Reduce the risks 

Risk is a direct result of the total number of parts and their critical features and dimensions. Reducing risk by reducing parts is done by dimensioning and assessing the tolerance stack-up of the parts – those that are made on the minimum material condition and those that are made on the maximum material condition – that must always fit together to give you the result you want from your device. If you combine two parts into one, you now have one part tolerance, and, if that part is made with the net shape manufacturing process (like moulding, casting, or stamping), those variations in parts and features are going to be smaller over the lifetime of that part than if you had multiple parts added together.   

Reduce supply chain setbacks 

Reduction of parts in a medical device also means having to procure fewer parts, which reduces supply/availability and shipment setbacks during production. The overall workload is reduced, as is the number of things that could potentially go wrong during first- and next-generation manufacturing if there is a multitude of parts that must always be readily available and affordable.  

Certified parts received by the manufacturer don't need to be inspected, but, when they are subject to a lot of variation, an inspection step is added to the production process. It takes time for 1,000 parts to come in the door, get measured, and be deemed acceptable before they can be put into inventory and eventually make their way to the production line.  

Reducing the headaches by reducing the parts in your next medical device is simple math: There is less process, problems, time, and money involved with one part vs. the multiplier effect of several. The earlier this equation is understood, the better chances you have to increase the success of your project, and your company.