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September 25-27,2024 | SWEECC H1&H2

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Designing for Manufacturing: 5 Common Startup Mistakes (and How to Avoid Them)

Your medical device may be novel, easy to use, even groundbreaking. But it won’t have the chance to be any of those things to real users – and earn real revenue – if you can’t manufacture it rapidly, efficiently, and consistently.

That manufacturing process starts with design – designing the device for manufacturing, to be precise. Countless start-up medical device developers miss the mark because they create intricately designed devices that can’t be manufactured for market use. The result is that their device is unable to get to market in time, or even to secure FDA clearance. To make sure your device has the best chance of success, review these common startup mistakes, and learn how to avoid them.

Mistake No. 1: Overlooking the GD&T Stack-Up

Not that long ago, before the advent of advanced 3D design techniques, it was important – and standard practice – to put tolerances on every dimension when designing a device. In fact, it was relatively easy to do when designing with less-sophisticated CAD programs. Today’s CAD programs, though, allow a designer to make everything fit perfectly, and not account for the inevitable variability to the real, tangible parts. If this variability isn’t accounted for, manufacturing will go awry.

Medical device developers need to accept that there is variability in every part. From the screws you buy at the local hardware store to custom-machined parts to injection-molded parts – even 3D-printed parts – every item has a tolerance. In prototyping, engineers can put parts together and make them work. But on the manufacturing floor, it may not always work. The key is always. It’s not uncommon to find that one lot of parts will work, and the next lot will not because the tolerances are just a tad off. In some cases, companies have had to custom-manufacture every device for a time period.

The solution is a GD&T (geometric, dimensioning, and tolerancing) stack-up on all parts. While good designers will perform the analysis, we also live in a world of 3D printing and electronic design and communications. You design a device in a computer program, then email the documents to others for review on a computer screen. It’s easier, faster and more accessible, but it doesn’t mean it always works. Taking time to learn how to do a GD&T stack-up, and consistently doing it, will pay off every time.

Mistake No. 2: Neglecting Servicing Needs

You may have heard about cars that required dropping the engine to change a spark plug or oil filter, and wondered why on earth someone wouldn’t have thought about that in the design phase. Medical devices are no different. Frequently, device developers will design beautifully for functionality, but forget about designing for servicing.

When designing durable equipment, whether large or small, complicated or simple in operation, it’s critical to remember that these devices have lifetimes. That means a real person – who likely isn’t an engineer and who isn’t intimately familiar with all the nuances and inner workings of the device – has to be able to calibrate the device from time to time to assure accuracy and precision, and to fix it as needed. Designing well for manufacturing means identifying the part(s) of the device that will need calibration or servicing most often, and then making sure those parts are accessible to the servicer.

Designers also can work on keeping things simple. Is there a real reason you need two or three or more sizes of screws? And more than one type of screwdriver or Allen key? Probably not. And while security is always important, is the threat of someone breaking into your device so great that you need multiple tools to get into it? For most devices, the answer again is “probably not.”

By thinking through the lifetime of the device, instead of focusing solely on optimizing the initial design, designers can avoid overcomplication and assure a manufacturable, serviceable product.

Mistake No. 3: Siloed Teams

Inherent in designing for manufacturing is making sure all components of a device work together. Usually, devices are designed by teams, not individuals. When those teams design with a laser focus on meeting their own needs and requirements, they often aren’t talking with each other about the needs and requirements of the entire device.

The classic analogy is the team whose goal was to design a horse but ended up with an elephant. How? The team in charge of leg design creates legs that are strong. The team in charge of hearing designs big ears. The team in charge of dexterity designs a trunk. And suddenly, you have a result that meets each team’s specifications, but loses sight of the initial goal.

In the medical device field, consider the design of a pump. It could be the best pump out there, but if it’s too big – or requires too much power, creates too much noise, doesn’t fit in the space in which it must work or myriad other issues – it won’t succeed in the marketplace.

The solution starts with good project management, and the upfront work to understand true customer and market needs – including shipping, storage, cleaning, and disinfecting or sterilizing the device. Strong requirements documents must consider all possible constraints at the beginning of the design phase, not at the end. If the design team knows that the pump can support only a certain battery size or physical size, they can work from the beginning toward that goal.

Or, coming from the other direction, maybe a top-line challenge is that only one designated pump will make a device work. In one true scenario, an IV pump was well-designed for use in normal conditions, but presented special challenges to work in the flight-for-life helicopter that needed it. The design team must understand that the goal is to make sure the device works under all applicable conditions, and then coordinate to reach that goal.

Mistake No. 4: Neglecting to Specify Parts TogetherThis is a classic mistake of the disconnect between design and manufacture. It is critical for every member of the design team to understand the context of how and why components and subassemblies work together. In other words, things can look really good on paper, but when you build them, reality says otherwise.

For example, a cardiac output computer prototype was unable to pass testing, as it would seemingly randomly reset itself. The problem was in the placement of capacitors on the circuit card. The capacitors for maintaining operating voltages for nearby circuit components were not distributed on the board. While the engineer understood the distribution requirement, the person laying out the board put all the capacitors together in one place; nothing on the schematic diagram said otherwise.

To help avoid this mistake, a device developer can create system and subsystem requirements documents in addition to individual component specs. With a “black-box” understanding of their subsystem – mechanical, electrical and otherwise – team members can establish context to help guide each part and circuit design, and design with the whole product in mind. The old saying about a round plug and a square socket becomes reality without proper context and coordination.

Mistake No. 5: Treating Packaging as an Afterthought of the Manufacturing Process

Packaging might take place at the end of a device’s product development, but its design impacts shipping, sterilization, and the end-user experience more than many development firms realize.

Just as you define end-user needs for the device itself, it’s critical to define how users – and there may be many as the device moves from a receiving dock to shelf to provider use – will interface with the device in its packaging. If you only find this information out when the device is fully designed and into manufacturing, you face likely costs and time in taking the device back into the design phase.

As an example, consider an innovative surgical robot design in early field testing. The robot arms had specialized tips that were single-use, sterile disposables. The arms, however, were intended to be cleaned and re-sterilized at the hospital. When the team went to design packaging at the end of the product development process, they discovered that the arms, at 44 inches in length, were too long to be packaged to fit any hospital sterilizers. The company had to redesign the arms for the required package design.

One of the most common design mistakes is making packaging too big. When that happens, you’ll need more warehouse space to store it, use more pallets to prepare for shipping, and end up shipping a significant amount of air. Fewer of your devices will fit on a customer’s shelf. In addition, developers do not want to – and should not – pay to sterilize more air than needed.

Avoiding the problem is straightforward: Incorporate packaging design considerations into the early phases of the product development process. You’ll avoid costly design errors, get your device to market faster and less expensively, and increase market acceptance.


Making the time and effort to take these steps can be hard for start-up device developers. It’s always a race to the finish line, to get your device to market, to beat the competition, to start earning revenue. Indeed, moving quickly is critical. But sidestepping essential steps will only serve to slow the process. Device developers who learn key mistakes to avoid will, unequivocally, be those who have the best chances of success.

Article Source:MPO