A recent trip to Sweden, a hub of modular design, inspired this engineer to reflect on the pros and cons of modular design for medical devices.
A number of buildings in Sweden take advantage of modular design to reuse parts.
|This blue box controls the crosswalk. Though it sticks out like a sore thumb, it is easy to install and replace|
Modular design is a way of life in Sweden: it reflects the simplicity, commitment to quality, and expertise that is ubiquitous around the country. Modular design, which means designing a product to be reused, reapplied, and repaired easily, has huge benefits for a successful product line with long-term sales goals.
Though we can also find some examples of modularity here in North America, it is much more common to find “full package” solutions: a street post with built-in buttons, a shower installed directly into your bathroom, and unique houses are the norm. Though these look nice, they must each be designed individually and are difficult to replace.
The classic example of Swedish engineering is IKEA. Styled with square edges, a simple look, and focused usability, IKEA furniture is often easy to spot right away. Another feature that may be somewhat less obvious is modularity.
|IKEA furniture is often mix-and-match.|
It’s not typical North American style to have a bathroom that looks like all the fixtures were just dropped in place, but at IKEA you can buy a sink, a cabinet, and a shower and stick them all in your bathroom yourself (with a couple screws). Many products are mix and match, allowing customers to reuse modules to make a bookcase that’s tall and narrow, short and wide, or even two separate units. This also inherently comes with a degree of customizability—if you design separate products that work together, you can create a kitchen that works for you and fits your needs. Though modular design requires heavy investment in upfront planning, it has many long-term advantages
Pedigree in Medical Devices
In medical devices, we have one main reason to use a modular design: the ability to reuse approved components in multiple products. Testing is cumbersome in medicine, for obvious reasons, but reusing an approved power module in a few different devices leads to a safer product with an extensive history and saves cost and time in development.
Some might argue against module reuse by saying that the best design is always custom for each use case. How could a module designed for a blood analysis tool truly be the best option for a physiotherapy device? Are we risking our newest patients’ safety by cutting a corner and reusing a design?
In fact, modular design is a form of custom design that is safer in many ways because it comes with a pedigree of successful and fully characterized parent products.
If Google Is Doing It . . .
Google is maximizing the relationship between customizability and modular design with “Project Ara,” a modularized smartphone. Their tagline is “Designed exclusively for 6 billion people,” which speaks directly to the have-your-cake-and-eat-it-too benefits of modularity—you get a unique product with existing hardware.
Though smartphones are typically held in high regard for being sleek, small, and lightweight, Google feels the benefits of replaceable and customizable components will outweigh drawbacks in those features. Each component needs an interface, a casing, and must fit a standard profile, which adds considerably to the design effort. This size versus modularity trade-off applies to medical devices too.
|Google's "Project Ara" focuses on development of a modularized smartphone|
Is Modular Design Right for Your Medical Device Line?
Let’s reflect on the pros and cons of modular design to evaluate whether this approach is right for your medical device.
Cheaper medium-volume products—Existing modules can easily be adapted to make a single unit, or many. For high to mega volumes, a fully customized product will likely be cheaper in the long run.
Faster assembly—Once all the modules are produced, it is straightforward to hook them all together, rather than soldering or gluing an integrated unit.
Easier to maintain—The customer can simply swap out the part that is not working.
Longevity—One part failure does not doom the entire product.
Easier to upgrade and customize—The customer can upgrade the parts as they need, keeping the product up to date and spreading out purchasing costs.
Next generation is one step away—When a superior technology makes your product obsolete, simply upgrade the outdated part rather than the whole device. This also keeps your clients up to date and invested in your product.
Known problems and pedigree – Because your modules have been used before, they are characterized, reliable and predictable. It is also easier to invest time supporting and improving units that have a long life span.
Testing is easier – Once a module has been tested in one product, re-testing in another product is straightforward and will (almost) certainly be successful.
Higher initial design cost—More design up front is often needed to make a reusable module in the first place, which pays off later with reduced iterative costs.
Often bulky and sharp edged—The simplest things to put together are cubic and blocky, so modular products often lack a sleek, streamlined aesthetic.
Expensive connectors—Though the overall bill of materials cost is often lower with modular design (by leveraging higher volumes and investing in manufacturing improvements), connectors are an expensive key feature.
May not be exactly what you need—Sometimes it may be difficult to adapt a module for what you need, which is by definition no problem for custom design.
With the pace of the industry, it’s hard to imagine anyone taking the time to invest in modularity up front, but in reality stable components like power entries, battery packs, user interfaces, and networking adapters don’t really change that often.
As size is often a noncritical metric in medical devices (especially cart or table-top units), trading off for a larger unit can make sense if you have the budget for the initial design effort to make simple, reusable parts and get the most out of your labor. Simplicity is complicated, but like so many things in life it’s worth the effort.
|Check out the future of medical technology at the world's largest medical design and manufacturing event—register for the MD&M West Conference, February 9-11, 2016.|
Nigel Syrotuck is a mechanical engineer at StarFish Medical, a medical device design company headquartered in Victoria, British Columbia.
[Images courtesy of NIGEL SYROTUCK, IKEA, AND PROJECT ARA/THE VERGE.COM]