Here are the basics to get you started on rapid prototyping. 

Jeff Schipper, Proto Labs

Getting a medical device to market is a time-consuming, high-stakes challenge. While clearing FDA approval gates and passing clinical trials are essential requirements, they don't guarantee commercial success. Medical device designers can take advantage of rapid manufacturing processes--3-D printing, machining, and injection molding, including new time-saving advances in the process known as overmolding--to accelerate the development cycle and create products that not only work but also possess the feel, aesthetics, and other features that will help win market adoption.

Designers who use rapid manufacturers that deliver parts within days can develop prototypes faster, taking months out of the development cycle so products can get to and pass device verification and validation stages sooner and get to market more efficiently. Designers can quickly evaluate design options, including pursuing multiple parallel paths in materials that represent production parts. This allows time to try creative solutions that help bring the best product to market, not just one that performs as intended. This can boost the likelihood of adoption of a device among doctors, other health care professionals, and consumers. Rapid prototyping also can produce savings by condensing the development timeline and by leading to approaches that are more production-friendly or reduce manufacturing costs.

Here are five ways rapid prototyping can be accomplished:

1. 3-D Printing

Prototyping processes that will benefit device design include industrial 3-D printing or additive manufacturing, which works well with complex designs, multipart assemblies, and even end-use parts. Among these are stereolithography (SL) for concept modeling of thermoplastic-like parts; selective laser sintering (SLS) for functional prototypes and industrial-grade nylon components; and direct metal laser sintering (DMLS) for production-grade metal parts that can incorporate geometries and internal features that would be impossible to cast or machine.

2. CNC Machining

CNC machining, a subtractive manufacturing process, produces end-use metal parts and works well for prototyping and form and fit testing of parts. High-speed CNC milling produces parts from engineering-grade plastics and metals, while CNC turning works with both soft metals and steel.

3. Injection Molding

Injection molding performs best with functional prototyping, pilot runs, bridge tooling, and low-volume production of on-demand parts in an extensive range of thermoplastic and liquid silicone rubber materials. A rapid manufacturer that offers cost-effective tooling for injection molding, with the mold and parts available within days instead of the conventional steel tooling that often takes months to produce at a cost of $50,000, is an ideal choice for producing smaller quantities of parts.

4. Overmolding

Overmolding is an injection-molding process that involves applying a soft, durable material such as liquid silicone rubber to an underlying plastic or metal part--like the soft-touch handles on screwdrivers or many kitchen tools. Proto Labs' new rapid overmolding service uses cost-effective tooling to produce custom prototypes and on-demand, low-volume production in just days, reducing the turnaround time for this tried-and-true but otherwise time-consuming manufacturing process.

Overmolding improves grip and durability, dampens vibrations, and adds two-color aesthetics to parts. Overmolded products in the medical industry include surgical instruments with nonslip grips, chemical resistance and biocompatibility, and impact-resistance monitors and instrument housing. Overmolding also creates seals or gaskets that keep water, air, and dust out of sealed devices.

5. Bringing in Human Factors Engineering

Another way to add value to the device development process is to use rapid prototyping, particularly overmolding, in conjunction with human factors engineering. This practice involves applying human skills and abilities to device design, including interfaces, displays, and controls. The FDA is emphasizing this approach to minimize use errors and the possible harm that can result. In practice, considering how people interact with a device--how it looks, how it feels, its color--in addition to how it performs, can have a great influence on its adoption. Early use of manufacturing to make prototypes that incorporate the human factors design elements of the final product will enjoy an advantage in the marketplace.

Jeff Schipper is global segmentation manager at Proto Labs (Maple Plain, MN).