Five reasons why Protomold® isn’t the best option for your medical device

Every custom injection molder will tell you, “There’s no such thing as an easy part.” Even Class 1 medical devices would rarely be referred to as “simple.”

When choosing an injection molding partner for your medical device, there are many considerations that come into play, including the technologies and materials they offer, their manufacturing capabilities, and the quality control processes they employ.

One of the largest players in the rapid tooling and parts marketplace is Proto Labs® (NYSE:PRLB), also previously and commonly known as Protomold®. Proto Labs has developed a custom injection molding operation that provides excellent service in both cost and delivery. Their rapid tooling process can often accelerate product development timelines and help minimize development costs.

But your partner in product development should be able to go beyond just delivering a part built to your model – they should be able to deliver a part that meets your desired outcome. With that in mind, here are five reasons why Proto Labs isn’t the best option for injection molded medical devices.

DFM has become DFx

What has traditionally been termed “design for manufacturability” (DFM) has evolved into “design for manufacturability, test, or production readiness” (DFx). In other words, DFx is a comprehensive approach to design that requires consideration of both the product and the business objectives, including reliability, regulatory requirements, cost, and supply chain.

In order to choose the right manufacturing technology to meet your DFx objectives, you must evaluate the cost, timeline, and product output capabilities of each technology. Your development partner should have broad experience with injection molding of medical devices and should be able to conduct tool design reviews to recommend the best technology for your part.

Proto Labs can supply a molded part based on your solid model, but they do not provide design guidance or share best practices, leaving you to navigate the manufacturing choices on your own.

Change is expensive

Source Graphic: Plastics – October 2016

Design freeze is that mythical place that most “built-to-print” shops are looking for from a designer. But you cannot get to design freeze without building a few parts, and many times during this process, parts that are critical to function need to be built in the exact design and intended material of the final part. Of course, you want to do this inexpensively and have the flexibility to change when design inputs change, without breaking the bank.

One way to reduce the costs associated with changes is to adopt a “steel safe” approach to the mold design. “Steel safe,” or “metal safe,” refers to the practice of leaving a small amount of extra material on the mold – for example, an inner diameter that should be 0.250 inches might initially be left at 0.255 inches. This allows the mold to be modified (removing material is generally easy; adding material is nearly impossible) as the mold and product design are evaluated and “dialed-in.”

Although Proto Labs uses metal safe mold designs, they do not offer engineering support to review the mold design and check for aspects that could interfere with assembly or bonding processes, such as ejector pin and gate locations. Without a design review, if a problem is discovered after the mold is produced, the cost to correct or replace it could be significant.

Materials are important

Material selection has an impact on everything from device performance, to testing and sterilization methods, to cost and profitability. When designing a new device, manufacturers often prefer to use materials that they already have biocompatibility data for, since this simplifies the qualification process. In addition, the shrink rate of the chosen material is an important factor that has to be considered when determining the manufacturing process for your product.

While Proto Labs offers a wide range of materials for injection molded parts, they do not offer an option to source materials not in their standard offering. If your preferred material is not included in this list, you must bear the cost and logistics burden of sourcing the material and shipping it to their facility.


There is a lot of complexity to the decision of whether to validate a component or the entire assembly of a device. The decision is risk-based, depending on the criticality of the device and your FMEA (failure modes and effects analysis).

Proto Labs will not provide a COC (Certificate of Conformance), nor will they complete a validation protocol on your behalf. There is no ability to validate the component before it ships to you, effectively forcing you to capture any issues with the part during your incoming inspection process.

It’s your product – shouldn’t you own the tool?

Proto Labs is able to provide inexpensive tools, but in their business model, you don’t own the tool – they do. This means that your design is not directly in your control and isn’t an asset that you can use when or where you choose.

This is why it’s often better, from a confidentiality and flexibility standpoint, to choose a manufacturer who gives ownership and warranty of the tool to the customer. By owning the tool, you have the freedom to do what is required for your business.

Conclusion: Your prototypes vendor choice can have broad consequences for your product

In the fast-paced requirements of product development, many development teams focus on price and lead-time as the most important factors in getting parts in hand. Proto Labs offers a great service for proof of concept parts prior to project funding as long as you understand that these tools may not survive the entire development process. In medical devices, the next stages of the development cycle are just as important, including the ability to service the longer term needs of your development project.

One of your goals should be to identify a product development firm that can help you make the right manufacturing choice for your product development needs. Working with your development team to make process recommendations for your part, conduct design reviews of your mold, and provide parts and make changes in order to meet the tolerances and exact materials required by medical devices.

Vaupell Inc. has ISO 13485 registered facilities in Michigan, Massachusetts, and New Hampshire. Our Product Innovation Center in New Hampshire offers multiple technologies to get your product to market including stereolithography (SLA), selective laser sintering (SLS), direct metal laser sintering (DMLS), cast urethane, 3-5 axis machining, and of course rapid injection tooling and injection molding using both horizontal and vertical presses. Learn more about our capabilities here.

Proto Labs® & Protomold® are registered trademarks of Proto Labs, Inc. (NYSE:PRLB) and are not used under license or with permission.