Leveraging DFM to Gain Production Benefits—A Medtech Makers Q&A

By Sean Fenske, Editor-in-Chief

The development phase of a medical device is a fantastic time, when a napkin sketch can be crafted into a working prototype, enabling a doctor to hold and manipulate the device. However, if the product cannot be reliably and repeatably produced at scale, it’s not going to be successful. It’s critical a novel design can be produced in the necessary volumes.

To help ensure this transition between development and manufacturing can take place seamlessly and without raising red flags in the production environment, design for manufacturability (DFM) needs to be incorporated. Making the necessary revisions early, before design freeze, to confirm manufacturability results in an elimination of surprise costs and time-to-market delays.

To help further illustrate the value of DFM early in the product lifecycle, John Lipari, Chief Commercial Officer at PrecisionX Group, addressed several questions about the topic. In the following Q&A, Lipari defines DFM, offers an overview of the advantages realized from its use, and explains the importance of early manufacturing partner involvement.

Sean Fenske: Design for manufacturability (DFM) is often mentioned but not always explained. What is DFM within the context of medical device development?

John Lipari: DFM in medical isn’t a checklist; it’s a conversation that has to start the moment a device is being sketched. Done right, the design engineer, manufacturing partner, and regulatory lead operate off the same physics, the same tolerances, and the same producibility constraints from day one. Performed late, you end up making components you didn’t need, holding tolerances you didn’t have to hold, and discovering the gap between “feasible” and “producible” at the worst possible time.

What makes DFM uniquely consequential in medical is the regulatory weight every design choice carries. Tolerances that drift, materials that don’t behave the way they’re supposed to, or features that introduce unanticipated failure modes don’t just show up as scrap or warranty claims—they show up in your FMEA, your fault tree analyses, your design history file, and eventually, in regulatory questions during the 510(k) or PMA review. Every decision has to survive design controls and ISO 14971 risk traceability. The discipline becomes designing for production reliability and design-control traceability simultaneously.

When we engage early at PXG, we ask different questions than a traditional contract manufacturer might. “Is this tolerance critical to clinical performance, or did it come from a default CAD setting?” “Can we change a feature to eliminate a failure mode instead of inspecting around it?” “Where do design-output drawings become manufacturing instructions—and is anything lost in translation?” Those are the conversations that prevent rework, surprise yield issues, and the kind of late-stage redesigns that cost months of program timeline.

Fenske: Concerning DFM, why is it so important to bring a manufacturing partner into the development/design phase early?

Lipari: Early-stage manufacturing input is the highest-leverage engineering investment in the program. By the time a design is locked, the cost of changing it has grown by an order of magnitude—and in medical, “locked” means baked into your design history file. As a result, change isn’t just a rework cost; it’s a regulatory event. Bringing a manufacturing partner in at concept gives you a producibility judgment at the moment it’s still cheap to act on.

Practically, two things happen in parallel. The obvious one is flagging features that can’t be made, won’t be repeatable at volume, or will fight the material. The other is documenting why each design choice was made with manufacturing context in the room. That second piece matters more than people realize. A design history file (DHF) written with manufacturing input from day one reads as a coherent decision trail. A DHF written without it reads as a series of justifications added after the fact. Regulators pay attention to this.

There’s also a less-discussed benefit: process capability planning starts at concept, not after design freeze. You know which features will run inside Cpk 1.67 and which need a different approach. You’re not discovering capability gaps during process validation.

Fenske: How does DFM help reduce risk in manufacturing?

Lipari: DFM reduces manufacturing risk by moving the work upstream—designing out failure modes instead of inspecting for them. Inspection finds failure modes; DFM prevents them. In medical, that distinction matters because every defect that escapes is a candidate for a CAPA, every recall is a candidate for a regulatory inquiry, and every regulatory inquiry threatens the next submission. Every failure mode increases the required sample size for trials (if applicable).

Concretely, DFM-driven risk reduction shows up in three places. First, tolerance disciplines enable engineers to open up dimensions that don’t drive function and tighten only what matters, which collapses the variation budget into features that actually need it. Second, feature simplification—combining steps, eliminating undercuts, reducing setups so there are simply fewer opportunities for things to go wrong. Third, material-process fit—a.k.a., making sure the metal and the method are complementary.

The risk story compounds. A design with five failure modes in its FMEA needs five mitigations, five validations, five process controls, and a fault tree that grows accordingly. A design with two failure modes—the same function, just designed differently—has a smaller regulatory surface, a faster validation path, and a leaner ongoing quality system. DFM is how you get to the second one without sacrificing what the device has to do.

Fenske: Does DFM help get a product to market faster? If so, how?

Lipari: Yes, and more economically. DFM shortens the timeline from both ends. On the front end, you avoid iteration loops where a design gets sent to production with complications and requires redesign. In a program that is racing for IP protection, FDA submission, and other deadlines, this is unnecessarily extending the program window. On the back end, DFM means tooling and process development run in parallel with design refinement instead of starting after design freeze. By the time the design history is locked, the fixtures are already designed and tested, gauges are specified, and the pilot runs are ready to launch. The first validation builds are true prototypes, not a curiosity of whether you can make it. The biggest schedule upside is avoiding late-stage redesigns that require you to iterate on your locked design file history. This would repeat the entire process, adding time, cost, complexity, and in some cases, a program halt. DFM done well keeps momentum in the process.

Fenske: How does DFM relate to material selection?

Lipari: Material selection in medical is paramount as DFM, biocompatibility, sterilization compatibility (if applicable), and supply chain risk intersect. A material that satisfies ISO 10993 and meets sterilization criteria may still be problematic if it does not suit the manufacturing methods required to commercialize at scale. The reverse can also be true. DFM is what drives the conversation to make optimal trade-off decisions. It asks you not only if this will work clinically, but also if it will be manufactured reliably at the volumes needed, and if the supply chain is stable enough for a device that may be on the market for decades. These are all questions we ask ourselves before locking in material.

Fenske: When it comes to DFM, where are the mistakes made? What should device makers avoid to get the most value from DFM?

Lipari: The biggest mistake is treating DFM as a checklist item as opposed to a methodology or discipline. A form DFM review at design freeze is too late. DFM needs to be built into every conversation from an early stage, not tacked on at the end.

Another mistake is locking the design before the manufacturing partner sees it (this is most common and most expensive). We have seen countless proprietary designs with novel mechanisms that are unrealistic to produce at the necessary volumes and tolerances required for the regulatory framework. In addition, this means that treating default CAD tolerances as design requirements is also a common mistake. Proprietary devices don’t follow templates, and neither should specs.

Another mistake is picking material prior to understanding the feasibility of production. All of the elements that DFM drives should be done in the early stages to prevent negative downstream impact.

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