Mini Makers, Major Impact: Micromolding’s Role in Medtech

Micromolding has become a foundational technology for medical device miniaturization. It enables the high-volume production of extremely small, high-precision components used in a variety of medical applications, including minimally invasive devices, diagnostic platforms, microfluidics, wearables, and implantable technologies. Medical device manufacturers (MDMs) and their contract manufacturers (CMs) constantly push the boundaries of technology to develop smaller, more intricate components with tighter tolerances than ever before—which they can accomplish with micromolding.

“Micromolding has become a critical enabling technology for these applications, allowing the production of highly precise components that would be difficult or impossible to manufacture using conventional molding methods,” said Vijay Kudchadkar, director of plastics and sales engineering for New Richmond, Wis.-based Nissha Medical Technologies, home to its Isometric Micro Molding Center of Excellence, which specializes in micro tooling, micromolding, micro automation, and precision manufacturing.

Advances in micro tooling, precision molding, automation, and metrology enable the high-volume production of extremely tight-tolerance, complex molded components. The value in micromolding is not simply making smaller components—it also creates functional features that allow devices to be smaller, less invasive, and more capable, thereby improving patient outcomes. 

“As medical devices become smaller and more complex, there will naturally be an expanding range of applications for micromolding,” said Dominykas Turčinskas, CEO of Micromolds, a Lithuania-based precision manufacturing company specializing in micro and precision injection molding for medical, microfluidic, and other high-tech applications.

Applications include drug delivery systems, catheter-based devices, diagnostics, wearables, and implantables—”all of which rely on micro-scale features that influence sealing, fluid management, dosing accuracy, and overall device performance,” said Trevor Kasprzak, director of medical molding for Saint-Gobain Medical, a global manufacturer of custom medical components and engineered systems for medical devices.

Micromolding is especially in demand when miniaturization, functional integration, and dimensional control converge to have a direct impact on device performance. Key applications include minimally invasive surgical components such as catheter components, guidewires, cannulas, micro instruments, diagnostics, microfluidics (where channel geometry and sealing performance are critical), and implantable devices across cardiovascular, neuromodulation, ophthalmic, and drug-delivery applications. 

“Wearable sensors, for example, are creating high demand for smaller housings and more integrated designs,” said Ratheesh Theeyareth, chief engineer of precision plastics for Cicor Group, a Switzerland-based development and manufacturing partner for advanced electronics solutions in healthcare technology. “Micro insert molding, such as molding polymers directly around metal electrodes or contacts, can reduce component count and eliminate downstream assembly operations.” 

The role of micromolding in medical device manufacturing continues to expand as components get smaller, especially for minimally invasive procedures. “As MDMs continue to add functionality within smaller form factors, micromolding will provide the precision, repeatability, and scalability required to manufacture complex features at micron-level tolerances, while maintaining cost-effective production,” said Steve Lents, vice president of global sales for Carclo, a U.K.-based global provider of precision contract manufacturing for medical device and other high-tech industries.

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Micromolding has become the go-to technology for next-generation medical device development for a growing number of applications, “where very small geometries and precise features are central to how a device functions,” said Lindsay Mann, director of commercial strategy for MTD Micro Molding, a Charlton, Mass.-based provider of precision micro injection molding for medical device and other highly engineered applications. 

An ongoing trend in micromolding is the continued push toward miniaturization. Wall sections are getting thinner, part sizes and critical features are becoming smaller, aspect ratios are increasing, and tolerances are becoming tighter. “At the same time, medical device manufacturers are demanding higher production volumes, which require increasingly sophisticated sub-micron precision high-cavitation tooling to produce these complex components consistently and repeatably,” said Kudchadkar.

Although miniaturization continues to drive innovation in the medical device market, the focus is shifting from simply making features smaller to providing the required functionality. MDMs are looking to incorporate more performance into a smaller footprint by combining multiple functions into a single component.  

“There continues to be strong growth in microfluidics, wearable drug delivery, diagnostics, and catheter-based technologies, where small features directly influence device performance,” said Kasprzak. “There is also increased focus on reducing part count and assembly through overmolding and insert molding at the micromolding scale.”

Multi-material molding is gaining traction because it can improve design flexibility, sealing, and functional integration. The market is also moving toward highly integrated component designs. “In addition to traditional thermoplastic micromolding, MDMs are adopting technologies such as micro liquid silicone and two-shot molding to combine multiple functions into a single component,” said Lents.

At the micro scale, geometry, material, tolerances, tooling, and inspection are all connected. A decision in one area will affect performance elsewhere in the device. This is where the use of digital process control and statistical process data is especially valuable. “Real-time process visibility, combined with supplier Cpk data and disciplined process monitoring, provides a stronger basis for assessing manufacturing robustness,” said Theeyareth.

Producing smaller components with complex geometry and greater functionality drives the need for high-precision metrology. “At this scale, molding the component is only half the job,” observed Maggie Beauregard, director of quality for MTD Micro Molding. “You have to be able to measure the critical features accurately and repeatedly and have confidence in the measurement system itself. As features get smaller and tolerances get tighter, metrology will be critical for determining whether a design is truly manufacturable.”

What MDMs Want

MDMs want precision, repeatability, high quality, and shorter lead times. Designs are increasingly centered on miniaturization, tight and functionally justified tolerances, and high levels of integration. “This includes insert and overmolding around metal components, electrodes, or circuitry, as well as designs that combine multiple functions into a single molded assembly,” said Theeyareth.

To facilitate quality, lead times, and speed to market, MDMs are always on the lookout for suppliers that can support the broader manufacturing flow, from design for manufacturability (DFM) and tooling through molding, assembly, and process validation, rather than building a molded component in isolation. Most MDMs are focused on reducing development risk and accelerating commercialization. This includes finding CMs that can provide development, metrology, automation, validation support, and supply chain scalability. “A micro feature only creates value if it can be produced consistently throughout the life of the program,” said Kasprzak.

MDMs often present designs to their molders that push the limits of manufacturability. Micromolding typically involves either extremely small components or larger components with critical micro features such as sharps, ultra-thin wall sections, microfluidic channels, and exceptionally tight tolerances. Beyond technical feasibility, noted Kudchadkar, MDMs are focused on scaling production while maintaining precision and quality in three primary areas of demand:

• Molding components that have never been molded before to enable lifesaving and life-changing medical technologies
• High-volume manufacturing of extremely complex, tight-tolerance molded components while maintaining consistency, repeatability, and quality
• Utilizing advanced micro tooling and micromolding technologies such as micro two-shot molding, micro overmolding, micro insert molding, and micro in-mold assembly to eliminate secondary operations, reduce assembly complexity, and improve overall product performance 

Ultimately, MDMs seek CMs that can reduce development risk, accelerate commercialization, and simplify supply chains. “They want dependable manufacturing partners that can look at the design, identify possible problems, manufacture the mold, develop the molding process, measure the critical features, and support production,” said Turčinskas. 

Materials Matter

For demanding interfaces and applications, engineering teams tend to favor high-performance materials such as liquid crystal polymer (LCP), polyetherimide, and polyether ether ketone (PEEK), where the final decision is determined by the required thermal, mechanical, chemical, and sterilization performance. The challenge increases when highly engineered materials such as PEEK, LCP, bioresorbables, or implantable-grade resins are combined with thin-wall features, micro ports, or small flow channels. MDMs often work directly with polymer and compounding partners to evaluate the rheology, additives, fillers, and surface behavior for specific micro-scale replication.

Careful material selection is required when designing microfluidic chips, assay plates/cartridges, dispensing tips, or syringes/containers. The most common resin families for these applications are polycarbonate (PC), cyclic-olefin copolymer (COC), and cyclic-olefin polymer (COP). These have relatively low shrinkage rates and shrinkage variance throughout the part, enabling molders to consistently hold tight tolerances, even with part geometry that causes shrinkage variations, such as uneven wall thicknesses, long flow lengths, or anisotropic effects. 

“These materials are also preferred for applications that require optical clarity,” said Brett Lenz, director of engineering at Scottsdale, Ariz.-based Plastic Design Company (PDC), which specializes in micro injection molding for medical components and devices. “Because of their particularly high chemical resistance, COC and COP are well-suited for the containment of drugs and reagents. Both are available as thin films, making an ideal capping or sealing layer to many devices via thermal bonding, laser welding, plasma bonding, or even insert overmolding when part geometry allows.”

The use of multiple materials in a component is an option that should be considered early in the design process. “Micromolding provides an opportunity to place specific materials in a component where their physical properties are needed, such as seals and bearing surfaces,” said Jeff Randall, chief technical officer for Butler, Wis.-based MRPC, a provider of precision injection molding, multi-material molding, early-stage engineering support, and device assembly and sterilization. “Micromolding with multiple materials also reduces the component size as compared to a micro assembly, when all that is needed is a localized difference in material properties.” 

Tooling Developments

Tooling remains one of the biggest challenges in micromolding. It must withstand increasingly demanding geometries, including ultra-thin cores, micro channels, and high-aspect-ratio features, which can be difficult to manufacture and maintain. If the mold requires slides, actions, or other moving components, these mechanisms must be strong enough to survive production, but small enough that they do not interfere with the features around them.

Recent micromolding advances are in-process control, repeatability, and the ability to predict and control process variation. Purpose-built micro-injection units provide better control than simply adapting conventional molding equipment. Closed-loop process control is also becoming more important, enabling real-time correction rather than relying primarily on post-process inspection. 

“Toolmaking technology continues to expand what we can create in steel,” said Randy Guertin, lead tooling designer and supervisor for MTD Micro Molding. “Precision electrical discharge machining [EDM] and micro EDM, for example, allow us to manufacture details that would be extremely difficult or impossible to produce with conventional machining methods. That directly affects what designers can ask for in the molded component. If we can manufacture finer and more complex details accurately in the tool, we can continue to push what is possible in the finished part.”

Modern micromolding machines are specifically engineered for processing extremely small shot sizes with exceptional repeatability. Advances in servo-driven controls, injection systems, screw designs, process monitoring, and closed-loop control have significantly improved shot-to-shot consistency and process stability. “Innovations such as Sumitomo Demag’s ActiveLock technology help reduce shot-size variation by minimizing material leakage during injection,” said Lents. “These developments enable manufacturers to hold tighter tolerances and scale micro components from prototype to high-volume production more effectively than ever before.”

MDMs are very interested in shifting from molding individual parts to developing integrated manufacturing systems. “In-cavity sensing, improved process monitoring, and more advanced machine control help us understand what is happening during every single shot,” said Turčinskas. “Simulation and data-driven process optimization are also becoming more important and, in some cases, we are already moving toward AI-supported process stabilization.”

Some of the most exciting advances in micromolding come not from single breakthroughs, but from the combination of technologies from different disciplines. For example, laser polishing and laser structuring complement ultra-precision machining and EDM, enabling finishing and the creation of complex micro-scale surfaces that are difficult to access mechanically. Emerging micro hot-runner and near-cavity melt-control systems bring precise melt delivery extremely close to microcavities, reducing material volume and enabling very rapid filling of milligram-scale components. “Together, these developments point toward a future defined by hybrid tooling, engineered materials, and highly localized control of surfaces, melt, temperature, and gas, rather than simply smaller machines and tighter tolerances,” added Turčinskas. 

An often-overlooked obstacle in micromolding is the mindset that certain designs are “impossible” to mold, based on previous experience with conventional molding rather than advanced micromolding technologies. Continued innovation requires a willingness to challenge traditional assumptions and develop new approaches that expand the boundaries of what can be manufactured.

“For example, innovations in molding equipment, tooling design, and process control are helping manufacturers successfully produce components with extremely thin wall sections and challenging geometries that were previously considered beyond the limits of injection molding,” noted Kudchadkar.

How Small Is Small?

Advanced micromolding processes can produce extremely small components, including parts with masses on the order of 0.1 milligrams. Dimensional capability can reach approximately ±3.0 microns in specific applications, although ±10 microns is a more practical production benchmark for many designs. Wall thicknesses down to approximately 0.1 mm are achievable, depending on material rheology and process conditions. 

MTD Micro Molding is currently developing tooling for a component that is only 0.011 inches in diameter and evaluating another application that calls for a uniform wall thickness of approximately 0.003 to 0.004 inches. “We continue to see designs that propose dimensions we would have considered extremely difficult even a few years ago,” said Guertin.

“The important engineering point is that the nominal capability of the molding process is only one part of the tolerance stack,” noted Theeyareth. “Tooling, parting lines, material shrinkage, process variation, measurement capability, and handling can all consume the available tolerance. Design teams should therefore establish the complete tolerance budget and measurement strategy before specifying extreme feature sizes.”

There is no single dimensional limit for micromolding. Aspect ratio is often more important than absolute feature size, and achievable replication depends strongly on material rheology, tool surface, venting, temperature control, and the combination of tooling technologies. 

A shallow sub-micron texture can be easier to replicate than a much larger but deep and narrow microchannel. “Technologies such as variothermal molding and vacuum-assisted filling can push these boundaries significantly by keeping the polymer mobile longer and removing trapped air from microfeatures,” said Turčinskas. “In principle, aggressive thermal control can make extremely demanding geometries moldable, but the practical compromise becomes feature replication versus cycle time and process economics.”

“We have successfully molded components weighing as little as 0.00004 grams—approximately the weight of an eyelash,” said Kudchadkar. “The practical limits of micromolding are typically driven less by part size alone and more by the ability to consistently manufacture parts at production volumes. Having spent more than 35 years pushing the boundaries of injection molding and micromolding, we view each new challenge as an opportunity to further expand those limits.”

Moving Forward

MDMs are gaining a broader understanding of what can be achieved with modern micromolding technologies. They often discover that components once considered too complex or too small to manufacture—such as high-volume, tight-tolerance parts with complex micro features, ultra-thin-wall cannulas for drug delivery, thin-wall PEEK components, and even plastic sharps—are moldable. Engineering teams are also learning how advanced molding technologies can consolidate functions, eliminate secondary operations, and improve overall product quality and consistency.

Some of the most successful applications involve eliminating complexity from the device or the manufacturing process. Multiple functions can often be integrated into a single molded component using technologies such as overmolding, insert molding, two-shot molding, and micro liquid silicone rubber. This approach reduces assembly steps, minimizes tolerance stack-up, improves reliability, and enables smaller device footprints.

Some of the best micromolding solutions are derived from rethinking the manufacturing approach, rather than changing the design itself. Features that initially appear too complex, too small, or too costly can often be successfully molded via the right combination of tooling, materials, and process design. “We frequently see opportunities where insert molding, overmolding, or two-shot molding can reduce part count, eliminate assembly steps, and improve reliability while simplifying the overall device architecture,” said Kasprzak.

The next wave of micromolding advances will result from improved integration of tooling, automation, metrology, and process data. Closed-loop process control, advanced simulation, smarter inspection systems, and improved material characterization will continue to improve consistency and reduce development risk.

What excites Kasprzak the most is the convergence of multiple technologies. For example, microfluidics, wearable devices, advanced drug delivery systems, sensors, robotics, and personalized medicine are all moving toward smaller and more integrated designs. “Micromolding will help many of these innovations be commercially viable by enabling features and functionality that would have been difficult or impossible to manufacture at scale just a few years ago,” he added.

Kudchadkar is impressed by the pace of innovation in drug delivery systems, cardiovascular devices, patient monitoring technologies, wearable devices, and implantable solutions. MDMs are developing increasingly sophisticated products that will deliver therapies more precisely, continuously monitor patient health, restore critical functions, and provide real-time data to both patients and healthcare providers. 

“Micromolding plays a key role in enabling these next-generation devices,” said Kudchadkar. “As these technologies continue to evolve, we expect demand for highly engineered micro-scale components to grow significantly, creating new opportunities to improve healthcare, enhance quality of life, and expand access to innovative treatments.”

Mark Crawford is a full-time freelance business and marketing/communications writer based in Corrales, N.M. His clients range from startups to global manufacturing leaders. He has written for MPO and ODT magazines for more than 15 years and is the author of five books.