Exciting prototypes and whirlwind advances in MedTech technology are triumphs, but it’s always been precision and efficiency that drive the success of micro-component production runs. It’s at the intersection of innovation and excellence, then, that a true prototyping-to-production solution can be found.
CNC machining and metal injection molding — today’s most preferred processes for micro parts manufacturing — produce intricate, high-performance medical devices that save lives. From ophthalmic instrumentation and orthodontic brackets to jaws, clevises, and linkages for surgical robotics, it’s micro-manufacturing solutions like these that make interventional devices and minimally invasive procedures possible across MedTech applications.
However, MedTech miniaturization is accelerating and the percentage of small devices and robotic surgeries that demand micro-scale parts is increasing:
- From 2012 to 2018, the use of robotic surgery increased from 1.8% to 15.1%.
- By 2022, the proportion of surgical procedures in the US that were carried out using robotic technology had risen by 22%.
- Critical devices like pacemakers, meanwhile, continually get smaller. “It's becoming much smaller components, smaller parts,” an R&D director told Medical Device and Diagnostic Industry, “so the micro is getting more prominent because of the need to reduce the size of the devices.”
For these reasons, newer and better solutions are always needed in micro-scale manufacturing. Whether you're a seasoned professional or new to the field, join us as we delve into the solutions that are shaping the future of micro-manufacturing and medical technology from prototyping to production.
Table of Contents
- Materials For Medical Micro-Manufacturing Products
- The Difference Between Macro & Micro-Manufacturing
- Micro-Manufacturing Technology For Prototyping
- What Is Resin-Infused Powder Lithography (RIPL)?
- The Transition From Proto to Production
- Mass Production of Micro Metal Parts
- Contact Trio Labs For Leading-Edge Micro-Manufacturing Solutions
Materials For Medical Micro-Manufacturing Products
MedTech components rely on a diverse array of metals and other materials chosen for precision, durability, and biocompatibility. Robust corrosion resistance makes stainless steel grades popular, whereas materials like nitinol and tungsten offer unique benefits like high elasticity or thermal conductivity. Each material serves a unique purpose in enhancing the functionality and reliability of micro-manufactured medical devices.
Here’s a quick look at some of the core materials and metals used in MedTech micro components as well as the traits that make them useful:
- 17-4 Stainless Steel: corrosion resistance, strength, and machinability
- 316L Stainless Steel: exceptional corrosion resistance for biocompatibility
- 304L Stainless Steel: low carbon for improved resistance to intergranular corrosion
- 440C Stainless Steel: heat treated for high strength
- MP35N: nickel-cobalt alloy, toughness, corrosion resistance
- Ti64: alloy of titanium, aluminum, and vanadium for high strength, low weight, corrosion resistance, biocompatibility
- F75: alloy of cobalt, chromium, and molybdenum for high wear resistance against mechanical stress
- Nitinol: alloy of nickel and titanium, highly elastic
- Tungsten and Tungsten Carbide: high melting point and thermal conductivity
- Zirconia: similar to titanium but metal-free, used for ceramic medtech products
- Alumina: high strength, good wear resistance, used to create ceramic biomaterials
The Difference Between Macro & Micro-Manufacturing
Regardless of the materials selected, micro-manufacturing techniques present unique challenges compared to manufacturing at a macro scale. Materials and physical properties simply behave differently on a part that’s a millimeter wide than they do on a part measured in inches, feet, or meters.
While there is no defined scale where the line is drawn between “micro” and “macro,” the term micro-manufacturing is generally accepted to mean the making of parts measured from the scale of millimeters down to the scale of microns (millionths of a meter — a micron is roughly 0.0000393 inches).
Since a human hair is 50-120 microns wide, this should provide an idea of how fine the tools must be to machine the features of such parts. Some micro parts may be produced at a total width of 10mm or 12mm, while others might have an overall size of only 0.05mm. A sharp resolution of 5-micron voxels (0.0002”) provides ideal precision with the miniscule feature size of these tiny parts.
There are several key differences between macro- and micro-manufacturing processes:
- Materials: Macro materials have well-known and established properties. Familiar materials may behave differently at small scales due to factors like grain size, defects, surface roughness, and microstructure. Variables like mass, temperature, gravity, and pressure can have more influence on larger macro sizes.
- Scale: Macro-scale parts measure in centimeters, inches, feet, or meters, and require large enough equipment to hold and work on materials at that size. Micro-scale parts measure in millimeters or sub-millimeter sizes, requiring the use of specialized equipment and processes that work at resolutions too fine for macro tools to manage.
- Tolerances: A tenth of a millimeter may be an acceptable tolerance at a macro level, but smaller micro-scale parts absolutely require tight tolerances measured in microns. A tolerance of 0.0005 inches (12.7 microns) is effective for many MedTech components used in laparoscopic implements, cutting-edge robotic surgeries, or interventional devices.
- Design Constraints: While new designs can present novel challenges, macro-scale manufacturing is largely familiar territory. Micro-manufacturing equipment must account for not only the unusual ways micro scales affect mass and friction, but also the difficulty of achieving complex shapes. Each technology used for micro processes — CNC, MIM, or additive — has its own limitations.
Micro-Manufacturing Technology For Prototyping
Manufacturing technologies are often distinguished sharply between the stages of prototyping and production. Prototyping machines or techniques may require substantial adjustments to facilitate the efficient mass production of tiny components, particularly when the materials used during the proto phase differ from those intended for the final product.
Any viable prototyping process will have pros and cons. Nonetheless, broadly speaking, the process you select will benefit from a combination of desirable traits:
- Design flexibility: A process that has few design limitations and that makes it easy to iterate and alter the design without too much reconfiguration of equipment is ideal.
- Quick lead times: Prototypes, by design, are a temporary design — they’ll soon be replaced by a new proto that features adjustments. The R&D process grinds to a halt if it takes months to produce each new prototype.
- Low volume manufacturing: Since not many parts are needed at a time, the solution chosen must be cost-effective at these production levels. Job shops that specialize in low volume, high mix machining are a place many businesses will look first.
- Low setup costs: The high costs associated with tooling (mold creation) for metal injection molding rule it out as a viable prototyping option. Each new mold can require an enormous investment.
The CNC machining process has long been the gold standard for precision in micro metals. It also offers relatively few limitations on design and works at all levels of complexity when volumes are low. The achievable complexity is mainly limited by the size of the machine tools. Tool shapes may also affect the possible geometries.
CNC machining also produces prototypes faster and at lower costs than metal injection molding (MIM) — but still not “fast”. Lead times can typically extend to from six weeks to three months. When the design is finalized and converted to a full production run, more complex CNC-machined parts also become less cost-efficient due to the machine time required per part.
These limitations have opened the door for an innovative new technology that can replicate CNC’s benefits while mitigating its drawbacks: Resin-Infused Powder Lithography (RIPL).
What Is Resin-Infused Powder Lithography (RIPL)?
Among micro-manufacturing systems, both CNC and MIM suffer from long lead times and can’t navigate the shift from proto to production without challenges.
Trio Labs developed a new additive technology called RIPL to improve upon traditional methods of microscale manufacturing. The proprietary process uses standard metal injection molding powders to produce high-precision, 99% dense, metal parts for medical device prototypes with CNC-level precision. Prototypes made through RIPL match the functionality and finish of net-shape parts — they’re as good as the final product.
Importantly, as an additive process, RIPL can quickly adapt to design changes, only requiring updates in the digital model. This significantly improves design flexibility and reduces the time and expense needed to make modifications. RIPL produces its high-precision prototypes with quick turn times for rapid design iteration cycles.
The Transition From Proto to Production
Many manufacturers are familiar with the re-evaluation of technology that’s necessary during the switch from R&D to full-scale production of parts in high volumes. Careful consideration is needed because the processes typically seen in micro-manufacturing, CNC and MIM, both have the potential to create obstacles in the shift from proto to production.
Switching processes requires a new setup and increases costs. However, it’s not always possible to keep the same process — especially for complex micro parts. MIM is prohibitively expensive and design-limiting for prototyping, and CNC is costly when used for the production of complex parts that have longer cutting times.
The result is that a switch can sometimes be seen as “the cost of doing business” when transitioning from CNC machining 10 complex prototype parts to a 1,000,000-part production run. Scaling at that level can make the tooling costs of MIM worth the initial investment in the long run.
However, it doesn’t have to be this way.
RIPL technology provides a third way — a process that can seamlessly transition from prototyping to production. Creating parts is efficient whether you need 10 parts or 1,000,000. Significant savings in cost, time, and convenience can be realized when the same materials and processes that created the final prototype can now turn to full-scale production with no delays.
Mass Production of Micro Metal Parts
Metal Injection Molding (MIM) molds are micro-manufacturing solutions that are well-suited to extremely high-volume production. MIM uses molds with metal feedstocks to produce parts more quickly than other processes. It does not require the time-on-machine of CNC or the gradual build-up of additive 3D printing processes like RIPL.
As volumes increase for simple or moderately complex metal parts, the high up-front cost and long lead times for MIM mold creation are gradually overcome by the cost-savings of MIM’s rapid production speeds.
MIM does restrict the overall complexity of the design to the physical limitations of the mold, and this technology’s resolution and surface finish are a step down from CNC machining or RIPL. This means it’s less ideal for the production of extremely complex parts or those that require the utmost precision. However, when high complexity is needed and MIM isn’t capable of producing the part, CNC is a poor replacement due to the cost of long machining times per part.
This is where the scalability of RIPL truly shines. For the first time, RIPL has advanced 3D printing technology to the point where it’s possible to produce incredibly complex parts, at volume, faster, and with lower costs than CNC or MIM.
Contact Trio Labs For Leading-Edge Micro-Manufacturing Solutions
Trio Labs is breaking new ground in micro-manufacturing with our proprietary RIPL technology. Where other 3D printing technologies have fallen short of CNC and MIM, RIPL produces parts that observers assume have been machined at volumes that scale easily from handfuls to tens of thousands.
We produce medical device prototypes with extreme precision, full design flexibility, and rapid lead times. Connect with us to receive samples, request parts, or meet a team member for a demo of our capabilities. We look forward to showing you how RIPL is revolutionizing micro metal parts manufacturing from proto to production.