Medical device components have extremely high requirements for precision, material safety, and structural design. At present, miniaturization and complexity have become the development trends of medical accessories, and traditional processing methods are gradually finding it difficult to meet the industry’s demands. Relying on the advanced MIM metal injection molding process, it is possible to produce compliant and precise medical components. Now, let’s take a deep look at the relevant knowledge of MIM.
What is Metal Injection Molding (MIM)
Metal Injection Molding (MIM for short) is a near-net forming manufacturing process developed by combining plastic injection molding technology with traditional powder metallurgy technology.
This process involves uniformly mixing ultrafine metal powder with high-molecular binders to form a feed. The raw materials are then pressed into a custom mold by injection molding equipment to obtain a green body. Subsequently, the binders are removed through deglazing and high-temperature sintering, resulting in dense metal finished parts.
MIM has broken through the manufacturing limitations of traditional CNC machining, forging, and stamping. It not only possesses the feature of injection molding that can produce complex and irregular structures, but also ensures the original physical properties of metal materials. It is particularly suitable for mass production of micro, thin-walled, and complex-shaped precision metal parts. Nowadays, it has become the core preparation method for the production of high-end medical device parts.
Importance of MIM In Medical Device Manufacturing
As a preferred processing method for medical device components, MIM aligns with the strict industry standards of the medical field, empowering the development of the medical device industry from multiple dimensions such as product design, dimensional accuracy, material compatibility, production cost, and delivery cycle.
High design freedom, creating complex and irregular structures：
Most of the internal components of medical devices have a tortuous shape and feature fine hollowed-out and micro snap-on structures. Among them, surgical instrument accessories and orthopedic connection parts are particularly prominent.
Traditional machining is difficult to complete such complex structures, while MIM, relying on the principle of injection molding, can form various complex geometric profiles in one piece without disassembling parts for assembly. This is a core advantage that is hard to achieve with conventional processing techniques.
Ultra-high dimensional accuracy, controllable tolerance, and strong product stability：
Medical devices have an extremely low tolerance for dimensional errors. Even minor deviations can affect the effectiveness of device usage and even surgical safety.
The tolerance of products processed by MIM can reach ±0.1-0.02mm, with high consistency in part dimensions. The specifications of each batch of products are uniform, significantly enhancing the assembly matching degree and long-term reliability of implants and surgical accessories.
Safe and compliant material selection
Medical devices that come into contact with the human body have extremely strict control over raw materials.
MIM can be made of alloy materials that have passed medical certification. These materials have stable properties and will not cause rejection reactions after being implanted in the human body, ensuring the safety of patients’ use from the source.
At the same time, it can also prepare special functional materials such as tungsten alloys, meeting the production requirements of radioactive medical accessories.
Streamline subsequent machining and shorten the delivery cycle
MIM is a near-net-shape forming process. After sintering, the finished products basically reach the usable state of parts, significantly reducing secondary post-treatment processes such as grinding, cutting, and polishing.
It not only avoids the problem of parts scrapping caused by human errors during secondary processing, but also shortens the production cycle, which is in line with the current situation of the medical device industry where new products are updated rapidly, and project cycles are tight.
Achieve cost control under large-scale production conditions
If complex and small parts are processed one by one by CNC, the production cost per piece remains high. MIM consumes very little raw materials during mass production, simplifies the entire production process, and effectively reduces the cost of individual products while strictly adhering to the quality standards of medical devices, helping medical device enterprises gain stronger market competitiveness.
Characteristics and advantages of MIM materials
The MIM process can be adapted to a variety of materials suitable for medical scenarios, such as stainless steel, titanium alloy, cobalt-chromium alloy, tungsten alloy, tool steel, magnetic alloy, and low alloy steel. The material performance advantages are as follows:
1、Material has excellent biocompatibility:
The 316L stainless steel, Ti-6Al-4V titanium alloy, and Co-Cr-Mo cobalt-chromium alloy all comply with the medical industry standards.
The chemical composition of the material is stable. Long-term contact with human body fluids will not release harmful substances, reducing postoperative adverse reactions such as allergies and inflammation in the body.
In addition, the tungsten-nickel-copper series of tungsten alloys also has excellent radiation protection capabilities and can be used to make parts for radiation drug syringes, filling the gap of traditional processes.
2、Outstanding mechanical properties:
After high-temperature sintering, MIM parts have extremely high density, and their tensile strength and hardness are completely comparable to those of forged materials.
Orthopedic implants and surgical clamping components are subject to long-term force and repeated opening and closing. Relying on the high strength property of MIM material, the service life of the components is longer, ensuring the stability of the instruments during long-term use.
3、Outstanding corrosion resistance:
Medical stainless steel and titanium alloy raw materials inherently possess strong corrosion resistance. When parts are immersed in physiological saline, human body fluids, or medical disinfectants for a long time, they are less likely to rust or suffer from material corrosion and aging, thus extending the service life of implanted instruments and reusable surgical accessories.
4、H3 Excellent surface quality of the finished product:
After the sintering of the parts is completed, the surface is smooth and flat, and a clean surface can be obtained without additional polishing.
The smooth surface is less likely to retain blood and tissue residues, significantly reducing the probability of bacterial adhesion and meeting the strict hygiene conditions of the operating room.
At the same time, the appearance of the parts is regular, and the product condition is better.
5、H3 Supports multi-material integrated one-piece molding:
The MIM process can integrate metal materials with different properties into the same component. Some materials enhance toughness, some strengthen strength, and some are adapted to the drug contact environment, thereby meeting the diversified functional design requirements of medical devices and the customized R&D needs.
6、H3 High precision, suitable for large-scale mass production:
The precision of MIM parts can reach ±0.02mm, and complex micro parts can be produced in large quantities in a standardized manner.
Compared with machining, which significantly reduces the time for secondary processing, it has a prominent cost advantage in the mass production stage, facilitating the large-scale implementation of projects by medical device enterprises.
Optional MIM materials available for medical devices
Relying on a mature material research and development system, the MIM process can supply a series of alloy materials recognized by the medical industry, covering mainstream application scenarios：
| Stainless Steel | Low Alloy Steel | Tungsten Alloy | Titanium Alloy | Tool Steel |
| MIM-304 | MIM-2200 | MIM W-Cu | MIM Ti-6Al-4V (Grade 5) | MIM-A2 |
| MIM-316L | MIM-2700 | MIM W-Fe | MIM Ti-6Al-7Nb (Grade 26) | MIM-M2 |
| MIM-420 | MIM-4065 | MIM W-Ni-Cu | MIM Ti-5Al-2.5Fe (Grade 38) | MIM-M4 |
| MIM-430 | MIM-4140 | MIM W-Ni-Fe | MIM Ti-3Al-2.5V (Grade 9) | MIM-D2 |
| MIM-440C | MIM-4340 | MIM W-Ni-Co | MIM Ti-10V-2Fe-3Al (Grade 20) | MM-S7 |
| MIM 17-4 PH | MIM-8620 | MIM Ti-10V-2Fe-3Al (Grade 20) | MIM-H13 | |
| MIM-9310 | MIM Ti-15V-3Cr-3Al-3Sn | MIM-T15 | ||
| MIM-52100 | ||||
| MIM-430L |
Typical applications of medical MIM parts
Application 1: Orthopedic implant accessories (hip and knee joint matching components)
Titanium alloy and cobalt-chromium alloy parts processed by MIM are widely used in hip joint inner lining clips, knee joint fixing screws, and orthopedic locking washers.
Orthopedic implants need to precisely fit the human skeleton. MIM one-piece molding creates complex threaded and bionic concave-convex structures. The part strength meets the standards, and the biocompatibility complies.
Compared with the split-processed parts, the one-piece formed structure reduces the risk of part loosening, improves the adaptation effect after implantation, and alleviates the postoperative discomfort of patients.
Application 2: Components of minimally invasive surgical instruments
The internal micro-transmission parts of the endoscope clamp head, hemostatic clamp, and minimally invasive scissors are mostly made of MIM-316L stainless steel.
The internal space of minimally invasive surgical instruments is small, with many thin-walled parts and complex internal structures. CNC processing is difficult, and the yield rate is low.
MIM can mass-produce small-sized irregular parts with smooth surfaces for easy disinfection. The opening and closing actions of the parts are stable and reliable, making minimally invasive surgical instruments more compact and precise, and reducing surgical incisions.
Application 3: Dental restoration accessory parts
MIM-Ti-6AL-4V titanium alloy is used to make dental abutments, orthodontic self-locking brackets, and dental implant fastening accessories.
The oral environment is humid, and saliva is highly corrosive. MIM titanium alloy has strong corrosion resistance and will not be corroded even if it remains in the oral cavity for a long time.
The parts are precisely sized, and the brackets and abutments fit the contour of the teeth, providing higher wearing comfort. The parts are compact in size, meeting the development trends of modern invisible orthodontics and minimally invasive dental implants.
Comparison between MIM and traditional processing techniques
At present, the production methods of precision components for medical devices mainly include CNC machining, forging, powder metallurgy, metal 3D printing, and the MIM process. Let’s compare them from the core dimension.
Complex forming capability:
CNC is restricted by tool paths, and the processing of complex hollow structures is extremely difficult. Forging is only suitable for simple large pieces. 3D printing can create complex shapes, but the production cycle is long.
MIM relies on the principle of mold injection molding to form thin-walled, deep-hole, and irregular-shaped snap-fit structures in one piece, and has prominent advantages in forming complex structures.
Dimensional accuracy range:
Conventional forging tolerance ±0.3-0.5mm. The CNC precision machining tolerance is ±0.03-0.05mm, but the processing stability of micro and small parts is relatively poor. The tolerance of MIM mass production is stably controlled within ±0.02-0.1mm, and the dimensional consistency of mass production far exceeds that of CNC loose parts processing.
Material utilization rate:
The material utilization rate of CNC cutting is only 40-55%. The utilization rate of forging materials is approximately 60-70%. The utilization rate of MIM materials is close to 98%, significantly reducing the raw material loss of expensive medical alloys.
Mass production cost difference:
CNC has more advantages in the small-batch sample stage. When the order quantity exceeds 5,000 pieces, MIM, leveraging its mold-sharing advantage, can reduce the unit cost by 30-50% compared to CNC. The mass production cost of 3D printing remains high, making it only suitable for sample research and development.
Post-processing difficulty:
There are many burrs after forging and CNC machining, and the subsequent grinding and deburring processes are cumbersome. The finished products of MIM near-net-shape molding have very few burrs, and the post-processing procedures are simplified, which can reduce the quality risks of products caused by human factors.
Overall, when dealing with a large number of micro and complex medical parts, the comprehensive performance of MIM is superior to that of other processing methods.
During the small-batch sample stage, CNC Machining and 3D printing still have practical value.
Why choose NOBLE as your medical parts manufacturer
NOBLE is a Sino-British joint venture awarded by the government as a “National High-tech Enterprise”. We have two major business directions: “Smart Manufacturing” and “Care Products”. The “Smart Manufacturing” business specializes in providing customers with project support services, including parts machining and manufacturing.
More than 10 years of professional manufacturing and rapid prototyping experience. Our efficient team provides strong support for your new projects to 100% realize your requirements; Standardized management brings strict quality control of parts & products; Reasonable workflow gets lower cost with the same quality.
After years of hard work and development, NOBLE has gradually transformed from a precision parts machining and manufacturing enterprise with complete industrial chain supporting service capabilities, to a service-oriented enterprise that provides full support for customers’ entire projects.
Noble has ISO 9001:2015 – Robust quality management for general manufacturing. Consistent processes. Documented control. Traceable inspection.
ISO 13485:2016 – Stricter quality standards for medical device parts—rigorous process validation. Full traceability. Required for implantable and surgical parts.
Conclusion
MIM (metal injection molding) aligns perfectly with the development trend of modern medical devices towards miniaturization, structural complexity, medical-grade materials, and large-scale mass production. Compared with traditional CNC machining, forging, and other processes, MIM has become the preferred processing method for orthopedic implants, minimally invasive instruments, dental accessories, and radiation protection accessories due to its comprehensive advantages such as forming complex parts, optional medical materials, stable precision, and reasonable mass production cost.
In the development process of the medical device industry, the rational selection of MIM technology for component production can not only overcome the manufacturing barriers of complex and precise parts, but also balance product quality and production costs, promoting the high-quality development of the medical device industry.
FAQS
1、Q: Which certifications do MIM medical components obtain?
A: Our finished parts can pass ISO 10993 and relevant FDA-compliant tests.
2、Q: What surface finishing options are available for medical MIM products?
A: Electropolishing, passivation, and micro‑deburring are mainstream choices.
3、Q: Can MIM‑made parts undergo sterilization repeatedly?
A: Qualified MIM alloys resist high‑temperature and ethylene‑oxide sterilization cycles.
4、Q: Will MIM medical‑grade materials trigger metal allergies?
A: High‑purity medical‑grade alloys greatly lower the risk of allergic reactions.
5、Q: Is it feasible to add laser‑marked logos on MIM medical parts?
A: Precise laser marking is available without damaging part performance.
