Metal Injection Molding (MIM) employs cutting-edge technology to facilitate the production of complex metal parts from the combination of metal particles and plastic binders for different industries. While its plastic counterpart was invented in the early 1870s, this state-of-the-art technique was created in the 1960s and gained recognition for manufacturing use later in the 1990s.
In recent years, MIM has been gaining popularity in many industries due to its ability to create top-notch and precise complex shapes. This article delves into the intricacies of the MIM process, exploring its benefits, limitations and how it impacts contemporary manufacturers.
What is MIM Manufacturing?
The Basics of MIM
Metal Injection Molding (MIM) is a metalworking process where metal powder particles are fused with binder material to form a feedstock, which is shaped and solidified using injection molding. By blending the superior traits of these two elements, it enables a seamless, streamlined creation of compact parts of exceptional mechanical attributes. MIM utilizes different kinds of metal materials and turns them into fine particles for product creation.
Applications of MIM Manufacturing
The utilization of Metal Injection Molding (MIM) in various industries has reshaped manufacturing processes by allowing the production of complex metal parts with efficiency and precision.
By leveraging its versatility, metal injection molding companies in singapore gain access to a wide array of designs and a broad range of components. This increases product performance and guarantees efficient cost management, maximizing manufacturing success.
MIM manufacturing leverages the shaping benefits of plastic injection molding and metal particles to create small, intricate metal parts, making it a suitable go-to solution for many industries. Due to its versatility, MIM has emerged as the preferred manufacturing solution across a wide range of industries.
For example, in the medical industry, MIM makes it possible to manufacture complex components for surgical tools, endoscopy surgical device and lifescience analyzers. Aside from that, MIM can also be utilised in the automotive industry to craft parts for sensors, actuators and Selective Catalytic Reduction Systems (SCR).
Additionally, the MIM process can also be adapted into the electronic sectors, facilitating the production of fibres optics transceivers, heat sinks and Co-Packaged Optics (CPO). Moreover, the industrial field can utilise the adaptability of MIM to manufacture control valve systems.
Metal injection molding manufacturer see the potential in the versatility of MIM, as it offers a unique opportunity to produce high-quality metal components with unmatched accuracy and finesse, catering to diverse industry needs.
Unveiling the MIM Manufacturing Process
Part design is pivotal in determining the feasibility of Metal Injection Molding (MIM), influencing factors such as complexity, size, and tolerances.
In terms of complexity, MIM outshines in designing parts with intricate features, overcoming issues that can cause loss of time and cost.
MIM can produce relatively small parts and larger parts, ensuring efficient production and optimal material utilization. Furthermore, MIM can achieve precision tolerances to meet the required specifications.
When considering Design for Manufacturability (DFM) principles for MIM, several key factors come into play.
In the metal injection molding process, maintaining moderate wall thicknesses prevents defects. Excessively thick or thin sections may lead to issues during the molding process. Consistent wall thickness also needs to be ensured throughout the parts to fill the component, prevent defects like sinks, and diminish warpage during sintering.
Additionally, proper gate design is pivotal for efficient part filling. Gates should be positioned in areas with the largest cross-section to guarantee complete filling, particularly from thick to thin sections. Thoughtful placement of ejector pins is essential to minimize witness marks on the final part.
Leveraging cam actions permits the creation of undercuts without necessitating secondary operations. Designing parts with undercuts should contemplate the direction of cam movements to form the features effectively.
By embracing these design elements and DFM principles, manufacturers can optimise part design for MIM, ensuring cost-effectiveness, efficient production, and superior quality.
A Step-by-Step Guide to the MIM Process
Feedstock Preparation
The first step of the MIM involves mixing the desired blend of metal powders with a plastic and wax binder.
The mixing of metal powders and binders occurs in a two-step process. Initially, metal powders are blended with plastic and paraffin binders depending on powder size and desired tool shrinkage.
Feedstock provides the basis for the final part. Selecting the appropriate powder mixture is essential for ensuring the production of high-quality components. Tailored feedstock blends can be formulated to meet particular requirements, including resistance to weight optimization, high temperatures, and desired mechanical characteristics.
Molding
The injection molding stage involves the heating and pressurized injection of feedstock into a mold cavity. MIM feedstock usually consists of a blend of metal powders and binders. The precise mixing of metal powders with thermoplastic and wax binders results in a homogenous pelletized feedstock through a proprietary compounding process, rendering it suitable for injection molding akin to plastic.
Through this process, the feedstock is heated and injected into the mold cavity under high pressure, facilitating the production of intricate shapes and enabling shorter cycle times. The resulting component is known as a “green” part.
Similar to plastic injection molding, the MIM injection molding process involves introducing the feedstock into the MIM machine, where it undergoes heating and pressurized injection into the mold cavity. Once injected, the ‘green’ part cools within the mold before being removed, allowing the process to be repeated.
Debinding
In Metal Injection Molding (MIM), the debinding process stands as a crucial phase where the binder is removed from the injected parts, resulting in a metal “brown” part. This process utilizes two techniques for binder removal: catalytic and solvent. The catalytic process involves the use of fuming nitric acid to eliminate a portion of the binder. On the other hand, solvent debinding involves soaking the green parts in a bath for several hours to remove the majority of the binders before the sintering process.
Sintering
The MIM sintering process is the final stage of the manufacturing process, wherein the ‘brown part’ transforms into a dense solid component. This process entails heating the parts within high-temperature furnaces, available in continuous or batch types. Continuous furnaces offer the advantage of simultaneous debinding and sintering, while batch furnaces, with shorter processing times, are well-suited for high-volume production. Operating under vacuum, these furnaces utilise flow gasses such as nitrogen, argon, or hydrogen to shield the metal part from oxidation or over-carbonization.
Secondary Operations
After the sintering process, Metal Injection Molding (MIM) parts undergo further refinement through secondary operations such as machining, surface finishing or heat treatment. These processes aim to improve dimensional accuracy, achieve tighter tolerances, enhance mechanical properties, and elevate visual appeal. Typically, these operations are either managed internally or delegated to specialized facilities.
Benefits and Limitations of MIM Manufacturing
Advantages of MIM
The advantages of metal injection molding span its versatility, cost-effectiveness, and precision, rendering it a prime option for fabricating intricate components with unparalleled accuracy and efficiency.
With Metal Injection Molding (MIM), intricate parts with complex geometries are effortlessly crafted, generating near-net-shape components that reduce material wastage and deliver cost-effective solutions for producing precise, small metal parts in high volumes.
MIM parts ensure comparable mechanical properties that has exceptional dimension control. MIM also offers efficiency and cost-effectiveness in high-volume manufacturing, tailored for large-scale production of small, complex metal components.
The MIM process allows for the production of complex parts in various metal alloys, including titanium, steel and copper, allowing for the production of parts with specific properties. This versatility not only improves design possibilities but also contributes to the potential cost-effectiveness of MIM for manufacturing intricate components.
Limitations of MIM
While MIM technology has many advantages, it also has limitations. Some of these limitations include material constraints, as not all metals are suitable for this process. Besides, MIM may not be the optimal solution for manufacturing larger components. Moreover, MIM parts might exhibit internal porosity, influencing mechanical properties and overall quality. These parts also require additional processes to refine their properties and achieve the desired specifications.
Conclusion
Metal Injection Molding (MIM) is an innovative manufacturing process that produces high-precision, complex metal components.
The MIM process combines the benefits of plastic injection molding and powder metallurgy to create near-net-shape parts with intricate geometries and tight tolerances. MIM materials include a wide range of metal alloys, including steel, titanium, and copper, which further expands the potential applications of MIM.
However, MIM is not without its limitations. Size constraints, material suitability and potential for internal porosity are some factors that need to be taken into account when employing this process.
Despite these limitations, MIM remains an attractive manufacturing process for a wide range of industries, including medical devices and consumer goods. The potential cost-effectiveness, high precision, and mass production capabilities make the metal injection molding process a valuable addition to the manufacturing landscape, offering a unique solution for the production of complex, meticulous metal components.
Occupying a leading position in the metal injection molding industry, AMT is a tier-2 manufacturer with smart manufacturing of industrial 4.0, implementing automation into its systems to enhance productivity and efficiency. Boasting advanced manufacturing facilities in MIM technology, coupled with a wealth of expertise accumulated over years of experience, have propelled AMT to the forefront of the sector.
AMT’s unwavering commitment to quality and precision has earned them a reputation for delivering high-performance components tailored to meet the diverse needs of their clients.
If you require top-quality MIM manufacturing services, look no further than AMT. Their expertise, advanced capabilities, and commitment to excellence make them an ideal partner for all your metal injection molding needs. Visit their website or contact them today to explore how AMT can help bring your projects to life through their exceptional MIM solutions.
