What Are Metal Injection Molding Parts? A Beginner’s Guide!

Introduction

Did you know about metal injection molding parts? These are real strong shapes made with metal powder! This guide illustrates how these parts come to have their shape, size, and strength. OK, so let’s learn some steps, tools, and checks, to check it out!

What Are Metal Injection Molding Parts?

Metal Injection Molding (MIM) parts start as metal powder and binder mixed. This shape molds as a mix. And when you do, you can make small parts that weigh as little as 1 gram or as much as 100 or more grams, with detailed designs. Parts shrink 15–20%, ‘like shrink wrap’ after being molded and then baked (sintered) in a special bake at 5500C to make them strong. Things like medical tools or car parts work with MIM parts. These parts are very precise and strong due to a high density (98-99%).

The Metal Injection Molding Process!

·        Feedstock Preparation

First, you combine tiny metal powders with a thermoplastic and wax binder. The mix becomes a paste like material and then into pellets. Into the machine go these pellets. Accuracy requires tiny powder size less than 20 microns.

·        Injection Molding Phase

The feedstock is pressed at high pressure into a mold with a heated material, forming into a “green part.” The first part cools and hardens quickly, and the next is ready.

Metal injection molding parts are able to maintain very exact dimensions within ±0.1 mm, a perfect way to make small parts. Each shape requires this phase to achieve perfection, but it’s all done at up to 138 MPa.

·        Binder Removal

The removal of wax and polymers doing the binder removal hold metal. This creates a relatively “brown part” with small controlled pores for relatively easy sintering.

These binders can be removed, resulting in the improved final strength. Here, each metal injection molding part gets 20-30% porosity here. The process of making the parts strong and ready to go on to the next step is called sintering.

·        Sintering Process

The “brown part” processes in a high heat area that can reach 1,400°C. The particles are fused tightly at the high heat. Metal injection molding parts become dense and solid. The material shrinks every part about 15–20%, which keeps it tough. The result? Very workable, solid parts.

·        Final Densification

Lastly, final densification causes each MIM Part to be even tighter and pushes out any remaining small holes. Parts are pushed to greater than 95% density by heat or pressing, which makes each one feel like cast metal. That way the parts are strong enough for their jobs, and everything is the right size and shape.

Advantages of Metal Injection Molding Parts!

·        High Dimensional Accuracy

Metal Injection Molding (MIM) parts fit precisely, often within ±0.3% tolerance. They fill the molds tightly with metal powders. Finally, they shrink 15 20% on their way to final shape during sintering. Thus, MIM is ideal for small parts. With no extra steps needed, you can make complex structures, knowing your parts will fit exactly.

·        Minimal Material Waste

Up to 98% of the material becomes parts with the MIM process. That’s because when you make something with MIM, there are no scraps because everything is exact metal powder.

MIM is cheap, especially with expensive metals because its approach yields this high efficiency. This is why industries such as aerospace love MIM. Metal injection molding parts waste less, save more.

·        Complex Part Production

MIM manufacturing leads to small and intricate parts in one go. The fine details; thin walls and small internal shapes favor MIM. It is a strong method that helps make parts like medical tools and gear pieces durable. Metal injection molding functions can be molded into the shape you need without any extra assembly; all from one mold.

·        Consistent Repeatability

That’s because MIM makes the same parts each time. Because machines make the metal to tight tolerances you always get the same result in each batch. Medical uses MIM because it will always fit the minute specifications. Metal injection molding parts are very reliable, so the metal parts last longer and are perfect working parts.

·        Excellent Surface Finish

The MIM parts come straight out of the mold smooth and polished. Because of this quality finish, you won’t need to do any extra polishing, meaning more time saved, and less work for you.

Parts made by MIM can go from being ready to use or coat, from doing electronics to car parts. Every time you use Metal Injection Molding you get clean, polished parts.

Materials Used in Metal Injection Molding Parts!

·        Stainless Steel

The rust resistant feature of Metal injection molding parts is stainless steel. 17-4 PH and 316L are strong and stainless like. Types like 420 are tough for tools. It’s shiny due to chromium. Parts work well for kitchens as well as medicine. Easily handle heat to 1200°. Stainless steel parts are in many things!

·        Tool Steel

Metal injection molding parts is extremely strong Tool steel! A2 types keep shape well and D2 types are hard. It is great for strength in car and plane parts. The high heat tool steel resists, up to 1100°F. Even doing hard work, parts don’t break easily. Tool steel may be seen in sturdy tools.

·        Tungsten Alloys

Parts made from tungsten alloys are strong and heavy!! W-Ni-Fe is great for blocking out radiation, and W-Cu conducts heat pretty good. Parts work in high heat as Tungsten melts at 5000°F. Precise tools are balanced with these heavy parts.

·        Copper and Titanium

Special on parts: copper and titanium! Well, if copper can move electricity well then, it’s great for electronics. But titanium is both light and strong, and is used in planes and medicine. It doesn’t rust and can take near 2000°F in heat. Why are these metals useful for cool machines?

·        Specialty Metals

Parts with specialty metals are amazing! Cobalt chromium is safe for the body and lasts long. Because Inconel is heat-safe past 2000°F, it’s used in jet engines. Perfect for medical tools, shape-memory metals like Nitinol bend and go back. Parts made with specialty metals are super strong, and super special for big tasks.

Table on Materials Used in Metal Injection Molding Parts!

Limitations of Metal Injection Molding Parts!

·        Size Constraints

Metal injection molding parts are small. Bigger parts shrink 20%, making them tricky, while they measure up to 2 inches, or 50 mm. When parts weigh more than 100 grams, they get more expensive to make. Molds really have to be tended to and scaled. This helps to keep costs nice and low, but works only ok for tiny parts.

·        Tooling Costs

Metal injection molding parts has a high tooling cost. Molding each mold can cost approximately $2,000. Molds must not break under heat. Parts are kept tight precise molds, ±0.03 mm, switching molds costs extra. Big runs and parts well, these special molds save money and.

·        Shrinkage Control

Metal injection molding parts can shrink 20% in sizes. What makers do is adjust with bigger molds. Control of size during sintering is controlled by high heat, around 1,300°C. Tolerances then are very important: if parts shrink unevenly, they can turn out wrong. Shrinking tight shapes need careful watching to make sure they stay the right size.

·        Post-Processing Needs

Metal injection molding parts require extra work such as CNC cutting after they are made. Heat treatment is added steps; they make parts better, but they cost more. These steps help make parts strong and smooth, if parts have hard shapes. It takes longer, but makes parts fit well and look nice.

·        Material Flow Challenges

A binder is needed to flow metal into Metal injection molding parts. And parts with thin walls or that have unique shapes don’t flow as smoothly. To maintain strength of parts, feedstock has to remain even. Each part is kept sturdy from being set on correct flow, pressure and heat.

Cost Considerations in Metal Injection Molding Parts!

·        Initial Tooling Investment

It takes no peas to get the money to create molds for Metal injection molding parts. Basic molds cost $2,000; the complex can run $100,000. Parts can be made faster using multi cavity molds.

Parts will die a little more slowly because you are using more specialized machine such as CNC and EDM which shape your parts exactly. One mold only allows you to create many parts at once.

·        High-Volume Cost-Efficiency

Metal injection molding parts are cheaper to make lots of pieces! Molds make thousands of things at reduced cost by sharing cost through parts. Multi cavity molds help you to make more pieces faster. Raw materials cost less when bulk order. It’s a good way to do it if you need lots of parts that are all exactly the same.

·        Reduced Secondary Processing

Once molded, MIM parts don’t need much work. Parts are smooth, and ready for use, requiring only simple finishing as they are made with precise molds. Less work, less money, and less time.

No extra steps. For some steps, like debinding and sintering, the steps actually happen within the mold, decreasing labor on more complicated shapes since the mold is now doing most, if not all, of the work.

·        Complex Mold Design

Fancy mold tools are needed for MIM complex shapes. Detailed, undercuts, require special machines such as EDM, to be made. Hard designs require more expensive hot runner systems and multi-cavity molds in order to lower the cost.

·        Long Lead Times

It takes 8–12 weeks to make MIM parts. It takes time to set up molds and complex machines. Using overseas factories has the added time of shipping. However, quick tool, like 3D printing, can get molds quicker. If you got a high priority and still a quality job to do, it’s great.

Choosing the Right Partner for Metal Injection Molding Parts!

• Industry Expertise: Metal injection molding parts are a good partner. They use CAD/CAM tools that are designed to keep fit perfect. H-13 or A-2 steel materials lasts long. They are great for making strong, safe parts for aeroplanes and hospitals. JH MIM, a leader in MIM technology, provides expert mold-making for durable parts. When choosing partners, look for experience!

• Tooling Capabilities: Metal injection molding parts relies on tooling. Core tooling is good partners made from strong steel such as D2. Tiny, 0.0001-inch vents, stop the sharp edges. Shapes can happen really fast, with tools like CNC machines. It fits 50,000+ parts perfect for car parts. JH MIM’s tooling centers are precise, providing safe molds. These tools pick partners for safe products.

• Material Selection Range: Some of those jobs can be done by many materials. Stainless steel works great in hospitals because it’s strong metal. they are lighter than titanium and alloys. Every material is designed for other projects. JH MIM offers a wide range of MIM materials, like MIM-316L, used in health and tech. Strong and safe parts in many industries mean right metal.

• Quality Assurance: Metal injection molding parts really needs quality checks. Check ISO 9001 certification of the partner. They check at every step. Like CMM, machines measure sizes exactly. Early, they find problems and then fix them. JH MIM provides exact checks, keeping all parts safe. Checking the goodness of part means that phones or the machines do not get defective parts.

• Scalability Options: You can grow with a good partner. Others produce a few parts or many in very short times, such as 30 seconds per part. For big changes, look for real time tools. They cost less and work for small to big projects. JH MIM can scale quickly to fit many project sizes! Pick the one that matches your part requirements!

Conclusion

Metal injection molding parts are so small, so strong, with special checks. Every part is made to last from materials to finish. Need these parts? Check out JHMIM for more info and solutions!