The choice between metal injection molding vs die casting can make a big difference in your product’s quality and cost, especially with small, complex metal parts. MIM is great at creating intricate components that have wall thicknesses as thin as 100 micrometers. This makes it perfect for medical devices, firearms, and aerospace industries. Die casting brings its benefits to the table. A die’s lifespan is nowhere near what MIM offers – it can handle more than one million shots, while MIM typically manages between 150,000 to 300,000 shots.
Making smart manufacturing decisions requires a solid grasp of metal injection molding and its comparison with die casting. MIM works with more alloy options including stainless steels, titanium, and nickel. Looking at die casting vs metal injection molding reveals a clear cost advantage – die casting costs at least 30% less. Metal injection molding creates almost zero material waste. But you need to factor in MIM’s high shrinkage rate of up to 30%. Die casting performs better here with just 0.007 inches per inch shrinkage. This piece will get into both processes and help you pick the right manufacturing method for your needs.
Understanding the Core Processes
A key distinction exists between metal injection molding and die casting in their manufacturing processes. Manufacturers need this knowledge to pick the right method that matches their part requirements.
How Metal Injection Molding Works: From Feedstock to Sintering
The metal injection molding process starts by creating feedstock – a precise mix of fine metal powders with thermoplastic binders. This mixture contains metal and binder in a volume ratio close to 60:40. The manufacturing happens in four key stages:
- Injection molding – High-pressure equipment heats and injects the feedstock into a mold cavity. This creates what experts call a “green part.”
- Debinding – The next step removes most of the binder through solvent, thermal, or catalytic processes. This results in a delicate, porous structure known as a “brown part”.
- Sintering – The process heats the brown part in a protective atmosphere furnace. Temperatures reach close to the metal’s melting point—around 1,350 to 1,400°C for stainless steel. This heat makes metal particles bond together.
- Densification – Parts shrink by 15-20% in each dimension during sintering. This happens as the binder’s space gets eliminated.
The sintering process creates parts that are 96-99% solid. These parts match the quality of traditional metalworking methods. MIM technology can produce extremely thin walls and complex shapes that traditional machining cannot achieve.
Die Casting Explained: Hot vs Cold Chamber Methods
Die casting pushes molten metal into a mold cavity made from hardened tool steel dies under high pressure. This process comes in two main varieties:
Hot chamber die casting puts the furnace inside the casting machine. This method works like this:
- A “gooseneck” connects the metal reservoir straight to the die cavity
- Molten metal moves from furnace to die through hydraulic pressure between 1,000-5,000 psi
- Parts take about 15 minutes to complete
- Zinc, magnesium, and lead alloys with lower melting points work best with this method
Cold chamber die casting takes a different approach:
- A separate furnace melts the metal before moving it to the casting machine
- Workers pour molten metal into the “cold chamber” where hydraulic force pushes it into the die cavity
- Pressure ranges hit 2,000 to 20,000 psi
- Aluminum, copper, and some magnesium alloys need this method due to their higher melting points
Both techniques produce parts with smooth surfaces and consistent dimensions. Each serves different material needs and production goals. Your specific application determines which process – metal injection molding or die casting – fits best.
Material and Design Capabilities
Material selection is a vital factor that determines which manufacturing process will work best for your specific part requirements. Metal injection molding and die casting each have unique capabilities that make them ideal for different applications.
Material Compatibility: Ferrous vs Non-Ferrous Metals
The biggest difference between these processes shows up in what materials they can work with. Metal injection molding works with many types of metals, including both ferrous and non-ferrous alloys. MIM does great with stainless steel, titanium, tungsten, and even certain superalloys that you can’t die cast at all. You can also use MIM to process nickel-based superalloys and specialty materials like cobalt-chromium.
Die casting, on the other hand, mostly works with non-ferrous metals that have lower melting points. This process shines with aluminum, zinc, magnesium, and copper alloys. The limitation exists because ferrous metals melt at temperatures that are nowhere near suitable and would quickly damage die casting molds.
Wall Thickness and Tolerance Limits
These processes are great at making thin-walled components, though each has its limits:
Metal Injection Molding:
- Minimum wall thickness: 0.3mm (0.012″)
- Maximum wall thickness: 8mm (0.30″)
- Typical thickness range: 0.04″ to 0.12″
- Standard dimensional tolerance: ±0.5% of dimension
- Better precision possible: ±0.3% with process control
Die Casting:
- Minimum wall thickness: 0.5mm for aluminum, 0.3mm for zinc
- Typical thickness range: 0.04″ to 0.2″
- Linear tolerance: approximately ±0.12mm (±0.005″) for aluminum
Design Complexity: Thin Walls and Intricate Features
Metal injection molding stands out when it comes to making intricate, small parts with complex geometries. MIM creates components with fine details, undercuts, and complex internal structures that would be tough or impossible to die cast. The process achieves remarkable dimensional accuracy between ±0.1 to ±0.5% of target dimensions.
Die casting might not match MIM for fine details, but it still produces parts with good dimensional accuracy of ±0.002 to ±0.005 inches. Die-cast parts usually come out with smoother surfaces than MIM components and often don’t need additional finishing.
MIM proves especially valuable when you need super-thin walls (around 100 micrometers). Die casting can make thin walls, too but can’t quite match MIM’s ability to create tiny, intricate geometries. Companies like Ningbo Jiehuang exploit these different capabilities to serve industries of all sizes, from 3C electronics to automotive parts and industrial components.
Applications Across Industries
Metal injection molding and die casting play unique yet complementary roles in manufacturing. These processes serve different needs across industries, and each brings specific advantages to the table.
3C Electronics: Connectors, Casings, and Heat Sinks
The electronics sector relies heavily on metal injection molding. Asian manufacturers dominate the market with over 50% of global MIM parts sales. This process shines when creating small components that modern devices need:
- Smartphone components: Camera housings, buttons, and hinges for folding phones
- Lightning connectors: Production rates reach tens of millions weekly during peak times
- Thermal management: Copper coldplates feature complex pin designs that maximize heat transfer
MIM creates thin-walled (<1 mm) intricate housings for fiber optic connectors, making it crucial for networking and telecom equipment. Many manufacturers choose 17-4 PH stainless steel for its durability and precision. Die casting also produces electronic housings, antenna mounts, and RF filters.
Automotive: Shift Levers, Turbo Vanes, Gear Housings
Both manufacturing methods have found their place in automotive production, each meeting specific component requirements:
Metal injection molding creates:
- Turbocharger vanes with precise dimensional tolerances (±0.015 mm on wing profiles)
- Lightweight hollow rocker arms for engines with variable valve strokes
- High-volume manual transmission parts using Fe-2% Ni alloy
Die casting produces:
- Powertrain systems and gear housings
- GPS and entertainment system housings
- Engine components and transmission parts
Medical and Aerospace: Surgical Tools and Engine Components
MIM technology produces surgical instruments like scissors, forceps, and retractors. The process’s precision makes it perfect for orthopedic implants, including hip and knee replacements.
The aerospace industry uses metal injection molding to create:
- High-performance engine components like HPC stator vanes
- Electrical connectors for wire-harness systems
- Frame and plate parts in the aircraft turbine system’s armature assemblies
MIM works well with superalloys such as Inconel 625, Hastelloy X, and various titanium alloys – a key advantage for aerospace applications. The materials offer uniform microstructure and isotropic properties without the connected porosity common in powder metallurgy parts.
Die casting also supports aerospace manufacturing by producing structural components, though it’s limited to non-ferrous metals.
Cost, Volume, and Tooling Considerations
Manufacturing economics helps decide between metal injection molding and die casting. These processes have different cost structures, tooling needs, and volume requirements that affect project success a lot.
Tooling Lifespan: 300K Shots vs 1 Million Shots
Die casting and MIM tools show a big difference in durability. Die casting molds can last for over 1 million shots. MIM tools usually last between 150,000 to 300,000 shots. This gap makes a big difference in long-term production costs.
Tool material quality plays a key role in how long they last. Die casting uses hardened steel (Class 101) molds that work well for high-volume production. MIM tools deal with more abrasive metal powders, so they need replacement more often.
The starting costs also vary. MIM tools cost between USD 1,400 and USD 2,800. Die casting tools range from USD 1,200 to USD 4,200.
Shrinkage and Post-Processing Requirements
These processes handle shrinkage differently. MIM parts shrink a lot during sintering—usually 15% to 20%, and sometimes up to 30%. Mold designers must plan carefully to deal with these size changes.
Die-cast parts barely shrink, about 0.007 inches per inch. This makes it easier to predict and control final part sizes.
Each process needs different finishing steps. MIM parts need debinding and sintering, which takes longer, even though the first molding step is faster. Die casting usually needs fewer finishing steps.
Cost Efficiency in High vs Low Volume Production
Die casting works better for making lots of parts. The high tool cost gets spread across many pieces, which means each part costs less when you make more.
MIM costs more at first but saves money on complex parts that need tight tolerances. It works best for making between 10,000 and 20,000 pieces.
Running costs also separate these processes. Die casting machines cost thousands to run. MIM machines can cost tens of thousands.
Companies like Ningbo JHMIM offer both MIM and die casting. They help clients pick the best process based on their project needs, volume, and budget.
Choosing the Right Method for Your Project
Choosing the right manufacturing method needs a thorough look at your project requirements. Let’s explore how to make this crucial decision to get the best results.
At the Time to Use MIM for Small, High-Precision Parts
MIM stands out as the perfect choice for components that fit specific criteria. To name just one example, see part size – MIM performs best with parts smaller than 100mm that weigh less than 100 grams. Parts with intricate designs and features less than 2mm make MIM the only practical solution.
The process shines with complex geometries requiring precision tolerances as tight as 0.01mm. Yes, it is a superior option to manufacture high-strength components that need to withstand extreme conditions.
MIM proves most valuable when your project has:
- Thin walls (less than 0.5mm)
- Requirements for ferrous materials like stainless steel
- Production runs over 10,000 units
- Critical needs for component strength and wear resistance
At the Time, Die Casting Works Better for Larger, Simpler Parts
Die casting shows its strengths with a different set of project parameters. This method excels with bigger components and simpler geometries. The process delivers excellent dimensional accuracy with tight tolerances and creates a superior surface finish that often eliminates the need for additional work.
Die casting becomes the best choice when you have:
- Larger parts with simpler shapes
- Projects using non-ferrous metals like aluminum or zinc
- Requirements for both low and high volume production flexibility
- Projects needing quick production cycles
- Designs where impact resistance matters most
Alternatives: Binder Jetting and SLM for Prototyping
Testing alternative technologies for prototyping makes sense before starting full production. Binder jetting brings remarkable versatility to rapid prototyping and helps test and refine designs quickly. This technology creates prototypes with complex geometries that seem sort of hard to get one’s arms around using traditional methods.
Selective Laser Melting (SLM) gives you another great option by delivering high accuracy and resolution for detailed, intricate parts. SLM creates fully dense components with consistent, excellent mechanical properties.
These additive methods speed up early development phases compared to traditional manufacturing. Metal binder jetting components arrive in days instead of weeks.
Companies like Ningbo Jiehuang make use of information from manufacturing methods of all types to determine the best approach for your metal part needs.
Comparison Table
| Characteristic | Metal Injection Molding (MIM) | Die Casting |
|---|---|---|
| Material Compatibility | Ferrous and non-ferrous metals (stainless steel, titanium, tungsten, nickel-based alloys) | We use non-ferrous metals (aluminum, zinc, magnesium, copper alloys) |
| Minimum Wall Thickness | 0.3mm (0.012″) | 0.5mm for aluminum, 0.3mm for zinc |
| Typical Wall Thickness Range | 0.04″ to 0.12″ | 0.04″ to 0.2″ |
| Dimensional Tolerance | ±0.3% to ±0.5% of dimension | ±0.12mm (±0.005″) for aluminum |
| Shrinkage Rate | 15-20% (up to 30%) | 0.007 inches per inch |
| Tool Life | 150,000 to 300,000 shots | Over 1 million shots |
| Tooling Cost Range | USD 1,400 – 2,800 | USD 1,200 – 4,200 |
| Ideal Production Volume | 10,000 – 20,000 pieces | High volume production |
| Best Applications | Small, complex parts (<100mm) High-precision components Medical devices Electronics components |
Larger, simpler parts Automotive components Housing units Structural parts |
| Key Advantages | – Very precise details – Complex geometries – Wide material selection – High-strength components |
– Lower cost for high volumes – Faster production cycles – Better surface finish – Minimal shrinkage |
Conclusion
Our comparison between metal injection molding and die casting shows that neither process is a match for the other in all situations. Each manufacturing method works best under specific conditions. Die casting is without doubt more cost-effective for high-volume production, especially when you have larger, simpler parts made from non-ferrous metals. The process yields minimal shrinkage at 0.007 inches per inch. The tool life is a big deal as it means that it can last beyond one million shots.
MIM excels at creating intricate, small components with wall thicknesses as thin as 0.3mm. It also handles more materials, including stainless steels and superalloys that die casting can’t process. Despite higher material costs and 15-20% shrinkage rates, MIM remains the best choice for complex geometries in medical devices, aerospace parts, and precision electronics.
Your project’s specific needs should guide your choice between these methods. These needs include complexity, materials, production volume, and budget limits. Binder jetting and SLM are worth looking at during prototyping before you commit to full production.
Ningbo Jiehuang is your one-stop solution provider for metal parts, with unmatched experience in both processes. The company’s expertise covers powder metallurgy, metal injection molding, and die casting services for 3C electronics, automotive, and industrial uses. Ask about your custom metal part needs to get their complete project support from planning through design, production, and logistics.
The best manufacturing choice comes down to balancing part complexity, material selection, volume needs, and costs. MIM and die casting play vital roles in modern manufacturing. Each method brings unique benefits that solve specific production challenges.
FAQs
Q1. What are the key differences between metal injection molding and die casting? Metal injection molding (MIM) uses a wider range of metals including stainless steels and titanium, and excels at producing small, complex parts with thin walls. Die casting primarily uses non-ferrous metals like aluminum and zinc, and is better suited for larger, simpler parts in high volumes.
Q2. Can metal injection molding be used for intricate metal parts? Yes, metal injection molding is ideal for creating intricate, small metal components with complex geometries and fine details. It can produce parts with wall thicknesses as thin as 0.3mm and is particularly useful for industries like medical devices and aerospace.
Q3. How does the cost of die casting compare to metal injection molding? Die casting is generally more cost-effective for high-volume production of larger, simpler parts. While initial tooling costs can be higher, die casting becomes economical over longer production runs. Metal injection molding may have higher material costs but can be more cost-effective for complex, precision parts in smaller volumes.
Q4. What are the material limitations for die casting? Die casting is primarily limited to non-ferrous metals with lower melting points, such as aluminum, zinc, magnesium, and copper alloys. It cannot typically be used with ferrous metals or high-temperature alloys due to the risk of rapid mold deterioration.
Q5. How do shrinkage rates differ between metal injection molding and die casting? Metal injection molding experiences significant shrinkage during the sintering process, typically 15-20% and sometimes up to 30%. This requires careful mold design to compensate. Die casting, on the other hand, has minimal shrinkage of approximately 0.007 inches per inch, making dimensional prediction more straightforward.