Die Casting and Metal Injection Molding (MIM) are two popular manufacturing processes used globally. Both produce metal parts but they are worlds apart in terms of cost, precision and material options. In this blog post you will learn about main differences between die casting and MIM. This will help you to decide which process is best for your manufacturing needs.
What is Die Casting?
In simple terms, die casting is a high pressure manufacturing procedure in which molten metal is injected into precision steel molds mostly between 10 and 175 MPa pressure. Mainly used metals are zinc, aluminum and magnesium.
This process not only produces highly detailed and complicated parts but gives extraordinary dimensional accuracy too. It is best for high volume production in industries such as electronics and automotive.
See Also: What is Vacuum Casting and How Does It Work?
What is Metal Injection Molding (MIM)?
In Metal Injection Molding (MIM) a feedstock is created from fine metal powders mixed with a thermoplastic binder. Manufacturers then inject this feedstock into molds to form complicated shapes. After injection molding, the binder is removed and then parts are sintered at high temperatures. This sintering procedure not only produces dense, strong metal parts but gives tight tolerances and precise details too.
Die Casting vs MIM Comparison
To choose between die casting and Metal Injection Molding (MIM) you need to clearly understand how each procedure meets your design, material and production requirements. Here are the main differences between the two processes.
1. Material Compatibility
Die casting mainly accommodates non ferrous metals like zinc, aluminum & magnesium alloys. These materials have outstanding casting properties which make them best for high volume and lightweight parts. On the contrary die casting doesn’t support ferrous metals such as steel.
Metal Injection Molding, on the other hand, supports a range of metals no matter if it is ferrous or non-ferrous. Examples are stainless steel, titanium, low alloy steels and nickel based super alloys. Since MIM has broad material compatibility it’s appropriate when you need corrosion resistant and strong parts for demanding applications.
2. Design Adaptability and Part Complexity
MIM is great for intricate and small parts with complicated geometries. It can create thin walls, undercuts and detailed shapes which can be hard or impossible to do with die casting. So use MIM if your design has miniaturized or highly detailed parts.
Unlike MIM die casting can do moderately complicated parts but has limitations with thin walled sections or very fine details. It is better for larger, sturdier parts. And if your design has extremely small or intricate features then die casting may not be your best option.
3. Quality of Surface Finish
Die casting mostly gives average surface finishes. Surface roughness is normally between Ra 1 and 25 μm. For most industrial applications this is acceptable. But for touch sensitive or highly visible parts you may need additional finishing steps like coating or trimming.
With MIM you get extraordinary surface finishes. Routine roughness values can be as low as Ra 1 μm. Mostly this finish removes the need for extra machining or polishing. So if your application needs smooth surfaces or visual appeal then MIM is the way to go.
4. Dimensional Accuracy and Tolerances
MIM has extraordinary dimensional accuracy normally ±0.1 to ±0.5% of the target dimensions. This is because of the use of controlled sintering and fine metal powders. These parts have high repeatability and mostly require minimal secondary finishing.
Die casting also has good dimensional accuracy generally ±0.002 to ±0.005 inches. You may need additional trimming processes to meet strict quality standards. It has less control over wall thickness which can cause dimensional variations in complicated designs.
If your application needs even tighter tolerances than what die casting can achieve then secondary CNC machining can help. RICHCONN gives these machining services to refine critical features & surfaces.
5. Production Volume and Scalability
Die casting scales very well. One mold can produce over one million parts. Ability to make larger parts and rapid cycle times makes it best for mass producing simple to intermediate complicated parts.
For hundreds of thousands of small‐to‐medium sized parts MIM is cheaper. It can easily make complicated parts. But because of longer processing times it is not practical for extremely large production volumes.
6. Density and Mechanical Properties
MIM parts have densities from 95 to 99% of wrought material values. So these parts have good material functionality and strong mechanical properties. Thus if your application needs high durability and strength then use MIM.
Die cast parts are fully dense but can have trapped gases which can cause internal porosity. So die cast parts may not be as strong as MIM parts.
7. Cycle Time and Manufacturing Process
Die casting has much faster cycle times. Depending on part complexity and size, every part takes 1 to 30 seconds. This is why die casting is a preferred method for high volume manufacturing particularly when time to market is important.
In comparison MIM procedure has multiple stages which are injection, debinding & sintering. Total cycle time per batch is 24 to 36 hours. Every injection stage is 15 to 60 seconds. Debinding and sintering stages take most of the total processing time.
8. Cost Efficiency and Economics
MIM has higher upfront costs because of multi stage processing and complicated molds. For small, complex parts at large volumes, these upfront costs become viable. In most cases MIM is only economical for high volume manufacturing. But experienced manufacturers like RICHCONN can help reduce these upfront costs with modular tooling and optimized sintering processes. These features reduce economic barriers which make MIM more accessible at medium volume.
Die casting is cheaper as compared to MIM particularly at high volume. Longer mold life, simpler process and less labor requirements all lead to lower cost per piece. If you need to produce non ferrous metal components in large quantities then die casting is an affordable solution.
9. Mold Lifespan and Tooling
MIM molds normally last between 150,000 to 300,000 shots. Less abrasive feedstock and lower operating temperatures contribute to this lifespan. Although this life span is good for many applications but it is shorter as compared to die casting molds.
Die casting molds can go over one million shots. At RICHCONN, we increase mold life even further with real time thermal monitoring and hardened H13 steel. These features minimize downtime for high volume consumer electronics and automotive manufacturers.
10. Applications
Die casting is used in electrical, automotive and appliance industries. Engine blocks, electrical enclosures and transmission housings are well known die cast products. If your application needs large yet less complex parts in high volume then die casting is appropriate because of its fast production and scalability.
Medical, aerospace, automotive and firearms industries normally use MIM. Small, high strength as well as complicated parts like automotive sensors, medical devices, aerospace fasteners and firearm parts are some of its general uses.
Pros and Cons of Die Casting
Pros
Short Cycle Times and Fast Production
Die casting is super-fast. You can produce one off parts in seconds and it is best for tight deadlines and mass production.
Extraordinary Surface Finish and Dimensional Accuracy
Die cast components can get surface finishes of Ra 1.6 μm and tolerances of IT13 to IT15. This mostly removes or reduces the need for secondary machining.
Affordable for Large Runs
Die casting is very economical for large volumes. As your volume increases the cost per unit decreases greatly. This makes die casting perfect for large production.
Cons
High Starting Investment
Equipment and tooling for die casting need a big upfront investment. So this method is not practical for prototypes or low volume production.
Material and Defect Limitations
Die casting can work on nonferrous metals. Also its prone towards defects such as porosity. These defects can limit post casting heat treatment and affect mechanical properties.
Pros and Cons of Metal Injection Molding
Pros
Complex Geometries
MIM can produce fine details and intricate shapes. It can make internal channels, undercuts and threads that other manufacturing methods can’t.
Material Output
MIM reduces material waste greatly. You can convert 95 to 99% of your input material to usable parts. This is particularly useful when working with expensive metals such as titanium or specialty alloys.
Stable Quality
MIM gives repeatable results with tight tolerances mostly within ±0.1%. Your parts will meet particular traits and also have minimal changes.
Cons
High Starting Costs
Equipment and tooling costs are high in case of MIM. So it is only economical for production of volumes greater than 10,000 units. As for smaller production runs these upfront costs may not be justified.
Lengthy Lead Times
MIM needs special mold creation and multiple stages (debinding and sintering). These additional steps prolong lead times. Frequent design changes or rapid prototyping not only become time consuming but expensive too. At RICHCONN, we mostly recommend alternative methods to start prototyping, like industrial 3D printing or rapid CNC machining, before investing in MIM tooling.
Die Casting vs Metal Injection Molding– Which is Best for Your Project?
Your project needs will decide whether die casting or Metal Injection Molding is better for you.
MIM is best if your parts are small and intricate and need high strength and precise tolerances. This process is perfect for ferrous alloys. On the other hand die casting is faster and more budget‐friendly for lighter and larger parts. It is best for high volume runs with non-ferrous materials like zinc or aluminum.
For unbiased guidance you can talk to a knowledgeable manufacturing expert like RICHCONN. We have experience in die casting, MIM, CNC machining and different finishing services. So we can help you find the best solution for your project.
To Sum Up
Die casting and Metal Injection Molding each have their own advantages. MIM is best for complicated, small as well as high precision parts whereas die casting is best for large, affordable and non-ferrous parts. So you should base your final decision on your project’s particular requirements for part size, material selection and production quantity.
If you need any type of services related to die casting, MIM or any other CNC machining services then Richconn is your best option. You can contact us anytime.
Related Questions
What are limitations of MIM in terms of weight and part size?
Because of sintering and equipment limitations MIM is mostly good for small to medium size parts, normally under 50g.
What are typical cycle times for die casting and MIM?
Die casting has short cycles of 2 seconds to 1 minute. In contrast MIM processes have longer cycles of 25 to 30 days because of debinding and sintering stages.
Is there any difference in types of alloys which can be used in die casting and MIM?
Yes, die casting mainly uses non ferrous alloys such as zinc and aluminum. On the other hand MIM can use both ferrous and non-ferrous metals.
Can we use die casting for ferrous metals like steel?
Yes you can use die casting for ferrous metals like steel but it’s not ideal in most cases. This is because ferrous alloys have shorter die lives and higher melting points.
Can die casting and MIM processes be automated for mass production?
Yes both die casting and MIM processes can be fully automated. Automation reduces labor costs in large scale production.
