MIM is the shorthand for Metal Injection Molding, it’s a method of forming mixture of a metal powder and binder into a mold, and then the mixture is  granulated and then injection molding the desired shape of the initial parts,  and then through the high temperature sintering to get the expected metal parts with strength.

It’s an advanced and supplementary technology of metal parts manufacturing. Different from traditional technology, when producing small size, complex shapes metal components in large quantities, MIM advantages has been maximized, so many small and complex metal parts we used today have a great chance made by MIM.

MIM Advantage

Compared to other technologies, Metal Injection Molding(MIM) is a complementary method which has progressed substantially over the past 25 years. More and more MIM Parts applied for a wide range of fields, from ordinary machinery to precise instruments; from the hardware tools to the large-scale machinery; from the electronics industry to the motor manufacturing; from the civilian industry to the military industry; from the general technology to cutting-edge tech. Metal Injection Molding had proved that it offers several advantages over other production technologies.

1. High utilization rate of raw materials. Material properties equivalent to wrought alloys

 

Commonly used MaterialsDensity(g/cm3)Tensile Strength(MPa)Yield Strength(MPa)Elongation(%)Hardness
Stainless Steel 316L 7.8 510 180 50 120HV
Stainless Steel 17-4PH 7.6950/1100/1180 660/950/1050 2003/8/810/38/42HRC
Stainless Steel 420 7.7 1174 1290 3.5 50HRC

Mainly used materials of MIM

2.Manufacture small size metal parts (0.02-200g) with complicated geometric shapes directly like producing plastic parts.

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Different advantages of three metal parts manufactuting tech

3.MIM parts have superior mechanical properties to castings and other PM parts, reflecting fine particle size and high sintered density.

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Factors of cost changes for different tech

Capable of production complex shape small metal parts as plastic injection process. Powder injection molding parts typical weigh is 0.1-200g;
◇Capable of forming kinds of complex shapes, such as external cuts, threads, tapered external surface, cross holes & blind holes, slots, ribs&webs, knurling, and so on.
◇Good surface finishes and high precision dimensions(typical in±0.3%~0.5%)
◇Wide range of material optional for MIM process. Parts with high density (typical 95%~99% relative density) and homogeneous structure and excellent performance easy to acquire;
◇ Able to realize high-volume production with stable quality and high efficiency.

Table 1 and 2 show the comparison between MIM and other processes.

Table 1 The comparison between MIM and Precision casting

characteristics

Precision casting

MIM

Minimum hole diameter

2mm

0.4mm

Maximum depth of ∮2mm blind hole

2mm

20mm

Minimum wall thichness

2mm

<1mm

Maximum wall thichness

No limit

10mm

Tolerance of ∮4mm

±0.2mm

±0.06mm

Surface roughness(Ra)

5um

1um

 

Table 2 The overall comparison between MIM and other processes

items

MIM

PM

Precision casting

machining

Density

98%

86%

98%

100%

Tensile strength

high

low

high >

high

Roughness

high

medium

medium

high

Miniaturization capability

high

medium

low

medium

Thin wall capability

high

medium

medium

low

Complexity

high

low

medium

high

Design toleration

high

medium

medium

medium

Material range

high

high

medium

high