MIM
Metal injection moulding (MIM) is a hybrid technology whereby it integrates the shaping capability of plastic injection moulding and materials flexibility of conventional powder metallurgy.
MIM is preferred for mass manufacturing of small, intricate geometry components of a variety of materials as it can achieve 95% to 98% dense, as good as wrought condition.
The Technology |
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The initial step to MIM is material selection and preparation. Once the appropriate combinations of metal powder blended and binders compounded into an injection mouldable feedstock.
Using an injection-moulding machine, the parts produced are then subjected to a binder removal process. Depending upon the type of binder used, different methods of debinding are applied.
The parts, after debinding, will then go through a sintering process.
The Materials |
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Due to the flexibility of MIM technology, DYT is able to customise material compositions according to the specific attributes required by the customers. (See Tables 1 and 2 for material compositions and physical properties.)
| Table 1: Material Composition |
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| Types | Properties | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C | Cr | Ni | Mn | Mo | Si | V | W | Co | Cu | Nb+Ta | Fe | |||
| Stainless Steels | 17-4PH 304L 316L 317L 430L 440C F75 |
<0.07 <0.03 <0.03 <0.03 <0.03 0.9-1.2 <0.1 |
15-16 18-20 16-18 18-20 16-18 16-18 27-30 |
4-5 9-13 12-15 13-15 <1 <0.6 <1 |
<1 <2 <2 <0.5 <0.5 <1 <1 |
2-3 3-4 <0.75 5-7 |
<1 <1 <1 <1 <1 <1 <1 |
3-4 |
<0.45 |
Bal. Bal. Bal. Bal. Bal. Bal. <0.75 |
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| Low Alloy Steels | 4140 8620 |
0.38-0.45 0.18-0.25 |
0.9-1.2 0.4-0.6 |
0.4-0.7 |
0.2-0.3 0.2-0.3 |
Bal. Bal. |
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| Carbon Steels | Low Medium High |
<0.2 0.2-0.5 >0.5 |
<1 <1 <1 |
<1 <1 <1 |
Bal. Bal. Bal. |
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| Ni-Alloys | FeNi2 FeNi8 FeNi50 Kovar |
0.6-0.8 0.4-0.6 <0.1 <0.015 |
<0.5 |
1.8-2.2 7.5-8.5 49-51 29-30 |
<0.2 |
<1 <1 <0.5 <0.3 |
16-17 |
Bal. Bal. Bal. Bal. |
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| Tool Steels | M2 SKDII |
0.8-1.0 1.4-1.6 |
3.5-4.5 11-13 |
<0.3 <0.5 |
<0.4 <0.6 |
4.5-5.5 0.8-1.2 |
<0.5 <0.4 |
1.8-2.2 0.2-0.5 |
5.5-6.5 | <0.25 <0.25 |
Bal. Bal. |
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| Tungsten Alloy | WHA | <0.03 | 4.8-5.2 | 93-94 | 1.8-2.2 | |||||||||
| Table II: Typical Physical Properties of MIM Materials | |
| Types | Mechanical Properties (minimum value) | |||||
|---|---|---|---|---|---|---|
| Density (g/cm3) | 0.2% Yield Strength (MPa) | UTS (MPa) | Elongation (%) | Hardness (HV300gf) |
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| Stainless Steels | 17-4PH 304L 316L 317L 430L 440C F75 |
7.60 7.80 7.85 7.85 7.55 7.55 7.60 |
550 205 210 240 205 1900 427 |
950 515 510 540 415 1970 724 |
6 35 40 35 30 2 14 |
320 120 120 150 120 550 264 |
| Low Alloy Steels | 4140 8620 |
7.40 7.40 |
400 400 |
650 650 |
3 3 |
130 190 |
| Carbon Steels | Low Medium High |
7.70 7.60 7.40 |
150 250 400 |
250 400 700 |
25 5 2 |
80 130 320 |
| Fe-Ni Alloys | FeNi2 FeNi8 FeNi50 |
7.60 7.70 8.05 |
150 200 250 |
250 350 400 |
25 15 20 |
90 100 120 |
| Low Thermal Exp | Kovar | 7.70 | - | - | - | 150 |
| Tool Steel | M2 | 8.05 | 1000 | 1100 | 1 | 520 |
| Tungsten Alloy | WHA | 18.0 | - | - | - | 450 |
The Applications |
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MIM technology has found increasing applications in the commercial world, from home appliances to watches, automobiles to aerospace, medical to weaponry.
The Advantages |
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Greater design freedom
With MIM, parts can be designed and manufactured without any design restrictions. In addition, almost all design changes are possible within the shortest development cycle and turnaround time.
Miniaturisation
MIM technology is the best viable process for producing miniature parts economically.
Complex and Intricate Shaped Parts
MIM is ideal for producing complex-shaped components as well as parts that require assembly or multiple steps to put together.
The Technology