What is MIM
Our Design Guide
Contact Way
E-MAIL：sales@mdmmetal.com
ADD：RM 1306, NO.249, Zhen’an Road East, Chang’an Twon, Dongguan City, China. 523859
Contact Way
E-MAIL：sales@mdmmetal.com
ADD：RM 1306, NO.249, Zhen’an Road East, Chang’an Twon, Dongguan City, China. 523859
Design Guide for Metal Injection Molding
Computer simulation of the injection molding process is advanced and allows the study of every detail of mold filling in 3D.
The design engineer can analyse the filling dynamics in thick and thin areas on screen, study the effects of gate position, thermal gradients in the mold and phenomena such as jetting and binder segregation.
Designers can also optimise the kinetics of mold filling and determine shrinkage and distortion of the green compact relative to the mold dimensions.
A careful analysis and optimisation of the mold cavities can reduce design time and cost while significantly improving yield and quality.
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“The Design Should Considerations”
- Metal Part must be so designed to allow for easy ejection from the die. Sidewalls should be perpendicular; hole axes should be parallel to the direction of opening and closing of the die.
- Holes, even complicated profiles, are permissible in the direction of compressing. The minimum hole diameter is 1.5 mm (0.060 in).
- The wall thickness should be compatible with the process typically 1.5 mm (0.060 in) minimum. Length to thickness ratio can be up to 18 maximum-this is to ensure that tooling is robust. However, wall thicknesses do not have to be uniform, unlike other processes, which offers the designer a great amount of flexibility in designing the parts.
- Undercuts are not acceptable, so designs have to be modified to work around this limitation. Threads for screws cannot be made and have to be machined later.
- Drafts are usually not desirable except for recesses formed by a punch making a blind hole. In such a case a 2-degree draft is recommended. Note that the requirement of no draft is more relaxed compared to other forming processes such as casting, molding etc.
- Tolerances are 0.3 % on dimensions. If repressing is done, the tolerances can be as good as 0.1 %. Repressing, however, increases the cost of the product.
“Designing New MIM Products and Solutions”
We know that timeliness is critical. Designing new products and solutions from scratch is all very well, but the designs need to be proven in real world situations. And they need to be proven fast. That’s where MDM Mmetal’s capabilities are truly world class, and where we continue to invest in our service. We work with our customers at the earliest stages of the design cycle. From an initial concept we can prototype new designs at incredible speed – sometimes even within 24-hours – thanks to our highly skilled design engineers and harnessing our expertise.
Commonly used materials for MIM process and their application fields:
| Material system | Alloy model | Application filed |
| Low alloy system | Fe2Ni, Fe8Ni | Structural parts in automobile, mechanical industries etc. |
| Stainless steel | 316L, 304, 17-4PH, 420, 440C | Medical devices, watch |
| Hard alloy | WC-Co | Various kinds of cutting tools, watches |
| Heavy alloy | W-Ni-Fe, W-Ni-Cu, W-Cu | Military, tele-communication |
| Titanium alloy | Ti, Ti6Al4V | Medical devices, military structural parts |
| Tool steel | CrMo4, M2 | All kind of tools |
The performance of several typical materials:
| Material | Density | Hardness | Tensile strength | Elongation | |
| g/cm³ | Rockwell | Mpa | % | ||
| Iron base alloy | PIM-2200(sintering state) | 7.65 | 45HRB | 290 | 40 |
| PIM-2700(sintering state) | 7.65 | 69HRB | 440 | 26 | |
| PIM-4605(sintering state) | 7.62 | 62HRB | 415 | 15 | |
| PIM-4605(quenching, tempering) | 7.62 | 68HRB | 1655 | 2 | |
| Stainless steel | PIM-316L(sintering state) | 7.92 | 67HB | 520 | 50 |
| PIM-17-4PH(sintering state) | 7.50 | 27HRC | 900 | 6 | |
| PIM-17-4PH(sintering state) | 7.50 | 40HRC | 1185 | 6 | |
| PIM-430L | 7.50 | 65HRC | 415 | 25 | |
| Tungsten alloy | 95%W-Ni-Fe | 18.1 | 30 | 960 | 25 |
| 97%W-Ni-Fe | 18.5 | 30 | 940 | 15 | |
Forming ability comparison of MIM and precision casting:
| Feature | Precision casting | MIM |
| Min hole diameter | 2mm | 0.4mm |
| Max depth for 2mm blind hole | 2mm | 20mm |
| Min wall thickness | 2mm | 0.3mm |
| Max wall thickness | No limit | 10mm |
| Tolerance for 4mm diameter | ±0.2mm | ±0.04 |
| Surface roughness(Ra) | 5μm | 1μm |
Comprehensive comparison of MIM and other processes:
| Process Content | MIM | PM | Precision casting | CNC machining |
| Density | 90% | 86% | 98% | 100% |
| Tensile strength | high | Low | High | High |
| Finish | high | middle | Middle | high |
| Miniaturization capability | high | middle | Low | Middle |
| Thin all capability | high | middle | middle | Low |
| Complexity | high | Low | middle | High |
| Tolerance of design | high | Middle | middle | Middle |
| Material range | high | high | middle | high |
Application of Metal MIM Parts
Metal powder injection molding has been widely used in mechanical industry, electronic industry, automobile industry, office automatic industry, watch, photoelectric industry, military industry, medical devices etc.
1) Computers and auxiliary facilities: printer parts, core, striker shaft pin, drive parts
2)Tools: such as gun drill, drill chuck, power tools, hand tools, wrenches and other spare parts, milling heads, nozzles, etc.
3) Household appliances: such as watch case, bracelet, electric toothbrushes, scissors, fans, golf head,
simulation jewelry, tool heads and other parts;
4) Medical equipment parts: dental orthopedic frame, orthopedic bracing parts, scissors, tweezers;
5) Military ordnance parts: the missile tail, firearms parts, warheads, liner, Fuze parts;
6) Electrical parts: such as micro-motor parts, electronic parts, sensors, cell phones etc.
7) Mechanical Parts: complex parts such as small loose cotton, textile machines, sewing machines.
Technical Assistance
The metal injection machining process begins with experienced design engineers reviewing a part’s dimensions per customer drawing and then creating an AutoCAD rendition of the measurements in preparation for tooling. Our design engineer determines how many parts and offers suggestions of how the part can be manufactured with the lowest tolerances within our machining capabilities.
If your business is in need of a high quality and cost-effective metal injection molding service, then Mdm Metal have the solution to your problem.