Metal Injection Molding -(MIM)
Service Detail from Qingdao Eversun Precision Manufacture Co., Ltd.
Metal Injection Molding, also called MIM for short, delivers the precision shape forming ability of plastic injection molding yet produces nearly 100% dense parts with machined-like features from your trusted high performance materials in form of feedstock. The desired part geometry is created in one shot. None or only minimal finishing is necessary. Net-shaping allows efficient use of material, as you only need as much material as the part volume requires. In principle, MIM allows the same freedom of design as is available from plastic injection molding, e.g.:
- Almost unlimited complexity of geometry
- Free-form surfaces
- Complex design of inner contours that are difficult to shape by metal-cutting procedures
- Direct addition of labels and logos, both immersed and raised
- Inner and outer threads
Parts that can only be manufactured in an extensive and costly way by metal-cutting procedures are best suited for MIM. If your part is relatively small, complex shaped, a challenge for machining, or requires machining, or requires machining a casting blank, then MIM will probably be able to save money for you. There are, of course, certain areas where MIM is exclusively viable, as in forming refractory hard metals.
A typical MIM production route consists of the following steps:
- Mixing: temporarily adding a multi-component binder into the powder, compounding the composite into ready-to-mold feedstock
- Molding: shaping the parts from feedstock as in plastic injection molding
- Debinding: removing the binder in the molded parts
- Sintering: a thermal cycle where debound parts are densified to a high final density
A predetermined shrinkage takes place during sintering, thus an equivalent oversizing factor must be considered for the tool cavities. After sintering, it may require limited secondary operations to finish the parts, such as tapping, reaming, grinding, polishing, sandblasting, etc.
The following characteristics are typical for Eversun's MIM products:
- High precision up to ±0.3% of the desired dimensions (recommended ±0.5%)
- High density, 98% or more of theoretical
- High surface quality, typical Ra-values after sintering are 1 to 3 µm
- Homogeneous microstructure, free of internal flaws
- Competitive tooling and part prices
Although production quantities of 200,000 pcs or more per year are attractive, we do not set up a lower limit to the annual quantities. If a project is small-sized, but can give us a toehold in new application fields, then we are willing to take on it.
The list of materials below can be processed:
- Low alloy steels: Fe-2Ni, Fe-7Ni, MIM 4605
- Stainless steels: AISI 316L, AISI 17-4PH
- Tool steels: M2, 100Cr6, AISI 420, AISI 440C
- Hard metals: tungsten heavy alloy, tungsten carbide (WC), cemented carbide (WC-Co), tungsten-copper (W-Cu)
- Soft magnetic alloys: Fe-2Ni, Fe-50Ni, Fe-80Ni, Fe-3Si, Fe-7Si, AISI 430L, iron
- Controlled expansion alloys: Fe-36Ni (Invar), Fe-42Ni, ASTM F15 (Kovar)
At Eversun, we deliver not just parts, but precision, innovation and continued satisfaction.