mim powder metallurgy office products

mim powder metallurgy office products
certificate:iso9001
process:mim
materials:stainless steel,iron,nickle...
Metal powder injection molding product series l
1. The computer and auxiliary facilities, such as printer parts, head, magnetic cores, firing pin shaft pins, driving parts
2. Tools: such as electrician tools, hand tools, such as all kinds of locks and components
3. Household appliances: such as atlas, bracelet, golf ball head, fish to fall, metal structure, camera parts, etc
4. Medical devices use parts: such as organization sampling grips, connecting rod, tooth orthopaedic frame etc
5. Communications equipment parts: such as substrate, etc
6. Electrical parts: miniature motor, electronic parts, sensor pieces etc
7. The mechanical parts: such as pine cotton machine, m., crimping machine, office equipment, etc
8. Car shipping parts: such as clutch inner loop, rocker set pieces, fork sets, valve catheter, etc
Dimensions of products and Dimensional tolerances

Material type
Dimensions (mm)
General torelance
Special torelance
Dimensional tolerance
<10
0.10
0.03
10<L<20
0.15
0.10
20<L<30
0.20
0.15
30<L<50
0.30
0.20
50<L
0.5%
0.4%
Angle

General tolerance(±')
Special tolerance(±')

0.5'
0.3'
Surface roughness
Rmax
<12S
about 6S
Ejector pin mark

0.05~0.1mm

Parting Line

0.05~0.1mm

They vary according to materials and shapes.

As a metal forming process, Metal Injection Molding (MIM) combines the material flexibility of powder metallurgy and the design flexibility of plastic molding. With properties comparable, or better than, those of wrought steel, the MIM process is ideally suited to producing small and complex-shaped parts with outstanding mechanical properties.
In addition to cost-effective, high-volume production, other MIM benefits include:
Complex geometries
Close porosity
Excellent surface finish
High performance
High final density (93-99%)
MIM
– A Highly Technical Manufacturing Process
1.) Feedstock preparation
For the preparation of the feedstock, metal powders are first blended according to the desired alloy composition. Then thermoplastic polymers and additives are kneaded with the powder mix and heated to obtain a viscous mass. The mass is then cooled down and processed into granular pellets (feedstock). The metal powder alloy determines the mechanical and chemical
properties achieved by the finished product. Hengrui engineers have excellent knowhow for powder development as well as for controlling the feedstock properties achieved.
2.) Injection molding
Thermoplastics injection molding machines with special modifications are used in MIM technology, similar process as applied in conventional plastics injection molding. After being dosed and fed into the injection unit the input material (feedstock) is molten and densified in front of the screw conveyor. By a forward movement of the screw the plasticized mass is injected with high pressure through a sprue and runner system into the individual cavities of the mold. Subsequently the mass is 'frozen' inside the mold cavities with their geometric design ('green compact'). After cooling down to the ejection temperature the mold is opened along the parting plane. The solidified parts, i. e the green compacts, are ejected from their cavities by means of ejection pins and can then be removed by suitable handling systems.
3.) Debinding and sintering
Subsequent debinding serves to remove the polymer binder from the green compacts. This first step is carried out in continuous sintering equipment. A catalyst is fed into the debinding muffle which is evaporated at temperature, thereby forming a reactive atmosphere by which the polymer is completely de-polymerised. The binder is continuously degraded during the reaction and escapes in a gaseous form from the compact. The resulting structure has an open porosity. This porous structure is known as the 'brown part'. The brown parts are directly transferred into the sintering muffle. Here the temperatures are increased almost to the melting point in a well-controlled process until the metal particles sinter. The furnace atmospheres applied may be inertor reducing. Processing conditions in the computer controlled equipment are precisely monitored. Only due to this effort is it possible to keep the 16 to 18 percent shrinkage of the parts under control in order to attain the final dimensions as specified by the customer.