Metal powder injection molding mobile phone accessories molding process

Metal powder injection molding mobile phone accessories molding process

Metal powder injection molding is a metal processing method used to create a completely dense, clean mobile phone accessory. When it is started, the metal powder is suspended in an adhesive matrix (or raw material) and injected into the tool. In a process very similar to injection molding, resulting in a green part. The green part is then degummed to remove most of the polymer carrier, resulting in a brown part. The process of heating the brown part in the furnace is called sintering to remove the remaining binder and form a completely dense metal part. Metal powder injection molding is a mature, existing manufacturing process to form relatively small metal parts.

The metal powder injection molding process begins with the correct design of metal powder injection molding mobile phone accessories. Any part familiar with the design of injection molding should find that the design of metal powder injection molding part is very similar. However, in the case of a metal injection molding part, more attention needs to be paid to the smooth material flow that needs to pass through the part (therefore, more attention should be paid to the thick, thin transition, and proper slicing of the joint). This process also requires all parts to be supported in the whole degreasing and sintering process.

Mold production

When an order is placed, the original laboratory will design a metal injection molding tool. In this process, the gate and vent are added to the part, and the selection and placement of tools for pushing the finished part of the push rod. The designer also added any undercut for side operation. MIM tools are made of aluminum and use Protomold technology. Like a standard Protomold aluminum tool, a MIM tool is manufactured using a combination of CNC milling machine and CNC electrical discharge machining (EDM). After grinding, polish the tool manually to the customer's specifications.

Partial production

Finished tools are loaded into the green part of the metal injection molding press for production. A MIM news is almost equivalent to a standard plastic injection molding machine with special screw and barrel design to reduce the separation of adhesive and metal powder during the injection process. The MIM raw material pellets are loaded into the hopper of the machine. These pellets are then volumetric metered to an injection cylinder and a screw similar to an injection molding press. Once the particles are heated (by using the electric heater and screw movement), the lens tube is placed against the tool and the raw material are injected. After solidification, some of them come from the press and pop up repeatedly. After spraying, the green part is deselected and placed on the ceramic substrate (or setter), which helps to maintain the shape of the part during the whole degreasing and sintering process.

Degrease

The green part tray is loaded into the debind oven to remove most of the adhesive in the process of metal powder injection molding. The adhesive is about 20% of the raw material. In the original laboratory, we used the raw materials for degumming by the catalytic method used. The length of degreasing time required is the function of the thick part of your part. As an adhesive, it must migrate out of the part all the way. At the end of the degreasing process, the brown part obtained is approximately the same size of the green part, but only 80% is dense. Just enough for the binder to keep the powder particles together, so the brown part is quite fragile.

sinter

Generally, the pallets of parts are moved directly from the oven to the sintering furnace. The furnace is controlled to remove the required temperature of the remaining adhesive, protect the gas and vacuum profile, and sinter the parts to the final product. Circulating in the furnace, part of the shrinkage is about 20% to their final size. After sintering, any auxiliary operation is performed and the part is complete.