1. Raw materials: Metal powder metallurgy (iron, stainless steel 5%-8%) + binder (plastic powder 92%-95%) ---- mixed-- -Mixing---Crushing-Granulation
Iron powder granulation: air spray powder (rounder particles), water spray powder (irregular shape) Powder preparation: atomization powder, reduction method, mechanical alloying , Vapor deposition, sol-gel, spontaneous combustion reaction synthesis, electrolysis
①Improve powder fluidity, have both lubrication and wetting, prevent fine powder from agglomerating, and may cause mold wall friction and powder-grain binder during the injection molding stage Phase separation.
②Avoid the generation of heterogeneous embryos and shrinkage and deformation of different sizes.
③Binder can be used as the backbone of the product after degreasing. There is a little residual binder to improve the strength and shape retention of the embryo body, and form a porous channel, which is convenient for the next stage. break down. (Paraffin/Polymer)
2. Injection molding:
①Pour the raw materials into the inverted funnel, and inject them into the cube mold through the injection gun at high temperature and high pressure (first pour the granular feed into the inverted funnel Enter the injection gun and heat it to a certain temperature to make it fluid, and inject it into the square mold through the feed port, and then flow into the required mold cavity through the water port to press and cool to form, and the ejector pin is ejected to obtain the MIM molding blank)
②The obtained blank does not have any metal properties, so it is not easy to break or break.
③The equipment tonnage is 80T, 120T (14 sets in total), and the product weight can be 500g.
④The product density is 7.8 ⑤Hardness: iron HRC50-60, stainless steel HRC35-40.
Remove the binder component inside the blank to obtain the brown embryo, temperature: 90-110℃, time: 4-6h, the brown embryo is fragile and fragile (remove the inside 98% binder).
4. Sintering: Vacuum sintering furnace Temperature: 800-1200℃ Time: 24h Remove 2% of the binder inside, with all metal properties.
①Sculpting treatment②Polishing and grinding③Flat grinding④Deburring⑤Surface treatment⑥Anti-rust treatment It can be electroplated directly.