The invention discloses a powder metallurgy mould pressing process for metal zipper teeth. The powder metallurgy mould pressing process for the metal zipper teeth comprises the following steps: S1, preparing materials, namely, uniformly mixing metal powder and an adhesive; S2, pressing and moulding, namely, filling a pressing mould of a powder moulding machine with the mixed metal powder for pressing and moulding to obtain a metal zipper tooth green body in a specific shape; S3, sintering and moulding, namely, performing vacuum sintering and moulding on the metal zipper tooth green body in a stainless steel vessel or a ceramic vessel in a vacuum sintering furnace to obtain metal zipper teeth which meet mechanical properties, wherein the sintering temperature is 1,200 DEG C to 1,300 DEG C, and the sintering time is 90 minutes to 120 minutes; S4, after the sintering and moulding are performed, filling nitrogen gas or argon gas to cool the metal zipper teeth; and S5, after the metal zipper teeth are cooled, taking out the metal zipper teeth, and performing surface grinding treatment on the metal zipper teeth. The powder metallurgy mould pressing process for the metal zipper teeth does not need stamping machining, is high in precision and high in production efficiency, can directly manufacture porous, semi-dense or full-dense products, and moreover, is suitable for machining zipper teeth of various shapes and various materials.

Powder metallurgy mould pressing process for metal zipper teeth

According to an embodiment of the present invention, a helical gear forming apparatus is capable of forming a helical gear comprising: a gear tooth part including a screw thread inclined in one direction through metal powder; a gear shaft part into which a rotary shaft is inserted; and a gear body part connecting the gear shaft part with the gear tooth part. The helical gear forming apparatus includes: a die; a lower punch unit having a shape corresponding to the helical gear, and installed on the die to be able to be elevated to form a cavity with an open upper part and a screw thread corresponding to the gear tooth part on the inner edge surface thereof; and an upper punch unit installed in the upper part of the lower punch unit, and elevated without spinning towards the lower punch unit along the inner edge surface of the die to press and form the metal powder in the cavity by making the edge come into contact with a flat surface of the lower punch unit.

Compacting apparatus of helical gear

The invention relates to a high-density gear preparation method. The method comprises the following steps that a raw material is stirred through a blender mixer to obtain a mixture, wherein the raw material is prepared from, by mass, 1.45%-1.55% of copper powder, 1.80%-2.10% of nickel powder, 0.55%-0.65% of carbon powder and the balance iron powder; a lubricating agent is added into the mixture, and high-speed stirring is conducted to obtain a uniformly stirred raw material, wherein the stirring speed ranges from 650 r/Min to 850 r/Min, and the stirring time is not shorten than 0.5 H; the rawmaterial is sent into a pressing die of a molding press, and then an initial blank is obtained; the initial blank is sequentially put into a preheating furnace and a sintering furnace for sintering toobtain a gear, wherein the preheating furnace and the sintering furnace are both filled with protective gas, the temperature of the preheating furnace is 950+/-20 DEG C, the heat preservation time isnot shorter than 0.5 H, the temperature of the sintering furnace ranges from 1,100 DEG C to 1,150 DEG C, and the heat preservation time ranges from 0.8 H to 1.5 H; density and hardness tests are conducted on the gear, wherein the density of the gear is not smaller than 7.35 g/cm , and the HRB value of the hardness is not smaller than 80. According to the high-density gear preparation method, the prepared raw material is pressed into the initial blank, and the initial blank is sintered in the preheating furnace and the sintering furnace, so that the initial blank is metallized to obtain thehigh-density gear.

High-density gear preparation method

The present invention relates to a method for manufacturing powder metallurgy of a helical gear capable of manufacturing a helical gear with powder metallurgy with improved high hardness, wear resistance, lubricating properties, and corrosion resistance in order to be used as a deceleration gear whose rotation number is few but a compressive force is high. Moreover, the method for manufacturing powder metallurgy of a helical gear which is a cylindrical gear for transmitting rotary motion between two parallel shafts, and wherein a teeth of the gear is inclined to one side comprises: a powder mixing step for forming metal powder by mixing an additive including 4.5-5.5 wt% of nickel (Ni), 2.7-3.3 wt% of copper (Cu), 0.7-0.9 wt% of molybdenum (Mo), 0.3-0.5 wt% of manganese (Mn), 0.1-0.3 wt% of silicon (Si), 1.3-1.7 wt% of carbon, and 0.3-0.7 wt% of a lubricant, and a main raw material of other residual iron (Fe); a powder forming step for pressing and forming after inserting the metal powder into a mold having a cavity coupled with the helical gear; a powder sintering step for applying heat to the powder pressed and formed in the form of the helical gear by the mold at a certain temperature for a certain time; a post processing step of post processing a sintered body wherein powder is sintered; and an electroless nickel plating step for electroless nickel plating the surface of the sintered body post processed.

Seo Yeon Deok

Papers

Method for manufacuring a helical gear using powder metallugy