Powder metallurgy process coating electrical contact material with continuous silver layer on the side and its pressing preparation method

Abstract

The application discloses a pressing die for powder metallurgy process multilayer electric contact material with continuous silver layer on side surface and a pressing preparation method thereof. The die comprises an upper punch, a lower punch corresponding to the position of the upper punch and a die cavity platform arranged between the upper punch and the lower punch. The die cavity platform is provided with a square die cavity and four push die cavities located at four sides of the square die cavity. The square die cavity and the four push die cavities are connected to form a cross-shaped structure groove. The upper punch and the lower punch are matched with the shape of the square die cavity and are respectively located on the upper and lower sides of the square die cavity. The outer ends of the four push die cavities are respectively provided with hydraulic channels. Each push die cavity is respectively provided with a push die. One end of the push die extends into the hydraulic channel and is sealingly matched with the inner wall of the hydraulic channel. The other end of the push die is matched with the shape of the push die cavity and can slide in the horizontal direction in the push die cavity under the hydraulic action. The application has simple and reasonable structure, improves the mechanical life and the electrical life of the powder metallurgy process multilayer electric contact material in the use process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrical contact materials, in particular to a powder metallurgy process multilayer electrical contact material pressing mold with a continuous silver layer on the side and a pressing preparation method thereof. BACKGROUND

[0002] In the electrical contact material manufacturing industry, powder metallurgy multilayer electrical contact products often only have a multilayer material on the bottom surface, such as AgWCC, AgNiC, mold pressing process AgC, AgZnO, etc. The existing powder metallurgy multilayer electrical contact products are prone to welding deformation and cracking during welding, affecting the mechanical life of the electrical contact.

[0003] Through retrieval, Chinese patent CN113284767B discloses a preparation method of silver graphite electrical contact with a continuous pure silver layer on the side, and Chinese patent CN113245547B discloses a preparation method of silver nickel graphite electrical contact with a continuous decarburized layer on the side. The technical solution is to make the side of the multilayer electrical contact material have a continuous pure silver layer through the process of preliminary pressing-sintering-repressing-decarburizing-cutting / pressure milling-cleaning. With the plasticity of the pure silver layer, the deformation of the contact under stress during the closing process is greatly reduced, thereby improving the mechanical life. Through the above two patents, it can be understood that the process method for obtaining a pure silver layer of the existing powder metallurgy multilayer electrical contact material is through preliminary pressing-sintering-repressing-decarburizing-cutting / pressure milling-cleaning. The mold and process method proposed in this application can use ordinary forming methods: preliminary pressing-sintering-repressing-cleaning, solving the problems of complexity, long manufacturing cycle and high manufacturing cost in the manufacturing process.

[0004] Therefore, developing a simple and easy-to-implement preparation method for making the side of the powder metallurgy process multilayer electrical contact material have a continuous silver layer has important practical application value for improving the mechanical life of such contact materials. SUMMARY

[0005] In order to overcome the shortcomings and deficiencies of the prior art, a powder metallurgy process multilayer electrical contact material pressing mold with a continuous silver layer on the side and a pressing preparation method thereof are provided.

[0006] The technical solution adopted by the present application is as follows:

[0007] As a first aspect of the present application, a powder metallurgy process multilayer electrical contact material pressing mold with a continuous silver layer on the side is provided, comprising an upper punch, a lower punch corresponding to the position of the upper punch, and a mold cavity platform arranged between the upper punch and the lower punch, wherein the mold cavity platform has a square mold cavity and four push mold cavities located at the four sides of the square mold cavity, and the square mold cavity and the four push mold cavities are connected to form a cross-shaped structure recess;

[0008] The upper punch and the lower punch are adapted to the shape of the square die cavity and are respectively located on the upper and lower sides of the square die cavity;

[0009] The four push die cavities are respectively provided with hydraulic channels, and each push die cavity is respectively provided with a push die.

[0010] Further, the upper surface of the push die is 1-5 mm away from the die cavity platform.

[0011] As a second aspect of the present application, a pressing preparation method of a powder metallurgy process layered electrical contact material with a continuous silver layer on the side is provided, which uses the die as claimed in claim 1, and the method comprises the following steps:

[0012] S1. The lower punch is pushed to the bottom of the square die cavity, the push die is pushed to the side of the square die cavity and pushed into the square die cavity by a certain distance; the base powder is filled in the square die cavity, and the base powder is pressed by the pressure applied by the upper punch to the base powder to form a base material;

[0013] S2. The push die is retracted to form a silver layer material pressing cavity on four sides of the base material obtained in the filling step S1, and silver layer material powder is filled in the silver layer material pressing cavity.

[0014] Further, the step S2 specifically comprises:

[0015] S2.1. The push die is pushed out by 0.1 mm, the lower punch is pushed up to coincide with the bottom surface of all the push dies, 5.24-5.34 g of AgWC12C3 powder is added in the die cavity, then the upper punch is pushed down, 3-6 T pressure is applied for pressing, pressure maintaining is performed for 1-3 s, after the pressing is completed, the upper punch, the lower punch and the push die are reset to obtain an electrical contact material with a side layer; the dust collector is pushed forward to suck the residual base powder and then reset.

[0016] S2.2. After 0.35-0.55 g of Ag powder is added in the die cavity, the upper punch is pushed down, 10-15 T pressure is applied for pressing, pressure maintaining is performed for 1-3 s, after the pressing is completed, the upper punch is reset, the lower punch is raised, and the pressed product is pushed out of the die cavity platform to obtain an electrical contact material with a bottom layer; the dust collector is pushed forward to suck the residual powder and then push the product into the box.

[0017] As a third aspect of the present application, a powder metallurgy process layered electrical contact material with a continuous silver layer on the side is provided, which is prepared by the above preparation method.

[0018] Further, the thickness of the side layer of the material is 0.05-1 mm, and the thickness of the bottom layer is 0.2-1.5 mm.

[0019] The present application has the advantages over the prior art in that:

[0020] By special mold structure design and pressing method, the side of the powder metallurgy process multi-layer electric contact material has a continuous silver layer. The deformation and cracking of the powder metallurgy process multi-layer electric contact material product during welding is reduced, and the plasticity and mechanical life of the powder metallurgy process multi-layer electric contact material product are improved.

[0021] The present application provides a special mold design structure, and the process method can be used as the ordinary forming method: initial pressing-sintering-repressing-cleaning, which solves the problems of complicated manufacturing process, long manufacturing period and high manufacturing cost caused by special process method. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the device design scheme of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other functionally similar drawings obtained according to these drawings without creative labor still belong to the scope of the present application.

[0023] Figure 1 It is a schematic diagram of the mold cavity platform structure of the present application;

[0024] Figure 2 It is a schematic diagram of the silver layer material pressing cavity of the present application;

[0025] Figure 3 It is a schematic diagram of the push mold pushing out of the present application;

[0026] Figure 4 It is a schematic diagram of the push mold back of the present application;

[0027] Figure 5 It is a schematic diagram of the metallographic phase of the product with continuous silver layer on the side of the present application;

[0028] Figure 6 It is a schematic diagram of the metallographic phase of the product without continuous silver layer on the side of the present application.

[0029] In the figure, 10-square cavity, 20-push mold cavity, 40-mold cavity platform, 401-hydraulic channel, 50-push mold. DETAILED DESCRIPTION

[0030] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0031] Example one

[0032] Take the product with the size specification of 20x10x3 as an example, the pressed base layer is AgWC12C3 powder, and the complex layer material is Ag powder.

[0033] 1. Select the upper punch 20 with the length and width dimensions of 19.9x9.9 according to the drawing, wherein the length and width dimensions of the upper punch outer mold are 19.9x9.9 mm, and the length and width dimensions of the upper punch inner mold are 19.8x9.8 mm.

[0034] Select the lower punch 30 with the length and width dimensions of 30x20, wherein the length and width dimensions of the lower punch outer mold are 30x20 mm, and the length and width dimensions of the lower punch inner mold are 24x16 mm.

[0035] Select the push mold 50 with the length and height dimensions of 19.9x25, wherein the length and height dimensions of the push mold outer mold are 19.9x25 mm, and the length and height dimensions of the push mold inner mold are 19.8x24 mm.

[0036] 2. Check whether there are defects in the size and appearance of the mold by using a vernier caliper and visual inspection method.

[0037] 3. Install the lower punch 30, the mold cavity platform 40, and the upper punch 20 on the powder automatic forming machine in the order from bottom to top, and fix them on the machine with screws.

[0038] 4. After installing the pusher on the mold cavity platform, place the left and right support frames on the supports on both sides of the pusher, buckle the spring in the circle below the pusher, pour AgWC12C3 powder into the right hopper, pour AgNi10 powder into the left hopper, and shake the hose to make the powder flow into the pusher.

[0039] 5. Install the dust collector on the mold cavity platform 40.

[0040] 6. Push the push mold inner mold out by 0.1 mm, push the lower punch inner mold upward to coincide with the bottom surface of all push mold inner molds, shake the right hopper, add 5.24-5.34 g of AgWC12C3 powder in the mold cavity, then push the upper punch inner mold downward, apply a pressure of 3-6 T for pressing, and keep the pressure for 1-3 s. After pressing, reset the upper punch 20, the lower punch 30, and the push mold 50, and push the dust collector forward to suck up the excess base powder and then reset it.

[0041] 7. The left hopper is shaken, 0.35-0.55 g of Ag powder is added into the die cavity, the upper punch of the outer die is pushed down, 10-15 T pressure is applied for pressing, pressure is maintained for 1-3 s, after the pressing is completed, the upper punch of the outer die 201 is reset, the lower punch of the inner die is raised, the pressed product is pushed out of the die cavity platform 40, the dust collector is pushed forward to suck the residual powder and push the product into the box.

[0042] Example 2

[0043] Taking the product with the size specification of 31.8 x 12.2 x 2 as an example, the base layer is pressed by AgZnO10 powder, and the complex layer material is Ag powder.

[0044] 1. The upper punch 20 with the length and width of 31.65 x 12.05 is selected according to the drawing, wherein the length and width of the upper punch of the outer die is 31.65 x 12.05 mm, and the length and width of the upper punch of the inner die is 31.45 x 11.85 mm.

[0045] The lower punch 30 with the length and width of 38 x 20 is selected, wherein the length and width of the lower punch of the outer die is 38 x 20 mm, and the length and width of the lower punch of the inner die is 34 x 18 mm.

[0046] The push die 50 with the length and height of 31.65 x 25 is selected, wherein the length and height of the push die of the outer die is 31.65 x 25 mm, and the length and height of the push die of the inner die is 31.45 x 24 mm.

[0047] 2. The size and appearance of the die are checked by using the vernier caliper and visual method.

[0048] 3. The lower punch 30, the die cavity platform 40 and the upper punch 20 are installed on the powder automatic forming machine in the order from bottom to top, and are fixed on the machine by screws.

[0049] 4. After the pusher is installed on the die cavity platform, the left and right support frames are placed on the supports on both sides of the pusher, the spring is buckled in the circle below the pusher, the AgZn10 powder is poured into the right hopper, the Ag powder is poured into the left hopper, and the hose is shaken to make the powder flow into the pusher.

[0050] 5. The dust collector is installed on the die cavity platform 40.

[0051] 6. The push die is pushed out by 0.2 mm, the lower punch of the inner die is pushed up to coincide with the bottom surface of all the push dies of the inner die, the right hopper is shaken, 5.5-5.8 g of AgZn10 powder is added into the die cavity, the upper punch of the inner die is pushed down, 4-8 T pressure is applied for pressing, pressure is maintained for 1-3 s, after the pressing is completed, the upper punch 20, the lower punch 30 and the push die 50 are reset, and the dust collector is pushed forward to suck the residual base powder and reset.

[0052] 7. The left hopper is shaken, 0.35-0.55 g of AgNi10 powder is added into the die cavity, the upper punch outer die is pushed down, 10-15 T pressure is applied for pressing, pressure is maintained for 1-3 s, after pressing, the upper punch outer die is reset, the lower punch inner die is raised, the pressed product is pushed out of the die cavity platform 40, the dust collector is pushed forward to suck up the residual powder and push the product into the box.

[0053] Example Three

[0054] The pressed base layer is AgNi25C2 powder, the re-layer material is Ag powder, and the product size is 85x10x1.5.

[0055] 1. According to the drawing, the upper punch 20 with a length-width size of 85.5x10.2 is selected, wherein the length-width size of the upper punch outer die is 85.5x10.2 mm, and the length-width size of the upper punch inner die is 85x10 mm.

[0056] The lower punch 30 with a length-width size of 96x20 is selected, wherein the length-width size of the lower punch outer die is 96x20 mm, and the length-width size of the lower punch inner die is 90x18 mm.

[0057] The push die 50 with a length-height size of 85.5x25 is selected, wherein the length-height size of the push die outer die is 85.5x25 mm, and the length-height size of the push die inner die is 85x24 mm.

[0058] 2. The size and appearance of the mold are checked for defects by using a vernier caliper and visual inspection.

[0059] 3. The lower punch 30, the die cavity platform 40, and the upper punch 20 are installed on the powder automatic forming machine in the order from bottom to top, and are fixed on the machine by screws.

[0060] 4. After the pusher is installed on the die cavity platform, the left and right support frames are placed on the supports on both sides of the pusher, the spring is buckled in the circle below the pusher, AgNi25C2 powder is poured into the right hopper, Ag powder is poured into the left hopper, and the hose is shaken to make the powder flow into the pusher.

[0061] 5. The dust collector is installed on the die cavity platform 40.

[0062] 6. The push die inner die is pushed out by 0.15 mm, the lower punch inner die is pushed up to coincide with the bottom surface of all the push die inner dies, the right hopper is shaken, 9.32-10.02 g of AgNi25C2 powder is added into the die cavity, the upper punch inner die is pushed down, 6-9 T pressure is applied for pressing, pressure is maintained for 2-4 s, after pressing, the upper punch 20, the lower punch 30, and the push die 50 are reset, and the dust collector is pushed forward to suck up the residual base powder and reset.

[0063] 7. The left hopper is shaken, 1.41-2.01g of Ag powder is added into the cavity, the upper punch of the outer die is pushed down, 10-15T pressure is applied for pressing, pressure maintaining time is 1-3s, after the pressing is completed, the upper punch of the outer die is reset, the lower punch of the inner die is lifted, the pressed product is pushed out of the cavity platform 40, the dust collector is pushed forward, the residual powder is sucked clean, and the product is pushed into the box.

[0064] The above only discloses the preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so the equivalent changes made according to the claims of the present application still belong to the scope covered by the present application.

Claims

1. A method for preparing a powder metallurgy process coated electrical contact material with continuous silver layer on the side by pressing, which is applied to a powder metallurgy process coated electrical contact material with continuous silver layer on the side by pressing mold, characterized in that: the pressing mold comprises an upper punch, a lower punch corresponding to the position of the upper punch, and a mold cavity platform (40) arranged between the upper punch and the lower punch, the mold cavity platform (40) has a square cavity (10) and four push mold cavities (20) located at the four sides of the square cavity (10), and the square cavity (10) and the four push mold cavities (20) are connected to form a cross-shaped structure recess; the upper punch and the lower punch are matched with the shape of the square cavity (10) and are respectively located on the upper and lower sides of the square cavity (10); the outer end of each push mold cavity (20) is provided with a hydraulic channel (401), and each push mold cavity (20) is provided with a push mold (50) arranged therein, one end of the push mold (50) extends into the hydraulic channel (401) and is in sealing cooperation with the inner wall of the hydraulic channel (401), and the other end is matched with the shape of the push mold cavity (20) and can slide in the horizontal direction in the push mold cavity (20) under the action of hydraulic pressure; the upper surface of the push mold (50) is 1-5 mm away from the mold cavity platform (40); the method comprises the following steps: S1. The lower punch is pushed to the bottom of the square cavity (10), the push mold (50) is pushed to the side of the square cavity (10) and pushed into the square cavity (10) by a certain distance; the square cavity (10) is filled with base powder, and the upper punch applies pressure to the base powder to form a base material by pressing; S2. The push mold (50) is retracted to form a silver layer material pressing cavity on the four sides of the base material obtained in the filling step S1, and silver layer material powder is filled in the silver layer material pressing cavity. The steps specifically include, 2. A method of making a powder metallurgy process multilayer electrical contact material compact with a continuous silver layer on the side according to claim 1, characterized in that: S1.

1. Push the push mold (50) out by 0.1 mm, push the lower punch upward to coincide with the bottom surface of all push molds (50), add 5.24-5.34 g of AgWC12C3 powder in the mold cavity, then push the upper punch downward, apply a pressure of 3-6 T for pressing, and keep the pressure for 1-3 s; after pressing, the upper punch, the lower punch, and the push mold (50) are reset to obtain the pressed base material; the dust collector is pushed forward to suck up the excess base powder and then reset; S2.

1. Add 0.35-0.55 g of Ag powder in the mold cavity, then push the upper punch downward, apply a pressure of 10-15 T for pressing, and keep the pressure for 1-3 s; after pressing, the upper punch is reset, the lower punch is raised, the pressed product is pushed out of the mold cavity platform (40), and the electrical contact material with a side coating is obtained; the dust collector is pushed forward to suck up the residual powder and then push the product into the box.

3. A powder metallurgy process coated electrical contact material with continuous silver layer on the side, which is prepared by the method of claim 1. The thickness of the side coating of the material is 0.05-1 mm.

4. The powder metallurgy process multilayered electrical contact material with continuous silver layer on the side according to claim 3, characterized in that: ​

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