Double-layer filter disc pressing mold and forming process

Abstract

The present invention provides a double-layer filter disc pressing mold and molding process, which belongs to the field of filter disc production technology, including an upper mold plate and a lower mold plate, the lower end surface of the upper mold plate is provided with an upper mold seat, the lower end surface of the upper mold seat is provided with an upper mold head, the upper end surface of the lower mold plate is provided with a lower mold seat, the upper end surface of the lower mold seat is provided with a charging trough for holding metal powder, the charging trough is adapted to the upper mold head, a guide mechanism is provided between the upper mold plate and the lower mold plate, the upper mold plate is longitudinally lifted relative to the lower mold plate through the guide mechanism, and transverse sliding components are provided on both sides of the lower end surface of the upper mold plate, and main pads are installed on the transverse sliding components, and the main pads are moved between the upper mold seat and the lower mold seat through the transverse sliding components to limit the downward movement distance of the upper mold plate. The double-layer filter disc pressing mold provided by the present invention can complete the molding of the double-layer filter disc with the same mold compared to the method of preparing two filter discs separately and then molding them as a whole, and its process is simpler and the preparation efficiency is higher.

Description

Technical Field

[0001] The invention belongs to the technical field of filter disc production, and more specifically, relates to a double-layer filter disc pressing mold and a molding process. Background Art

[0002] Metal filter discs have the functions of filtering, purifying, separating, and reducing noise, and are widely used in the fields of gas-solid separation, solid-liquid separation, etc. In order to improve the filtering efficiency of the filter disc, it is necessary to increase the filter disc flux while maintaining the filtering accuracy. The double-layer filter disc is composed of a support layer made of coarse powder and a filter layer made of fine powder. The double-layer filter disc takes into account both filtering accuracy and strength, and has a higher flux than the filter disc with the same filtering accuracy and the same thickness. In the prior art, two filter discs are usually prepared separately and then assembled as a whole, or a thin filter disc is made with an additional support to form a double-layer filter disc. The process is relatively complicated, the production efficiency is low, and the reliability is not high. Summary of the invention

[0003] The purpose of the present invention is to provide a double-layer filter disc press-fitting die, which can complete the molding of the double-layer filter disc and improve the preparation efficiency of the double-layer filter disc.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a double-layer filter disc pressing mold, including an upper mold plate and a lower mold plate, the lower end surface of the upper mold plate is provided with an upper mold seat, the lower end surface of the upper mold seat is provided with an upper mold head, the upper end surface of the lower mold plate is provided with a lower mold seat, the upper end surface of the lower mold seat is provided with a loading trough for holding metal powder, the loading trough is adapted to the upper mold head, a guiding mechanism is provided between the upper mold plate and the lower mold plate, the upper mold plate is longitudinally lifted relative to the lower mold plate through the guiding mechanism, transverse sliding components are provided on both sides of the lower end surface of the upper mold plate, main pads are installed on the transverse sliding components, and the main pads are moved between the upper mold seat and the lower mold seat through the transverse sliding components to limit the downward moving distance of the upper mold plate.

[0005] In a possible implementation, a longitudinal through hole is formed through the lower template and the lower mold base, a sealing block is provided at the lower portion of the longitudinal through hole, the sealing block is fitted with the inner wall of the longitudinal through hole, and the sealing block and the inner wall of the upper portion of the longitudinal through hole form the loading trough opening upward.

[0006] In a possible implementation, a gasket is detachably mounted on the upper end surface of the blocking block.

[0007] In a possible implementation, a linear drive mechanism is connected to the lower end of the blocking block, and the linear drive mechanism is used to drive the blocking block to slide along the axial direction of the longitudinal through hole.

[0008] In one possible implementation, the lateral sliding assembly includes a slide rail laterally arranged in the middle of the lower end surface of the upper mold plate and a slider slidably arranged on the slide rail, the two slide rails are symmetrically arranged on both sides of the upper mold base, the main pad is fixed on the lower end surface of the slider, and an extension section is provided at one end of the main pad close to the upper mold head, and the extension section protrudes from the outer wall of the slider close to the upper mold head.

[0009] In one possible implementation, the main pad is a U-shaped block, including a connecting plate connected to the slider and side plates arranged on both sides of the slider, the side plate extends toward one side of the upper mold base, and the lower end of the main pad is detachably connected to an auxiliary pad, and the auxiliary pad is a U-shaped block with the same shape as the main pad.

[0010] In one possible implementation, a dovetail groove is provided on the lower end surface of the side plate, and the dovetail groove is provided along the length direction of the slide rail. One end of the dovetail groove is an open end extending to the side wall of the side plate away from the upper mold base, and the other end of the dovetail groove is a closed end extending to the middle of the side plate. Wedge blocks are respectively provided on both sides of the upper end surface of the auxiliary pad, and the wedge blocks are inserted from the open end and slidably set in the dovetail groove.

[0011] The beneficial effect of the double-layer filter disc pressing mold provided by the present invention is that: compared with the prior art, the lower end surface of the upper mold plate is installed with an upper mold base, and the lower end surface of the upper mold base is installed with an upper mold head; the upper end surface of the lower mold plate is installed with a lower mold base, and a loading trough is provided on the lower mold base. When pressing the double-layer filter disc, the crude metal powder is first added from the upper port of the loading trough, and the two main pads are moved to the two sides of the lower end surface of the upper mold base through the lateral moving assembly, and the upper mold plate is moved downward, so that the upper mold head is inserted from the upper port of the loading trough until the lower end surfaces of the two main pads are against the upper end surface of the lower mold base. At this time, the upper mold head completes the pressing and molding of the crude metal powder filled in the loading trough. The upper template moves upward to separate the upper die head from the charging trough, and fine metal powder is added to the charging trough. The two main pads are moved to the outside of the upper die seat through the lateral moving assembly, and the upper template moves downward, so that the upper die head is inserted from the upper port of the charging trough until the lower end surface of the upper die seat is against the upper end surface of the lower die seat. At this time, the upper die head completes the overall pressing and molding of the fine metal powder filled in the charging trough and the initially pressed coarse metal powder. The coarse metal powder pressed and molded at the bottom and the fine metal powder pressed and molded at the top are finally pressed into a double-layer filter disc structure. Compared with the method of preparing two filter discs separately and then molding them as a whole, the double-layer filter disc pressing mold provided by the present invention can use the same mold to complete the molding of the double-layer filter disc, and its process is simpler and the preparation efficiency is higher. In addition, the obtained double-layer filter discs have high bonding strength and will not be delaminated or cracked.

[0012] The present invention also provides a double-layer filter disc forming process, using the double-layer filter disc pressing mold, comprising the following steps:

[0013] S1: The upper die plate rises, the upper die head leaves the charging trough, and a certain amount of coarse metal powder is filled into the charging trough. The mesh number of the coarse metal powder is 20 mesh to 250 mesh;

[0014] S2: The main pads on both sides of the upper mold plate are moved toward the middle at the same time through the sliding assembly until both main pads are moved to the bottom of the upper mold base, the upper mold plate is lowered, and the upper mold head enters the charging trough from top to bottom until the two main pads abut against the upper mold base, and a certain amount of coarse metal powder is preliminarily pressed;

[0015] S3: The upper mold plate rises, the upper die head leaves the charging trough, and a fixed amount of fine metal powder is filled into the charging trough, and the mesh number of the fine metal powder is 150 mesh to 800 mesh;

[0016] S4: The main pads on both sides of the upper template are moved to both sides simultaneously through the sliding assembly until the two main pads leave the lower area of ​​the upper die seat, the upper template descends, and the upper die head enters the loading trough from top to bottom until the upper die seat abuts against the upper die seat, and a certain amount of fine metal powder and the initially pressed coarse metal powder are pressed and formed as a whole to prepare a double-layer filter disc.

[0017] In one possible implementation, in step S2, before the upper template descends, auxiliary pads are installed at the lower ends of the two main pads, and the main pads on both sides of the upper template are connected to the auxiliary pads through the sliding assembly and moved toward the middle at the same time until the two auxiliary pads are moved to the bottom of the upper die seat, the upper template descends, and the upper die head enters the loading trough from top to bottom until the two auxiliary pads abut against the upper die seat, and a certain amount of coarse metal powder is preliminarily pressed, which can limit the thickness of the initial pressing of the coarse metal powder and control the initial density of the coarse metal powder.

[0018] In one possible implementation, after step S4, the upper template rises, the upper die head leaves the loading trough, and the sealing block at the bottom of the loading trough moves upward through a linear drive mechanism, thereby ejecting the pressed double-layer filter disc from the loading trough and transferring it to a high-temperature sintering furnace. The double-layer filter disc is clamped by a fixture and subjected to vacuum or gas high-temperature sintering.

[0019] The beneficial effect of a double-layer filter disc forming process provided by the present invention is that, compared with the prior art, due to the use of the above-mentioned double-layer filter disc pressing mold, compared with the method of separately preparing two filter discs and then forming them as a whole, the double-layer filter disc can be formed using the same mold, the process is simpler and the preparation efficiency is higher, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic structural diagram of a double-layer filter disc press-fitting mold provided by an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of the structure of a double-layer filter disc pressing mold provided by an embodiment of the present invention when pressing coarse metal powder;

[0023] Figure 3 A schematic diagram of the structure of a double-layer filter disc pressing mold provided by an embodiment of the present invention when pressing fine metal powder;

[0024] Figure 4 for Figure 3 Sectional view along AA;

[0025] Figure 5 A schematic diagram of a structure in which a gasket is installed on a blocking block provided in an embodiment of the present invention;

[0026] Figure 6 A schematic diagram of the structure of installing an auxiliary pad on a main pad provided by the first embodiment of the present invention;

[0027] Figure 7 A schematic diagram of the structure of installing an auxiliary pad on a main pad provided in the second embodiment of the present invention.

[0028] Description of reference numerals:

[0029] 1. Upper template; 2. Upper die base; 3. Upper die head; 4. Lower template; 5. Lower die base; 6. Loading chute; 7. Guide pillar; 8. Guide sleeve; 9. Slide rail; 10. Slider; 11. Main pad; 12. Sealing block; 13. Gasket; 14. Linear drive mechanism; 15. Extension section; 16. Connecting plate; 17. Side plate; 18. Auxiliary pad; 19. Dovetail groove; 20. Wedge block. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0031] See also Figures 1 to 4Now, a double-layer filter disc press-fitting mold provided by the present invention is described. A double-layer filter disc press-fitting mold comprises an upper mold plate 1 and a lower mold plate 4, an upper mold seat 2 is provided on the lower end surface of the upper mold seat 2, an upper mold head 3 is provided on the lower end surface of the lower mold plate 4, a lower mold seat 5 is provided on the upper end surface of the lower mold seat 5, a charging trough 6 for holding metal powder is provided on the upper end surface of the lower mold seat 5, and the charging trough 6 is adapted to the upper mold head 3, a guide mechanism is provided between the upper mold plate 1 and the lower mold plate 4, and the upper mold plate 1 is longitudinally lifted relative to the lower mold plate 4 through the guide mechanism, and transverse sliding components are provided on both sides of the lower end surface of the upper mold plate 1, and main pads 11 are installed on the transverse sliding components, and the main pads 11 are moved between the upper mold seat 2 and the lower mold seat 5 through the transverse sliding components to limit the downward movement distance of the upper mold plate 1.

[0032] The double-layer filter disc pressing die provided by the present invention is compared with the prior art. The lower end surface of the upper die plate 1 is installed with an upper die seat 2, and the lower end surface of the upper die seat 2 is installed with an upper die head 3; the upper end surface of the lower die plate 4 is installed with a lower die seat 5, and a charging trough 6 is provided on the lower die seat 5. When pressing the double-layer filter disc, the coarse metal powder is first added from the upper port of the charging trough 6, and the two main pads 11 are moved to the two sides of the lower end surface of the upper die seat 2 through the lateral moving assembly, and the upper die plate 1 is moved downward, so that the upper die head 3 is inserted from the upper port of the charging trough 6 until the lower end surfaces of the two main pads 11 are against the upper end surface of the lower die seat 5. At this time, the upper die head 3 completes the pressing and forming of the coarse metal powder filled in the charging trough 6. The upper die plate 1 is moved upward, so that the upper die head 3 is separated from the charging trough 6, and fine metal powder is added to the charging trough 6. The two main pads 11 are moved to the outside of the upper die seat 2 through the lateral moving assembly, and the upper die plate 1 is moved downward, so that the upper die head 3 is inserted from the upper port of the charging trough 6 until the lower end face of the upper die seat 2 is against the upper end face of the lower die seat 5. At this time, the upper die head 3 completes the overall pressing and molding of the fine metal powder filled in the charging trough 6 and the initially pressed coarse metal powder. The coarse metal powder pressed and molded at the bottom and the fine metal powder pressed and molded at the top are finally pressed into a double-layer filter disc structure. After the initial pressing and secondary overall molding, the fine metal powder can be embedded in the coarse metal powder to increase the bonding force between the two and avoid stratification during sintering. The double-layer filter disc pressing mold provided by the present invention can use the same mold to complete the molding of the double-layer filter disc, compared with the methods of preparing two filter discs separately and then assembling them as a whole or making thin filter discs with additional supports, and the process is simpler and the preparation efficiency is higher.

[0033] Among them, the guiding mechanism is a plurality of guide sleeves 8 vertically installed on the lower end surface of the upper template 1 and a plurality of guide columns 7 vertically installed on the upper end surface of the lower template 4. The plurality of guide sleeves 8 are evenly distributed on the circumference of the lower end surface of the lower template 4. Similarly, the plurality of guide columns 7 are arranged one by one corresponding to the guide sleeves 8. The upper template 1 is raised and lowered by a hydraulic press, and the guide columns 7 slide in the guide sleeves 8 to play a guiding role, thereby ensuring that the upper die head 3 can be accurately inserted into the loading trough 6.

[0034] In some embodiments, see Figure 1 The longitudinal through hole is a circular hole, which passes through the lower template 4 and the lower mold base 5 longitudinally. A blocking block 12 is provided at the lower part of the longitudinal through hole. The outer wall of the blocking block 12 fits with the inner wall of the longitudinal through hole. The blocking block 12 and the inner wall of the upper part of the longitudinal through hole form a loading trough 6 which opens upward.

[0035] When metal powder is filled into the charging trough 6, the metal powder is contained in the space formed by the upper end surface of the blocking block 12 and the inner wall of the upper part of the longitudinal through hole. The upper die head 3 moves downward to press the metal powder into a round cake shape.

[0036] The longitudinal through hole corresponds to the upper die head 3 and is respectively arranged in the middle of the lower die base 5 and the middle of the upper die base 2. With the cooperation of the guide column 7 and the guide sleeve 8, the upper die head 3 can be accurately inserted into or leave the charging trough 6.

[0037] The lower end of the blocking block 12 is connected to a linear drive mechanism 14, which can be a pneumatic cylinder or a hydraulic cylinder. The linear drive mechanism 14 drives the blocking block 12 to slide along the axial direction of the longitudinal through hole, thereby adjusting the height of the upper end surface of the blocking block 12, and then changing the height of the upper die head 3 from the upper end surface of the blocking block 12 in the pressing state, thereby achieving the adjustment of different filter disc thicknesses and the height limit of the initial pressing.

[0038] The lateral sliding assembly includes a slide rail 9 and a slider 10. There are two slide rails 9. The two slide rails 9 are symmetrically installed on the lower end surface of the upper mold plate 1. Both are arranged horizontally. The opposite ends of the two slide rails 9 extend to the edge of the upper mold base 2 respectively. The two sliders 10 are respectively and correspondingly arranged on the two slide rails 9. Among them, the lower end surface of the slider 10 is flush with the lower end surface of the upper die base 2, and the main pad 11 is installed on the lower end surface of the slider 10 by bolts. An integrally formed extension section 15 is installed at one end of the main pad 11 close to the upper die base 2. When the slider 10 slides to contact the outer wall of the upper die base 2, the extension section 15 can extend to between the upper die base 2 and the lower die base 5. When the upper die base 2 moves downward, the extension sections 15 on the two main pads 11 can be padded between the upper die base 2 and the lower die base 5, thereby blocking the upper die base 2 from continuing to move downward, thereby limiting the depth of the upper die head 3 inserted into the charging trough 6. Relative to the depth of the upper die head 3 inserted into the charging trough 6 when the upper die base 2 and the lower die base 5 are directly abutted, the height difference between the two is the molding height of the initial pressed coarse metal powder.

[0039] Reference Figure 4The main pad 11 is a U-shaped block, which includes an integrally formed connecting plate 16 and side plates 17 located on both sides of the connecting plate 16. The connecting plate 16 is welded or bolted to the lower end surface of the slider 10. The side of the side plate 17 close to the upper mold base 2 is the above-mentioned extension section 15, which can extend between the upper mold base 2 and the lower mold base 5, thereby limiting the downward movement distance of the upper mold base 2.

[0040] Reference Figure 6 and Figure 7 , an auxiliary pad 18 can be installed on the lower end surface of the main pad 11. The auxiliary pad 18 has the same shape as the main pad 11 and is also a U-shaped plate composed of a connecting plate 16 and two side plates 17. By adding the auxiliary pad 18, the limit height between the upper die base 2 and the lower die base 5 is increased, and the depth of the upper die head 3 mixed into the charging trough 6 is further limited, thereby increasing the thickness of the filter disc to meet the use requirements of different filter discs.

[0041] In order to realize the rapid installation of the auxiliary pad 18 and the main pad 11, dovetail grooves 19 are transversely opened on the lower end faces of the two side plates 17 of the main pad 11. The dovetail groove 19 extends from the end away from the upper die seat 2 to the outer wall of the main pad 11, forming an open end; the dovetail groove 19 extends from the end close to the upper die seat 2 to the middle of the main pad 11, forming a closed end. Similarly, wedge blocks 20 are transversely opened on the upper end faces of the two side plates 17 of the auxiliary pad 18. The wedge blocks 20 are adapted to the above-mentioned dovetail grooves 19. With the help of the sliding fit between the wedge blocks 20 and the dovetail grooves 19, the auxiliary pad 18 is inserted from the outside of the main pad 11. The upper end face of the auxiliary pad 18 fits with the lower end face of the main pad 11, and slides from the outside to the bottom of the main pad 11, thereby increasing the height of the overall pad.

[0042] In addition, in order to further increase the height of the overall pad, the height of the auxiliary pad 18 can be increased, or multiple auxiliary pads 18 can be set from top to bottom. At this time, two dovetail grooves 19 are also opened on the lower end surface of the auxiliary pad 18 to meet the need to install more auxiliary pads 18 from the bottom again.

[0043] Since the closed section of the dovetail groove 19 only extends to the middle of the main pad 11 and does not extend to the extension section 15, it will not affect the use of the extension section 15. Similarly, the setting method of the dovetail groove 19 of the auxiliary pad 18 is the same as that of the main pad 11, and it will not affect the use of the corresponding extension section 15 on the auxiliary pad 18.

[0044] Reference Figure 5The molding thickness of the filter disc can be adjusted by installing a gasket 13 on the upper end surface of the blocking block 12. In order to facilitate the installation and use of the gasket 13, the gasket and the blocking block 12 are magnetically attracted. The upper port of the gasket 13 loading trough 6 is placed in it, and the gasket 13 is directly magnetically attracted to the upper end surface of the blocking block 12, or before the blocking block 12 is inserted into the longitudinal through hole, a suitable gasket 13 is first magnetically attracted to the upper end surface of the blocking block 12, and finally the blocking block 12 and the gasket 13 are inserted upward from the lower end of the longitudinal through hole.

[0045] The upper end surface of the gasket 13 is provided with a spherical convex surface protruding upward, which can make the lower part of the integrally formed double-layer filter disc form a spherical surface with a concave middle part inward, which can make the lower part of the integrally formed double-layer filter disc form a spherical surface protruding upward. At the same time, the lower end surface of the upper die head 3 is also provided with a spherical surface with a concave middle part inward, which can make the upper part of the integrally formed double-layer filter disc form a spherical surface protruding upward. The spherical radius range of the spherical surface die head is about 1 / 4r 2 +1~r 2 +0.25, where r is the radius of the die projection surface.

[0046] During the final sintering, since the lower part of the double-layer filter disc is a filter layer formed by coarse metal powder and the upper part is a filter layer formed by fine metal powder, the deformation amplitude of the lower part during sintering shrinkage is smaller than that of the upper part formed by fine metal powder. Therefore, the double-layer filter disc will generate strong shrinkage stress from the fine metal powder surface, so that the whole will form a bowl-shaped deformation defect. The above-mentioned improved structure can make the double-layer filter disc after molding and before sintering reach a structure in which the middle of the lower part is concave upward and the middle of the upper part is convex upward, thereby forming an anti-deformation structure opposite to the defect. During sintering, the shrinkage stress of the fine powder layer is used to make the double-layer filter disc that has finally completed sintering reach a state in which the upper and lower end surfaces are basically flat, thereby reducing the workload of repairing the upper and lower end surfaces of the double-layer filter disc in the later stage.

[0047] Based on the same inventive concept, the present invention also provides a double-layer filter disc forming process, using the above-mentioned double-layer filter disc pressing mold, comprising the following steps:

[0048] S1: The upper mold plate 1 rises, the upper die head 3 leaves the charging trough 6, and a certain amount of coarse metal powder is filled into the charging trough 6, where the mesh number of the coarse metal powder is 20-250 mesh;

[0049] S2: The main pads 11 on both sides of the upper mold plate 1 are moved toward the middle at the same time through the sliding assembly until both main pads 11 are moved to the bottom of the upper mold base 2, the upper mold plate 1 is lowered, and the upper mold head 3 enters the charging trough 6 from top to bottom until the two main pads 11 abut against the upper mold base 2, and the quantitative coarse metal powder is preliminarily pressed;

[0050] S3: the upper mold plate 1 rises, the upper die head 3 leaves the charging trough 6, and a fixed amount of fine metal powder is filled into the charging trough 6, the mesh number of the fine metal powder is 150 mesh to 800 mesh;

[0051] S4: The main pads 11 on both sides of the upper mold plate 1 are moved to both sides simultaneously through the sliding assembly until the two main pads 11 leave the lower area of ​​the upper mold base 2, the upper mold plate 1 descends, and the upper mold head 3 enters the loading trough 6 from top to bottom until the upper mold base 2 abuts against the upper mold base 2, and a certain amount of fine metal powder and the preliminarily pressed coarse metal powder are pressed and formed as a whole to prepare a double-layer filter disc.

[0052] Before filling the metal powder, the filling amount of the coarse metal powder and the fine metal powder is calculated in advance according to the molding pressure and the required filter thickness, that is, a fixed amount of coarse metal powder and fine metal powder is filled. The required space volume is calculated by combining the calculated required weight of the metal powder with the loose density of the metal powder and the cross-sectional area of ​​the charging trough 6, and then the height between the upper die head 3 and the bottom of the charging trough 6 when the main cushion block 11 is used and the height between the upper die head 3 and the bottom of the charging trough 6 when the main cushion block 11 is not used is adjusted according to the required space volume.

[0053] For metal powders that are difficult to be pressed and double-layer filter discs that are easy to be layered during sintering, it is necessary to mix the required powders with a binder (which can be paraffin, PE, PMMA, etc.) in a certain proportion at a certain temperature. After the coarse powder layer is formed, the mixed fine powder is added to the charging trough 6. Due to the presence of the binder at this time, the fine powder layer has poor fluidity, uneven thickness distribution, and lumps. At this time, there is a heat source in the lower die seat 5, which can preheat the blocking block 12, the charging trough 6 and the coarse powder layer, and then heat the fine powder layer, so that the fine powder layer maintains good fluidity and is easier to form. After cooling, the double-layer filter disc has a uniform thickness and strong bonding force. In addition, through this method, metal powders that are difficult to be pressed can also be used as the fine powder layer of the double-layer filter disc.

[0054] Finally, the upper template 1 rises, the upper die head 3 leaves the loading trough 6, and the sealing block 12 at the bottom of the loading trough 6 moves upward through the linear drive mechanism 14, thereby ejecting the pressed double-layer filter disc from the loading trough 6 and transferring it to a high-temperature sintering furnace. In order to avoid cracking, stratification and other defects during sintering of the double-layer filter disc, 80-120 mesh alumina is used as a supporting filler, which is spread on a flat ceramic substrate. The double-layer filter disc is placed on top of it, and the fine metal powder faces downward, and 80-120 mesh alumina is used to completely cover the double-layer filter disc, and a ceramic plate is placed on top of it to press the double-layer filter disc, and then vacuum or gas high-temperature sintering is carried out. The sintering temperature is 900-1200°C, the heating rate is 1°C / min-5°C / min, and the temperature is kept constant for 1-4h, thereby completing the final sintering process.

[0055] If there is a binder, the heating curve, heating rate and constant temperature time will be different. At this time, the heating rate should be controlled at 0.2℃ / min-0.5℃ / min, and the temperature should be kept constant at 250℃, 350℃, and 550℃ for 1-3h, and then the temperature should be raised to 900-1200℃ at 1℃ / min-5℃ / min, and the temperature should be kept constant for 1-4h.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A double-layer filter disc press mold, characterized in that: The invention comprises an upper mold plate (1) and a lower mold plate (4), wherein the lower end surface of the upper mold plate (1) is provided with an upper mold base (2), the lower end surface of the upper mold base (2) is provided with an upper mold head (3), the upper end surface of the lower mold plate (4) is provided with a lower mold base (5), the upper end surface of the lower mold base (5) is provided with a loading trough (6) for containing metal powder, the loading trough (6) is adapted to the upper mold head (3), a guide mechanism is provided between the upper mold plate (1) and the lower mold plate (4), the upper mold plate (1) is longitudinally lifted relative to the lower mold plate (4) by the guide mechanism, transverse sliding components are provided on both sides of the lower end surface of the upper mold plate (1), main pads (11) are installed on the transverse sliding components, the main pads (11) are moved between the upper mold base (2) and the lower mold base (5) by the transverse sliding components, so as to limit the downward movement distance of the upper mold plate (1); The lower mold plate (4) and the lower mold base (5) are provided with a longitudinal through hole, a blocking block (12) is provided at the lower part of the longitudinal through hole, the blocking block (12) is fitted with the inner wall of the longitudinal through hole, and the blocking block (12) and the inner wall of the upper part of the longitudinal through hole form the loading trough (6) opening upward; The upper end surface of the blocking block (12) is detachably provided with a gasket (13), which is directly magnetically attracted to the upper end surface of the blocking block (12). The upper end surface of the gasket (13) is provided with a spherical convex surface protruding upward, and the lower end surface of the upper die head (3) is also provided with a spherical surface with a middle portion concave inward.

2. A double-layer filter disc pressing mold according to claim 1, characterized in that: The lower end of the blocking block (12) is connected to a linear drive mechanism (14), and the linear drive mechanism (14) is used to drive the blocking block (12) to slide along the axial direction of the longitudinal through hole.

3. A double-layer filter disc pressing mold according to claim 1, characterized in that: The lateral sliding assembly comprises a slide rail (9) arranged transversely in the middle of the lower end surface of the upper mold plate (1) and a slider (10) slidably arranged on the slide rail (9), the two slide rails (9) are symmetrically arranged on both sides of the upper mold base (2), the main pad (11) is fixed to the lower end surface of the slider (10), and an extension section (15) is provided at one end of the main pad (11) close to the upper mold head (3), and the extension section (15) protrudes from the outer wall of the slider (10) close to the upper mold head (3).

4. A double-layer filter disc pressing mold as claimed in claim 3, characterized in that: The main pad (11) is a U-shaped block, comprising a connecting plate (16) connected to the slider (10) and side plates (17) arranged on both sides of the slider (10), wherein the side plates (17) extend toward one side of the upper die seat (2), and the lower end of the main pad (11) is detachably connected to an auxiliary pad (18), wherein the auxiliary pad (18) is a U-shaped block having the same shape as the main pad (11).

5. A double-layer filter disc pressing mold as claimed in claim 4, characterized in that: A dovetail groove (19) is provided on the lower end surface of the side plate (17), and the dovetail groove (19) is provided along the length direction of the slide rail (9). One end of the dovetail groove (19) is an open end extending to the side wall of the side plate (17) away from the upper mold base (2), and the other end of the dovetail groove (19) is a closed end extending to the middle of the side plate (17). Wedge blocks (20) are respectively provided on both sides of the upper end surface of the auxiliary pad block (18), and the wedge blocks (20) are inserted from the open end and slidably set in the dovetail groove (19).

6. A double-layer filter disc forming process, characterized in that: A double-layer filter disc pressing mold as described in any one of claims 1 to 5 is used, comprising the following steps: S1: the upper mold plate (1) rises, the upper die head (3) leaves the charging trough (6), and a certain amount of coarse metal powder is filled into the charging trough (6), wherein the mesh size of the coarse metal powder is 20 to 250 meshes; S2: The main pads (11) on both sides of the upper mold plate (1) are moved toward the middle simultaneously through the sliding assembly until both main pads (11) are moved to the bottom of the upper mold base (2), the upper mold plate (1) is lowered, and the upper mold head (3) enters the charging trough (6) from top to bottom until the two main pads (11) abut against the upper mold base (2), and a certain amount of coarse metal powder is preliminarily pressed; S3: the upper mold plate (1) rises, the upper die head (3) leaves the charging trough (6), and a fixed amount of fine metal powder is filled into the charging trough (6), wherein the mesh size of the fine metal powder is 150 to 800 meshes; S4: The main pads (11) on both sides of the upper mold plate (1) are moved to both sides simultaneously by means of a sliding assembly until the two main pads (11) leave the lower area of ​​the upper mold base (2), the upper mold plate (1) descends, and the upper mold head (3) enters the loading trough (6) from top to bottom until the upper mold base (2) abuts against the lower mold base (5), and a certain amount of fine metal powder and the initially pressed coarse metal powder are pressed and formed as a whole to prepare a double-layer filter disc.

7. A double-layer filter disc forming process as claimed in claim 6, characterized in that: In step S2, before the upper mold plate (1) is lowered, auxiliary pads (18) are installed at the lower ends of the two main pads (11), and the main pads (11) on both sides of the upper mold plate (1) are connected to the auxiliary pads (18) through the sliding assembly and moved toward the middle at the same time until the two auxiliary pads (18) are moved to the bottom of the upper mold base (2). The upper mold plate (1) is lowered, and the upper mold head (3) enters the charging trough (6) from top to bottom until the two auxiliary pads (18) abut against the upper mold base (2), and a certain amount of coarse metal powder is initially pressed, so that the thickness of the initial pressing of the coarse metal powder can be limited and the initial density of the coarse metal powder can be controlled.

8. A double-layer filter disc forming process as claimed in claim 6, characterized in that: After step S4, the upper template (1) rises, the upper die head (3) leaves the loading trough (6), and the blocking block (12) at the bottom of the loading trough (6) moves upward through the linear drive mechanism (14), thereby ejecting the pressed double-layer filter disc from the loading trough (6) and transferring it to a high-temperature sintering furnace. The double-layer filter disc is clamped by a fixture and subjected to vacuum or gas high-temperature sintering.

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