Preparation method of a highly wear-resistant polyurethane sieve plate

Abstract

A preparation method of a highly wear-resistant polyurethane sieve plate includes the following steps: S1. Open ceramic positioning grooves on a ceramic arrangement plate; S2. Apply an adhesive to the ceramic blocks except for the upper surfaces, and place them in the ceramic positioning grooves to obtain a ceramic arrangement plate with ceramic blocks; S3. Precast a cavity bottom plate, stick the cavity bottom plate to the ceramic arrangement plate, and remove the ceramic arrangement plate to obtain a cavity bottom plate with ceramic blocks stuck; S4. Precast a metal skeleton, a mold core and a cavity frame, and combine them with the cavity bottom plate to obtain a forming cavity; S5. Pour preheated polyurethane into the preheated forming cavity; S6. Keep the forming cavity warm for forming, and demold to obtain the highly wear-resistant polyurethane sieve plate. The present invention can better control the arrangement of the ceramic blocks and the sieve holes, the prepared sieve plate has good overall wear resistance, and the preparation method is simple, can be mass-produced, and has a low preparation cost.

Description

Technical Field

[0001] The present invention relates to the technical fields of mining machinery and composite material preparation, and particularly relates to a preparation method of a highly wear-resistant polyurethane sieve plate. Background Art

[0002] A vibrating screen passes a group of fragmented materials with different particle sizes through a single-layer or multi-layer screen surface with uniformly distributed holes multiple times, and screens them into several materials with different particle size levels, which is widely used in industries such as mining, coal, smelting, and building materials. The sieve plate or sieve mesh on the vibrating screen directly bears the impact and screening operations of the materials. When it is worn to a certain extent, it must be replaced. Usually, materials such as wear-resistant rubber, polyurethane, and wear-resistant alloy are used to improve the wear resistance of the sieve plate.

[0003] In the polyurethane wear-resistant plate, the wear resistance of the plate has been further improved by setting ceramic blocks. However, most of them are applied to liners that do not need to leave sieve holes. For sieve plates, due to the structural characteristics of the product itself, there are the following process difficulties: 1. There is usually a rigid skeleton inside the sieve plate, and it is located at the bottom surface, while the ceramic is located on the working surface (i.e., the upper surface) of the sieve plate. Therefore, before pouring polyurethane, one of the rigid skeleton and the ceramic must be suspended in the mold cavity; 2. The positioning problem of the ceramic. Each ceramic block must be accurately located on the sieve ribs and avoid the sieve holes, otherwise it will affect the installation of the mold core. At present, there is no mature method for preparing polyurethane sieve plates that can overcome the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a highly wear-resistant polyurethane sieve plate, which uses the positioned ceramic blocks and the mold core to cooperate and prepares a highly wear-resistant polyurethane sieve plate by pouring polyurethane.

[0005] The technical solution adopted by the present invention to achieve the above purpose is as follows:

[0006] A preparation method of a highly wear-resistant polyurethane sieve plate includes the following steps:

[0007] S1. According to the distribution of ceramic blocks in the to-be-prepared highly wear-resistant polyurethane sieve plate, ceramic positioning grooves with a depth lower than the height of the ceramic blocks are opened on a ceramic arrangement plate to obtain a ceramic arrangement plate with ceramic positioning grooves;

[0008] S2. First, apply an adhesive to other surfaces of the ceramic block except the upper surface, and place the ceramic block coated with the adhesive in the ceramic positioning groove of S1, and expose the upper surface of the ceramic block out of the ceramic positioning groove. Then, stick a heat-resistant double-sided tape on the upper surface of the ceramic block, and peel off the release paper of the heat-resistant double-sided tape to obtain a ceramic arrangement plate with ceramic blocks;

[0009] S3. Pre-fabricate a cavity bottom plate adapted to the size of the to-be-prepared highly wear-resistant polyurethane sieve plate, stick the cavity bottom plate to the double-sided adhesive on the ceramic arrangement plate with ceramic blocks obtained in S2, and remove the ceramic arrangement plate to obtain the cavity bottom plate with ceramic blocks stuck thereto.

[0010] S4. Pre-fabricate a metal skeleton as the support of the highly wear-resistant polyurethane sieve plate, a mold core for being buckled between ceramic blocks, and a frame adapted to the cavity bottom plate, and combine the metal skeleton, the mold core, the frame and the cavity bottom plate with ceramic blocks stuck thereto obtained in S3 to obtain a formed cavity.

[0011] S5. Preheat the formed cavity obtained in S4, and pour the preheated polyurethane into the formed cavity.

[0012] S6. Insulate and form the formed cavity after pouring polyurethane in S5, and demold to obtain the highly wear-resistant polyurethane sieve plate.

[0013] As a preferred embodiment of the present invention, in S1, the depth of the ceramic positioning groove satisfies that after the ceramic block is placed in the ceramic positioning groove, the height difference between the upper surface of the ceramic block and the notch of the ceramic positioning groove is 3 - 5 mm.

[0014] As a preferred embodiment of the present invention, in S2, the used binder satisfies that after heat preservation and forming, the bonding strength between the ceramic block and the polyurethane is ≥15 KN / m.

[0015] As a preferred embodiment of the present invention, in S2, the heat-resistant double-sided adhesive can withstand a high temperature of 120 °C.

[0016] As a preferred embodiment of the present invention, in S1, a first positioning hole is reserved on the arrangement plate, in S2, a second positioning hole is reserved on the cavity bottom plate, in S4, a positioning pin is pre-fabricated, and the positioning pin is inserted into the second positioning hole.

[0017] As a preferred embodiment of the present invention, in S4, in the formed cavity, the mold core includes a bottom plate and protrusions provided on the bottom plate, the bottom plate fits the plane formed by the ceramic blocks, the convex blocks are inserted into the gaps between adjacent ceramic blocks, and the metal skeleton is arranged between the mold core and the frame.

[0018] As a preferred embodiment of the present invention, in S5, the preheating temperature is 120 - 150 °C.

[0019] As a preferred embodiment of the present invention, in S5, the polyurethane is subjected to vacuum degassing before pouring.

[0020] As a preferred embodiment of the present invention, in S6, before heat preservation and forming, the air bubbles floating on the polyurethane in the formed cavity are baked and burst with hot air or a gas combustion flame.

[0021] As a preferred embodiment of the present invention, after demolding, secondary vulcanization, flash removal and burr removal treatments are sequentially carried out.

[0022] Advantages of the present invention:

[0023] 1. When preparing the highly wear-resistant polyurethane sieve plate of the present invention, the ceramic blocks are first positioned by a ceramic arrangement plate, and the positioned ceramic blocks are integrally bonded to the bottom plate of the mold cavity through double-sided adhesive. Then, the mold core is provided with sieve holes of the sieve plate adapted to the ceramic blocks, and a forming mold cavity is formed by using the frame, the bottom plate of the mold cavity and the mold core. Finally, the highly wear-resistant cast polyurethane sieve plate with ceramic blocks is obtained by pouring polyurethane. It can better control the arrangement of the ceramic blocks and sieve holes on the prepared polyurethane sieve plate. The overall wear resistance is good, and it is especially suitable for the first-stage screening or the screening operation of the upper layer of the vibrating screen containing large pieces and large granular materials. Moreover, the preparation method is simple, can be mass-produced, and the preparation cost is low.

[0024] 2. When preparing the highly wear-resistant polyurethane sieve plate of the present invention, an adhesive is brushed on the surfaces of the ceramic blocks where they are connected to the cast polyurethane. After heat preservation and molding, the adhesive reacts with the polyurethane to crosslink, ensuring the connection strength between the ceramic blocks and the polyurethane, and the ceramics do not fall off, which is stable and reliable.

[0025] 3. By using the positioning tooling in the present invention, each ceramic block is accurately positioned, ensuring that the gap between some ceramic blocks will not be too large due to the displacement of some ceramics (the gap is resisted by polyurethane against wear), so that the local life of the product is reduced and the whole fails;

[0026] 4. For the highly wear-resistant polyurethane sieve plate made in the present invention, the ceramics on its working surface are flush with the polyurethane, making the material pass more smoothly and having less local impact on the sieve surface, especially on the ceramics, which can further extend the service life. Description of the drawings

[0027] Figure 1 is a schematic structural view of the highly wear-resistant polyurethane sieve plate in the present invention;

[0028] Figure 2 is a schematic structural view of the ceramic arrangement plate in the present invention;

[0029] Figure 3 is a schematic structural view of the bottom plate of the mold cavity in the present invention;

[0030] Figure 4 is a schematic structural view of the mold cavity frame in the present invention;

[0031] Figure 5 is a schematic structural view of the mold core in the present invention;

[0032] Figure 6 is a schematic structural view of the ceramic arrangement plate with ceramic blocks in the present invention;

[0033] Figure 7It is a schematic structural diagram of the die cavity bottom plate with ceramic blocks adhered in the present invention;

[0034] Figure 8 It is a schematic structural diagram of the forming die cavity in the present invention.

[0035] Markings in the figure: 1. Ceramic block, 101. Ceramic bevel edge, 2. Polyurethane, 3. Metal skeleton, 4. Sieve plate mounting hole, 5. Ceramic arrangement plate, 501. Ceramic positioning groove, 502. First positioning hole, 6. Die cavity bottom plate, 601. Second positioning hole, 7. Die cavity frame, 701. Core positioning groove, 8. Core, 9. Straight steel wire, 10. Positioning pin (used for forming the sieve plate mounting hole, and positioning and supporting the skeleton). Specific embodiments

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. In the description of the present invention, it should be noted that unless otherwise specified, the meaning of "a plurality" is two or more; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0037] The present invention provides a preparation method for a highly wear-resistant polyurethane sieve plate. In combination with Figures 1 to 8 As shown, the highly wear-resistant polyurethane sieve plate includes a metal skeleton 3, a ceramic block 1, and polyurethane 2. Among them, the metal skeleton 3 can be made of carbon steel as the strength support of the sieve plate. The ceramic block 1 is connected to the metal skeleton 3 by polyurethane 2. The ceramic block 1 is alumina ceramic as the wear-resistant carrier, and the polyurethane serves as a flexible support and buffer layer, fully releasing the risk of brittle fracture or shedding of the ceramic block caused by the impact of materials, doubling the service life of the sieve plate and greatly reducing the consumption of the sieve plate.

[0038] In the actual operation of bearing the impact of materials, due to the different landing points and particle sizes of the materials, the overall sieve surface is unevenly stressed. Therefore, the ceramic blocks 1 on the sieve surface are placed in blocks to avoid excessive local deformation leading to ceramic fracture, and the flexible connection between blocks can also well release most of the stress generated by excessive local deformation.

[0039] When preparing the highly wear-resistant polyurethane sieve plate, the following steps are specifically included:

[0040] S1. Select the ceramic arrangement plate 5 according to the size of the to-be-prepared highly wear-resistant polyurethane sieve plate. According to the distribution of the ceramic blocks 1 in the to-be-prepared highly wear-resistant polyurethane sieve plate, open ceramic positioning grooves 501 with a depth lower than the height of the ceramic blocks on the ceramic arrangement plate 5 to obtain the ceramic arrangement plate 5 with the ceramic positioning grooves 501. Among them, the depth of the ceramic positioning grooves 501 is lower than the height of the ceramic blocks. Specifically, after the ceramic block 1 is placed in the ceramic positioning groove 501, the height difference between the upper surface of the ceramic block 1 and the notch of the ceramic positioning groove 501 is 3 - 5 mm. The purpose is that after the ceramic block 1 is placed in the ceramic positioning groove 501, the upper surface can expose the ceramic positioning groove 501.

[0041] Specifically when opening the positioning grooves, they can be opened according to the arrangement of the ceramic blocks. In this embodiment, the flexible connection between the ceramic blocks may become a weak link in the wear resistance of the sieve plate. Since the movement of the material on the inclined sieve surface usually rolls or slides downward, when specifically setting the flexible connection between the ceramic blocks, it should be inclined or perpendicular to the direction of the material rolling or sliding downward, and the width should be appropriately controlled. Thus, in the direction of the material rolling or sliding downward, even for fragmented materials, there is always a ceramic surface to bear the rolling or sliding wear, and furthermore, it can also prevent the flexible connection from wearing out and failing prior to the ceramic surface.

[0042] Combined Figure 1 As shown, in this embodiment, the ceramic blocks 1 are classified into two categories. One category has a ceramic bevel edge 101, and the other category does not have a ceramic bevel edge 101. Arrange such ceramic blocks in the Y direction of the sieve plate. The Y direction of the sieve plate is perpendicular to the discharge direction of the material rolling or sliding. The ceramic blocks without the ceramic bevel edge will be arranged in the X direction of the sieve plate. The X direction of the sieve plate is parallel to the discharge direction of the material rolling or sliding. It can be understood that in other embodiments, if the distribution of the ceramic blocks on the sieve plate changes, the ceramic positioning grooves 501 can be opened according to the actually required arrangement of the ceramic blocks.

[0043] S2. First, apply an adhesive on other surfaces of the ceramic block 1 except the upper surface. The adhesive can adopt a commercially available type. However, to ensure that the final wear resistance of the sieve plate is in a good state, the adhesive should meet the requirement that after the product is heat-insulated and formed, the bonding strength between the ceramic block 1 and the polyurethane 2 is not less than 15 KN / m.

[0044] Combined Figure 2 As shown, place the ceramic block 1 coated with the adhesive into the ceramic positioning groove 501 of S1, and place it with the upper surface of the ceramic block 1 exposing the ceramic positioning groove 501. Then, stick a heat-resistant double-sided tape on the upper surface of the ceramic block 1. The heat-resistant double-sided tape is preferably able to withstand a high temperature of 120 °C to ensure the smooth progress of the subsequent pouring of the polyurethane. Then, remove the release paper of the heat-resistant double-sided tape to obtain the ceramic arrangement plate 5 with the ceramic block 1. The ceramic arrangement plate 5 with the ceramic block 1 is as Figure 6 shown.

[0045] S3. Combine Figure 3 As shown, prefabricate a cavity bottom plate 6 that is adapted to the size of the high-wear-resistant polyurethane sieve plate to be prepared, and keep the plane of the cavity bottom plate 6 clean without oil stains and dirt. Stick the cavity bottom plate 6 to the double-sided tape on the ceramic arrangement plate 5 with ceramic blocks 1 obtained in S2. Flip the ceramic arrangement plate 5 and the cavity bottom plate 6, and remove the ceramic arrangement plate 5. As Figure 7 shown, obtain the cavity bottom plate 6 with ceramic blocks 1 stuck on it.

[0046] S4. Combine Figure 4 and Figure 5 As shown, prefabricate a cavity frame 7 that is adapted to the cavity bottom plate, and assemble the cavity bottom plate 6 into the cavity frame 7. Before assembly, the inner surface of the cavity frame 7 can be coated with release oil. In order to facilitate the positioning of the mold core 8, a mold core positioning groove 701 is provided on the frame of the cavity frame 7. The mold core positioning groove 701 is used to place a straight steel wire 9 for positioning the mold core 8. After the mold core 8 is assembled, the straight steel wire 9 can be withdrawn.

[0047] Prefabricate a metal skeleton 3 as the support of the high-wear-resistant polyurethane sieve plate and a mold core 8 for buckling between ceramic blocks. As Figure 5 and Figure 8 shown, the mold core 8 includes a bottom plate and protrusions provided on the bottom plate. After assembly, the bottom plate fits the plane formed by the ceramic blocks 1, and the convex blocks are inserted into the gaps between adjacent ceramic blocks 1. After the mold core 8 is finally demolded and removed, sieve holes of the sieve plate are formed at the protrusion positions. Combine the metal skeleton 3, the mold core 8, the cavity frame 7, and the cavity bottom plate 6 to obtain a forming cavity. In the forming cavity, the metal skeleton 3 is arranged between the mold core 8 and the cavity frame 7, and the bottom plate of the mold core 8 is higher than the casting plane of the forming cavity.

[0048] In order to facilitate the precise docking of the ceramic arrangement plate 5 and the cavity bottom plate 6, a first positioning hole 501 is reserved on the ceramic arrangement plate 5 in S1. The first positioning hole 501 is used to position the ceramic arrangement plate 5 and the cavity bottom plate 6. A second positioning hole 601 is reserved on the cavity bottom plate 6 in S2. A positioning pin 10 is prefabricated and matched in S4. During preparation, the positioning pin 10 is inserted into the second positioning hole 601. Among them, the positioning pin can also be made of ordinary carbon steel. When placing the positioning pin 10, it is best to coat it with release oil. As mentioned above, the metal skeleton 3 is arranged between the mold core 8 and the cavity frame 7. The positioning pin 10 can be in the shape of a stepped shaft, that is, a circumferential surface extending radially is provided on the part of the positioning pin 10 located in the forming cavity. The circumferential surface is used to support and place the metal skeleton 3.

[0049] S5. Preheat the formed mold cavity obtained in S4, and pour the preheated polyurethane into the formed mold cavity. During preheating, the preheating temperature of the formed mold cavity is usually 120 - 150 °C. During pouring, preheat the raw materials of the casting-type polyurethane in a polyurethane casting machine. The preheating temperature depends on the requirements of raw material mixing. At the same time, perform vacuum degassing on the raw materials before preparing for pouring.

[0050] S6. Insulate and form the formed mold cavity after pouring polyurethane in S5. After pouring the polyurethane and before insulation and forming, observe whether there are bubbles floating on the pouring surface. Before the polyurethane solidifies, use hot air or a gas combustion flame to burst the bubbles floating in the polyurethane pouring liquid to obtain a sieve plate of higher quality.

[0051] Among them, the bottom plate of the mold core 8 is higher than the pouring plane after the mold core 8 is placed in the mold cavity, which is also to facilitate bursting the large bubbles floating in the polyurethane pouring liquid with hot air or a gas combustion flame.

[0052] After insulation and forming, the material solidifies. Demold the formed mold cavity, remove the mold core 8, the mold cavity frame 7, and the mold cavity bottom plate 6, remove the residual double-sided tape on the ceramic block in the product, perform a secondary vulcanization treatment on the product, and then remove the flash and burrs of the product to obtain the Figure 1 high wear-resistant polyurethane sieve plate as shown.

[0053] It can be understood that for the convenience of the assembly operation of the sieve plate during application, sieve plate mounting holes 4 can be opened at the four corners of the sieve plate.

[0054] It should be noted that the parts not detailed in this article are prior art. The above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention all fall within the protection scope of the present invention.

Claims

1. A preparation method of a highly wear-resistant polyurethane sieve plate, characterized in that, It includes the following steps: S1. According to the distribution of ceramic blocks in the to-be-prepared high-wear-resistant polyurethane sieve plate, ceramic positioning grooves with a depth lower than the height of the ceramic blocks are opened on the ceramic arrangement plate to obtain a ceramic arrangement plate with ceramic positioning grooves. The depth of the ceramic positioning grooves meets the requirement that after the ceramic blocks are placed in the ceramic positioning grooves, the height difference between the upper surface of the ceramic blocks and the notch of the ceramic positioning grooves is 3-5 mm; S2. First, apply an adhesive on all surfaces of the ceramic blocks except the upper surface, place the ceramic blocks coated with the adhesive in the ceramic positioning grooves of S1, and expose the upper surfaces of the ceramic blocks outside the ceramic positioning grooves. Then, stick a heat-resistant double-sided tape on the upper surfaces of the ceramic blocks, and peel off the release paper of the heat-resistant double-sided tape to obtain a ceramic arrangement plate with ceramic blocks; S3. Pre-fabricate a mold cavity bottom plate adapted to the size of the to-be-prepared high-wear-resistant polyurethane sieve plate, stick the mold cavity bottom plate to the double-sided tape in the ceramic arrangement plate with ceramic blocks obtained in S2, and remove the ceramic arrangement plate to obtain a mold cavity bottom plate with ceramic blocks stuck; S4. Pre-fabricate a metal skeleton for supporting the high-wear-resistant polyurethane sieve plate, a mold core for being buckled between ceramic blocks, and a mold cavity frame adapted to the mold cavity bottom plate. Combine the metal skeleton, the mold core, and the frame with the mold cavity bottom plate with ceramic blocks stuck in S3 to obtain a formed mold cavity. There is a mold core positioning groove on the frame body of the mold cavity frame, and the mold core positioning groove is used for placing a straight steel wire for positioning the mold core. After the mold core is assembled, the straight steel wire can be removed; In the formed mold cavity, the mold core includes a bottom plate and protrusions provided on the bottom plate. The bottom plate fits the plane formed by the ceramic blocks, and the convex blocks are inserted into the gaps between adjacent ceramic blocks. The metal skeleton is arranged between the mold core and the mold cavity frame, and the bottom plate of the mold core is higher than the casting plane of the formed mold cavity; S5. Preheat the formed mold cavity obtained in S4, and pour preheated polyurethane into the formed mold cavity; S6. Insulate and form the formed mold cavity after pouring polyurethane in S5, and demold to obtain the high-wear-resistant polyurethane sieve plate.

2. The preparation method of a highly wear-resistant polyurethane sieve plate as described in claim 1, characterized in that, In S2, the used adhesive meets the requirement that after heat preservation and forming, the bonding strength between the ceramic blocks and the polyurethane is ≥15 KN / m.

3. The preparation method of a highly wear-resistant polyurethane sieve plate according to claim 1, characterized in that, In S2, the heat-resistant double-sided tape can withstand a high temperature of 120 °C.

4. The preparation method of a highly wear-resistant polyurethane sieve plate as described in claim 1, characterized in that, In S1, a first positioning hole is reserved on the arrangement plate, in S2, a second positioning hole is reserved on the mold cavity bottom plate, and in S4, a positioning pin is pre-fabricated and inserted into the second positioning hole.

5. The preparation method of a highly wear-resistant polyurethane sieve plate according to claim 1, characterized in that, In S5, the preheating temperature is 120-150 °C.

6. The preparation method of a highly wear-resistant polyurethane sieve plate as described in claim 1, characterized in that, In S5, vacuum degassing is carried out on the polyurethane before pouring.

7. The preparation method of a highly wear-resistant polyurethane sieve plate as described in claim 1, characterized in that, In S6, before heat preservation and forming, use hot air or a gas combustion flame to break the bubbles floating in the polyurethane in the formed mold cavity.

8. The preparation method of a highly wear-resistant polyurethane sieve plate as described in claim 1, characterized in that After demolding, secondary vulcanization, flash removal, and burr removal treatments are carried out in sequence.

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