Method for chamfering the upper die surface of the green blank in an automatic blank taking and stacking system for ring magnetic pressing

Abstract

This invention relates to the field of magnetic ring pressing molding automatic blank removal and stacking system, specifically a method for chamfering the upper die surface of the green blank. The steps are as follows: S1: Open the mold, exposing the upper die surface of the green blank; S2: Chamfer the upper die surface, using a cutting tool to perform a rotary chamfering process on the upper die surface of the green blank that is magnetically attracted to the mold; S3: Demagnetize and remove the green blank, chamfering the lower die surface; S4: Stack the blanks. This invention, by chamfering the upper die surface while the green blank is magnetically attracted to the mold, eliminates the need for mechanisms such as flipping and repositioning the green blank after removal, simplifying the mechanical and electrical structure and reducing equipment costs and maintenance difficulty. Because chamfering is performed using magnetic attraction, the green blank is stably positioned during processing, reducing processing errors and green blank damage caused by inaccurate positioning, and lowering the defect rate of the pressing molding process. Defective products can be directly converted into slurry for reuse, improving raw material utilization and reducing production costs.

Description

Technical Field

[0001] This invention relates to the field of toroidal magnet production technology, specifically to a method for chamfering the green blank on the upper die surface in an automatic blank taking and stacking system for toroidal magnet pressing and forming. Background Technology

[0002] In the production of toroidal magnets, chamfering is typically performed on the forming mold. However, due to gaps in the mold and the draft taper, the pressed green blank will have large sharp edges, i.e., burrs. Currently, there are two main methods to remove these burrs: one is to add a chamfering grinder to the sintered green blank and chamfer it by grinding; the other is to directly chamfer the green blank using a scraping and chamfering machine. The current mainstream method is to chamfer the green blank by grinding after sintering.

[0003] In existing methods for chamfering green blanks, the lower die surface can be chamfered using a single chamfering of the entire die or a recombined chamfering method. However, if the same method is used for chamfering the upper die surface of the green blank, it is necessary to flip and reposition the green blank after it is removed before the chamfering can be performed. This not only increases the complexity of the mechanical structure, but also causes damage to the green blank due to multiple operations, thus increasing the defect rate.

[0004] The existing chamfering method for the upper die surface has problems of complex structure and cumbersome operation, which limits its application in actual production. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for chamfering the green blank on the upper die surface in an automatic blank taking and stacking system for ring magnetic pressing. This method overcomes the problem in the prior art where chamfering the green blank on the upper die surface in ring magnetic pressing and automatic blank taking and stacking systems requires flipping and repositioning the green blank, resulting in complex mechanical structures, cumbersome operation, and a higher defect rate.

[0006] In view of this, the method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of the present invention is as follows: S1: Open the mold, open the upper mold to expose the upper mold surface of the green blank; S2: Chamfering of the upper die surface. A cutting tool is used to chamfer the upper die surface of the green blank that is magnetically attracted to the die. S3: Demagnetize and remove the blank, chamfer the lower mold surface; S4: Blank stack.

[0007] The method for chamfering the upper die surface of the green blank in the automatic blank taking and stacking system of the ring magnetic pressing molding according to an embodiment of the present invention has at least the following technical effects: The present invention performs chamfering of the upper die surface while the green blank is still magnetically attracted to the mold, eliminating the need for mechanisms such as flipping and repositioning the green blank after removal, simplifying the mechanical and electrical structure, and reducing equipment costs and maintenance difficulty. Because the green blank is chamfered using magnetic attraction, its positioning is stable during processing, reducing processing errors and green blank damage caused by inaccurate positioning, and lowering the defect rate of pressing molding. This method can complete the chamfering of the upper and lower die surfaces during the green blank stage, significantly reducing the defect rate in kiln sintering and subsequent grinding processes. Furthermore, defective products can be directly converted into slurry for reuse, improving raw material utilization and reducing production costs. It is suitable for ring magnetic production using an upper die scraping mode and has broad applicability and promotional value.

[0008] According to some embodiments of the present invention, the vacuum degree of the vacuum cleaning is -0.05MPa to -0.1MPa, and the cleaning time is 2s-5s; the air pressure of the compressed air blowing cleaning is 0.3MPa-0.6MPa, and the cleaning time is 1s-3s.

[0009] According to some embodiments of the present invention, before S1, the process further includes press preparation, material injection and scraping, mold closing, magnetization, pressing to rated pressure, ending magnetization and holding pressure, and pressure release.

[0010] According to some embodiments of the present invention, in S3, before chamfering the lower die surface, the process further includes fixing the blank taker, demagnetizing, and taking the blank.

[0011] According to some embodiments of the present invention, in S2, the cutting tool used is a white steel or cemented carbide cutting tool, and the cutting speed of the cutting tool is 500 r / min-1500 r / min.

[0012] According to some embodiments of the present invention, in S3, when the billet taking machine fixes the green billet, a vacuum suction cup method is adopted, and each green billet is held and moved by four suction cups.

[0013] According to some embodiments of the present invention, in S2, the angle of the rotary chamfer is 30°-60°, and the chamfer width is 0.5mm-2mm.

[0014] According to some embodiments of the present invention, the pressure value for pressing to the rated pressure is 15MPa-20MPa, and the pressure holding time is 3s-10s.

[0015] According to some embodiments of the present invention, the depressurization process is a slow depressurization, with a depressurization rate of 5MPa / s-15MPa / s.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 The process of chamfering the upper die surface of the green blank in the existing ring magnetic pressing automatic blank taking and stacking system. Figure 1 ; Figure 2 The process of chamfering the upper die surface of the green blank in the existing ring magnetic pressing automatic blank taking and stacking system. Figure 2 ; Figure 3 This is a flowchart of the method for chamfering the upper die surface of the green blank in the automatic blank taking and stacking system of the annular magnetic pressing molding of the present invention.

[0019] The purpose, features, and advantages of this accompanying drawing will be further explained in conjunction with the embodiments and with reference to the accompanying drawing. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0022] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] Example 1 like Figure 1 As shown, the traditional wet process for producing ring magnets consists of: slurry preparation, pressing and molding, stacking the green blanks onto a sintering plate, sintering in a kiln, grinding (including chamfering the inner and outer circles), and inspection and packaging. If the green blank chamfering process is integrated into the stacking process after pressing and molding, the process becomes: slurry preparation, pressing and molding, stacking (including chamfering the inner and outer circles), stacking the green blanks onto a sintering plate, sintering in a kiln, grinding, and inspection and packaging. Adding the green blank chamfering process to the molding process significantly reduces the defect rate during kiln sintering and grinding, because wet-pressed green blanks are often difficult to demold. Due to the possibility of uneven filling of the mold cavity or leakage of material in a certain cavity during the pressing process, defective products are formed (the green blanks in cavities with insufficient material are not compacted). During the green blank chamfering process, the green blanks often break, and are thrown into the scrap pile, increasing the breakage rate. Green blanks in cavities with insufficient material and not compacted will crack during sintering and grinding; discarding them in advance will definitely improve the overall pass rate. At the same time, chamfered green blanks are less likely to chip or break during subsequent transfer and processing. Furthermore, defective products can be directly turned into slurry for re-forming and pressing, while sintered waste blanks must undergo crushing and other processes before being downgraded for use. Therefore, placing the chamfering of the inner and outer circles in the current process before kiln sintering can reduce the defect rate during kiln sintering and grinding, save energy and protect the environment, and reuse waste materials. Therefore, chamfering at the green blank stage has significant practical value. However, the existing chamfering method for the upper mold surface has problems such as complex structure and cumbersome operation, which limits its application in actual production.

[0027] See Figure 2As shown, in existing technologies, if the chamfering of the upper die surface green blank uses the same method as the chamfering and recombination (including individual chamfering) of the lower die surface, it requires flipping and repositioning the green blank after it is removed before the chamfering tool can be applied. This not only increases the complexity of the mechanical structure but may also damage the green blank due to multiple operations, increasing the defect rate. To eliminate the need for flipping and repositioning, a new chamfering method for the upper die surface green blank in an automatic blank removal and stacking system for ring magnetic pressing is designed. The new method involves adjusting the process steps during molding and performing the chamfering before blank removal.

[0028] See Figure 3 As shown, the method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of the present invention using the ring magnetic pressing molding method is described in detail below: S1: Open the mold, open the upper mold to expose the upper mold surface of the green blank; S2: Chamfering of the upper die surface. A cutting tool is used to chamfer the upper die surface of the green blank that is magnetically attracted to the die. S3: Fixing the blank taker, demagnetizing, taking the blank, and chamfering the lower die surface; S4: Blank stack.

[0029] In this embodiment, S1: Mold opening, opening the upper mold to expose the upper mold surface of the green blank; The mold opening operation must be performed under specific process conditions, namely after the pressure relief and non-demagnetization steps are completed. At this point, the pressure inside the mold has been released, while the green blank remains stably adsorbed onto the lower mold surface under magnetic force. The mold opening process is automated, with a drive device raising the upper mold along a preset trajectory. The height of the upper mold opening should be such that it fully exposes the green blank without affecting subsequent chamfering operations, typically set to 300cm-400cm beyond the upper mold surface. After mold opening, sensors must be used to detect whether the upper mold position is correct, ensuring that the green blank's upper mold surface is fully exposed, providing stable operating space for the subsequent chamfering process. Because wet-pressed green blanks often have multiple molds and the material is injected into the upper mold, the cutting tools of the scraping and chamfering machine are designed with corresponding cavities, using multiple tools to simultaneously chamfer multiple green blanks at once. The height of the injection mechanism and cutting tools is often greater than 200cm.

[0030] S2: Chamfering of the upper mold surface. A cutting tool is used to chamfer the upper mold surface of the green blank that is magnetically attracted to the mold.

[0031] Before chamfering the upper die surface, the cutting tool must be preheated and calibrated to ensure it is in optimal working condition. High-speed steel or carbide cutting tools are used. During chamfering, the tool moves from its initial position along a preset path to the edge of the upper die surface of the green blank. During the rotary cutting process, the perpendicular distance between the tool and the green blank surface must remain stable, with an error not exceeding ±0.1mm. The rotary cutting speed can be adjusted according to the hardness of the green blank. The cutting speed is 500r / min-1500r / min. For green blanks with higher hardness, the rotary cutting speed can be appropriately reduced to ensure chamfering quality; for green blanks with lower hardness, the rotary cutting speed can be increased to improve processing efficiency. During the chamfering process, the stress on the tool and the condition of the green blank must be monitored in real time. If any abnormalities occur (such as severe tool wear, cracks in the green blank, etc.), processing should be stopped immediately and addressed. The chamfering angle is 30°-60°, and the chamfer width is 0.5mm-2mm.

[0032] S3: Fixing the blank taker, demagnetizing, taking the blank, and chamfering the lower die surface. The lower die face chamfer can be achieved using the same tool as the upper die face chamfer, or by selecting a suitable tool based on the characteristics of the lower die face. The chamfering parameters (such as angle or width) are set according to the product requirements. The operation process is similar to that of the upper die face chamfer, and attention should also be paid to protecting the blank and controlling the processing quality.

[0033] S4: Stacking blanks Before stacking the green billets, the sintering plate must be cleaned and inspected to ensure its surface is flat and free of debris. During stacking, the green billets should be placed in the same direction to facilitate subsequent kiln sintering and processing. The spacing between the green billets should be 2mm-5mm. This spacing ensures sufficient space for heat exchange during sintering while avoiding excessive spacing that would reduce the utilization rate of the sintering plate. The number of stacked layers should not exceed 10, and the overall height should be less than the kiln inlet height, meeting process limitations. This is to prevent excessive pressure from upper layers of green billets on lower layers, which could lead to deformation. The stacking process is completed by automated equipment, using positioning devices to ensure the positional accuracy of the green billets on the sintering plate, with an error not exceeding ±1mm. After stacking, the stacked green billets are inspected to ensure there are no tilted or misaligned billets, and then the sintering plate is moved to the kiln sintering area. This invention performs chamfering on the upper mold surface while the green blank is still magnetically attracted to the mold, eliminating the need for mechanisms such as flipping and repositioning the green blank after removal. This simplifies the mechanical and electrical structure, reduces equipment costs, and lowers maintenance difficulty. Because chamfering is performed using magnetic attraction, the green blank maintains stable positioning during processing, reducing processing errors and green blank damage caused by inaccurate positioning, and lowering the defect rate in pressing. This method can complete chamfering on both the upper and lower mold surfaces during the green blank stage, significantly reducing the defect rate in kiln sintering and subsequent grinding processes. Furthermore, defective products can be directly converted into slurry for reuse, improving raw material utilization and reducing production costs. It is suitable for annular magnetic production using an upper mold scraping method and has broad applicability and promotional value.

[0034] Furthermore, in the existing technology, the original process demagnetizes the green billet at the same time after pressing, but in this solution, demagnetization is not performed at this stage.

[0035] Example 2 The only difference between this embodiment and Embodiment 1 is that, in step two, after the upper mold surface is chamfered, the mold surface is cleaned by vacuum or compressed air blowing.

[0036] In this embodiment, both vacuum suction and compressed air blowing can effectively remove debris and powder generated during the chamfering process of the upper mold surface. Compressed air uses the impact force of the airflow to quickly blow loose impurities away from the mold surface, making it convenient and efficient. Vacuum suction, on the other hand, actively adsorbs debris, providing a more thorough cleaning for small debris adhering to the gaps and corners of the mold surface, minimizing debris residue. Vacuum suction works reliably for debris of different materials and sizes, making it particularly suitable for ring magnet production scenarios with high cleanliness requirements. Furthermore, vacuum suction allows for centralized processing of collected debris, reducing pollution to the production environment. In contrast, improper operation of compressed air blowing can cause scattered debris to affect workshop air quality, potentially impacting the health of operators.

[0037] Furthermore, the vacuum degree of vacuum cleaning is -0.05MPa to -0.1MPa, and the cleaning time is 2s-5s; the air pressure of compressed air blowing cleaning is 0.3MPa-0.6MPa, and the cleaning time is 1s-3s.

[0038] Example 3 The method for chamfering the upper die surface of the green blank in the automatic blank taking and stacking system of the present invention, before S1, further includes the steps of press preparation, material injection and scraping, mold closing, magnetization, pressing to rated pressure, ending magnetization and holding pressure, and pressure release. The specific steps are as follows: S1-1: Press preparation, ensure the press is in normal working condition.

[0039] S1-2: Injection and scraping: The prepared slurry is injected into the mold and scraped to ensure uniform distribution of the slurry.

[0040] S1-3: Mold closing, closing the upper and lower molds of the mold.

[0041] S1-4: Magnetization, performing a magnetization operation on the mold.

[0042] S1-5: Press to rated pressure. The slurry in the mold is pressed to the rated pressure by the press to form the green body. The rated pressure is 15MPa-20MPa.

[0043] S1-6: End magnetization and maintain pressure. Stop the magnetization operation and maintain the current pressure for a period of time, which is 3s-10s.

[0044] S1-7: Depressurization without demagnetization. The pressure is released, but demagnetization is not performed. At this time, the green billet is attracted to the mold under the action of magnetic force. The depressurization process is slow, with a depressurization rate of 5MPa / s-15MPa / s.

[0045] Example 4 The only difference between this embodiment and embodiment 3 is that in this embodiment, S3 further includes fixing the billet taking machine, demagnetizing, and taking the billet.

[0046] Specifically, the upper mold of the mold is opened; a cutting tool is used to perform a rotary chamfering process on the upper mold surface of the green blank that is magnetically attracted to the mold; the blank taker enters and holds the green blank, the blank taker moves to the mold and holds the green blank; the mold is demagnetized so that the green blank is no longer magnetically attracted and is taken out, the blank taker removes the green blank from the mold; the lower mold surface of the removed green blank is chamfered.

[0047] When the billet is fixed in place by the billet take-off machine, a vacuum chuck can be used. Generally, four chucks per billet are sufficient. The outer diameter of the toroidal magnet does not require grinding. The demagnetization operation typically uses one-third the magnitude of the magnetizing current, but in the opposite direction, to ensure a smooth loss of magnetism from the mold. The demagnetization time is controlled between 0.5s and 2s to avoid displacement of the billet due to sudden changes in magnetic force caused by excessively rapid demagnetization. After demagnetization, the billet take-off machine removes the billet from the mold at a steady speed, maintaining its horizontal position during removal to prevent tilting or collision. After removal, the billet is transferred to the chamfering station on the lower mold surface.

[0048] In this embodiment, firstly, ensure that all parameters of the press are normal and that it is in a ready-to-work state.

[0049] Inject an appropriate amount of annular magnetic slurry into the mold, and use a scraper to level the slurry, ensuring that the slurry is evenly distributed in the mold.

[0050] Control the closing of the upper and lower molds to ensure a tight, gapless mold.

[0051] The magnetizing device is activated to magnetize the mold, causing the magnetic slurry particles inside the mold to align in a regular manner according to the magnetic field. Therefore, the pressed green body has residual magnetism before demagnetization.

[0052] Start the press to pressurize the slurry in the mold to the rated pressure, and maintain this pressure for a period of time to allow the green body to be initially formed.

[0053] Turn off the magnetization device and stop magnetization. At the same time, keep the pressure of the press constant and perform a pressure holding operation to further compact the green billet.

[0054] After the pressure holding is completed, the pressure of the press is slowly released, but the demagnetizing device is not activated. At this time, the green blank is firmly attached to the lower mold of the mold under the action of magnetic force.

[0055] The upper mold of the control mold opens, exposing the upper mold surface of the green blank.

[0056] The chamfering tool is activated, and it performs a rotary chamfering operation on the upper die surface of the green blank adsorbed on the mold according to a preset trajectory, completing the chamfering of the inner and outer circles of the upper die surface. After processing, the vacuum adsorption device is activated to clean the mold surface and remove debris and other impurities generated during processing.

[0057] The billet take-off machine moves above the mold, and its clamping mechanism accurately aligns with the billet and gently presses it down.

[0058] Activate the demagnetizing device to demagnetize the mold, causing the mold to lose its magnetism and the green blank to no longer be attracted.

[0059] The clamping mechanism of the billet extractor removes the green billet from the mold.

[0060] The removed green blank is transferred to the lower die chamfering station, where the lower die surface of the green blank is chamfered using a corresponding chamfering device.

[0061] Finally, the green blanks with chamfered upper and lower mold surfaces are stacked on the sintering plate according to the predetermined arrangement, so that they can enter the subsequent kiln sintering process.

[0062] As demonstrated by the above embodiments, the chamfering method of this invention can successfully complete the chamfering of the upper die surface of the ring magnet blank. The entire process is simple to operate, with a low blank damage rate, effectively improving the efficiency and quality of ring magnet production. This method can achieve the inner and outer chamfering of the upper die surface of the blank using the simplest mechanical and electrical structure. It is suitable for ring magnet production using the upper die scraping mode.

[0063] The above content is merely a modification or supplement to the structure of the present invention or a substitution in a similar manner. As long as it does not deviate from the structure of the invention or exceed the scope defined in the claims, it shall fall within the protection scope of the present invention.

Claims

1. A method for chamfering the green blank on the upper die surface in an automatic blank taking and stacking system for ring magnetic pressing, characterized in that, The specific steps are as follows: S1: Open the mold, open the upper mold to expose the upper mold surface of the green blank; S2: Chamfering of the upper die surface. A cutting tool is used to chamfer the upper die surface of the green blank that is magnetically attracted to the die. S3: Demagnetize and remove the blank, chamfer the lower mold surface; S4: Raw material stacking; Before S1, the process also includes press preparation, material injection and scraping, mold closing, magnetization, pressing to rated pressure, ending magnetization and holding pressure, and pressure release. The pressure value for pressing to the rated pressure is 15MPa-20MPa, and the pressure holding time is 3s-10s; The depressurization process is a slow depressurization, with a depressurization rate of 5MPa / s-15MPa / s.

2. The method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of the ring magnetic pressing forming according to claim 1, characterized in that, In step S2, after the upper mold surface is chamfered, the mold surface is cleaned by vacuum suction or compressed air blowing.

3. The method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of ring magnetic pressing according to claim 2, characterized in that, The vacuum suction cleaning has a vacuum level of -0.05MPa to -0.1MPa and a cleaning time of 2s to 5s; the compressed air blowing cleaning has an air pressure of 0.3MPa to 0.6MPa and a cleaning time of 1s to 3s.

4. The method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of ring magnetic pressing forming according to claim 1, characterized in that, In step S3, before chamfering the lower die surface, the process also includes fixing the blank taker, demagnetizing, and taking the blank.

5. The method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of ring magnetic pressing according to claim 1, characterized in that, In step S2, the cutting tool used is a high-speed steel or carbide cutting tool, and the cutting speed is 500 r / min-1500 r / min.

6. The method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of ring magnetic pressing according to claim 1, characterized in that, In S3, when the billet taking machine fixes the green billet, it adopts a vacuum suction cup method, with each green billet being held and moved by four suction cups.

7. The method for chamfering the green blank on the upper die surface in the automatic blank taking and stacking system of ring magnetic pressing according to claim 1, characterized in that, In S2, the angle of the rotary chamfer is 30°-60°, and the chamfer width is 0.5mm-2mm.

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