Low-temperature cold air-multi-dimensional ultrasonic combined extrusion polishing device and method

Abstract

The invention discloses a low-temperature cold air-multi-dimensional ultrasonic combined extrusion polishing device and method, which combine low-temperature cooling, multi-dimensional ultrasonic vibration and extrusion polishing to perform surface polishing and strengthening treatment on parts such as die steel. In the machining process, a low-temperature medium forms a low-temperature environment in a machining area, thermal chemical abrasion of a diamond tool to-be-polished object and periodic contact and separation of the tool and a workpiece under the multi-dimensional ultrasonic effect can be effectively restrained, and the problem that in the low-temperature machining process, it is difficult for a cooling medium to completely enter the machining area can be effectively solved. Ultrasonic vibration can conduct high-frequency reciprocating ironing on the surface of the workpiece, so that the polishing and surface strengthening effects are achieved under the condition that tool abrasion is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical polishing of material surfaces, and in particular relates to a low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device and method. Background Art

[0002] Superhard mold steel has the advantages of strong wear resistance and good hardenability, and is widely used in the manufacture of large-size, ultra-precision molds in the fields of aerospace, automobiles, etc. The parts required in these fields have complex shapes, high dimensional accuracy requirements, and mirror-like surfaces. Natural diamond can grind out extremely sharp cutting edges and is an indispensable tool material for mirror processing. However, natural diamond has poor machinability and it is difficult to make tools with complex shapes. At the same time, the graphitization phenomenon when diamond tools process ferrous metals will cause tool wear and sub-surface damage to the workpiece, making it difficult to achieve an ultra-smooth surface with high surface accuracy. Therefore, there is a need for a low-temperature cold air-multidimensional ultrasonic composite extrusion polishing device and method with a simple structure, easy operation and good polishing effect. Summary of the invention

[0003] The purpose of the present invention is to provide a low-temperature cold air-multidimensional ultrasonic composite extrusion polishing device and method with a simple structure, convenient operation and good polishing effect. Low-temperature cooling, multidimensional ultrasonic vibration and extrusion polishing are combined to perform surface polishing and strengthening treatment on parts such as mold steel. During the processing, the low-temperature medium forms a low-temperature environment in the processing area, which can effectively suppress the thermochemical wear of the diamond tool waiting to be polished. Under the action of multidimensional ultrasound, the tool and the workpiece produce periodic contact and separation, which can effectively improve the problem that the cooling medium is difficult to fully enter the processing area during low-temperature processing. In addition, ultrasonic vibration can perform high-frequency reciprocating ironing on the surface of the workpiece, so that it has polishing and surface strengthening effects while effectively improving tool wear.

[0004] To achieve the above object, the present invention adopts the following technical solution: A low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device comprises a frame on which a longitudinal-torsion ultrasonic vibration tool holder unit, a two-dimensional ultrasonic vibration platform unit, a low-temperature eddy current cold air unit and an extrusion polishing unit are installed; The longitudinal torsional ultrasonic vibration tool handle unit comprises a transmitting disk, a receiving disk, a tool handle and a first ultrasonic vibrator which are coaxially arranged in sequence from top to bottom. The tool handle comprises an external shell, a mounting cavity is formed inside the external shell, the first ultrasonic vibrator is mounted in the mounting cavity, the bottom end of the first ultrasonic vibrator is connected to the extrusion polishing unit, the transmitting disk and the receiving disk are arranged at the upper end of the external shell, a rivet is arranged in the central part of the transmitting disk and the receiving disk along the vertical direction, the bottom of the rivet is connected to the top outer surface of the tool handle, and the top of the rivet is connected to the external machining center spindle; The two-dimensional ultrasonic vibration platform unit includes a working vibration platform, a second ultrasonic vibrator and a third ultrasonic vibrator, wherein the second ultrasonic vibrator and the third ultrasonic vibrator are respectively vertically arranged on the left side and the rear side of the working vibration platform; The low-temperature vortex cold air unit includes a magnetic base, a swirl tube, an airflow rod, a cold air nozzle and a control valve. The swirl tube is installed on the magnetic base in the left and right directions. A swirl chamber is formed inside the swirl tube. The airflow rod is arranged at the left and right ends of the swirl tube. An airflow channel is arranged in the airflow rod. The airflow channel is connected with the swirl chamber. The cold air nozzle is arranged at the left end of the airflow rod at the left end of the swirl tube. A swirl hole is arranged on the upper part of the swirl tube. The control valve is arranged at the right end of the airflow rod at the right end of the swirl tube. The extrusion polishing unit comprises a PCD micro-blade ball end milling cutter, the upper end of which is connected to a first ultrasonic vibrator, a working vibration platform is arranged below the PCD micro-blade ball end milling cutter, and a die steel workpiece is placed on the working vibration platform.

[0005] The first ultrasonic vibrator includes a transducer and a longitudinal torsion horn. The transducer is a sandwich piezoelectric ceramic transducer. The upper end of the longitudinal torsion horn is connected to the lower end of the transducer. The lower end of the longitudinal torsion horn extends out of the installation cavity and the bottom end of the external shell.

[0006] A flange is arranged at the bottom of the installation cavity, and the longitudinal-torsion amplitude transformer and the transducer are installed in the installation cavity through the flange.

[0007] The working vibration platform comprises an upper vibration plate and a lower vibration plate, and support columns are arranged between the four corners of the upper vibration plate and the lower vibration plate.

[0008] The second ultrasonic vibrator is connected to the left side surface of the upper vibration plate through threads, and the third ultrasonic vibrator is connected to the rear side surface of the upper vibration plate through threads.

[0009] The gap between the transmitting disk and the receiving disk is 0.5 to 1 mm.

[0010] The transducer includes a plurality of electrodes and piezoelectric ceramics which are alternately arranged at intervals.

[0011] The outer wall of the longitudinal-torsion amplitude transformer is provided with a plurality of spiral grooves spaced apart along the axial direction thereof.

[0012] The transmitting disk of the longitudinal-torsional ultrasonic vibration handle unit is connected to a first external ultrasonic power supply, the working vibration platform is connected to a second external ultrasonic power supply, the swirl cylinder of the low-temperature vortex cold air unit is connected to a swirl air inlet pipe through a swirl hole, the swirl air inlet pipe is connected to an external air compressor, and an external rotating device is arranged at the bottom of the working vibration platform.

[0013] The polishing method is implemented based on the above-mentioned low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device, and comprises the following steps: (1) starting a first external ultrasonic power supply, which outputs a high-frequency alternating current signal, which is sequentially transmitted to a transmitting disk, a receiving disk, and a transducer, and then drives the entire longitudinal-torsional ultrasonic vibration tool holder unit to generate longitudinal-torsional vibration, so that the surface of the PCD micro-blade ball end milling cutter generates a composite longitudinal and torsional ultrasonic vibration; (2) starting a second external ultrasonic power supply, which outputs a high-frequency alternating current signal, which is transmitted to the second ultrasonic vibrator and the third ultrasonic vibrator through a wire and then drives the two-dimensional ultrasonic vibration platform unit to generate ultrasonic vibrations in two perpendicular directions; (3) Starting the external air compressor, which delivers compressed air to the cyclone chamber of the low-temperature vortex cooling air unit to form a high-speed rotating airflow, and the compressed air is separated into cold and hot airflows through the cyclone chamber to cool the polishing area; (4) Start the external rotating device to rotate the two-dimensional ultrasonic vibration platform unit to a certain angle, start the CNC machining center spindle to rotate the PCD micro-blade ball end milling cutter and move it toward the direction close to the mold steel workpiece and abut against the mold steel workpiece, and perform fine extrusion and polishing treatment on the mold steel workpiece.

[0014] The transducer of the longitudinal-torsional ultrasonic vibration handle unit of the low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device of the present application adopts electrodes and piezoelectric ceramics arranged alternately at intervals, which can effectively enhance the conduction effect of ultrasonic vibration.

[0015] The present application arranges multiple spiral grooves on the longitudinal-torsion amplitude transformer, thereby converting one-dimensional longitudinal ultrasonic vibration into two-dimensional longitudinal-torsion ultrasonic vibration, and through the cooperation of the transmitting disk, receiving disk, transducer, longitudinal-torsion amplitude transformer and tool holder in the longitudinal-torsion ultrasonic vibration tool holder unit, it is possible to generate composite longitudinal and torsional ultrasonic vibrations on the surface of the PCD micro-blade ball end milling cutter. This composite vibration mode can effectively reduce the contact friction between the tool and the workpiece, reduce tool wear, and improve the surface quality of the workpiece.

[0016] The second ultrasonic vibrator and the third ultrasonic vibrator of the present application are connected to the upper vibration plate through threads, and can apply ultrasonic vibration to the workpiece in two vertical directions, thereby achieving repeated high-frequency ironing effect on the surface of the workpiece, effectively improving the surface flatness and smoothness.

[0017] The low-temperature vortex cooling unit of the present application adopts vortex cooling to form a low-temperature environment in the extrusion polishing area, which can effectively reduce the affinity between diamond and iron elements and reduce the wear of diamond tools. At the same time, the system has a flexible adjustment function, and the cooling temperature and cold air flow can be adjusted in real time according to processing needs to achieve the purpose of accurately controlling the cooling effect.

[0018] This application utilizes the micro-nano removal characteristics of the PCD micro-blade ball end milling cutter to perform fine extrusion polishing on the workpiece surface. By reasonably adjusting the equipment speed and tool angle, the polishing effect is optimized to meet different processing requirements. The PCD micro-blade ball end milling cutter performs fine strengthening treatment on the workpiece surface with the cooperation of multi-dimensional ultrasonic vibration. During the polishing process, intermittent contact and separation occur between the tool and the workpiece, and the relative speed and direction of the contact change periodically. This process can not only improve the processing efficiency, but also significantly improve the problem that the cooling medium is difficult to fully enter the processing area during low-temperature processing, effectively reducing tool wear and improving the surface quality of the workpiece.

[0019] To sum up, the present application is scientifically designed and reasonably structured. During the processing, the low-temperature medium forms a low-temperature environment in the processing area, which can effectively suppress the thermochemical wear of the diamond tool waiting to be polished. Under the action of multi-dimensional ultrasound, the tool and the workpiece produce periodic contact and separation, which can effectively improve the problem that the cooling medium is difficult to fully enter the processing area during low-temperature processing. In addition, ultrasonic vibration can perform high-frequency reciprocating ironing on the surface of the workpiece, so that it has polishing and surface strengthening effects while effectively improving tool wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the polishing device of the present invention.

[0021] Figure 2 It is a structural schematic diagram of a polishing device for a mold steel workpiece after it is rotated by a certain angle according to the present invention.

[0022] Figure 3 It is a structural schematic diagram of the longitudinal-torsional ultrasonic vibration handle unit of the present invention.

[0023] Figure 4 yes Figure 3 Section view of the AA plane.

[0024] Figure 5 It is a structural schematic diagram of the two-dimensional ultrasonic vibration platform unit of the present invention.

[0025] Figure 6 It is a structural schematic diagram of the low-temperature vortex cold air unit of the present invention.

[0026] Figure 7 It is a cross-sectional view of the low-temperature vortex cold air unit of the present invention.

[0027] Figure 8 It is a schematic structural diagram of the extrusion polishing unit of the present invention.

[0028] Fig. 9 It is a flow chart of the polishing method of the present invention. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0030] Embodiment 1 like Figure 1-8 As shown, the low-temperature cold air-multidimensional ultrasonic composite extrusion polishing device includes a frame (not shown in the figure), on which a longitudinal-torsional ultrasonic vibration handle unit 10, a two-dimensional ultrasonic vibration platform unit 40, a low-temperature eddy current cold air unit 50 and an extrusion polishing unit are installed; wherein, the longitudinal-torsional ultrasonic vibration handle unit 10 is longitudinally installed on the frame, the two-dimensional ultrasonic vibration platform unit 40 is installed on the frame and is located below the longitudinal-torsional ultrasonic vibration handle unit 10, and the low-temperature eddy current cold air unit 50 is installed on the frame and is located to the right of the two-dimensional ultrasonic vibration platform unit 40.

[0031] The longitudinal torsional ultrasonic vibration handle unit 10 includes a transmitting disk 102, a receiving disk 103, a handle 105 and a first ultrasonic vibrator which are coaxially arranged from top to bottom, and the gap between the transmitting disk 102 and the receiving disk 103 is 0.5-1 mm; the handle 105 includes an external shell, and a mounting cavity is formed inside the external shell, and the first ultrasonic vibrator is installed in the mounting cavity. The bottom end of the first ultrasonic vibrator is connected to the extrusion polishing unit, and the transmitting disk 102 and the receiving disk 103 are arranged at the upper end of the external shell. The center of the transmitting disk 102 and the receiving disk 103 is provided with a rivet 101 in the vertical direction, and the bottom of the rivet 101 is connected to the top outer surface of the handle 105, and the top of the rivet 101 is connected to the external machining center spindle; the transducer 104 includes a plurality of electrodes and piezoelectric ceramics which are alternately arranged at intervals. The transducer 104 of the longitudinal torsional ultrasonic vibration handle unit 10 of the present application uses electrodes and piezoelectric ceramics which are alternately arranged at intervals, which can effectively enhance the conduction effect of ultrasonic vibration.

[0032] The two-dimensional ultrasonic vibration platform unit 40 includes a working vibration platform, a second ultrasonic vibrator 404 and a third ultrasonic vibrator 405, and the second ultrasonic vibrator 404 and the third ultrasonic vibrator 405 are respectively vertically arranged on the left side and the rear side of the working vibration platform; The low-temperature vortex cold air unit 50 includes a magnetic base 505, a cyclone tube 506, an airflow rod 507, a cold air nozzle 501 and a control valve 504. The cyclone tube 506 is installed on the magnetic base 505 in the left and right horizontal direction. A cyclone chamber 502 is formed inside the cyclone tube 506. The airflow rod 507 is arranged at the left and right ends of the cyclone tube 506. An airflow channel 503 is arranged in the airflow rod 507, and the airflow channel 503 is connected to the cyclone chamber 502. The cold air nozzle 501 is arranged at the left end of the airflow rod 507 at the left end of the cyclone tube 506. A cyclone hole 5021 is arranged on the upper part of the cyclone tube 506. The control valve 504 is arranged at the right end of the airflow rod 507 at the right end of the cyclone tube 506. The low-temperature vortex cold air unit 50 of the present application adopts vortex cooling to form a low-temperature environment in the extrusion polishing area, which can effectively reduce the affinity between diamond and iron elements and reduce the wear of diamond tools. At the same time, the system has the function of flexible adjustment. The cooling temperature and cold air flow can be adjusted in real time according to processing needs to achieve the purpose of precise control of the cooling effect.

[0033] The extrusion polishing unit comprises a PCD micro-blade ball end milling cutter 20, the upper end of which is connected to a first ultrasonic vibrator, a working vibration platform is arranged below the PCD micro-blade ball end milling cutter 20, and a mold steel workpiece 30 is placed on the working vibration platform.

[0034] The first ultrasonic vibrator includes a transducer 104 and a longitudinal-torsion amplitude transformer 106. The transducer 104 is a sandwich piezoelectric ceramic transducer 104. The upper end of the longitudinal-torsion amplitude transformer 106 is connected to the lower end of the transducer 104. The lower end of the longitudinal-torsion amplitude transformer 106 extends out of the mounting cavity and out of the bottom end of the external shell. A flange 1061 is provided at the bottom of the mounting cavity. The longitudinal-torsion amplitude transformer 106 and the transducer 104 are installed in the mounting cavity through the flange 1061.

[0035] The working vibration platform includes an upper vibration plate 401 and a lower vibration plate, and support columns 402 are arranged between the four corners of the upper vibration plate 401 and the lower vibration plate, and the second ultrasonic vibrator 404 is connected to the left side of the upper vibration plate 401 by threads, and the third ultrasonic vibrator 405 is connected to the rear side of the upper vibration plate 401 by threads. The second ultrasonic vibrator 404 and the third ultrasonic vibrator 405 of the present application are connected to the upper vibration plate 401 by threads, and can apply ultrasonic vibration to the workpiece in two vertical directions, thereby achieving a repeated high-frequency ironing effect on the surface of the workpiece, and effectively improving the surface flatness and finish.

[0036] The outer wall of the longitudinal-torsion amplitude transformer 106 is provided with a plurality of spiral grooves 1062 spaced apart along its axial direction. The present application converts one-dimensional longitudinal ultrasonic vibration into two-dimensional longitudinal-torsion ultrasonic vibration by arranging a plurality of spiral grooves 1062 on the longitudinal-torsion amplitude transformer 106. The cooperation of the transmitting disk 102, the receiving disk 103, the transducer 104, the longitudinal-torsion amplitude transformer 106 and the tool handle 105 in the longitudinal-torsion ultrasonic vibration tool handle unit 10 can generate composite longitudinal and torsional ultrasonic vibration on the surface of the PCD micro-blade ball end milling cutter 20. This composite vibration mode can effectively reduce the contact friction between the tool and the workpiece, reduce tool wear, and improve the surface quality of the workpiece.

[0037] The transmitting disk 102 of the longitudinal torsional ultrasonic vibration shank unit 10 is connected to a first external ultrasonic power supply, the working vibration platform is connected to a second external ultrasonic power supply, the swirl tube 506 of the low-temperature vortex cold air unit 50 is connected to the swirl air inlet pipe through the swirl hole 5021, the swirl air inlet pipe is connected to an external air compressor, and an external rotating device is provided at the bottom of the working vibration platform. In addition, the present application can reduce tool wear, and the combined effect of the low-temperature cooling system and multi-dimensional ultrasonic vibration can effectively slow down the wear of the diamond tool and extend the service life of the tool. The present application can also improve the processing accuracy and surface quality. The longitudinal torsional ultrasonic vibration and the two-dimensional ultrasonic vibration can effectively improve the surface quality of the workpiece, reduce surface defects and scratches, and achieve a higher degree of finish. The present application can also improve the processing efficiency. Through multi-dimensional vibration and micro-nano removal technology, the processing efficiency can be improved without losing the processing quality. The present application has the characteristics of environmental protection and pollution-free. The low-temperature vortex cold air unit 50 adopts compressed air cooling, which avoids the pollution problem of traditional coolant and meets environmental protection requirements.

[0038] Embodiment 2 The polishing method is implemented based on the above-mentioned low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device, such as Fig. 9 As shown, the following steps are included: (1) starting a first external ultrasonic power supply, which outputs a high-frequency alternating current signal, which is sequentially transmitted to the transmitting disk 102, the receiving disk 103, and the transducer 104, and then drives the entire longitudinal-torsional ultrasonic vibration tool holder unit 10 to generate longitudinal-torsional vibration, so that the surface of the PCD micro-blade ball end milling cutter 20 generates a composite longitudinal and torsional ultrasonic vibration; (2) starting the second external ultrasonic power supply, which outputs a high-frequency alternating current signal. The high-frequency alternating current signal is transmitted to the second ultrasonic vibrator 404 and the third ultrasonic vibrator 405 through a wire, and then drives the two-dimensional ultrasonic vibration platform unit 40 to generate ultrasonic vibrations in two perpendicular directions. (3) Starting the external air compressor, which delivers compressed air to the cyclone chamber 502 of the low-temperature vortex cooling air unit 50 to form a high-speed rotating airflow, and the compressed air is separated into cold and hot airflows through the cyclone chamber 502 to cool the polishing area; (4) Starting the external rotating device to rotate the two-dimensional ultrasonic vibration platform unit 40 to a certain angle, starting the CNC machining center spindle to rotate the PCD micro-blade ball end milling cutter 20 and moving it toward the mold steel workpiece 30 and against the mold steel workpiece 30, and performing fine extrusion polishing on the mold steel workpiece 30.

[0039] The present application utilizes the micro-nano removal characteristics of the PCD micro-blade ball end milling cutter 20 to perform fine extrusion polishing on the workpiece surface. By reasonably adjusting the equipment speed and tool angle, the polishing effect is optimized to meet different processing requirements. The PCD micro-blade ball end milling cutter 20 performs fine strengthening treatment on the workpiece surface with the cooperation of multi-dimensional ultrasonic vibration. During the polishing process, intermittent contact and separation occur between the tool and the workpiece, and the relative speed and direction of the contact change periodically. This process can not only improve the processing efficiency, but also significantly improve the problem that the cooling medium is difficult to fully enter the processing area during low-temperature processing, effectively reduce tool wear and improve the surface quality of the workpiece. In addition, the present application is scientifically designed and reasonably structured. During the processing process, the low-temperature medium forms a low-temperature environment in the processing area, which can effectively inhibit the thermochemical wear of the diamond tool waiting for the polishing object. Under the action of multi-dimensional ultrasound, the tool and the workpiece produce periodic contact and separation, which can effectively improve the problem that the cooling medium is difficult to fully enter the processing area during low-temperature processing. In addition, ultrasonic vibration can perform high-frequency reciprocating ironing on the workpiece surface, so that it has polishing and surface strengthening effects while effectively improving tool wear.

[0040] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. Low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device, including a frame, characterized in that: The frame is equipped with a longitudinal-torsion ultrasonic vibration tool holder unit, a two-dimensional ultrasonic vibration platform unit, a low-temperature eddy current cold air unit and an extrusion polishing unit; The longitudinal torsional ultrasonic vibration tool handle unit comprises a transmitting disk, a receiving disk, a tool handle and a first ultrasonic vibrator which are coaxially arranged in sequence from top to bottom. The tool handle comprises an external shell, a mounting cavity is formed inside the external shell, the first ultrasonic vibrator is mounted in the mounting cavity, the bottom end of the first ultrasonic vibrator is connected to the extrusion polishing unit, the transmitting disk and the receiving disk are arranged at the upper end of the external shell, a rivet is arranged in the central part of the transmitting disk and the receiving disk along the vertical direction, the bottom of the rivet is connected to the top outer surface of the tool handle, and the top of the rivet is connected to the external machining center spindle; The two-dimensional ultrasonic vibration platform unit includes a working vibration platform, a second ultrasonic vibrator and a third ultrasonic vibrator, wherein the second ultrasonic vibrator and the third ultrasonic vibrator are respectively vertically arranged on the left side and the rear side of the working vibration platform; The low-temperature vortex cold air unit includes a magnetic base, a swirl tube, an airflow rod, a cold air nozzle and a control valve. The swirl tube is installed on the magnetic base in the left and right directions. A swirl chamber is formed inside the swirl tube. The airflow rod is arranged at the left and right ends of the swirl tube. An airflow channel is arranged in the airflow rod. The airflow channel is connected with the swirl chamber. The cold air nozzle is arranged at the left end of the airflow rod at the left end of the swirl tube. A swirl hole is arranged on the upper part of the swirl tube. The control valve is arranged at the right end of the airflow rod at the right end of the swirl tube. The extrusion polishing unit comprises a PCD micro-blade ball end milling cutter, the upper end of which is connected to a first ultrasonic vibrator, a working vibration platform is arranged below the PCD micro-blade ball end milling cutter, and a die steel workpiece is placed on the working vibration platform.

2. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 1 is characterized in that: The first ultrasonic vibrator includes a transducer and a longitudinal torsion horn. The transducer is a sandwich piezoelectric ceramic transducer. The upper end of the longitudinal torsion horn is connected to the lower end of the transducer. The lower end of the longitudinal torsion horn extends out of the installation cavity and the bottom end of the external shell.

3. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 2 is characterized in that: A flange is arranged at the bottom of the installation cavity, and the longitudinal-torsion amplitude transformer and the transducer are installed in the installation cavity through the flange.

4. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 3 is characterized in that: The working vibration platform comprises an upper vibration plate and a lower vibration plate, and support columns are arranged between the four corners of the upper vibration plate and the lower vibration plate.

5. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 4 is characterized in that: The second ultrasonic vibrator is connected to the left side surface of the upper vibration plate through threads, and the third ultrasonic vibrator is connected to the rear side surface of the upper vibration plate through threads.

6. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 5 is characterized in that: The gap between the transmitting disk and the receiving disk is 0.5 to 1 mm.

7. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 6 is characterized in that: The transducer includes a plurality of electrodes and piezoelectric ceramics which are alternately arranged at intervals.

8. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 7 is characterized in that: The outer wall of the longitudinal-torsion amplitude transformer is provided with a plurality of spiral grooves spaced apart along the axial direction thereof.

9. The low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to claim 8 is characterized in that: The transmitting disk of the longitudinal-torsional ultrasonic vibration handle unit is connected to a first external ultrasonic power supply, the working vibration platform is connected to a second external ultrasonic power supply, the swirl cylinder of the low-temperature vortex cold air unit is connected to a swirl air inlet pipe through a swirl hole, the swirl air inlet pipe is connected to an external air compressor, and an external rotating device is arranged at the bottom of the working vibration platform.

10. A polishing method, implemented based on the low-temperature cold air-multi-dimensional ultrasonic composite extrusion polishing device according to any one of claims 1 to 9, characterized in that: The steps include: (1) starting a first external ultrasonic power supply, which outputs a high-frequency alternating current signal, which is sequentially transmitted to a transmitting disk, a receiving disk, and a transducer, and then drives the entire longitudinal-torsional ultrasonic vibration tool holder unit to generate longitudinal-torsional vibration, so that the surface of the PCD micro-blade ball end milling cutter generates a composite longitudinal and torsional ultrasonic vibration; (2) starting a second external ultrasonic power supply, which outputs a high-frequency alternating current signal, which is transmitted to the second ultrasonic vibrator and the third ultrasonic vibrator through a wire and then drives the two-dimensional ultrasonic vibration platform unit to generate ultrasonic vibrations in two perpendicular directions; (3) Starting the external air compressor, which delivers compressed air to the cyclone chamber of the low-temperature vortex cooling air unit to form a high-speed rotating airflow, and the compressed air is separated into cold and hot airflows through the cyclone chamber to cool the polishing area; (4) Start the external rotating device to rotate the two-dimensional ultrasonic vibration platform unit to a certain angle, start the CNC machining center spindle to rotate the PCD micro-blade ball end milling cutter and move it toward the direction close to the mold steel workpiece and abut against the mold steel workpiece, and perform fine extrusion and polishing treatment on the mold steel workpiece.

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