Device and method for efficiently polishing surface of 3D printing stainless steel straight hole

Abstract

The invention discloses a device and method for efficiently polishing the surface of a 3D printing stainless steel straight hole, and the device comprises a rack, a workpiece clamping module, a multi-axis movement module, a polishing module, an auxiliary module and a control module; the multi-axis movement module drives the surface of the straight hole to be attached to and conduct circumferential and up-down reciprocating motion around the polishing line, the polishing line rotates at a high speed, hard abrasive particles on the polishing line cooperate with polishing liquid supplied by the auxiliary module, and a powder adhesion layer on the surface of the straight hole is efficiently and evenly removed through the strong mechanical action and the strong chemical action. According to the method, a fine polishing line is used as a polishing tool, and the method can be suitable for a straight hole with the hole diameter as small as 0.5 mm; similar to sub-aperture polishing (different from full-aperture polishing in the prior art), a single polishing line is utilized, the method can be suitable for different apertures through path planning, and the universality is high; and high polishing efficiency can be realized by utilizing the strong chemical action of the polishing solution and the strong mechanical action of the polishing line.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision machining, and in particular relates to a device and method for efficiently polishing the surface of a 3D printed stainless steel straight hole. Background Art

[0002] 3D printed channel parts are gradually applied to aerospace, transportation, biomedicine, energy and chemical industry and other fields, especially in rockets, automobiles, conformal cooling channels, heat exchangers, and fuel nozzles of aircraft engines. It plays an important role. According to the reference (Annalisa Acquesta, Tullio Monetta, The Electropolishing of Additively Manufactured Parts in Titanium: State of the Art, Advanced Engineering Materials, 2021, 23 (12): 2100545), in the 3D printing process, the size, shape and solidification of the molten pool are controlled by the energy distribution of the energy beam and are affected by the scanning path. If the energy distribution is uneven or the scanning path is unreasonable, it may cause insufficient melting of the metal powder. In addition, a faster cooling rate may also cause insufficient melting of the metal powder, thereby forming a powder adhesion layer on the surface of the part. The high surface roughness of the powder adhesion layer will bring a series of problems in subsequent use, such as: 1) in parts such as heat exchangers, high roughness will increase the resistance of the fluid, resulting in large energy loss; 2) when the fluid in the flow channel rubs against the surface at high speed, causing powder to fall off, it may cause the flow channel to be blocked or even cause equipment failure. Therefore, it is particularly important to find a polishing technology that can effectively remove the powder adhesion layer and reduce the surface roughness.

[0003] In order to remove the powder adhesion layer, researchers have developed a variety of polishing methods, such as chemical polishing, electrochemical polishing, magnetic grinding polishing, abrasive flow polishing, etc. However, each polishing method has certain limitations in practical applications and cannot be fully applied to all types of 3D printed parts, as shown below:

[0004] 1) According to the reference (Martin Bezuidenhout, Gerrit Ter Haar, Thorsten Becker, Sabrina Rudolph, Oliver Damm, Natasha Sacks, The effect of HF-HNO3 chemical polishing on the surface roughness and fatigue life of laser powder bedfusion produced Ti6Al4V, Materials Today Communications, 2020, 25: 101396), chemical polishing solution is consumed quickly, the efficiency is unstable, and as the processing time increases, a passivation layer will gradually form on the workpiece surface, resulting in a decrease in polishing efficiency; electrochemical polishing has high requirements for the initial surface roughness of the workpiece. A large initial surface roughness will cause impurities and bubbles in the polishing liquid to form a retention area on the workpiece surface, affecting the distribution uniformity of the polishing liquid and the uniformity of the current density, weakening the polishing effect. However, the initial surface roughness of 3D printed parts is usually large, which will affect the electrochemical polishing effect;

[0005] 2) According to the reference (Das M, Jain VK, Ghoshdastidar P S. Nanofinishing of flat workpieces using rotational-magnetorheological abrasive flow finishing process. International Journal of Advanced Manufacturing Technology, 2012, 62: 405-420), it is difficult to arrange the magnetic poles when processing workpieces with complex appearance shapes by magnetic grinding and polishing, and the magnetic field distribution is uneven, which will affect the polishing effect;

[0006] 3) According to the reference (Yao Yansheng, Zhou Ruigen, Zhang Chenglin, Mei Tao, Wu Min, Surface Polishing Technology of Complex Metal Components in Additive Manufacturing, Acta Aeronautica Sinica, 2022, 43(04): 244-256), the abrasive medium of abrasive flow polishing will exert MPa-level pressure on the workpiece surface, which may damage the thin-walled flow channel with low stiffness. At the same time, the increase in the flow channel length will lead to an increase in pressure loss, resulting in poor polishing effect at a position far from the abrasive inlet.

[0007] The existing invention patent "A device and method for precision machining of stainless steel flow channels in 3D printing" (inventors: Jiang Liang, Zhang Xiang, Qian Linmao, Wang Chao, Ye Minheng, Ye Zuoyan, Yan Luwen, Xie Hongsheng, Ye Fuyi, patent name: A device and method for precision machining of stainless steel flow channels in 3D printing, 2023.01.03, China, ZL202210572967.1), discloses a device and method for precision machining of stainless steel flow channels in 3D printing. The machining device includes a frame, a sample clamping module, a tension spring positioning module, a machining module, a compound motion module and an auxiliary module. The sample clamping module clamps and positions the sample to be processed, the tension spring positioning module clamps one end of the machining module, and the compound motion module clamps the other end of the machining module, driving the machining module to move at high speed. The auxiliary module supplies machining fluid on demand, and the machining module brings the machining fluid into the contact area to realize the surface machining of the flow channel. However, this processing method uses flexible wires and polishing units as polishing tools. Investigations have found that the minimum diameter of such polishing tools on the market is 1.5 mm, which is not suitable for polishing channels with apertures less than 1.5 mm. In addition, this processing method is similar to full-aperture polishing, and corresponding polishing tools need to be made for different apertures, so its versatility needs to be improved.

[0008] In summary, the existing polishing methods have certain limitations in processing small channels (pore diameter less than 1.5 mm) and efficiently removing powder adhesion layers. Therefore, it is urgent to develop new polishing devices and methods to overcome the limitations of existing technologies and achieve efficient polishing of 3D printed stainless steel straight hole surfaces. Summary of the invention

[0009] The purpose of the present invention is to solve the above problems and provide a device and method for efficiently polishing the surface of 3D printed stainless steel straight holes with small apertures and strong versatility.

[0010] In order to solve the above technical problems, the technical solution of the present invention is: a device for efficient polishing of the surface of 3D printed stainless steel straight holes, characterized in that: it includes a frame, on which are respectively provided a workpiece clamping module, a multi-axis motion module, a polishing module, an auxiliary module and a control module, the workpiece clamping module is connected to the multi-axis motion module, the control module is electrically connected to the multi-axis motion module and the polishing module respectively, the workpiece clamping module is used to clamp the workpiece, the multi-axis motion module is used to ensure relative motion between the workpiece and the polishing module, so that the straight hole surface of the workpiece is tightly attached and performs circular and up and down reciprocating motion around the polishing line in the polishing module, the polishing module is used to drive the polishing line to rotate at high speed, the auxiliary module is used to supply polishing liquid and collect polishing waste liquid, and the control module is used to control the multi-axis motion module and the polishing module to move according to the set program, thereby controlling the relative motion of the polishing line and the straight hole surface.

[0011] Preferably, the frame includes a profile support frame and a linear optical axis. The profile support frame is used to install the multi-axis motion module, the polishing module, the auxiliary module and the control module. The linear optical axis is vertically arranged in the profile support frame and is connected to the multi-axis motion module. The linear optical axis is used to ensure the stiffness of the corresponding linear module in the multi-axis motion module and enhance its ability to resist elastic deformation when subjected to force.

[0012] Preferably, the workpiece clamping module includes a module connecting plate, a polishing liquid pool and a workpiece clamping plate. The module connecting plate is installed on the X and Y linear modules in the multi-axis motion module by bolts. The polishing liquid pool is installed on the module connecting plate by bolts. The workpiece clamping plate is installed in the polishing liquid pool for clamping the workpiece. The module connecting plate, the polishing liquid pool and the workpiece clamping plate are all designed according to the different external dimensions of the workpiece and manufactured by 3D printing. The 3D printing materials of the module connecting plate, the polishing liquid pool and the workpiece clamping plate can be selected from polylactic acid, acrylonitrile (A)-butadiene (B)-styrene (S), thermoplastic polyurethane rubber and carbon fiber composite materials.

[0013] Preferably, the multi-axis motion module includes a linear module, a profile mounting platform, a connecting plate and a linear slider bearing fixing seat, the linear module includes an X-axis, Y-axis linear module and a Z-axis linear module, the Z-axis linear module includes a ball screw and a stepper motor, the X-axis, Y-axis linear modules are installed on the profile mounting platform by bolts, the ball screw in the Z-axis linear module is installed on the profile support frame and connected to the profile mounting platform through a connecting plate, the profile mounting platform is connected to the linear slider bearing fixing seat through a connecting plate, a bearing is installed inside the linear slider bearing fixing seat, the linear slider bearing fixing seat is sleeved on the linear optical axis, and the stepper motor drives the profile mounting platform to move up and down through the ball screw when working.

[0014] Preferably, the polishing module includes a spindle motor, a polishing line, a follower and a tensioning device. The spindle motor is used to drive the polishing line to rotate at high speed. The polishing line is used to process workpieces. The follower can ensure that the polishing line rotates with the rotation of the spindle motor. The follower includes a motor shaft tool rod, a cylindrical clamp, a drill chuck and an outer spherical bearing seat. The motor shaft tool rod is installed on the spindle motor. A cylindrical clamp is installed on the end of the motor shaft tool rod. The cylindrical clamp is used to clamp the upper end of the polishing line. The drill chuck is used to clamp the lower end of the polishing line. The drill chuck is installed on the outer spherical bearing seat. The tensioning device includes a vertical lifting platform. The vertical lifting platform is installed on the auxiliary module by bolt connection. The lower end surface of the vertical lifting platform is connected to the outer spherical bearing seat by bolts. The polishing line is tensioned by adjusting the height of the vertical lifting platform.

[0015] Preferably, the auxiliary module includes a waste liquid collection tank, a silicone pad, a peristaltic pump, a magnetic agitator, a polishing liquid holding barrel, a polishing liquid delivery pipe and a tray. The polishing liquid holding barrel is placed on the magnetic agitator, the polishing liquid delivery pipe is connected to the peristaltic pump in the middle, one end is connected to the polishing liquid holding barrel, and the other end is located above the polishing liquid tank. The tray is installed on the frame by bolts to assist in collecting the polishing waste liquid generated during the polishing process. The waste liquid collection tank is installed on the vertical lifting platform by bolts, and the vertical lifting platform is installed on the tray by bolt connection. The silicone pad is fixed to the polishing line with waterproof glue and installed above the waste liquid collection tank. It rotates with the rotation of the polishing line to collect the waste liquid generated during the polishing process into the waste liquid collection tank.

[0016] Preferably, the control module includes an industrial all-in-one machine and a display screen bracket. The industrial all-in-one machine is electrically connected to the linear module and the spindle motor respectively to control the linear module and the spindle motor to move according to a set program, thereby controlling the relative movement of the polishing line and the straight hole surface.

[0017] The present invention also discloses a polishing method based on a device for efficiently polishing the surface of a 3D printed stainless steel straight hole, the method comprising the following steps:

[0018] S1. First, prepare the polishing liquid, stir it evenly, pour it into the polishing liquid bucket, and place it on a magnetic stirrer and stir it continuously;

[0019] S2. Clamp the workpiece on the workpiece clamping module, then connect the polishing wire in the polishing module to the drill chuck, pass the polishing wire through the hole of the workpiece, and connect the other end of the polishing wire to the cylindrical fixture. Then, adjust the positions of the vertical lifting platform of the tensioning module and the linear module of the multi-axis motion module in the horizontal and vertical directions so that the polishing wire of the polishing module is tensioned and close to the straight hole surface;

[0020] S3. Input the control program on the industrial integrated machine. The parameters set in the program include the spindle motor speed, the X, Y, and Z axis linear module movement speeds, and the polishing liquid flow rate is set on the peristaltic pump;

[0021] S4, turn on the peristaltic pump, start the control program, and start polishing;

[0022] S5. After polishing, remove the workpiece and check the surface quality of the polished hole. If it does not meet the requirements, repeat the process until it meets the requirements.

[0023] Preferably, the polishing liquid comprises: an oxidant, a chelating agent, water, and a pH value of 2-11, wherein the oxidant is selected from one or more of hydrogen peroxide, persulfate, iodate, periodate, and perchlorate, and the chelating agent is selected from one or more of organic acids and amino acids.

[0024] The beneficial effects of the present invention are:

[0025] 1. The present invention provides a device and method for efficient polishing of the surface of 3D printed stainless steel straight holes. A fine polishing wire (with a minimum diameter of 0.2 mm) is selected as a polishing tool. Combined with the clamping diameter of the cylindrical fixture (with a minimum diameter of 0.5 mm), it can be applied to straight holes with a diameter as small as 0.5 mm.

[0026] 2. The present invention is similar to sub-diameter polishing (different from the existing invention patent "A device and method for precision machining of stainless steel flow channels in 3D printing" which is similar to full-diameter polishing). It uses a single polishing line and a program-controlled multi-axis motion module to drive the straight hole surface to adhere to and perform circular and up and down reciprocating motion around the polishing line. Through path planning, uniform polishing of the surfaces of straight holes of different apertures can be achieved, and it has strong versatility.

[0027] 3. The present invention utilizes the strong chemical action of chemical reagents in the polishing liquid to generate a fragile surface film on the surface of the stainless steel straight hole, and simultaneously utilizes the strong mechanical action of hard abrasive particles on the polishing line to efficiently remove the generated fragile surface film. The strong chemical action and strong mechanical action cooperate synergistically to achieve high polishing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of a device for efficient polishing of the surface of a 3D printed stainless steel straight hole according to the present invention;

[0029] Figure 2 It is a structural schematic diagram of the frame of the present invention;

[0030] Figure 3 It is a structural schematic diagram of a workpiece clamping module of the present invention;

[0031] Figure 4 It is a schematic diagram of the structure and movement direction of the multi-axis motion module of the present invention;

[0032] Figure 5 is a structural schematic diagram of a polishing module of the present invention;

[0033] Figure 6 It is a schematic diagram of the force on the workpiece of the present invention;

[0034] Figure 7 It is a schematic diagram of the relative movement speed of the workpiece and the polishing line of the present invention;

[0035] Figure 8 It is a structural schematic diagram of the auxiliary module of the present invention;

[0036] Fig. 9 It is a structural schematic diagram of the control module of the present invention;

[0037] Fig.10This is a three-dimensional morphology measurement result diagram of the 3D printed stainless steel straight hole surface before polishing of the present invention;

[0038] Fig.11 This is a three-dimensional morphology measurement result diagram of the 3D printed stainless steel straight hole surface after polishing of the present invention.

[0039] Description of reference numerals: 1, frame; 2, workpiece clamping module; 3, multi-axis motion module; 4, polishing module; 5, auxiliary module; 6, control module; 101, profile support frame; 102, linear optical axis; 201, module connecting plate; 202, polishing liquid pool; 203, workpiece clamping plate; 301, mounting platform; 302, connecting plate; 303, linear slider bearing; 304, X, Y linear module; 305, ball screw; 306, step Inlet motor; 401, spindle motor; 402, motor shaft arbor; 403, cylindrical fixture; 404, polishing line; 405, drill chuck; 406, outer spherical bearing seat; 407, vertical lifting platform; 501, waste liquid collection tank; 502, silicone pad; 503, peristaltic pump; 504, magnetic stirrer; 505, polishing liquid storage bucket; 506, polishing liquid delivery pipe; 507, tray; 601, industrial all-in-one machine; 602, display screen bracket. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0041] like Figures 1 to 9 As shown, the present invention provides a device for efficient polishing of the surface of 3D printed stainless steel straight holes, comprising a frame 1, on which are respectively provided a workpiece clamping module 2, a multi-axis motion module 3, a polishing module 4, an auxiliary module 5 and a control module 6, the workpiece clamping module 2 is connected to the multi-axis motion module 3, the control module 6 is electrically connected to the multi-axis motion module 3 and the polishing module 4, respectively, the workpiece clamping module 2 is used to clamp the workpiece, the multi-axis motion module 3 is used to ensure relative motion between the workpiece and the polishing module 4, so that the straight hole surface of the workpiece is tightly attached to and performs circular and up and down reciprocating motion around the polishing line 404 in the polishing module 4, the polishing module 4 is used to drive the polishing line 404 to rotate at a high speed, the auxiliary module 5 is used to supply polishing liquid and collect polishing waste liquid, and the control module 6 is used to control the multi-axis motion module 3 and the polishing module 4 to move according to a set program, thereby controlling the polishing line 404 and the straight hole surface to perform relative motion.

[0042] like Figure 1 and Figure 2As shown, the frame 1 includes a profile support frame 101 and a linear optical axis 102. The profile support frame 101 is used to install the multi-axis motion module 3, the polishing module 4, the auxiliary module 5 and the control module 6. The linear optical axis 102 is vertically arranged in the profile support frame 101. The linear optical axis 102 is connected to the multi-axis motion module 3. The linear optical axis 102 is used to ensure the stiffness of the corresponding linear module in the multi-axis motion module 3 and enhance its ability to resist elastic deformation when subjected to force.

[0043] In this embodiment, the main function of the frame 1 is to carry other modules and serve as an installation reference. The profile support frame 101 is made of 8080 aluminum profile, and the profile support frame 101 is provided with multiple mounting holes. The linear optical axis 102 is made of hardened chrome-plated rod to ensure its rigidity. The linear optical axis 102 is installed on the profile support frame 101 through the existing guide shaft support, and the multi-axis motion module 3 is installed on the profile support frame 101 through screws.

[0044] like Figure 3 As shown, the workpiece clamping module 2 includes a module connecting plate 201, a polishing liquid pool 202 and a workpiece clamping plate 203. The module connecting plate 201 is installed on the X, Y linear module 304 in the multi-axis motion module 3 by bolts. The polishing liquid pool 202 is installed on the module connecting plate 201 by bolt connection. The workpiece clamping plate 203 is installed in the polishing liquid pool 202 for clamping the workpiece. The workpiece clamping plate 203 is designed with grooves according to the different outer dimensions of the workpiece to clamp the workpiece. The module connecting plate 201, the polishing liquid pool 202 and the workpiece clamping plate 203 are all designed according to the different outer dimensions of the workpiece and manufactured by 3D printing. The 3D printing materials of the module connecting plate 201, the polishing liquid pool 202 and the workpiece clamping plate 203 can be selected from polylactic acid, acrylonitrile (A)-butadiene (B)-styrene (S), thermoplastic polyurethane rubber, and carbon fiber composite materials.

[0045] In this embodiment, the 3D printing material of the module connecting plate 201, the polishing liquid pool 202, and the workpiece clamping plate 203 is polylactic acid, which meets the strength requirements and takes a short printing time. The workpiece clamping plate 203 is a circular flat plate structure with a stepped through hole in the middle. The workpiece is placed in the through hole to achieve clamping and fixation.

[0046] like Figure 4As shown, the multi-axis motion module 3 includes a linear module, a profile mounting platform 301, a connecting plate 302 and a linear slider bearing fixing seat 303. The linear module includes an X-axis and a Y-axis linear module 304 and a Z-axis linear module. The Z-axis linear module includes a ball screw 305 and a stepper motor 306. The X-axis and the Y-axis linear modules 304 are installed on the profile mounting platform 301 by bolts. The ball screw 305 in the Z-axis linear module is installed on the profile support frame 101 and is connected to the profile mounting platform 301 through the connecting plate 302. The profile mounting platform 301 is connected to the linear slider bearing fixing seat 303 through the connecting plate 302. The linear slider bearing fixing seat 303 is internally installed with bearings. The linear slider bearing fixing seat 303 is sleeved on the linear optical axis 102. When the stepper motor 306 is working, it drives the profile mounting platform 301 to move up and down through the ball screw 305.

[0047] In this embodiment, the main function of the multi-axis motion module 3 is to ensure relative motion between the workpiece and the polishing module 4, so that the straight hole surface of the workpiece is closely attached to and performs circular and up and down reciprocating motion around the polishing line 404 in the polishing module 4, so as to achieve uniform polishing of the straight hole surface. Specifically, the vertical height of the profile mounting platform 301 is adjusted by the Z-axis linear module, and the position of the module connecting plate 201 is comprehensively adjusted by the X- and Y-axis linear modules. The profile mounting platform 301 is a rectangular structure composed of four profiles connected end to end. The profile mounting platform 301 is fixedly connected to the connecting plate 302 by screws, and the connecting plate 302 is fixedly connected to the linear slider bearing fixing seat 303 by screws. The stepper motor 306 uses a 57 stepper motor, which is connected to the ball screw 305 through a coupling, thereby driving the profile mounting platform 301 to move up and down.

[0048] like Figure 5 As shown, the polishing module 4 includes a spindle motor 401, a polishing wire 404, a follower device and a tensioning device. The spindle motor 401 is used to drive the polishing wire 404 to rotate at a high speed. The polishing wire 404 is used to process the workpiece. The follower device can ensure that the polishing wire 404 rotates with the rotation of the spindle motor 401. The follower device includes a motor shaft shank 402, a cylindrical fixture 403, a drill chuck 405 and an outer spherical bearing seat 406. The motor shaft shank 402 is installed on the spindle motor 401, and the end of the motor shaft shank 402 is installed with a cylindrical fixture 403. 3. The cylindrical clamp 403 is used to clamp the upper end of the polishing line 404, the drill chuck 405 is used to clamp the lower end of the polishing line 404, the outer spherical bearing seat 406 is equipped with a bearing, the drill chuck 405 is installed on the bearing in the outer spherical bearing seat by a set screw, and the tensioning device includes a vertical lifting platform 407, which is installed on the auxiliary module 5 by bolt connection, and the upper end surface of the vertical lifting platform 407 is connected to the outer spherical bearing seat 406 by bolts, and the polishing line 404 is tensioned by adjusting the height of the vertical lifting platform 407.

[0049] In this embodiment, the main function of the polishing module 4 is to drive the polishing line 404 to rotate at high speed. A motor support seat is installed on the spindle motor 401. The spindle motor 401 is installed on the profile support frame 101 through the motor support seat and screws. The motor shaft arbor 402 is installed on the spindle motor 401 through a locking screw. The cylindrical clamp 403 is installed in the motor shaft arbor 402 through a thread. The outer spherical bearing seat 406 is installed on the vertical lifting platform 407 through screws. The drill chuck 405 is installed on the outer spherical bearing seat 406 through a locking screw. The polishing line 404 uses a diamond abrasive polishing line. The two ends of the polishing line 404 are clamped by the cylindrical clamp 403 and the chuck 405 respectively. The cylindrical clamp 403 uses the existing ER collet, and the vertical lifting platform 407 uses the existing Z-axis large-stroke lifting platform HTZ60.

[0050] like Figure 6 As shown in the figure, it is a schematic diagram of the force on the workpiece of the present invention. The deformation of the polishing line will generate a force on the surface of the workpiece. According to the schematic diagram of the force, F N =2F1=2F×cosθ.

[0051] like Figure 7 As shown, it is a schematic diagram of the relative movement speed of the workpiece and the polishing line of the present invention, the polishing line rotation speed is V1, the workpiece circular motion speed is V2, the workpiece up and down motion speed is V3, and the relative movement speed of the workpiece and the polishing line is obtained comprehensively.

[0052] like Figure 8 As shown, the auxiliary module 5 includes a waste liquid collection tank 501, a silicone pad 502, a peristaltic pump 503, a magnetic stirrer 504, a polishing liquid holding barrel 505, a polishing liquid delivery pipe 506 and a tray 507. The polishing liquid holding barrel 505 is placed on the magnetic stirrer 504. The polishing liquid delivery pipe 506 is connected to the peristaltic pump 503 in the middle, one end is connected to the polishing liquid holding barrel 505, and the other end is located above the polishing liquid pool 202. When the peristaltic pump 503 is working, the polishing liquid in the polishing liquid holding barrel 505 is delivered to the polishing liquid pool 202 through the polishing liquid delivery pipe 506. 02, the polishing module 4 supplies polishing liquid during the polishing operation. The tray 507 is installed on the frame 1 by bolts, which is used to assist in collecting the polishing waste liquid generated during the polishing process. The waste liquid collection tank 501 is installed on the vertical lifting platform 407 by bolts. The vertical lifting platform 407 is installed on the tray 507 by bolt connection. The silicone pad 502 is fixed to the polishing line 404 with waterproof glue and installed above the waste liquid collection tank 501. It rotates with the rotation of the polishing line 404 to collect the waste liquid generated during the polishing process into the waste liquid collection tank 501.

[0053] In this embodiment, the main functions of the auxiliary module 5 are to store and stir the polishing liquid and supply the polishing liquid at a set flow rate, while collecting the polishing waste liquid generated during the polishing process to reduce pollution and protect the environment. The position of the outlet of the polishing liquid delivery pipe 506 can be adjusted to adapt to different working conditions.

[0054] like Fig. 9 As shown, the control module 6 includes an industrial all-in-one machine 601 and a display bracket 602. The industrial all-in-one machine 601 is electrically connected to the linear module and the spindle motor 401 respectively, controls the linear module and the spindle motor 401 to move according to the set program, and then controls the relative movement of the polishing line 404 and the straight hole surface.

[0055] In this embodiment, the main function of the control module 6 is to control the linear module and the motor to move according to the set program, and then control the relative movement of the polishing line and the straight hole surface. The display bracket 602 is installed on the profile support frame 101 by screws, and the industrial all-in-one machine 601 is installed on the display bracket 602 by screws.

[0056] The present invention also discloses a method for efficient polishing of a 3D printed stainless steel straight hole surface, the method comprising the following steps:

[0057] S1. First, prepare the polishing liquid, stir it evenly, pour it into the polishing liquid storage bucket 505, and place it on the magnetic stirrer 504 to continue stirring.

[0058] The polishing liquid comprises: an oxidant, a complexing agent, water, and a pH value of 2-11, wherein the oxidant is selected from one or more of hydrogen peroxide, persulfate, iodate, periodate, and perchlorate, and the complexing agent is selected from one or more of organic acids and amino acids.

[0059] In the preparation of the polishing liquid, it is necessary to comprehensively consider the polishing efficiency and the surface quality. In view of the fact that the material of the 3D printed part is 316L stainless steel with a high chromium content, the polishing liquid components are selected to be 0.2wt% hydrogen peroxide, 1.2wt% oxalic acid, and the rest is water. The pH value is 4. Stir evenly and pour the polishing liquid into the polishing liquid holding bucket 505. The hydrogen peroxide and oxalic acid in the polishing liquid have a synergistic effect, so that a fragile surface film is generated on the surface of the stainless steel straight hole.

[0060] S2. Clamp the workpiece on the workpiece clamping module 2, then connect the polishing wire 404 in the polishing module 4 to the drill chuck 405, pass the polishing wire 404 through the hole of the workpiece, and connect the other end of the polishing wire 404 to the cylindrical fixture 403. Then, adjust the positions of the vertical lifting platform 407 of the tensioning module and the linear module of the multi-axis motion module 3 in the horizontal and vertical directions so that the polishing wire 404 of the polishing module 4 is tensioned and close to the straight hole surface.

[0061] In view of the high strength of the 3D printed parts made of 316L stainless steel, diamond abrasive polishing wire is used as the polishing wire. The strong mechanical action of the diamond abrasive on the polishing wire can effectively remove the fragile surface film generated by the polishing liquid and the straight hole surface, thereby achieving high polishing efficiency.

[0062] S3. Input the control program on the industrial integrated machine 601. The parameters set in the program include the spindle motor speed, the movement speed of the X-axis, Y-axis, and Z-axis linear module, and set the polishing liquid flow rate on the peristaltic pump.

[0063] S4, turn on the peristaltic pump 503, start the control program, and start polishing.

[0064] S5. After polishing, remove the workpiece and check the surface quality of the polished hole. If it does not meet the requirements, repeat the process until it meets the requirements.

[0065] like Fig.10 As shown in the figure, the three-dimensional morphology measurement result diagram of the surface of the 3D printed stainless steel straight hole is measured by selecting four points before polishing. The surface roughness S a They are 3.2μm, 2.1μm, 1.9μm, and 2.3μm respectively, and the average surface roughness S a The surface quality is poor and there is a powder adhesion layer.

[0066] like Fig.11 As shown in the figure, the three-dimensional morphology measurement result diagram of four points measured after the surface of the 3D printed stainless steel straight hole is polished in the present invention, and the surface roughness S a They are 0.54μm, 0.57μm, 0.66μm, and 0.48μm respectively, and the average surface roughness S a The surface quality is greatly improved and the powder adhesion layer is removed.

[0067] In summary, the present invention aims at the characteristics of small aperture of 3D printed stainless steel straight holes and the presence of a powder adhesion layer on the surface, and selects a fine polishing wire (with a minimum diameter of 0.2mm) as a polishing tool. Combined with the clamping diameter of the cylindrical fixture (with a minimum diameter of 0.5mm), it can be applicable to straight holes with an aperture as small as 0.5mm; the present invention is similar to sub-aperture polishing, using a single polishing wire and a program-controlled multi-axis motion module to drive the surface of the straight hole to adhere to and perform circular and up and down reciprocating motion around the polishing wire, and uniform polishing of the surfaces of straight holes of different apertures can be achieved through path planning, and it has strong versatility; the present invention utilizes the strong chemical action of chemical reagents in the polishing liquid to generate a fragile surface film on the surface of the stainless steel straight hole, and at the same time utilizes the strong mechanical action of the hard abrasive particles on the polishing wire to efficiently remove the generated fragile surface film, and the strong chemical action and strong mechanical action cooperate to achieve high polishing efficiency.

[0068] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A device for efficient polishing of 3D printed stainless steel straight hole surfaces, characterized in that: The invention comprises a frame (1), on which a workpiece clamping module (2), a multi-axis motion module (3), a polishing module (4), an auxiliary module (5) and a control module (6) are respectively arranged. The workpiece clamping module (2) is connected to the multi-axis motion module (3), and the control module (6) is respectively electrically connected to the multi-axis motion module (3) and the polishing module (4). The workpiece clamping module (2) is used to clamp the workpiece, and the multi-axis motion module (3) is used to ensure that the workpiece and the polishing module (4) form a relative motion, so that the straight hole surface of the workpiece is closely attached to and performs a circular and up-and-down reciprocating motion around a polishing line (404) in the polishing module (4). The polishing module (4) is used to drive the polishing line (404) to rotate at a high speed, and the auxiliary module (5) is used to supply polishing liquid and collect polishing waste liquid. The control module (6) is used to control the multi-axis motion module (3) and the polishing module (4) to move according to a set program, thereby controlling the polishing line (404) and the straight hole surface to perform relative motion.

2. The device for efficient polishing of 3D printed stainless steel straight hole surfaces according to claim 1, characterized in that: The frame (1) comprises a profile support frame (101) and a linear optical axis (102); the profile support frame (101) is used to install a multi-axis motion module (3), a polishing module (4), an auxiliary module (5) and a control module (6); the linear optical axis (102) is vertically arranged in the profile support frame (101); the linear optical axis (102) is connected to the multi-axis motion module (3); and the linear optical axis (102) is used to ensure the rigidity of a corresponding linear module in the multi-axis motion module (3).

3. The device for efficient polishing of 3D printed stainless steel straight hole surfaces according to claim 1, characterized in that: The workpiece clamping module (2) comprises a module connecting plate (201), a polishing liquid pool (202) and a workpiece clamping plate (203); the module connecting plate (201) is mounted on an X, Y linear module (304) in a multi-axis motion module (3) by means of bolts; the polishing liquid pool (202) is mounted on the module connecting plate (201) by means of bolts; the workpiece clamping plate (203) is mounted in the polishing liquid pool (202) and is used to clamp the workpiece; the module connecting plate (201), the polishing liquid pool (202) and the workpiece clamping plate (203) are all designed according to different external dimensions of the workpiece and manufactured by means of 3D printing; the 3D printing materials of the module connecting plate (201), the polishing liquid pool (202) and the workpiece clamping plate (203) can be selected from polylactic acid, acrylonitrile (A)-butadiene (B)-styrene (S), thermoplastic polyurethane rubber and carbon fiber composite materials.

4. The device for efficient polishing of 3D printed stainless steel straight hole surfaces according to claim 1, characterized in that: The multi-axis motion module (3) comprises a linear module, a profile mounting platform (301), a connecting plate (302) and a linear slider bearing fixing seat (303); the linear module comprises an X-axis linear module (304) and a Y-axis linear module; the Z-axis linear module comprises a ball screw (305) and a stepping motor (306); the X-axis linear module (304) and the Y-axis linear module (304) are mounted on the profile mounting platform (301) by bolts; the ball screw (305) in the Z-axis linear module is mounted on the profile mounting platform (301) by bolts; The support frame (101) is connected to the profile mounting platform (301) through a connecting plate (302); the profile mounting platform (301) is connected to a linear slider bearing fixing seat (303) through the connecting plate (302); a bearing is installed inside the linear slider bearing fixing seat (303); the linear slider bearing fixing seat (303) is sleeved on the linear optical axis (102); when the stepping motor (306) is in operation, it drives the profile mounting platform (301) to move up and down through a ball screw (305).

5. The device for efficient polishing of 3D printed stainless steel straight hole surfaces according to claim 1, characterized in that: The polishing module (4) comprises a spindle motor (401), a polishing wire (404), a follower device and a tensioning device. The spindle motor (401) is used to drive the polishing wire (404) to rotate at high speed. The polishing wire (404) is used to process a workpiece. The follower device can ensure that the polishing wire (404) rotates along with the spindle motor (401). The follower device comprises a motor shaft shank (402), a cylindrical fixture (403), a drill chuck (405) and an outer spherical bearing seat (406). The motor shaft shank (402) is mounted on the spindle motor (401). The motor shaft shank (402) ) is installed at the end of the auxiliary module (5), the cylindrical clamp (403) is used to clamp the upper end of the polishing line (404), the drill chuck (405) is used to clamp the lower end of the polishing line (404), the drill chuck (405) is installed on the outer spherical bearing seat (406), the tensioning device includes a vertical lifting platform (407), the vertical lifting platform (407) is installed on the auxiliary module (5) by bolt connection, the upper end surface of the vertical lifting platform (407) is connected to the outer spherical bearing seat (406) by bolts, and the polishing line (404) is tensioned by adjusting the height of the vertical lifting platform (407).

6. The device for efficient polishing of 3D printed stainless steel straight hole surfaces according to claim 1, characterized in that: The auxiliary module (5) comprises a waste liquid collection pool (501), a silicone pad (502), a peristaltic pump (503), a magnetic stirrer (504), a polishing liquid storage bucket (505), a polishing liquid delivery pipe (506) and a tray (507), wherein the polishing liquid storage bucket (505) is placed on the magnetic stirrer (504), the polishing liquid delivery pipe (506) is connected to the peristaltic pump (503) in the middle, one end is connected to the polishing liquid storage bucket (505), and the other end is located above the polishing liquid pool (202), and the tray (507) The device is installed on the frame (1) by bolts and is used to assist in collecting polishing waste liquid generated during the polishing process. The waste liquid collection pool (501) is installed on the vertical lifting platform (407) by bolts. The vertical lifting platform (407) is installed on the tray (507) by bolt connection. The silicone pad (502) is fixed on the polishing line (404) by waterproof glue and installed above the waste liquid collection pool (501). It rotates with the rotation of the polishing line (404) to collect the waste liquid generated during the polishing process into the waste liquid collection pool (501).

7. The device for efficient polishing of 3D printed stainless steel straight hole surfaces according to claim 1, characterized in that: The control module (6) comprises an industrial integrated machine (601) and a display screen bracket (602). The industrial integrated machine (601) is electrically connected to the linear module and the spindle motor (401) respectively, and controls the linear module and the spindle motor (401) to move according to a set program, thereby controlling the relative movement of the polishing line (404) and the straight hole surface.

8. A method for efficient polishing of the surface of a 3D printed stainless steel straight hole, characterized in that: A polishing method adopted by a device for efficient polishing of a 3D printed stainless steel straight hole surface according to any one of claims 1 to 7, the method comprising the following steps: S1. First, prepare a polishing liquid, stir it evenly, pour it into a polishing liquid storage bucket (505), and place it on a magnetic stirrer (504) and continue stirring; S2, clamping the workpiece on the workpiece clamping module (2), then connecting the polishing wire (404) in the polishing module (4) to the drill chuck (405), passing the polishing wire (404) through the hole of the workpiece, connecting the other end of the polishing wire (404) to the cylindrical fixture (403), and then adjusting the positions of the vertical lifting platform (407) of the tensioning module and the linear module of the multi-axis motion module (3) in the horizontal and vertical directions, so that the polishing wire (404) in the polishing module (4) is tensioned and close to the straight hole surface; S3, inputting a control program on the industrial integrated machine (601), wherein the parameters set in the program include the spindle motor speed, the X-axis, Y-axis, and Z-axis linear module movement speeds, and setting the polishing liquid flow rate on the peristaltic pump; S4, turning on the peristaltic pump (503), starting the control program, and starting polishing; S5. After polishing, remove the workpiece and check the surface quality of the polished hole. If it does not meet the requirements, repeat the process until it meets the requirements.

9. A method for efficient polishing of a 3D printed stainless steel straight hole surface according to claim 8, characterized in that: The polishing liquid comprises: an oxidant, a complexing agent, water, and a pH value of 2-11, wherein the oxidant is selected from one or more of hydrogen peroxide, persulfate, iodate, periodate, and perchlorate, and the complexing agent is selected from one or more of organic acids and amino acids.

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