CN114959691A - Surface modification equipment for 3D printing of titanium alloy and surface modification method thereof - Google Patents

Abstract

The invention discloses surface modification equipment for 3D printing of titanium alloy and a surface modification method thereof, and the equipment comprises a laboratory bench component, an optical detection component, a pressurizing component and a texture preparation component, wherein the pressurizing component comprises a combined type pressing plate device and a stress balance pressing head, the pressing plate device and the stress balance pressing head are connected with an upper pressurizing rod, the texture preparation component comprises a laser texture device and/or an extrusion texture device, and the equipment also comprises a preset texture stress plate, the preset texture stress plate is respectively matched with the laser texture device and/or the extrusion texture device, and the preset texture stress plate is used for limiting the texture edge from being raised in the texture preparation process. The technical scheme of the invention well continues the material increase concept of the 3D printing technology, obtains the required surface roughness and simultaneously improves the surface properties such as wear resistance and the like on the basis of not reducing the material of the 3D printing titanium alloy, and prolongs the service life of the 3D printing titanium alloy workpiece.

Description

Surface modification equipment for 3D printing titanium alloy and surface modification method thereof

technical field

The invention belongs to post-processing equipment for 3D printing metal, in particular to a surface modification equipment for 3D printing titanium alloy and a surface modification method thereof.

Background technique

Additive manufacturing (3D printing) technology is based on the characteristics of layered superposition, which is different from traditional subtractive manufacturing technology and is considered to be a major innovation in manufacturing technology in the 21st century. Additive manufacturing technology uses computer-aided design to build a three-dimensional model of the target, and input the layered model file into the additive manufacturing equipment to control the laser beam to melt the powder printed components according to the set trajectory. The additive manufacturing technology of the selective laser melting (SLM) process can realize the direct molding of complex configuration parts, which greatly simplifies the processing process and greatly improves the production efficiency. However, the SLM metal additive manufacturing technology faces the problem of unsatisfactory surface roughness of the formed parts, especially the roughness of more than ten microns or even tens of microns on the surface of 3D printed titanium alloys seriously affects the direct use of 3D printed titanium alloy formed parts. The surface post-treatment of 3D printed titanium alloy parts is an essential step, and the machined surface needs to be processed by subsequent subtractive grinding, so that the surface roughness can meet the corresponding requirements before it can be applied in the industrial field. However, the surface treatment of titanium alloys is very difficult. The traditional method of reducing the surface of titanium alloys will prolong the production cycle and increase the cost, and will also result in waste of materials. Therefore, for 3D printed titanium alloy workpieces, how to solve the problem of surface roughness through a new post-processing process can also improve the surface properties such as wear resistance of the workpiece and prolong its service life, which is one of the technical fields. A meaningful challenge.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies of the prior art, to provide a surface modification equipment for 3D printing titanium alloys, to continue the additive concept of the 3D printing technology itself, without reducing the basis of the materials of 3D printing titanium alloys themselves. On the other hand, while obtaining the required surface roughness, the surface properties such as wear resistance can be improved, and the service life of 3D printed titanium alloy workpieces can be prolonged.

According to the surface modification equipment for 3D printing titanium alloy provided by the present invention, the main technical scheme adopted is: including a test bench component, an optical detection component, a pressing component and a texture preparation component, and the experimental bench component includes a movable working Table and powder worktable, the left end of the movable worktable is a powder worktable, the bottom end of the movable worktable is provided with a displacement device, the position of the powder worktable is fixed, and the powder worktable is provided with a powder mixing device and a powder laying device, the said The optical detection component includes an optical topography measuring probe device and an information processing device, the optical topography measuring probe device is arranged directly above the movable worktable, and the pressing component includes a combined pressing plate device and a stress balance indenter, the pressing plate device and the stress The balanced pressure head is connected with the upper pressure rod, the texture preparation component is located on one side of the pressure component, and the texture preparation component includes a laser texture device, an extrusion texture device and a preset texture stress plate. The texture stress plate is matched with the laser texture device and the extrusion texture device, respectively, and is used to limit the bulge of the texture edge during the texture preparation process. The moving range of the movable table covers the compression component and the texture preparation component.

The surface modification equipment for 3D printing titanium alloys provided by the present invention also adopts the following subsidiary technical solutions:

The optical topography probe is used for mapping the three-dimensional topography of the workpiece surface.

The information processing device is used for model display and space volume calculation of the three-dimensional topography of the workpiece surface, the information processing device is connected with the pressing component and feeds back information to the pressing component in real time.

The powder mixing device discharges powder quantitatively and controllably through a rotating screw device.

The powder laying device is composed of a plurality of micro-pipe unit units arranged and combined into a whole. The bottom of the micro-pipe unit unit is provided with a closing plate to keep the powder in the micro-pipe unit body, and each micro-pipe unit body is provided with a corresponding Movable piston for expelling powder.

The combined pressing plate device includes a plurality of fine pressing rods, and the micro pressing rods are combined to obtain a corresponding pressing plane or curved surface.

The stress balance pressure head includes a center pressure head and an edge stress balance pressure plate, and the edge stress balance pressure plate is used to restrict the outer surface of the pressure region to bulge upward when the center pressure head is pressed.

The pressurizing assembly also includes a hydraulic rod connected to the stress equalizing head.

The laser beam emitted by the laser head of the laser texturing device is provided with a preset textured stress plate at the periphery of the action area of the titanium alloy surface for limiting the uplift of the textured edge, and the middle of the preset textured stress plate is provided with an inner hole For the laser beam to pass through, the cross section of the inner hole of the pre-textured stress plate matches the textured shape.

The extrusion head of the extrusion texture device is provided with a preset textured stress plate around the action area of the titanium alloy surface for limiting the uplift of the textured edge. The extrusion indenter is matched for the extrusion indenter to pass through.

The surface modification method for 3D printing titanium alloy provided by the present invention includes the following steps:

S1, place the 3D printed titanium alloy workpiece on the movable table, obtain the three-dimensional topography of the workpiece surface through the optical topography measuring probe, obtain the spatial volume and convex peak position of the material surface through the information processing device, and obtain the corresponding powder pavement. The powder feeding amount of each micro-pipe unit body of the release device and the selection of the pressure head of the combined pressure plate device corresponding to different positions and different hardnesses, so that the pressure surface is evenly stressed during the pressurization process, and the combined pressure plate device is installed;

S2, deliver quantitative metal powder to each micro-pipe unit of the powder laying device through the powder discharge device of the powder discharge bin of the powder mixing device. After the conveying is completed, the powder laying device is assembled and moved to the top of the workpiece surface to lay the powder. At this time The convex peak on the surface of the material is higher than the powder, and the combined pressing plate device performs the pressing operation. As the pressing surface moves down, the pressing surface bends the convex peak and presses it into the metal powder coating, and then pressurizes the coating surface. The combined pressing plate device Covering the entire pressing plane at one time, improving the flatness of the plane after pressing through the selection of the indenter, and completing the first combination of the powder layer and the titanium alloy workpiece substrate;

S3, prepare the mixed powder of the metal powder and the added components through the powder mixing bin of the powder mixing device, and lay a mixed powder layer of a certain thickness on the top of the metal powder coating in the previous step or place the mixed powder in local scattered points , and then the stress balance indenter performs continuous or interval pressure operation on the coating to realize the plastic deformation of the mixed coating powder. In this process, the edge stress balance plate of the stress balance indenter can restrain the unloading when the central pressure head exerts pressure. The bulge of the pressing area ensures the flatness of the plane and completes the second combination of the powder layer and the titanium alloy substrate;

S4, using an extrusion texture device and/or a laser texture device for texture preparation, the depth of the texture pits is required to exceed the trough of the contour of the 3D printed titanium alloy substrate, and enter the interior of the 3D printed titanium alloy substrate, according to the preset texture density. Setting and texture position, in the process of preparing texture, the preset texture stress plate limits the uplift of the texture edge area, and completes the third combination of the powder layer and the titanium alloy matrix;

S5, after the texture is finished, use the optical probe device to map the surface of the workpiece, and use the stress balance indenter for the surface roughness of the workpiece to perform the leveling operation to ensure that the surface roughness meets the requirements, and finally use the edge grinding device to grind the workpiece. Clean up burrs on the edges.

Compared with the prior art, the surface modification equipment for 3D printing titanium alloy and the surface modification method thereof provided by the present invention have the following advantages:

1. The present invention can obtain the same surface on the surfaces of different micro-regions, and form better bonding force with the surface of the 3D printed titanium alloy workpiece substrate. The three-dimensional topography of the material surface is obtained by analyzing and scanning the optical detection component, and the material plane is divided into sections corresponding to the combined pressure plate and the powder laying device. The hardness of the head is used to achieve the bending of the convex peak of the material. In order to leak the corresponding convex peak after the coating powder is put in, the space volume corresponding to the micro-pipe unit unit is obtained according to the topography map to determine the powder filled in each unit. After the powder coating is completed, the combined pressure plate is pressed down so that the convex peaks are bent into the coating powder, which enhances the bonding strength between the coating and the substrate. Select a high hardness indenter in the bulk powder area to achieve uniform stress on the material surface during the pressing process of the platen.

2. The present invention can satisfy the extrusion treatment of various 3D printed titanium alloy workpieces with different contour surfaces through the design of the extrusion structure. Through the design of a combined pressing plate device composed of multiple micro-pressing rods, the corresponding pressing plane or pressing surface can be obtained by combining the micro-pressing rods. Various special-shaped contours inside are extruded accordingly, so as to realize the corresponding treatment of the special-shaped surface roughness, which is especially suitable for 3D printing titanium alloy workpieces including surface contours of protruding or concave structures; and the design of the stress balance indenter makes the workpiece The specific position of the surface powder layer or the specific position of various special-shaped contours can be extruded in a targeted manner.

3. The present invention eliminates the deformation caused by the extrusion of the surrounding materials when the central pressure head works, and the texture preparation process through the edge stress balance pressure plate of the stress balance pressure head and the preset textured stress plate matched with the texture preparation equipment. The bulge of the mid-textured edge also improves the bonding force between the matrix and the powder layer. This not only ensures that the material surface can be kept flat during the powder extrusion process, but also can effectively control the effect of texture preparation on the roughness of the non-textured area. During the extrusion process after powder coating, the existence of the edge stress balance platen can make the extruded asperities deform toward the matrix; and in the texturing process, whether extrusion or laser treatment, will make the texture surrounding Cause material bulge or sputtering accumulation, so the bulge of the material can be effectively avoided by presetting the textured stress plate, and the periphery processed by the laser head can also be covered, so that the sputter falls on the surface of the preset textured stress plate without The surface of the material around the texture is destroyed. In order to enhance the bonding strength of the coating, the depth of the texture needs to penetrate the coating, so a large stress will be generated. The stress balance can be better achieved by presetting the textured stress plate.

4. The surface modification equipment for 3D printing titanium alloy of the present invention prepares a texture on the surface that can improve its surface properties through extrusion processing or texture processing, and at the same time makes the bonding force between the powder metal coating and the substrate. significantly improved. After the metal powder is extruded, the surface roughness of the 3D printed titanium alloy is improved. However, due to the use of the surface micro-convex deformation of the 3D printed titanium alloy itself and the metal coating formed by the extrusion plastic deformation of the metal coating itself, its surface The performance still needs to be improved, and the bonding strength needs to be strengthened. The texture depth obtained during the texture preparation process penetrates the substrate, which greatly enhances the metal coating and the substrate through mechanical extrusion deformation and/or laser melting metallurgical bonding. In order to improve the bonding strength of the coating and the substrate, the coating and texture together improve the roughness of the substrate material and enhance the surface friction and wear resistance of the material.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the equipment of the present invention.

2 is a cross-sectional view of a quantitative powder discharging screw of the powder mixing device of the present invention.

Figure 3 is a schematic diagram of a powder placement apparatus.

FIG. 4 is a schematic view of the pressing surface of the combined pressing plate device.

Figure 5 is a schematic view of the structure of the combined pressing plate pressing head.

FIG. 6 is a schematic diagram of the structure of a stress balance indenter.

FIG. 7 is a schematic diagram of a laser texturing device.

Figure 8 is a schematic diagram of an extrusion texturing device.

Figure 9 is a schematic diagram of the working pressure of the indenter of the extrusion texturing device.

Detailed ways

The surface modification equipment for 3D printing titanium alloy provided according to the present invention includes a test bench component, an optical detection component, a pressing component and a texture preparation component. The experimental bench component includes a movable workbench and a powder workbench. The left end of the movable table is a powder table. The bottom end of the movable table has a displacement device. The position of the powder table is fixed. The powder table is provided with a powder mixing device and a powder laying device. The optical detection component includes an optical topography measurement. The probe device and the information processing device, the optical topography measurement probe device is arranged directly above the movable worktable, the pressurizing assembly includes a combined pressing plate device and a stress balance indenter, and the combined pressing plate device is used for a large surface area and rapid The overall extrusion treatment is carried out, the stress balance indenter is used for local targeted extrusion treatment on the surface, the pressing plate device and the stress balance indenter are connected with the upper pressure rod, and the texture preparation component is located on one side of the pressure component, so The texture preparation assembly includes a laser texture device and/or an extrusion texture device, and also includes a preset texture stress plate, and the preset texture stress plate is respectively matched with the laser texture device and/or the extrusion texture device. The setting is used to limit the bulge of the texture edge during the texture preparation process, and the moving range of the movable table covers the pressing component and the texture preparation component.

The optical topography probe is used for mapping the three-dimensional topography of the workpiece surface.

The information processing device is used for model display and space volume calculation of the three-dimensional topography of the workpiece surface, the information processing device is connected with the pressing component and feeds back information to the pressing component in real time.

The powder mixing device discharges powder quantitatively and controllably through a rotating screw device. The top of the powder mixing device is a powder mixing bin, the powder is mixed by rotating the bin body, and a powder discharging bin is arranged at the lower end of the mixing bin, and the powder is quantitatively discharged through the rotation of the screw in the powder discharging pipeline of the powder discharging bin, and the device can be in the working plane. Pan. The powder is metal powder, such as pure copper, titanium alloy, pure aluminum and other metal powders, and a certain proportion of additives can also be added to the metal powder to improve its specific functions such as lubrication or wear resistance.

The powder laying device is composed of a plurality of micro-pipe unit units arranged and combined into a whole. The bottom of the micro-pipe unit unit is provided with a closing plate to keep the powder in the micro-pipe unit body, and each micro-pipe unit body is provided with a corresponding Movable piston for expelling powder. Further, the powder laying device is a drawer-type device, the bottom of the micro-pipe unit is a closed plate, and the top is a top cover with a piston. Powder work area, receiving powder. The cross-sectional area of the micro-pipe unit body of the powder laying device is the same as the cross-sectional area of the combined pressure plate micro-indenter, and has a one-to-one corresponding positional relationship.

The combined pressing plate device includes a plurality of fine pressing rods, and the micro pressing rods are combined to obtain a corresponding pressing plane or curved surface. Further, the combined pressing plate device has a circular frame, the pressing surface of the pressing head is a square, the pressing surface end of a single pressing head is a cuboid, and the other end is processed with a cylindrical screw, and the screw is connected to a cylinder engraved with an internal thread. , the upper end of the circular frame is provided with an inner thread, which is connected to the pressure stud to connect the combined pressure plate to the pressure device.

The stress balance pressure head includes a center pressure head and an edge stress balance pressure plate, and the edge stress balance pressure plate is used to restrict the outer surface of the pressure region to bulge upward when the center pressure head is pressed. Further, the edge stress balance pressure plate of the stress balance pressure head obtains the real-time pressure value through the pressure sensor, and completes the control of the stress balance device through the information processing device.

The shape and combination of the edge stress balance pressure plate of the stress balance pressure head are changed according to the shape of the center pressure head. The square pressure head is provided with four independent stress balance pressure plates with the same area as the center pressure head on the four sides. The head has four independent balanced stress pressure plates, two pressure plates are in contact with the semicircular surface of the pressure head, and the other two pressure plates are on the upper and lower sides of the pressure head.

The pressurizing assembly also includes a hydraulic rod connected to the stress equalizing head.

The laser beam emitted by the laser head of the laser texturing device is provided with a preset textured stress plate at the periphery of the action area of the titanium alloy surface for limiting the uplift of the textured edge, and the middle of the preset textured stress plate is provided with an inner hole For the laser beam to pass through, the cross section of the inner hole of the pre-textured stress plate matches the textured shape. Further, the melting point of the preset textured stress plate should be higher than the processing material to ensure that the pressing plate will not melt during laser processing, for example, the material is selected from tungsten.

The extrusion head of the extrusion texture device is provided with a preset textured stress plate around the action area of the titanium alloy surface for limiting the uplift of the textured edge. The extrusion indenter is matched for the extrusion indenter to pass through.

Example 1

Referring to FIG. 1 , a surface modification equipment for 3D printing titanium alloys, the test bench assembly includes a powder workbench 4 and a movable workbench 5 , the powder placement device 3 first fills the powder through the powder mixing device 1 , and then passes the displacement The device 2 is moved to the movable worktable, the optical topography measurement probe device 9 of the optical detection assembly is located above the worktable, the pressing assembly includes a combined pressing plate device 10 and a stress balance indenter 8, the texture preparation The assembly includes a laser texturing device 7 and/or an extrusion texturing device 6 .

Referring to FIG. 2 , the quantitative powder output screw 11 of the powder mixing device 1 changes the powder output volume through the screw rotation distance.

Referring to FIG. 3 , the powder laying device 3 is composed of a top cover with a piston 12 , a micro-pipe unit body 13 and a bottom plate 14 , the piston with the top cover of the piston 12 corresponds to each micro-pipe unit body, and the piston moves downward to clear each unit Body powder.

4 and 5, the circular frame 15 of the combined pressing plate device 10 is engraved with internal threads to connect the combined pressing plate device 10 with the upper pressing device. The combined pressing head is composed of a pressing head 18 and a cylindrical connecting handle 17. , through the cylindrical connecting handle 17, a single indenter can be easily removed from the whole for replacement.

Referring to Fig. 6, the stress balance pressure head 8 is composed of a stress balance pressure plate 19 and a central pressure head 20. When the central pressure head 20 is pressurized, the stress balance pressure plate 19 covers the periphery of the pressure head, and generates a balance stress through the sensor to maintain the surface of the material smooth.

7 and 8 , the laser texture preparation device consists of a preset textured stress plate 21 and a laser 22 , and the indenter texture preparation device consists of a texture extrusion indenter 23 and a preset textured stress plate 24 .

A working process of a surface modification device for 3D printing titanium alloys includes the following steps:

Step 1, place the 3D printed titanium alloy workpiece with a surface roughness of 40 microns on the movable table 5, obtain the three-dimensional topography of the workpiece surface through the optical topography measuring probe 9, and obtain the spatial volume of the material surface through the information processing device. and the position of the convex peak, the powder feeding amount corresponding to each micro-pipe unit body of the powder laying device 3 and the selection of the indenter corresponding to different positions of the combined pressing plate device 10 are obtained. The corresponding position of the convex peak and the space where the powder volume is greater than the unit area Select an indenter with a hardness of HRC60 for half of the volume, and select an indenter with a hardness of HRC40 for other positions to achieve uniform pressure on the pressing surface during the pressing process. After assembling the combined indenter, connect the combined pressing plate device 10 to the pressing device. superior.

Step 2, through the powder output device of the powder output bin of the powder mixing device 1, deliver a quantitative amount of pure copper powder to each micro-pipeline unit of the powder placement device 3. After the transportation is completed, the powder placement device is assembled and moved to the top of the workpiece surface for placement. After the powder is spread, the powder placement device 3 returns to its original position. At this time, the convex peak on the surface of the material is higher than the powder. The combined pressing plate device 10 performs the pressing operation, and the convex peak is bent as the pressing surface moves down. Press into the coating, then pressurize the surface of the coating, keep the pressure for 5 minutes, and then withdraw the pressure, the combined pressing plate device covers the entire pressing plane at one time, and the flatness of the pressed plane is improved by the selection of the indenter, and the powder layer is completed. The first bond with the titanium alloy workpiece substrate.

Step 3, prepare a mixed powder of pure copper powder and graphene through the powder mixing chamber of the powder mixing device 1, and lay a 20-micron-thick mixed powder layer and or the pure copper powder and graphene above the pure copper layer. The powder is mixed locally, and then the stress balance pressure head 8 performs continuous or interval pressure operation on the coating to realize the plastic deformation of the mixed coating powder, and the pressure holding time is 5 minutes. The edge stress balance plate 19 of the stress balance indenter 8 can suppress the bulge of the unpressurized area when the center pressure head 20 exerts pressure, ensure the flatness of the plane, improve the maximum pressure of the center pressure head, and complete the powder layer and titanium The second bonding of the alloy matrix. The combined pressing plate device 10 can also be used for re-pressurization as required.

Step 4: After the pressing operation is completed, the platform 5 can be moved to the texture processing station, and the texture preparation is carried out by using an extrusion texture device and/or a laser texture device. The depth of the texture pits is required to exceed the 3D printing titanium alloy. The trough of the substrate profile enters the interior of the 3D printed titanium alloy substrate, thereby effectively improving the bonding force between the powder coating and the substrate. Set the texture position according to the preset texture density, set the texture density to 40%, carry out the texture processing at the preset position, use the laser to process the pit texture in the vacuum chamber, and the pit depth is 60 microns to penetrate the coating When the material reaches the substrate, the metallurgical reaction of the laser melting material enhances the bonding strength of the coating and the substrate. If the indenter is used to process the conical texture, the depth of the pit is 60 microns through the coating to reach the substrate, and the coating and the substrate are further strengthened by extrusion. The bonding strength of the matrix and the texture can also improve the friction and wear resistance of the material surface. The preparation of texture makes the material penetrate deep into the matrix, and at the same time, it will produce bulge and sputtering of the material. During the preparation of texture, the pre-textured stress plate can limit the bulge of the edge area of the texture, and protect the outer area of the texture from sputtering and keep it flat. effect. When preparing the texture, the pre-textured stress plate 21 is first pressed on the edge of the texture to set the pre-pressure, and then the laser beam processes the pit texture, and the sputtering caused by the laser beam falls on the pre-textured stress plate 21. Surface, edge uplift is also suppressed; if the extrusion head is used to process the texture, see Figure 9, when the mixed powder layer exists as a whole layer, 25 is the mixed powder layer, 26 is the pure copper powder layer and 27 is the pure copper powder layer. For the titanium alloy matrix, when the mixed powder layer exists in local scattered points, the 25 mixed powder layer is extruded into the interior of the 26 pure copper powder layer, and the pre-textured stress plate 24 restricts the uplift of the texture edge and simultaneously presses against it. The pressure is applied to the covered area, so that when the indenter 23 is pressed, not only the materials in the texture are combined more closely, but also the pressure-covered area of the pre-textured stress plate 21 is also subjected to pressure to enhance the degree of bonding, and the texture is prepared to complete the powder layer and titanium alloy. The third bonding of the matrix.

Step 5: After the texture operation is completed, use the optical probe device to map the surface of the workpiece, and use the stress balance indenter 8 for the surface roughness of the workpiece to perform the leveling operation to ensure that the surface roughness meets the requirements, and finally use the corner grinding. The device cleans the burrs on the edge of the workpiece.

Embodiment 2

The difference between this embodiment and the first embodiment is that there is a concave area on the surface of the 3D printed titanium alloy workpiece. On the combined pressing plate device, a higher hardness HRC60 indenter should be selected in this area to cover the entire concave area. The combined pressing plate device can flexibly adjust the combination of indenters according to the contour of the material surface to achieve pressure balance on the pressing surface.

Embodiment 3

The difference between this embodiment and the first embodiment is that pure aluminum powder is placed on the surface of the 3D printed titanium alloy workpiece instead of pure copper powder as the base powder.

Claims (10)

1. a surface modification equipment of 3D printing titanium alloy, it is characterized in that: comprise experimental bench assembly, optical detection assembly, pressurization assembly and texture preparation assembly, and described experimental bench assembly comprises movable table and powder table , the left end of the movable table is a powder table, the bottom end of the movable table has a displacement device, the position of the powder table is fixed, the powder table is provided with a powder mixing device and a powder laying device, and the optical detection component includes an optical The topography measurement probe device and the information processing device, the optical topography measurement probe device is arranged directly above the movable worktable, the pressurizing assembly includes a combined pressing plate device and a stress balance indenter, and the platen device and the stress balance indenter are connected to the upper The pressure rod is connected, the texture preparation component is located on one side of the pressure component, and the texture preparation component includes a laser texture device and/or an extrusion texture device, and also includes a preset texture stress plate, a preset texture The textured stress plate is matched with the laser texture device and/or the extrusion texture device, respectively, to limit the bulge of the texture edge during the texture preparation process, and the moving range of the movable table covers the pressing component and the texture preparation component. . 2. The surface modification equipment for 3D printing titanium alloy according to claim 1, characterized in that: the optical topography probe is used for mapping the three-dimensional topography of the workpiece surface; the information processing device is used for the surface modification of the workpiece Model display of three-dimensional topography and calculation of space volume, the information processing device is connected with the pressurizing component and feeds back information to the pressurizing component in real time. 3 . The surface modification equipment for 3D printing titanium alloys according to claim 1 , wherein the powder mixing device discharges powder quantitatively and controllably through a rotating screw device. 4 . 4 . The surface modification equipment for 3D printing titanium alloy according to claim 1 , wherein the powder laying device is composed of a plurality of micro-pipe unit units arranged and combined into a whole, and the bottom of the micro-pipe unit unit is 5 . There is a closing plate to keep the powder in the micro-channel unit body, and a corresponding movable piston for expelling the powder is arranged above each micro-channel unit body. 5 . The surface modification equipment for 3D printing titanium alloys according to claim 1 , wherein the combined pressing plate device comprises a plurality of fine pressing rods, and the micro pressing rods are combined to obtain a corresponding extrusion plane or Extrude surface. 6 . The surface modification equipment for 3D printing titanium alloy according to claim 1 , wherein the stress balance pressure head comprises a center pressure head and an edge stress balance pressure plate, and the edge stress balance pressure plate is pressed when the center pressure head is pressed. 7 . Used to limit the upward bulge of the outer surface of the compression area. 7 . The surface modification equipment for 3D printing titanium alloy according to claim 1 , wherein the pressurizing component further comprises a hydraulic rod, and the hydraulic rod is connected with a stress balance head. 8 . 8 . The surface modification equipment for 3D printing titanium alloy according to claim 1 , wherein the laser beam emitted by the laser head of the laser texturing device is provided with an edge for limiting the texture around the action area of the titanium alloy surface. 9 . A raised pre-textured stress plate, the middle of the pre-textured stress plate is provided with an inner hole for the laser beam to pass through, and the cross-section of the inner hole of the pre-fabricated stress plate matches the texture shape. 9 . The surface modification equipment for 3D printing titanium alloy according to claim 1 , wherein the extrusion head of the extrusion texture device is provided with a bulge for limiting the texture edge around the action area of the titanium alloy surface. 10 . The preset textured stress plate, the cross section of the inner hole of the preset textured stress plate is matched with the extrusion pressure head for the extrusion pressure head to pass through. 10. The surface modification method of 3D printing titanium alloy according to claim 1-9, comprising the following steps: S1, place the 3D printed titanium alloy workpiece on the movable table, obtain the three-dimensional topography of the workpiece surface through the optical topography measuring probe, obtain the spatial volume and convex peak position of the material surface through the information processing device, and obtain the corresponding powder pavement. The powder feeding amount of each micro-pipe unit body of the release device and the selection of the pressure head of the combined pressure plate device corresponding to different positions and different hardnesses, so that the pressure surface is evenly stressed during the pressurization process, and the combined pressure plate device is installed; S2, deliver quantitative metal powder to each micro-pipe unit of the powder laying device through the powder discharge device of the powder discharge bin of the powder mixing device. After the conveying is completed, the powder laying device is assembled and moved to the top of the workpiece surface to lay the powder. At this time The convex peak on the surface of the material is higher than the powder, and the combined pressing plate device performs the pressing operation. As the pressing surface moves down, the pressing surface bends the convex peak and presses it into the metal powder coating, and then pressurizes the coating surface. The combined pressing plate device Cover the entire pressing plane at one time, improve the flatness of the plane after pressing by selecting the indenter, and complete the first combination of the surface powder layer and the titanium alloy workpiece substrate; S3, prepare the mixed powder of the metal powder and the added components through the powder mixing bin of the powder mixing device, and lay a mixed powder layer of a certain thickness on the top of the metal powder coating in the previous step or place the mixed powder in local scattered points , and then the stress balance indenter performs continuous or interval pressure operation on the coating to realize the plastic deformation of the mixed coating powder. In this process, the edge stress balance plate of the stress balance indenter can restrain the unloading when the central pressure head exerts pressure. The uplift of the pressing area ensures the flatness of the plane and completes the second combination of the surface powder layer and the titanium alloy substrate; S4, using an extrusion texture device and/or a laser texture device for texture preparation, the depth of the texture pits is required to exceed the trough of the contour of the 3D printed titanium alloy substrate, and enter the interior of the 3D printed titanium alloy substrate, according to the preset texture density. Setting and texture position, in the process of preparing texture, the preset texture stress plate restricts the uplift of the texture edge area, and completes the third combination of the surface powder layer and the titanium alloy matrix; S5, after the texture is finished, use the optical probe device to map the surface of the workpiece, and use the stress balance indenter for the surface roughness of the workpiece to perform the leveling operation to ensure that the surface roughness meets the requirements, and finally use the edge grinding device to grind the workpiece. Clean up burrs on the edges.

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