Cross structure electric arc additive and subtractive composite manufacturing method and device based on low surface roughness

Abstract

The invention provides an electric arc additive and subtractive composite manufacturing method and device for a cross structure based on low surface roughness. The device comprises an electric arc additive manufacturing forming system, a milling and subtractive system and a three-dimensional scanning detection system. Firstly, cross structure characteristics are analyzed, an additive manufacturing program is generated through an electric arc additive manufacturing forming system, and a layer is added; secondly, the flatness S, the average height # imgabs0 #, the weld reinforcement h and the height D of each position of the formed surface are analyzed through a three-dimensional scanning detection system, and whether the flatness S exceeds a specified value or not is judged; and finally, material increasing and decreasing judgment is conducted, and if # imgabs1 # imgabs2 #, material decreasing is conducted through a milling and cutting material decreasing system. And if # imgabs3 #, additive repair welding is conducted through an electric arc additive manufacturing forming system. In combination with a three-dimensional scanning detection system, flatness feedback of the formed surface can be obtained in real time, material increasing and decreasing are conducted in time in the cross structure forming process, the roughness of the formed surface of the cross structure is effectively reduced, and the forming precision is improved.

Description

Technical Field

[0001] The present invention relates to a cross - structure arc additive - subtractive composite manufacturing method and device based on low surface roughness, belonging to the technical fields of additive manufacturing technology and numerical control machining technology Background Art

[0002] In fields such as automobiles, aerospace, and ships, there are many places involving complex structural features. To meet the production and manufacturing requirements of large - scale complex components, by using CMT arc additive manufacturing and combining it with the subtractive machining method of a CNC machining center, complex metal structural parts can be manufactured, with high forming efficiency and forming accuracy, and can perfectly realize the composite manufacturing process of additive - quality inspection - subtractive, achieving precision requirements that cannot be reached by arc additive manufacturing technology

[0003] During the process of arc additive manufacturing of a cross - structure, each cladding layer overlaps with each other, and the subsequent cladding layer overlaps and forms on the previous cladding layer, with its height slightly higher than that of the previous cladding layer; as the number of layers increases, the height accumulation at the cross - structure connection is serious during the stacking process, resulting in a serious bulging phenomenon. At the same time, the height at the inner - side cross - structure corner is lower than the average height of the overall plane, and the forming accuracy error is relatively large

[0004] However, for the additive - subtractive composite manufacturing technology, real - time monitoring cannot be carried out, and corresponding post - processing operations of additive - subtractive are often carried out only after the additive manufacturing is completed. As a result, the height deviation accumulation during the forming process gradually becomes serious. As the number of additive layers increases, the surface roughness gradually increases, resulting in a large error in the final formed surface and forming accuracy. Even if post - processing of additive - subtractive is carried out after the final forming, the forming quality cannot be effectively improved

[0005] The patent "A Dual - Laser Composite - Format Metal Additive - Subtractive Device with Defect Monitoring and Surface Finishing Functions" (Application No. 202223401036.X) discloses a dual - laser composite - format metal additive - subtractive device with defect monitoring and surface finishing functions, which can perform on - line quality monitoring on the formed workpiece to timely detect internal defects, and eliminate the defects and trim the surface and contour of the part through the method of subtractive - remelting forming to improve the surface quality. Due to the large error of laser ultrasonic detection technology, the surface accuracy error after subtractive machining is relatively large, which results in a large error in the final formed surface of the structural part and affects the forming quality Summary of the Invention

[0006] The purpose of the present invention is to provide a cross - structure arc additive - subtractive composite manufacturing method and device based on low surface roughness. Combining with a three - dimensional scanning detection system, it can monitor the formed surface of the cross - structure in real time for the phenomenon of high surface roughness during the arc additive manufacturing process of the cross - structure, provide surface roughness and height data, and perform milling and additive manufacturing in a timely manner to keep its surface always maintaining a high forming accuracy

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method and device for cross - structure arc additive - subtractive composite manufacturing based on low surface roughness. The device includes an arc additive manufacturing forming system, a milling subtractive system, a three - dimensional scanning and detection system, and a workbench.

[0009] In the arc additive manufacturing forming system, the welding robot structure is connected to the wire feeding device and the gas feeding device;

[0010] In the milling subtractive system, the cutting tool is connected to the spindle. The Z - axis drive system and the Y - axis drive system control the movement directions of the spindle and the cutting tool. The tool magazine contains a variety of cutting tools.

[0011] The three - dimensional scanning and detection system includes a three - dimensional scanner and post - processing system software;

[0012] The workbench contains an X - axis drive system and a workbench base.

[0013] A method and device for cross - structure arc additive - subtractive composite manufacturing based on low surface roughness includes the following steps:

[0014] First step, turn on all the power supplies of the system device, fix the substrate on the workbench; determine the movement trajectory of the welding torch according to the actual size of the cross - structure model, determine the starting and ending arc points, and set the starting and ending arc commands, waiting and safety commands in the teaching pendant of the welding robot.

[0015] Second step, after the program is completed, start the first layer of the additive cross - structure. After the additive manufacturing is completed, wait for the temperature of the formed part to cool down to room temperature.

[0016] Third step, the three - dimensional scanning and detection system scans and images the formed cross - structure after the first layer of additive manufacturing. Analyze the flatness S of the formed surface, the average height and the weld reinforcement h and the height D at each position through the post - processing system. If the surface flatness S is less than the set value, the surface forming is good and enter the seventh step; if the surface flatness S is greater than the set value, proceed to the next additive - subtractive judgment;

[0017] Fourth step, if then the formed surface needs to be subtracted by the milling subtractive system; according to the height abnormal position displayed in the post - processing system, insert the rough machining and finish machining subtractive processes for the workpiece in the machining module of the milling subtractive system, generate the subtractive G - code according to the subtractive path and the milling depth, import and start milling;

[0018] Fifth step, if then perform additive repair welding through the arc additive manufacturing forming system. According to the additive position provided in the post - processing system, set the starting and ending arc procedures and the number of repair welding passes for repair welding at the determined position in the arc additive manufacturing forming system.

[0019] Step 6: Continue with the next layer of printing. Repeat steps 2 to 6 in sequence until additive manufacturing is completed, then turn off the power supply.

[0020] Preferably, in step 1, the programming of the welding robot teach pendant needs to determine the starting point and ending point of the arc according to the size of the cross - structure model, combined with the actual process weld width and the adjacent pass spacing.

[0021] Preferably, in step 2, when the cross - structure is additively manufactured by arc for one layer, the cladding layers overlap each other. The subsequent cladding layers are formed by overlapping on the previous cladding layer, and its height is slightly higher than that of the previous cladding layer. The height accumulation is obvious at the cross - corners, resulting in the height at the outer cross - structure corners being higher than the average height of the overall plane, and the height at the inner cross - structure corners being lower than the average height of the overall plane.

[0022] Preferably, in step 3, the post - processing system includes Geomatic Control software. The surface forming accuracy is represented by the size S of the standard deviation value, and the set value is 1 mm.

[0023] Preferably, in step 4, the height D at each position in the plane and the average height The difference determines the material removal in comparison with the weld reinforcement h; if It indicates that there is a specific position on the formed surface where the height difference from the overall plane height is too large, and continuing with additive manufacturing will affect the surface forming.

[0024] Preferably, in step 5, if It indicates that there is a specific position on the formed surface where the height difference from the overall plane height is too small, and continuing with additive manufacturing will affect the surface forming; the additive height is the average height of the plane minus the actual height of the depression, that is

[0025] The present invention has the following remarkable advantages:

[0026] (1) The present invention organically combines two technologies of additive manufacturing and subtractive manufacturing, can realize in - situ subtractive manufacturing in a timely manner during the additive manufacturing process, improves the disadvantage of poor forming accuracy of traditional additive manufacturing technology, and can improve the overall forming quality of the formed part surface, and to a certain extent, improves the performance of the formed part.

[0027] (2) The present invention combines the integrated additive - subtractive manufacturing technology with the three - dimensional scanning detection function, can monitor the surface roughness of complex formed parts in real - time. When the surface accuracy error of the formed part is large, the post - processing software can accurately provide the position and height deviation parameters required for additive - subtractive manufacturing, so that the surface roughness of the formed part is always maintained at a relatively low level, thereby ensuring a relatively high overall forming accuracy.

[0028] (3) The arc additive and subtractive hybrid manufacturing method and device constructed by the present invention can provide a method and device with low surface roughness and low material waste rate for the forming of cross structures for different sizes, different additive manufacturing methods, and material cross structures. Description of the Drawings

[0029] To more clearly illustrate the embodiments of the present invention and their design solutions, the accompanying drawings required for this embodiment will be briefly introduced below.

[0030] Figure 1 It is the flowchart of the arc additive and subtractive manufacturing of the present invention.

[0031] Figure 2 It is the schematic diagram of the device of the present invention.

[0032] Figure 3 It is the schematic diagram of subtractive manufacturing of the I-shaped cross structure.

[0033] Figure 4 It is the schematic diagram of additive manufacturing of the L-shaped structure. Detailed Embodiment

[0034] The present invention will be elaborated in detail below:

[0035] The present invention provides a cross-structure arc additive and subtractive hybrid manufacturing method and device based on low surface roughness. The device includes a CMT arc additive manufacturing forming system, a milling subtractive manufacturing system, a three-dimensional scanning and detection system, and a workbench.

[0036] Among them, in the arc additive manufacturing forming system, the welding robot structure 1 is connected to the wire feeding device 2 and the gas feeding device 3;

[0037] In the milling subtractive manufacturing system, the cutter 3 is connected to the main shaft 4, and the Z-axis drive system 5 and the Y-axis drive system 6 control the movement directions of the main shaft and the cutter. The tool magazine 7 contains a variety of tools;

[0038] The three-dimensional scanning and detection system includes a three-dimensional scanner 8 and post-processing system software 9; the post-processing software is GeomaticControl.

[0039] The workbench includes an X-axis drive system 10 and a workbench base 12.

[0040] To enable those skilled in the art to better understand the technical solutions of the present invention and be able to implement them, the present invention will be described in detail below with reference to the accompanying drawings and specific examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0041] The present invention provides a cross-structure arc additive and subtractive hybrid manufacturing method and device based on low surface roughness, including the following steps:

[0042] First step, turn on the power of all system devices, and fix the substrate on the workbench; determine the moving trajectory of the welding torch according to the actual size of the cross structure model, and determine the starting and ending arc points in the teaching pendant of the welding robot, set the starting and ending arc commands and waiting and safety commands;

[0043] Second step, start additive manufacturing after the program is completed. After one layer of additive manufacturing of the cross structure is completed, cool the surface temperature to room temperature;

[0044] Third step, the three-dimensional scanning detection system scans the cross structure that has been additively manufactured and formed one layer. Observe the three-dimensional imaging diagram through the post-processing system, and analyze the surface flatness S, average height and weld reinforcement h and the height D at each position of the formed cross structure. If the surface flatness S is less than the set value of 1 mm, the surface forming is good and enter the seventh step; if the surface flatness S is greater than the set value of 1 mm, proceed to the next step of additive and subtractive manufacturing judgment;

[0045] Fourth step, if then the formed surface needs to be machined and subtracted by the milling subtractive manufacturing system; according to the subtractive position provided in the post-processing system, determine the required milling depth and position, and import the G code into the processing module of the milling subtractive manufacturing system for the rough machining and finish machining subtractive programs of the workpiece;

[0046] Fifth step, if then perform additive repair welding through the arc additive manufacturing forming system. According to the additive position provided in the post-processing system, determine the required number of repair welding passes and positions, and start additive manufacturing after setting the starting and ending arc programs for repair welding in the arc additive manufacturing forming system;

[0047] Sixth step, continue printing the next layer, and repeat the second step to the sixth step in sequence until the additive manufacturing is completed, and then turn off the power.

[0048] This invention application combines the advantages of high efficiency of arc additive manufacturing and high precision of numerical control machining. During the manufacturing process, it combines a three-dimensional scanning detection system to perform three-dimensional scanning imaging on the formed surface roughness in real time during the additive manufacturing process of the cross structure, and can perform additive and subtractive manufacturing in a timely manner according to the abnormal position of the surface height of the cross structure, thereby reducing the surface roughness of the overall additive part and improving the additive forming accuracy of the cross structure.

[0049] Embodiment 1

[0050] Taking the additive manufacturing of a 304 stainless steel I-shaped cross structure as an example, specifically verify a cross structure arc additive and subtractive manufacturing method based on low surface roughness provided by the present invention

[0051] The specific steps include:

[0052] (1) Turn on all the power supplies of the system device, fix the substrate on the workbench, determine the starting point and ending point of each cross-cladding layer in the teach pendant program according to the size of the cross-structure model, combined with the actual weld width of 10 mm and the adjacent pass spacing of 6 mm, set the wire feeding speed to 4.1 mm / s, the gas to 99% Ar + 1% O2, the gas flow rate to 15 L / min, and set the safety point and waiting time to 3 s.

[0053] (2) After the program editing is completed, perform the additive manufacturing of the I-shaped cross-structure. After one layer of additive manufacturing is completed, wait for the formed part to cool to room temperature.

[0054] (3) Use a three-dimensional scanning detection system to scan and perform three-dimensional scanning imaging on the I-shaped cross-structure after additive manufacturing is completed. Transmit the point cloud file to the Geomatic Control post-processing software, observe the flatness of the cross-structure surface in the software, and determine the flatness S of the formed surface, the average height and the weld reinforcement h of 3 mm, as well as the height D at each position.

[0055] (4) When additive manufacturing is carried out for 1 to 4 layers, the flatness S of the first four layers of the surface is less than 1, and no additional material needs to be added or removed.

[0056] (5) When additive manufacturing reaches the fourth layer, the flatness S of the surface is greater than 1. At a specific position in the I-shaped cross-connection structure in the plane, the height exceeds the average height by 12 mm. The actual position height is 15.4 mm, and the height deviation is 3.4 mm, exceeding the weld reinforcement of 3 mm. Determine that the required milling depth is 3.4 mm, and import the G code into the machining module of the milling and subtractive manufacturing system to program the rough machining of 3 mm and the finish machining of 0.4 mm for the workpiece.

[0057] (6) When additive manufacturing reaches the sixth layer, when the height at a specific position in the plane is lower than the average height by 18 mm, the actual position height is 14.8 mm, and the height deviation is 3.2 mm, lower than the minimum value -3 mm of the reasonable deviation range. Its position is in the first pass of the sixth layer of the cladding layer. The required number of repair welding passes is 1. After setting the repair welding starting and ending arc programs in the arc additive manufacturing forming system, start additive manufacturing.

[0058] (7) Continue to print the next layer, and repeat in sequence according to the process steps until the additive manufacturing is completed, and then turn off the power.

[0059] (8) After the overall additive manufacturing is completed, perform three-dimensional scanning detection. The overall surface standard deviation is 0.64 mm, and the surface roughness is low and meets the requirements.

[0060] Example 2

[0061] Next, taking the additive manufacturing of the 304 stainless steel L-shaped structure as an example, specifically verify a cross-structure arc additive and subtractive manufacturing method and device based on low surface roughness provided by the present invention.

[0062] Using a cross - structure arc additive - subtractive composite manufacturing method based on low surface roughness of the present invention, the specific steps are as follows:

[0063] (1) Turn on all the power supplies of the system device, fix the substrate on the workbench. According to the cross - structure model size, combined with the actual weld width of 10 mm and the adjacent pass spacing of 6 mm, determine the starting point and ending point of each cross - clad layer in the teach - pendant program. Set the wire feeding speed to 4.1 mm / s, the gas to 99% Ar + 1% O2, the gas flow rate to 15 L / min, and set the safety point and waiting time of 3 s.

[0064] (2) After the program is edited, perform L - shaped cross - structure additive manufacturing. After one layer of additive manufacturing is completed, wait for the formed part to cool to room temperature.

[0065] (3) Use a three - dimensional scanning detection system to perform three - dimensional scanning imaging on the cross - structure after additive manufacturing. Transmit the point cloud file to the Geomatic Control post - processing software. Observe the flatness of the cross - structure surface in the software, and determine the flatness S of the formed surface, the average height and the weld reinforcement h of 3 mm, as well as the height D at each position.

[0066] (4) When additive manufacturing 1 - 6 layers, the flatness S of the first six layers of the surface is less than 1, and no additive - subtractive manufacturing is required.

[0067] (6) When additive manufacturing reaches the sixth layer, there is a specific position on the inner side of the L - shaped cross - structure where the height is 18 mm lower than the average height. The actual position height is 14.8 mm, and the height deviation is 3.2 mm lower than the weld reinforcement of - 3 mm. Its position is in the first clad layer of the sixth layer. The number of repair welding passes required is 1. After setting the repair welding starting and ending procedures in the arc additive manufacturing forming system, start additive manufacturing.

[0068] (7) Continue with the next layer of printing, and repeat in sequence according to the process steps until the additive manufacturing is completed, then turn off the power.

[0069] (8) After the overall additive manufacturing is completed, perform three - dimensional scanning detection. The overall surface standard deviation is 0.58 mm, and the surface roughness is low and meets the requirements.

[0070] This invention application combines the advantages of high efficiency of arc additive manufacturing and high precision of numerical control machining. During the manufacturing process, combined with a three - dimensional scanning detection system, three - dimensional scanning imaging is performed in real - time during the cross - structure additive manufacturing process to observe the surface roughness of the formed surface. Additive - subtractive manufacturing can be carried out in a timely manner according to the abnormal height positions on the cross - structure surface, thereby reducing the surface roughness of the overall additive - manufactured part and improving the forming accuracy of the cross - structure additive manufacturing.

Claims

1. An arc additive and subtractive hybrid manufacturing device with a cross structure based on low surface roughness, characterized in that, The device includes an arc additive manufacturing forming system, a milling subtractive system, a three-dimensional scanning and detection system, and a workbench; The arc additive manufacturing forming system includes a welding robot structure (1), a wire feeding device (2), and a gas feeding device (3); The milling subtractive system includes a cutting tool (4), a main shaft (5), a Z-axis drive system (6), a Y-axis drive system (7), and a tool magazine (8); The three-dimensional scanning and detection system includes a three-dimensional scanner (9) and a post-processing system (10); The workbench includes an X-axis drive system (11) and a workbench base (12).

2. A manufacturing method of a cross - structure arc additive - subtractive composite manufacturing device with low surface roughness according to claim 1, characterized in that, It includes the following steps: First step, turn on all the power supplies of the system device, and fix the substrate on the workbench; determine the moving trajectory of the welding torch according to the size of the cross structure model, and determine the starting and ending arc points in the welding robot teach pendant, and add starting and ending arc instructions, as well as waiting and safety instructions; Second step, after the program is completed, start the additive manufacturing of the first layer of the cross structure. After the additive manufacturing is completed, wait until it cools down to room temperature; Step 3: The three-dimensional scanning and detection system scans the cross structure that has been additively manufactured for one layer of forming. Through the post-processing system, observe the three-dimensional imaging of the cross structure, and analyze the flatness S of the formed surface, the average height and the weld reinforcement h, as well as the height D at each position; if the surface flatness S is less than the set value, the surface forming is good and proceed to Step 7; if the surface flatness S is greater than the set value, proceed to the next step to judge whether to increase or decrease the material; Step 4, if then the forming surface needs to be machined by a material removal system; according to the material removal position provided in the post-processing system, insert the material removal processes for rough machining and finish machining of the workpiece in the machining module of the material removal system, generate the material removal G-code based on the material removal path and the milling depth, and import the G-code to start milling; Step 5, if then perform additive repair welding through the arc additive manufacturing forming system; according to the additive position provided in the post-processing system, set the starting and ending arc procedures and the number of welding passes for repair welding in the arc additive manufacturing forming system according to the determined position, and perform repair welding. Sixth step, continue printing the next layer. The second step to the sixth step are repeated in sequence until the additive manufacturing is completed, and then turn off the power supply.

3. The manufacturing method according to claim 2, characterized in that, In the first step, determine the starting arc point and extinguishing arc point in the teach pendant program according to the size of the cross structure model, combined with the actual weld width and the adjacent pass spacing.

4. The manufacturing method according to claim 2, characterized in that, In the second step, during the process of arc additive manufacturing of one layer of the cross structure, each cladding layer overlaps with each other, and there is a certain height difference between the inside and outside of the cross structure, and the surface heights are different.

5. The manufacturing method according to claim 2, characterized in that In the third step, the post-processing system includes GeomaticControl software. The surface forming accuracy is represented by the magnitude S of the standard deviation value, and the set value is 1 mm.

6. The manufacturing method according to claim 2, characterized in that, In the fourth step, the additive and subtractive material determination is made by comparing the height D at each position in the plane with the average height difference and the weld reinforcement h. If it indicates that the height at a specific position on the formed surface is too different from the overall plane height, and continuing with additive material will affect the surface formation; the milling depth is the actual height at the convex position minus the average plane height, that is In the said milling and subtractive material system, the spindle speed is 1 - 6000 r / min, the spindle movement speed is 1 - 800 mm / min, and the cutting depth per pass of the spindle is 0.01 - 0.5 mm.

7. The manufacturing method according to claim 2, characterized in that, In the fifth step, if it indicates that the height at a specific position on the forming surface is too low compared to the overall plane height, and continuous additive manufacturing will affect the surface forming; the additive height is the average plane height minus the actual height of the depression, that is

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