Metal plate ribbing machining method

Abstract

The metal plate ribbing machining method comprises the steps that a ribbing sample piece is tested, and deformation data are obtained; laser compensation is performed on preset deformation, and numerical control programming is performed; the conformity is verified through ribbing; and batch production. According to the method, metal plate ribbing parameters are adjusted through three-dimensional simulation analysis and three-dimensional visual inspection in combination with setting of a process test metal plate ribbing test, and ribbing machining is carried out according to design parameters. In the processing method, laser prefabrication compensation dosage is adopted to ensure that secondary processing is not needed after ribbing, and the assembling requirement is met; the production method is low in cost, secondary processing after ribbing is not needed, and the manufacturing cost and the maintenance cost of a blanking die and the high investment of a plate shearing machine are avoided; the auxiliary cost of secondary manual work or mechanical arm feeding and discharging production and the like is reduced; the process period is shortened, and the product production efficiency is improved; the method has universality, is not limited by change of product appearance conditions, can meet the requirement by changing a numerical control laser program, and does not need additional investment; after ribbing and compensation, no excess materials exist, and the material utilization rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of metal processing and relates to a metal sheet metal rib processing method. Background Art

[0002] The mechanical manufacturing industry usually uses rib pressing to enhance the rigidity and strength of sheet metal parts. The existing sheet metal processing and manufacturing process is: blanking with shearing machine → rib pressing with stamping equipment and mold → after forming, the excess raw materials around are sheared by two methods: blanking with stamping equipment mold or shearing machine controlled by robot.

[0003] The existing methods have the disadvantages of large waste of raw materials, high cost of process equipment investment, long processing cycle, and high labor. When the existing manufacturing process uses blanking die processing, the product design size cannot be adapted after the change and needs to be remade. The extra labor required for punching or secondary shearing by shearing machine after rib pressing requires manual or mechanical loading and unloading, which is wasteful. Summary of the invention

[0004] The present invention discloses a sheet metal rib processing method based on the deficiencies of the prior art. The purpose of the present invention is to provide a sheet metal rib processing method which does not require secondary processing, has more accurate parameter settings, saves more materials, and can meet assembly requirements.

[0005] The present invention is achieved through the following technical solutions:

[0006] A sheet metal rib processing method, characterized by comprising the following steps:

[0007] Step S1, testing the rib sample and obtaining deformation data;

[0008] S11, determine the size of the ribbed blank; calculate the unfolded sample and determine the blanking size according to the 3D software simulation analysis;

[0009] Specifically include:

[0010] Assuming that the metal weight m and density ρ remain unchanged before and after beading, then:

[0011] V=m÷ρ; (1)

[0012] S=V÷t; (2)

[0013] L 理论 =S÷W 理论 ; (3)

[0014] W 理论 =S÷L 理论 ; (4)

[0015] The actual length L and width W of the blank are greater than the theoretical length and width of the product after rib pressing; they are obtained using the following formula:

[0016] L=L 理论 *K; (5)

[0017] W=W 理论 *K; (6)

[0018] Where V is the blank volume, m is the weight of the processed metal, ρ is the density of the processed metal, S is the blank area, t is the blank thickness, L is 理论 W is the theoretical length of the blank, 理论 is the theoretical width of the blank, L is the actual length of the blank, W is the actual width of the blank, and K is the widening coefficient, which is 1.1 to 1.3;

[0019] S12, according to the design parameters of step S11, a small amount of laser cutting rough parts are used for blanking, and the blanking is made in the shape of a square plate, and the straightness of the four sides meets the process requirements;

[0020] S13. After ensuring that the equipment and the pressing mold are normal, carry out the rib pressing test;

[0021] S14. After rib pressing, the shrinkage change data of the four edges of the square plate workpiece are detected, and the shrinkage changes of length and width are recorded as △ L ,△ W ;

[0022] S15, detecting deformation curves of four edge line segments of the square plate workpiece by laser three-dimensional vision;

[0023] Specifically, a non-contact measurement method is used to quickly collect point cloud data of the square plate workpiece using a 3D laser scanner to emit a laser beam to form a 3D model; an accurate 3D digital model is generated by processing the point cloud data;

[0024] Point cloud data processing includes:

[0025] Data preprocessing: remove noise and align multiple scan data;

[0026] Point cloud registration: stitching point cloud data from multiple scan positions into a complete model;

[0027] Feature extraction: Identify and extract geometric features in the point cloud, and extract the edge curve of the embossed workpiece, that is, the deformation curve of the four edge line segments of the square plate workpiece after embossing.

[0028] The purpose of this step is to accurately depict the shape, position, size and other information of the stamping edge.

[0029] Step S2, laser compensation preset deformation, numerical control programming;

[0030] S21. Taking the four corners of the square plate workpiece after the designed rib as the reference value, the rib offset length shrinkage change is designed to be half of the △ from the center point of the square plate workpiece to the four sides outward. L , the width shrinkage change is half△ W , obtain the design values ​​of the four corners of the ribbed square plate workpiece;

[0031] S22, according to the deformation curves of the four side line segments of the square plate workpiece obtained by the laser three-dimensional visual detection in step S15, and the design values ​​of the four corners of the ribbed square plate workpiece obtained in step S21, the side lines relative to each other are mirror-symmetrically processed to form a laser blanking compensation graph;

[0032] S23, performing CNC laser programming on the above graphics and performing cutting and blanking;

[0033] Step S3, verify compliance of rib pressing;

[0034] S31. After cutting and blanking, conduct rib pressing process test; adjust the positioning dimensions of the blank and the pressing die to ensure that the center point of the blank is aligned with the upper and lower centers of the pressing die;

[0035] S32. Under normal process parameters, carry out rib compression test, inspect product dimensions piece by piece, and verify compliance;

[0036] Step S4: batch production and qualified inspection.

[0037] The sheet metal rib processing method of the present invention is beneficial:

[0038] The sheet metal embossing processing method of the present invention adjusts the sheet metal embossing parameters through three-dimensional simulation analysis, three-dimensional visual inspection, and the setting of the sheet metal embossing test combined with the process test, and performs embossing processing according to the design parameters. The laser prefabrication compensation amount is used in the processing method to ensure that no secondary processing is required after embossing, so as to meet the assembly requirements. The method of the present invention has low production cost, does not require secondary processing after embossing, avoids the production cost and maintenance cost of blanking dies, and the high investment in shearing machines; reduces secondary labor or auxiliary costs such as manipulator loading and unloading production; shortens the process cycle and improves product production efficiency; the method of the present invention is universal and will not be restricted by changes in product appearance conditions. It can be satisfied by changing the CNC laser program without additional investment; after embossing and compensation, there is no excess material, which improves the material rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic plan view of a ribbed part according to an embodiment of the present invention;

[0040] Figure 2 2 is a schematic side view of a ribbed part according to an embodiment of the present invention;

[0041] Figure 3Schematic diagram of the contraction of the ribbed parts according to the embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of laser blanking compensation in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with specific implementation methods. The specific implementation methods are further descriptions of the principles of the present invention and do not limit the present invention in any way. Technologies that are the same or similar to the present invention do not exceed the scope of protection of the present invention.

[0044] Combined with the attached pictures.

[0045] The method for avoiding processing of sheet metal after beading involved in the present invention uses laser prefabrication compensation to ensure that no secondary processing is required after beading to meet assembly requirements through three-dimensional simulation analysis, three-dimensional visual inspection and process testing.

[0046] The specific steps include:

[0047] Step S1, testing the rib sample and obtaining deformation data;

[0048] S11, determine the size of the ribbed blank; calculate the unfolded sample and determine the blanking size according to the 3D software simulation analysis;

[0049] Assuming that the metal weight m and density ρ remain unchanged before and after beading, then:

[0050] Blank volume V = weight m ÷ density ρ; (1)

[0051] Blank area S = volume V ÷ thickness t; (2)

[0052] Theoretical calculation of the length L and width W of the blank: According to the area S = length L * width W, then:

[0053] Blank length L 理论 = Area S ÷ Width W 理论 ; (3)

[0054] Blank width W 理论 = Area S ÷ Length L 理论 ; (4)

[0055] The actual length L and width W of the blank are greater than the theoretical length and width of the product after embossing. Considering that the workpiece does not shrink uniformly in length and width during embossing, in order to ensure that the minimum size of the blank after shrinkage is not less than the edge requirements of blanking or shearing by shearing machine, it is necessary to multiply the theoretical size by the width factor K.

[0056] Length L = L 理论 *Releasing factor K; (5)

[0057] Width W = W 理论 *Releasing factor K; (6)

[0058] The relaxation coefficient K is set to 1.1-1.3 in this embodiment; if the K value is too small, the blank material will be insufficient, and if the K value is too large, there will be too much material edge, resulting in a waste of raw materials.

[0059] S12. Use a small amount of laser cutting to cut rough parts. In this case, square plates are used, and the straightness of the four sides meets the process requirements.

[0060] S13. After ensuring that all hydraulic equipment and pressing dies can produce normally, carry out the rib pressing test.

[0061] S14, after rib pressing, the workpiece detection collects the shrinkage change data of four line segments AB, BC, CD, and AD. Point A, point B, point C, and point D represent the four corner endpoints of the workpiece respectively. The shrinkage change of length and width is expressed by △ L ,△ W express.

[0062] S15, detection, detecting the deformation curves in the AB, BC, CD, and AD segments through laser three-dimensional vision.

[0063] Step S2, laser compensation preset deformation, numerical control programming;

[0064] S21. Take the four outer corners of the workpiece after rib pressing, points A, B, C and D as the reference, divide evenly from the center point O, and shrink the length and width by half of the change △ L ,△ W value, forming point A', point B', point C', and point D';

[0065] S22, based on the deformation curves in the AB, BC, CD, and AD line segments obtained by laser three-dimensional visual detection, the straight lines at points A', B', C', and D' are mirror-symmetrically processed to form a laser blanking compensation graph;

[0066] S23, performing CNC laser programming on the above graphics and performing cutting and blanking.

[0067] Step S3, verify compliance of rib pressing;

[0068] S31. After cutting and blanking, perform a rib pressing process test; adjust the positioning dimensions of the blank and the pressing die to ensure that the center point O of the blank is aligned with the upper and lower centers of the pressing die;

[0069] S32. Under normal process parameters, carry out rib compression test, inspect product dimensions piece by piece, and verify compliance; if not, adjust the preset deformation amount;

[0070] Step S4: batch production, sampling inspection and passing;

[0071] Due to the influence of factors such as the raw materials themselves and the hydraulic equipment, irregular dimensional inspections should be carried out during batch production, and continuous production should be carried out when they meet the requirements.

[0072] The method of the present invention is described below with a specific implementation research process.

[0073] The roof cover of the railway vehicle in this example is a sealing component in the roof cover of a certain type of grain hopper car. The quality of the part forming will affect the quality of the whole vehicle. There are four specifications and sizes of the roof cover in the roof cover. Each type of roof cover has the same pressing size and different lengths. For stamping parts, using different stamping processes usually has a great impact on the quality of the workpiece and the manufacturing cost.

[0074] 1. Process experiment:

[0075] 1. Parts introduction: The top cover component structure diagram is as follows Figure 1 As shown, the material is Q345NQR2, the thickness is 2.3mm, and the pressing depth is 14±2mm. By consulting the data, the chemical composition of the material is shown in Table 1, and the mechanical properties are shown in Table 2.

[0076] Table 1 Chemical composition:

[0077]

[0078] Table 2 Mechanical properties:

[0079]

[0080] 2. Top cover plate forming process test: The top cover plate has a profiling depth of 14±2mm, which is a shallow deep drawing and rolling structure. Since the structure is similar to the side wall structure of the P70 boxcar, the side wall plate mold is used for stamping process test. Before the test, the size of the top cover plate blank needs to be designed. The experiment adopts the conventional unfolding method of the folded parts to determine the test blank size of the top cover plate: 2.3X940X2020 (unit: mm), and the process margin is reserved in the length and width directions. After profiling, the shearing machine is used for trimming to ensure the length and width of the workpiece.

[0081] After pressing, the workpiece size was checked and the length dimension shrunk by about 3mm, while the width dimension direction remained basically unchanged.

[0082] 2. Forming process analysis:

[0083] According to the mechanical properties of the top cover material, CAE forming process software was used to simulate and analyze the top cover forming, and the strain cloud map, stress cloud map, and thickness change cloud map of the top cover forming were obtained. The stress-strain and thickness change cloud maps were analyzed to determine the change law of the top cover after forming. The stress-strain and thickness change cloud maps were used to guide the design of the top cover forming mold, shorten the mold development cycle, greatly improve the success rate of the die after mold design and manufacturing, avoid repeated adjustments of the forming mold, reduce the mold trial and debugging time, and provide guarantee for the on-time delivery of parts.

[0084] 3. Stamping plan formulation:

[0085] Since the structure of the top cover is similar to that of the side wall of the P70 boxcar, and the stamping process is similar to that of the P70 boxcar side wall, the mold structure is improved and designed based on the P70 boxcar side wall pressing mold. The mold structure is partially adjusted to meet the needs of top cover pressing. At the same time, when pressing top cover plates of different lengths, only the mold positioning stop needs to be adjusted to meet the requirements of top cover pressing. For this type of workpiece, four solutions are generally used for production:

[0086] Solution (1): Cutting → Leveling → Pressing → Blanking → Folding and Pressing;

[0087] Solution (2): Cutting and cutting → leveling → profiling → shearing (trimming) → folding and pressing;

[0088] Solution (3): Cutting and blanking → leveling → pressing and blanking → folding and pressing;

[0089] Solution (4): CNC cutting (standard size) → leveling → pressing → folding.

[0090] The specific production process is usually determined by the production quantity of the product. Different production processes have a great impact on the manufacturing cost of the workpiece.

[0091] Solution (1) requires adding a blanking process after the workpiece is pressed. In order to meet the production of the top cover plate, four sets of blanking dies are required. The mold investment cost is high and the mold manufacturing cycle is long. After adding the blanking process, the labor force increases, but the quality of the workpiece is easy to guarantee.

[0092] Solution (2) requires the workpiece to be profiled, sheared and trimmed, and the trimming requires 5 operators. Before shearing and trimming, a template is used to mark the lines, and then the operator cuts and trims the lines. The quality of the workpiece is not easy to guarantee using this process, resulting in a high scrap rate of the workpieces produced. At the same time, the labor intensity of the operators is high. Since the shearing equipment and the profiling equipment are distributed in different workshops, the workpieces need to be transported back and forth between different workshops in the production workshop. The transportation distance is long, and the workpieces need to wait during the transportation process, which is time-consuming and has low production efficiency.

[0093] Solution (3) requires the process to add 4 sets of press blanking dies. This solution reduces one process step compared to solution (1) and reduces the number of workers by 5 compared to solution (1) and solution (2), but the mold investment cost is high.

[0094] Solution (4) avoids all the disadvantages of solution (1), solution (2) and solution (3), and better solves the problems of large investment, high labor cost, difficult to ensure workpiece quality and low production efficiency in producing top cover plates. However, when using solution (4) for production, it is necessary to obtain the precise outer dimensions of the top cover plate blank to ensure that the workpiece meets the requirements after pressing.

[0095] Through on-site process tests and top cover plate forming process plan analysis, as well as the production quantity of the grain hopper car involved in the present invention, combined with the layout of production equipment, the top cover plate production process plan is determined as follows:

[0096] CNC cutting→pressing→folding and pressing.

[0097] 4. Determination of the size of the top cover blank:

[0098] The blank shape design is an important part of the process design, which directly affects the forming quality of the workpiece. Reasonable blank shape can save raw materials, prevent the workpiece from cracking, make the thickness of the formed part evenly distributed, improve the formability of the sheet, and reduce the workload of trimming after forming. At the same time, it helps to reduce the punching force required for deep drawing, thereby reducing the wear of the mold.

[0099] The design methods of stamping parts blanks include: table lookup method, experimental successive approximation method, slip line method, trial and error method, reverse simulation method, etc.

[0100] The CAE forming software is used to perform reverse simulation to design the outer dimensions of the top cover blank. During the analysis process, it is necessary to adjust the material mechanical properties in the model according to the part material, set reasonable boundary constraints, obtain the workpiece blank diagram, and determine the top cover plate expansion size in combination with the top cover plate press process test deformation data.

[0101] After production verification, the top cover plate is produced by thin plate shallow drawing without trimming forming process, which has stable product quality, reduces mold investment, optimizes production process, improves workpiece material utilization, reduces labor, reduces manufacturing costs, and ensures smooth production. The sealing of the assembled top cover meets the product technical requirements.

Claims

1. A sheet metal rib processing method, characterized in that The following steps are involved: Step S1, testing the rib sample and obtaining deformation data; S11, determine the size of the ribbed blank; calculate the unfolded sample and determine the blanking size according to the 3D software simulation analysis; S12. According to the design parameters of step S11, a small amount of laser cutting is used to cut the rough parts into pieces. The pieces are in the shape of square plates, and the straightness of the four sides meets the process requirements. S13. After ensuring that the equipment and the pressing mold are normal, carry out the rib pressing test; S14. After rib pressing, the shrinkage change data of the four edges of the square plate workpiece are detected, and the shrinkage change of length and width is recorded as △ L ,△ W ; S15, detecting deformation curves of four edge line segments of the square plate workpiece by laser three-dimensional vision; Step S2, laser compensation preset deformation, numerical control programming; S21. Taking the four corners of the square plate workpiece after the designed rib as the reference value, the rib offset length shrinkage change is designed to be half of the △ from the center point of the square plate workpiece to the four sides outward. L , the width shrinkage change is half△ W , obtain the design values ​​of the four corners of the ribbed square plate workpiece; S22, according to the deformation curves of the four side line segments of the square plate workpiece obtained by the laser three-dimensional visual detection in step S15, and the design values ​​of the four corners of the ribbed square plate workpiece obtained in step S21, the side lines relative to each other are mirror-symmetrically processed to form a laser blanking compensation graph; S23, performing CNC laser programming on the above graphics and cutting and blanking; Step S3, verify compliance of rib pressing; S31. After cutting and blanking, carry out rib pressing process test; adjust the positioning dimensions of the blank and the pressing die to ensure that the center point of the blank is aligned with the upper and lower centers of the pressing die; S32. Under normal process parameters, carry out rib compression test, inspect product dimensions piece by piece, and verify compliance; Step S4: batch production and qualified inspection.

2. The sheet metal rib processing method according to claim 1, characterized in that: In the step S11, the size of the ribbed blank is determined; according to the three-dimensional software simulation analysis, the unfolding sample is calculated and the blanking size is determined, including: Assuming that the metal weight m and density ρ remain unchanged before and after beading, then: V=m÷ρ; (1) S=V÷t; (2) L 理论 =S÷W 理论 ; (3) IN 理论 =S÷L 理论 ; (4) The actual length L and width W of the blank are greater than the theoretical length and width of the product after rib pressing; they are obtained using the following formula: L=L 理论 *K; (5) W=W 理论 *K; (6) Where V is the blank volume, m is the weight of the processed metal, ρ is the density of the processed metal, S is the blank area, t is the blank thickness, L is 理论 W is the theoretical length of the blank, 理论 is the theoretical width of the blank, L is the actual length of the blank, W is the actual width of the blank, and K is the widening coefficient, which is 1.1 to 1.

3.

3. The sheet metal rib processing method according to claim 1, characterized in that: In step S15, the deformation curve of the four edge line segments of the square plate workpiece detected by laser three-dimensional vision is: Through non-contact measurement methods, a 3D laser scanner is used to emit laser beams to quickly collect point cloud data of the square plate workpiece to form a 3D model; Generate accurate 3D digital models by processing point cloud data; Point cloud data processing includes: Data preprocessing: remove noise and align multiple scan data; Point cloud registration: stitching point cloud data from multiple scan positions into a complete model; Feature extraction: Identify and extract geometric features in the point cloud, and extract the edge curve of the embossed workpiece, that is, the deformation curve of the four edge line segments of the square plate workpiece after embossing.

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