Punching machine control method based on complex blanking

Abstract

The invention relates to the technical field of punching machine control, in particular to a punching machine control method based on complex blanking, which comprises the following steps of: dividing a punching part into a plurality of areas according to an initial contact area of a male die, and determining a transition area for a single area so as to determine the qualification of a die gap of a punching machine; a height stability characterization value is determined based on the judgment result that the die gap is qualified so as to adjust the pressure gradient of a punching machine, or the thickness of an equal-height gasket is adjusted according to the root circle radius of burrs on the cut surface based on the judgment result that the die gap is unqualified; determining a fillet curvature mean value based on the adjusted punching process to determine whether the rate gradient of the punching machine is qualified; adjusting a first rate at the initial stage of stamping or a second rate at the middle stage of stamping based on the judgment result that the rate is unqualified; and flaw detection is conducted on the stamped workpiece, and the optimized gradient adjustment coefficient or the rate correction coefficient is determined according to the feather degree. The machining precision of the stamping part is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of stamping machine control, and particularly to a stamping machine control method based on complex blanking. Background Art

[0002] In modern manufacturing, the demand for stamping parts with high precision and high surface quality is more urgent. Especially in the manufacturing of complex-shaped parts such as new energy vehicle battery trays and aerospace structural parts, traditional stamping processes face bottleneck problems of excessive edge burrs and insufficient finish. Complex-shaped blanking (such as multi-angled corners, special-shaped holes, variable cross-section profiles) leads to uneven material flow, resulting in the material strain rate in the corner area exceeding the critical value, triggering the propagation of microcracks, increasing the burr height. At the same time, the local stress at the edge of the complex-profile die reaches more than 800 MPa, resulting in a 40% reduction in the service life of cemented carbide dies. After the edge is passivated, the burr rate increases by 3 to 5 times. The insufficient elongation of high-strength steel during complex blanking leads to the fracture of edge fibers and an increase in the roughness value. Traditional stamping equipment is difficult to meet the requirements of complex blanking due to insufficient rigidity, rough speed control, and lack of dynamic compensation.

[0003] Chinese Patent Application Publication No.: CN101421095A discloses a stamping machine, a control device and a control method of the stamping machine. The stamping machine includes: a motor; a conversion mechanism having a rotating body driven by the motor to rotate and converting the rotational motion into a reciprocating motion; and a slider that reciprocates by being connected to the conversion mechanism. When the motor rotates at a constant command speed, the actual torque of the motor varies with the rotation angle of the rotating body. The control device of the stamping machine includes: an angle detection device that detects the rotation angle of the rotating body; a torque determination device that determines the required motor torque corresponding to the stamping machine characteristics according to the value of the rotation angle input from the angle detection device; and a speed adjustment device that increases the rotation command speed of the motor from the constant command speed when the rotation angle of the rotating body is such that the required motor torque is less than a pre-determined motor torque reference value.

[0004] There are also the following problems in the prior art: In the prior art, there is a lack of real-time detection and dynamic regulation in the stamping process of complex blanking, resulting in insufficient smoothness of the cut surface of complex-shaped stamping parts after stamping and low machining accuracy of the stamping parts. Summary of the Invention

[0005] Therefore, the present invention provides a stamping machine control method based on complex blanking to overcome the problems in the prior art that there is a lack of real-time detection and dynamic regulation in the stamping process of complex blanking, resulting in insufficient smoothness of the cut surface of complex-shaped stamping parts after stamping and low machining accuracy of the stamping parts.

[0006] To achieve the above object, the present invention provides a stamping machine control method based on complex blanking, including: The stamping parts are divided into several regions according to the initial contact area of the punch, and the transition region between the bright zone and the fracture zone of the cut surface is determined for a single said region, so as to determine the qualification of the die clearance of the stamping machine based on the height ratio of the said transition region; Based on the determination result of the qualification of the die clearance, the height stability characterization values of several said transition regions are determined to adjust the pressure gradient of the stamping machine by using the gradient adjustment coefficient, Or, based on the determination result of the unqualified die clearance, the thickness of the equal-height shim at the corresponding position is adjusted according to the root circle radius of the burr on the cut surface; Collect the average value of the fillet curvature of the cut surface, so as to determine the rate gradient of the stamping machine based on the average value of the fillet curvature, judge according to the curvature fluctuation frequency of the fillet, and adjust the first rate in the initial stage of stamping by using the rate adjustment coefficient or adjust the second rate in the middle stage of stamping by using the rate correction coefficient. Or, based on the overall flaw detection results of several workpieces, optimize the gradient adjustment coefficient or the rate correction coefficient according to the featheriness of the crack of the stamping part.

[0007] Further, the process of determining the qualification of the die clearance of the stamping machine according to the said transition region includes: Respectively determine the first preset angle range of the bright zone and the second preset angle range of the fracture zone according to the material parameters of the stamping part; Based on the first preset angle range, determine the first distribution range of the bright zone, and based on the second preset angle range, determine the second distribution range of the fracture zone; Determine the region between the first distribution range and the second distribution range as the transition region, and determine the ratio of the height of the transition region to the total height of the cut surface as the height ratio; Compare the height ratio with the first preset ratio; Based on the comparison result that the height ratio is greater than the first preset ratio, determine that the die clearance of the stamping machine is unqualified; Based on the comparison result that the height ratio is less than or equal to the first preset ratio, determine that the die clearance of the stamping machine is qualified.

[0008] Further, under the condition of determining that the die clearance of the stamping machine is unqualified, the process of adjusting the thickness of the equal-height shim includes: Establish a radius distribution histogram according to the root circle radius of the burr on the cut surface, and connect the midpoint positions of the tops of the rectangles of the radius distribution histogram to establish a radius curve; Coincide the radius curve with the standard curve with the origin of coordinates as the reference; Determine the first ratio of the coincident area to the area enclosed by the standard curve and the coordinate axes, and compare the first ratio with the second preset ratio; Determine to reduce the thickness of the equal-height spacer based on the comparison result that the first ratio is less than the second preset proportion; Wherein, subtract the first ratio from the second preset proportion to obtain a corresponding difference value, and set a number of thickness adjustment coefficients corresponding to the corresponding difference value to reduce the thickness of the equal-height spacer according to the thickness adjustment coefficients.

[0009] Further, under the condition of determining that the die gap is qualified, the process of determining the height stability characterization value of the transition region includes: Taking the transition region of the cut surface corresponding to a single region as the reference region, horizontally extending along the cut surface to close to establish a number of transition rings; Determine the second ratio of the overlapping area of each transition ring to the area of any one transition ring, and determine the maximum value of the second ratio as the height stability characterization value.

[0010] Further, the process of determining whether the pressure center of the stamping die is offset according to the height stability characterization value includes: Compare the height stability characterization value with a preset characterization value; Based on the comparison result that the height stability characterization value is less than the preset characterization value, determine that the pressure center of the stamping die is offset.

[0011] Further, under the condition of determining that the pressure center is offset, the process of adjusting the pressure gradient includes: Subtract the height stability characterization value from the preset characterization value to obtain a characterization difference value; Set a number of gradient adjustment coefficients corresponding to the characterization difference value to reduce the pressure gradient based on the gradient adjustment coefficients.

[0012] Further, the process of determining whether the rate gradient of the stamping machine is qualified according to the average roundness curvature includes: Compare the average roundness curvature with a preset average curvature respectively; Based on the comparison result that the average roundness curvature is greater than the first preset average curvature or less than the second preset average curvature, determine that the rate gradient of the stamping machine is unqualified.

[0013] Further, under the condition of determining that the rate gradient is unqualified, the process of determining to adjust the first rate or the second rate includes: Taking the position of the cut surface corresponding to the end time of the initial stage of stamping as the demarcation point, divide the fillet of the cut surface into an initial fillet and a middle fillet; Respectively determine the corresponding average initial fillet curvature and average middle fillet curvature; Set the rate adjustment coefficient corresponding to the initial fillet curvature mean value to adjust the first rate, and / or set the rate correction coefficient corresponding to the mid-term fillet curvature mean value to adjust the second rate.

[0014] Further, the process of determining and optimizing the gradient adjustment coefficient according to the featheriness of the cracks on the stamping part includes: Compare the featheriness with a preset featheriness; Based on the comparison result that the featheriness is greater than the preset featheriness, determine and optimize the gradient adjustment coefficient; Subtract the preset featheriness from the featheriness to obtain the first difference percentage; Set a number of gradient optimization coefficients corresponding to the first difference percentage to reduce the gradient adjustment coefficient according to the gradient optimization coefficients.

[0015] Further, the process of determining and optimizing the rate correction coefficient according to the featheriness of the cracks on the stamping part includes: Compare the featheriness with a preset featheriness; Based on the comparison result that the featheriness is less than or equal to the preset featheriness, determine and optimize the rate correction coefficient; Subtract the featheriness from the preset featheriness to obtain the second difference percentage; Set a number of rate optimization coefficients corresponding to the second difference percentage to increase the rate correction coefficient according to the rate optimization coefficients.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows. The present invention determines the qualification of the die clearance according to the determination of the height ratio of the transition region of any cross-sectional area. If the height ratio is too large, it means that the die clearance is too large, the crack propagates prematurely, and the material fractures without sufficient plastic deformation, increasing the elastic recovery amount of the material and resulting in a smaller size of the blanking part. If the height ratio is too small, it means that the die clearance is too small, the upper and lower cracks do not coincide, and a secondary shear band is generated, leading to a sudden change in the crack propagation path and causing local deformation. For the unqualified die clearance, ensure the qualification of the die clearance by adjusting the height of the equal-height spacer. For the qualified die clearance, determine the height stability characterization value of the transition region to determine whether the transition region of the cut surface remains within the same position range. If the transition region remains within the same position range, it means that the pressure center and the geometric center do not shift. If it does not remain within the same position range, it means that the pressure center shifts, resulting in an eccentric load, uneven stress on the stamping part, and thus affecting the processing accuracy of the stamping part. And a too large pressure gradient will cause a stronger moment in the high-pressure area, breaking the moment balance and forcing the pressure center to move towards the high-pressure side, and the pressure center deviates from the geometric center, resulting in low processing accuracy of the stamping part. By determining the degree of deviation of the transition region, accurately adjust the pressure gradient to improve the processing accuracy of the stamping part.

[0017] Furthermore, the present invention obtains the average value of the fillet curvature according to the adjusted stamping process. If the average value is too small, it will lead to uneven material flow and tearing in the corner collapse area. If the average value is too large, it will lead to a reduction in the proportion of the bright band and an increase in the slope of the fracture zone, thus affecting the assembly accuracy. A low first rate in the initial stage of stamping will result in a low material flow rate, causing the material to stay at the fillet for a longer time, leading to sufficient relaxation of the elastic deformation part, a decrease in the yield strength, and making the material more likely to flow towards the fillet area, thereby increasing the fillet curvature. An excessively high first rate in the initial stage of stamping will cause a sharp rise in the strain rate at the fillet, an increase in the yield strength of the material and an increase in the flow resistance, making it difficult for the material to fully spread at the fillet and reducing the actual fillet radius. When the second rate in the middle stage of stamping is too low, the flow rate of the material in the fillet area slows down, and the die surface cannot be filled in time, resulting in excessive material accumulation at the fillet and an excessive fillet curvature. When the second rate in the middle stage of stamping is too high, it will cause "overload shear" of the material in the fillet area, resulting in a local strain rate exceeding the material limit, and the material fibers at the fillet being overstretched, reducing the actual curvature radius and thus affecting the processing accuracy of the stamping part. The present invention accurately adjusts the first rate or the second rate by specifically adopting an adjustment coefficient according to the specific situation, thereby further improving the processing accuracy of the stamping part.

[0018] Furthermore, the present invention determines the featheriness of the crack, that is, the degree of crack bifurcation, through the flaw detection result after stamping. The greater the pressure gradient, the faster the stress intensity factor at the crack tip increases, increasing the probability of crack bifurcation. A large difference between the rate in the initial stage of stamping and the rate in the middle stage of stamping will cause the local strain rate of the material to exceed the critical value, increasing the crack propagation rate and also increasing the radial degree of the crack. Therefore, the severity of the crack can be reduced by optimizing the gradient adjustment coefficient or the rate correction coefficient, thereby further improving the processing accuracy of the stamping part. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the cut surface of the stamping part in the embodiment of the present invention; Figure 2 It is a flowchart of the stamping machine control method based on complex blanking in the embodiment of the present invention; Figure 3 It is a flowchart of the qualification of the die clearance in the embodiment of the present invention; Figure 4 It is a flowchart of determining whether the pressure center of the stamping die is offset in the embodiment of the present invention; Figure 5 It is a flowchart of determining whether the rate gradient of the stamping machine is qualified in the embodiment of the present invention; In the figure: 1, fracture zone; 2, transition area; 3, bright band. Detailed Embodiment

[0020] To make the objectives and advantages of the present invention more clear and understandable, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0022] Please refer to Figures 1 - 5 as shown Figure 1 which is a schematic diagram of the cut surface of the stamping part in the embodiment of the present invention; Figure 2 which is a flowchart of the stamping machine control method based on complex blanking in the embodiment of the present invention; Figure 3 which is a flowchart of the qualification of the die clearance in the embodiment of the present invention; Figure 4 which is a flowchart of determining whether the pressure center of the stamping die is offset in the embodiment of the present invention; Figure 5 which is a flowchart of determining whether the rate gradient of the stamping machine is qualified in the embodiment of the present invention.

[0023] The embodiment of the present invention provides a stamping machine control method based on complex blanking, including: Step S1: Divide the stamping part into several regions according to the initial contact area of the punch, and determine the transition region between the bright zone and the fracture zone of the cut surface for a single said region, so as to determine the qualification of the die clearance of the stamping machine based on the height ratio of the said transition region; Step S2: Determine the height stability characterization value of several said transition regions based on the determination result of the qualified die clearance, and use the gradient adjustment coefficient to adjust the pressure gradient of the stamping machine, or, based on the determination result of the unqualified die clearance, adjust the thickness of the equal-height shim at the corresponding position according to the root circle radius of the cut surface burr; Step S3: Collect the average value of the fillet curvature of the cut surface, so as to determine the rate gradient of the stamping machine based on the average value of the fillet curvature, judge according to the curvature fluctuation frequency of the fillet, and adjust the first rate in the initial stage of stamping with the rate adjustment coefficient or adjust the second rate in the middle stage of stamping with the rate correction coefficient, or, based on the overall flaw detection results of several workpieces, determine to optimize the gradient adjustment coefficient or optimize the rate correction coefficient according to the featheriness of the stamping part crack.

[0024] Specifically, according to the initial contact area of the punch, a stamping part with a complex shape is divided into several regions. During the processing of the stamping part, in the initial contact stage between the punch and the stamping part, only local contact with the stamping part occurs, forming several circular contact areas centered on the cutting edge. Taking the center of the circle of the circular contact area as the reference point, magnifying the area of the circular contact area can divide the cut surface into several cut surface regions corresponding to the initial contact area, and through regional division, the positions with large differences in material flow resistance can be accurately located according to the subsequent analysis results.

[0025] Specifically, the pressure gradient is the gradient of the pressure at the center of the die and the pressure at the edge, and the root circle radius of the burr refers to the arc radius of the burr root contour on the cross-section.

[0026] Specifically, the process of determining the qualification of the die clearance of the stamping machine according to the transition region includes: Respectively determining a first preset angle range of the bright zone and a second preset angle range of the fracture zone according to the material parameters of the stamping part; Based on the first preset angle range, determining a first distribution range of the bright zone, and based on the second preset angle range, determining a second distribution range of the fracture zone; Determining the region between the first distribution range and the second distribution range as the transition region, and determining the ratio of the height of the transition region to the total height of the cut surface as the height ratio; Comparing the height ratio with a first preset ratio; Based on the comparison result that the height ratio is greater than the first preset ratio, determining that the die clearance of the stamping machine is unqualified; Based on the comparison result that the height ratio is less than or equal to the first preset ratio, determining that the die clearance of the stamping machine is qualified.

[0027] It can be understood that the preset angle ranges of the bright zone and the fracture zone are determined according to the material plasticity. For example, for materials with an elongation greater than or equal to 30%, such as pure aluminum and mild steel, the first preset angle range of the bright zone is [1°, 3°], and the second preset angle range of the fracture zone is [5°, 8°]. For high-strength steel with an elongation less than 15%, such as Q460, the first preset angle range of the bright zone is [3°, 5°], and the second preset angle range of the fracture zone is [8°, 15°].

[0028] It can be understood that the bright zone is the area formed by the shear deformation of the material near the die edge during the stamping process. Its surface is smooth and perpendicular to the stamping direction. In an ideal state, the bright zone is completely perpendicular to the sheet plane, with an inclination angle of 0°. However, due to die wear or uneven material flow, the bright zone may have a slight inclination; the fracture zone is the area formed by the crack propagation of the material. Its surface is rough and has an inclination angle of 5° - 15° with the sheet surface. The specific angle is determined according to the material parameters. Specifically, according to the angle range, the corresponding distribution ranges of the bright zone and the fracture zone can be determined respectively, and the area between the distribution ranges of the bright zone and the fracture zone is determined as the transition zone.

[0029] Specifically, the value range of the first preset proportion is determined according to the specific material. For example, for high - plasticity materials such as pure aluminum and mild steel, the height proportion range of the transition zone is 10% - 15%. For low - plasticity materials such as stainless steel and high - carbon steel, the height proportion range of the transition zone is 20% - 30%. In the embodiments of the present invention, for high - plasticity materials, that is, materials with an elongation rate greater than or equal to 30%, the first preset proportion is preferably 12%. For low - plasticity materials, that is, materials with an elongation rate less than 15%, the second preset proportion is preferably 25%.

[0030] Specifically, under the condition of determining that the die clearance of the stamping machine is unqualified, the process of adjusting the thickness of the equal - height spacer includes: Establish a radius distribution histogram based on the root - circle radius of the cut - off surface burr, and connect the mid - point positions of the tops of the rectangles of the radius distribution histogram to establish a radius curve; Coincide the radius curve and the standard curve with the coordinate origin as the reference; Determine the first ratio of the coincident area to the area enclosed by the standard curve and the coordinate axes, and compare the first ratio with the second preset proportion; Based on the comparison result that the first ratio is less than the second preset proportion, determine to reduce the thickness of the equal - height spacer; Based on the comparison result that the first ratio is greater than or equal to the second preset proportion, determine that there is no need to adjust the thickness of the equal - height spacer; Among them, subtract the second preset proportion from the first ratio to obtain the corresponding difference, and set several thickness adjustment coefficients corresponding to the corresponding difference to reduce the thickness of the equal - height spacer according to the thickness adjustment coefficients.

[0031] It can be understood that a small root - circle radius of the burr indicates that the root of the burr is sharp, easy to break but prone to residual micro - cracks after removal. A large root - circle radius indicates that the root of the burr is smooth, with high removal efficiency but requires greater cutting force. The standard curve is a curve in which the distribution of the root - circle radius meets the process requirements.

[0032] Specifically, the value range of the second preset ratio is set to [0.7, 0.85], and preferably 0.8 in the embodiments of the present invention.

[0033] Specifically, the excessive height ratio of the transition region is mainly caused by the excessive die gap, which will cause the root radius of the burr to be too large, resulting in a small overlapping area between the radius curve and the standard curve. Therefore, the die gap can be adjusted according to the distribution curve of the root radius of the burr.

[0034] Specifically, subtract the first ratio from the second preset ratio to obtain a ratio difference, and compare the ratio difference with a preset difference; Based on the comparison result that the ratio difference is greater than or equal to the preset difference, determine to reduce the thickness of the equal-height spacer with a first thickness adjustment coefficient; Based on the comparison result that the ratio difference is less than the preset difference, determine to reduce the thickness of the equal-height spacer with a second thickness adjustment coefficient.

[0035] Specifically, the value range of the preset difference is set to [0.02, 0.05], and preferably 0.03 in the embodiments of the present invention; the value range of the first thickness adjustment coefficient is set to [0.85, 0.89], and preferably 0.87 in the embodiments of the present invention; the value range of the second thickness adjustment coefficient is set to [0.9, 0.94], and preferably 0.92 in the embodiments of the present invention.

[0036] Specifically, under the condition of determining that the die gap is qualified, the process of determining the height stability characterization value of the transition region includes: Taking the transition region of the cut surface corresponding to a single region as the reference region, horizontally extend along the cut surface to close to establish several transition rings; Determine the second ratio of the overlapping area of each transition ring to the area of any one transition ring, and determine the maximum value of the second ratio as the height stability characterization value.

[0037] It can be understood that under ideal conditions, extending to close with the transition ring of the transition region corresponding to any divided region as the reference, each ring should be on the same horizontal plane within the same range on the horizontal plane.

[0038] Specifically, the process of determining whether the pressure center of the stamping die is offset according to the height stability characterization value includes: Compare the height stability characterization value with a preset characterization value; Based on the comparison result that the height stability characterization value is less than the preset characterization value, determine that the pressure center of the stamping die is offset; Based on the comparison result that the height stability characterization value is greater than or equal to the preset characterization value, determine that the pressure center of the stamping die is not offset.

[0039] Specifically, the criterion for determining whether the center of pressure shifts is to determine whether the center of pressure coincides with the geometric center. If they coincide, it is determined that there is no shift; if they do not coincide, it is determined that there is a shift. The value range of the preset characterization value is set to [0.6, 0.8], and preferably 0.7 in the embodiments of the present invention.

[0040] Specifically, the process of adjusting the pressure gradient under the condition of determining that the center of pressure shifts includes: Subtracting the preset characterization value from the height stability characterization value to obtain a characterization difference; Setting a number of gradient adjustment coefficients corresponding to the characterization difference to reduce the pressure gradient based on the gradient adjustment coefficients.

[0041] Specifically, comparing the characterization difference with a preset characterization difference; Based on the comparison result that the characterization difference is greater than the preset characterization difference, it is determined to reduce the pressure gradient with a first gradient adjustment coefficient; Based on the comparison result that the characterization difference is less than or equal to the preset characterization difference, it is determined to reduce the pressure gradient with a second gradient adjustment coefficient.

[0042] Specifically, the value range of the preset characterization difference is set to [0.03, 0.06], and preferably 0.04 in the embodiments of the present invention; the value range of the first gradient adjustment coefficient is set to [0.9, 0.92], and preferably 0.91 in the embodiments of the present invention; the value range of the second gradient adjustment coefficient is set to [0.93, 0.96], and preferably 0.94 in the embodiments of the present invention.

[0043] Specifically, the process of determining whether the rate gradient of the stamping machine is qualified according to the average roundness curvature includes: Respectively comparing the average roundness curvature with a preset curvature average; Based on the comparison result that the average roundness curvature is greater than a first preset curvature average or less than a second preset curvature average, it is determined that the rate gradient of the stamping machine is unqualified; Based on the comparison result that the average roundness curvature is less than or equal to the first preset curvature average and greater than or equal to the second preset curvature average, it is determined that the rate gradient of the stamping machine is qualified.

[0044] Specifically, the value ranges of the first preset curvature mean and the second preset curvature mean are determined according to the material type. For example, for pure aluminum with a thickness range of 0.5 mm - 1.5 mm, the value range of the first preset curvature mean is 0.10 mm - 0.15 mm, and the value range of the second preset curvature mean is 0.05 mm - 0.08 mm; for mild steel with a thickness range of 0.8 mm - 2.0 mm, the value range of the first preset curvature mean is 0.15 mm - 0.20 mm, and the value range of the second preset curvature mean is 0.10 mm - 0.12 mm; for high-carbon steel with a thickness range of 2.0 mm - 4.0 mm, the value range of the first preset curvature mean is 0.25 mm - 0.30 mm, and the value range of the second preset curvature mean is 0.18 mm - 0.22 mm.

[0045] Specifically, under the condition of determining that the rate gradient is unqualified, the process of determining to adjust the first rate or the second rate includes: Taking the position of the cut surface corresponding to the end time of the initial stamping stage as the demarcation point, the fillet of the cut surface is divided into an initial fillet and a middle fillet; Respectively determine the corresponding initial fillet curvature mean and middle fillet curvature mean; Respectively set a rate adjustment coefficient corresponding to the initial fillet curvature mean to adjust the first rate, and / or set a rate correction coefficient corresponding to the middle fillet curvature mean to adjust the second rate.

[0046] Specifically, compare the initial fillet curvature mean with the preset curvature mean respectively, and compare the middle fillet curvature mean with the preset curvature mean respectively; Based on the comparison result that the initial fillet curvature mean is greater than the first preset curvature mean, determine to increase the first rate; Based on the comparison result that the middle fillet curvature mean is greater than the first preset curvature mean, determine to increase the second rate; Based on the comparison result that the initial fillet curvature mean is less than the second preset curvature mean, determine to decrease the first rate; Based on the comparison result that the middle fillet curvature mean is less than the second preset curvature mean, determine to decrease the second rate; Among them, a number of rate adjustment coefficients corresponding to the initial difference are set to increase or decrease the first rate according to the rate adjustment coefficients, and a number of rate correction coefficients corresponding to the middle difference are set to increase or decrease the second rate according to the rate correction coefficients. The initial difference is the difference between the average value of the initial fillet curvature and the average value of the first preset curvature or the difference between the average value of the second preset curvature and the average value of the initial fillet curvature. The middle difference is the difference between the average value of the middle fillet curvature and the average value of the first preset curvature or the difference between the average value of the second preset curvature and the average value of the middle fillet curvature.

[0047] Specifically, the average value of the fillet curvature is the average of the fillet curvatures. The fillet profile is directly measured using an optical profiler, and a curvature distribution curve is output. N points are randomly sampled from the curvature distribution curve, and the ratio of the sum of the curvatures of the N points to N is determined as the average value of the fillet curvature. For example, when N is 5 and the curvatures are 0.12 mm, 0.15 mm, 0.13 mm, 0.16 mm, and 0.18 mm respectively, the average value of the fillet curvature is 0.148 mm.

[0048] Specifically, the demarcation point between the initial stage and the middle stage of stamping of the stamping part is determined by the material deformation rate. The stage with an equivalent strain less than 0.2 is determined as the initial stage of stamping, and the stage with an equivalent strain greater than or equal to 0.2 is determined as the middle stage of stamping. In the initial stage of stamping, elastic deformation occurs to generate microcracks. In the middle stage of stamping, plastic deformation occurs, and the upper and lower cracks expand towards each other to form a mixed fracture zone. In the later stage of stamping, the cracks are completely penetrated and fractured, and no further deformation occurs.

[0049] Specifically, under the condition of determining to increase the first rate, the difference between the average value of the initial fillet curvature and the average value of the first preset curvature is calculated to obtain the first initial difference; The first initial difference is compared with the preset initial difference; Based on the comparison result that the first initial difference is greater than the preset initial difference, it is determined to increase the first rate with the first rate adjustment coefficient; Based on the comparison result that the first initial difference is less than or equal to the preset initial difference, it is determined to increase the first rate with the second rate adjustment coefficient.

[0050] Specifically, the value range of the preset initial difference is set to [0.03 mm, 0.04 mm], and preferably 0.03 mm in the embodiment of the present invention; the value range of the first rate adjustment coefficient is set to [1.1, 1.22], and preferably 1.15 in the embodiment of the present invention; the value range of the second rate adjustment coefficient is set to [1.05, 1.09], and preferably 1.05 in the embodiment of the present invention.

[0051] Specifically, under the condition of determining to increase the second rate, the mean value of the mid-term fillet curvature is subtracted from the first preset curvature mean value to obtain a first mid-term difference; The first mid-term difference is compared with a preset mid-term difference; Based on the comparison result that the first mid-term difference is greater than the preset mid-term difference, it is determined to increase the second rate by a first rate correction coefficient; Based on the comparison result that the first mid-term difference is less than or equal to the preset mid-term difference, it is determined to increase the second rate by a second rate correction coefficient.

[0052] Specifically, the value range of the preset mid-term difference is set to [0.01 mm, 0.02 mm], and preferably 0.02 mm in the embodiment of the present invention; the value range of the first rate correction coefficient is set to [1.08, 1.13], and preferably 1.1 in the embodiment of the present invention; the value range of the second rate correction coefficient is set to [1.03, 1.07], and preferably 1.04 in the embodiment of the present invention.

[0053] Specifically, under the condition of determining to decrease the first rate, the second preset curvature mean value is subtracted from the initial fillet curvature mean value to obtain a second initial difference; The second initial difference is compared with a preset initial difference; Based on the comparison result that the second initial difference is greater than the preset initial difference, it is determined to decrease the first rate by a third rate adjustment coefficient; Based on the comparison result that the second initial difference is less than or equal to the preset initial difference, it is determined to decrease the first rate by a fourth rate adjustment coefficient.

[0054] Specifically, the value range of the third rate adjustment coefficient is set to [0.88, 0.92], and preferably 0.89 in the embodiment of the present invention; the value range of the fourth rate adjustment coefficient is set to [0.93, 0.95], and preferably 0.93 in the embodiment of the present invention.

[0055] Specifically, under the condition of determining to decrease the second rate, the second preset curvature mean value is subtracted from the mid-term fillet curvature mean value to obtain a second mid-term difference; The second mid-term difference is compared with a preset mid-term difference; Based on the comparison result that the second mid-term difference is greater than the preset mid-term difference, it is determined to increase the second rate by a third rate correction coefficient; Based on the comparison result that the second mid-term difference is less than or equal to the preset mid-term difference, it is determined to increase the second rate by a fourth rate correction coefficient.

[0056] Specifically, the value range of the third rate correction coefficient is set to [0.89, 0.91], and 0.9 is preferred in the embodiments of the present invention; the value range of the fourth rate correction coefficient is set to [0.92, 0.97], and 0.95 is preferred in the embodiments of the present invention.

[0057] Specifically, the process of optimizing the gradient adjustment coefficient according to the featheriness of the cracks in the stamping parts includes: Comparing the featheriness with a preset featheriness; Determining to optimize the gradient adjustment coefficient based on the comparison result that the featheriness is greater than the preset featheriness; Subtracting the featheriness from the preset featheriness to obtain a first difference percentage; A number of gradient optimization coefficients corresponding to the first difference percentage are set to optimize the gradient adjustment coefficient according to the gradient optimization coefficients.

[0058] Specifically, the featheriness refers to the stripe density of the radial cracks, and the preset featheriness is the average value of the featheriness of the cracks with qualified processing accuracy in the historical processing process. The specific value range is determined according to the material. For example, for pure aluminum with a thickness range of 0.5 mm - 1.5 mm, the value range of the preset featheriness is 3 stripes / mm - 5 stripes / mm, and 4 stripes / mm is preferred in the embodiments of the present invention; for mild steel with a thickness range of 0.8 mm - 2.0 mm, the value range of the preset featheriness is 5 stripes / mm - 10 stripes / mm, and 6 stripes / mm is preferred in the embodiments of the present invention.

[0059] Specifically, comparing the first difference percentage with a preset percentage; Based on the comparison result that the first difference percentage is greater than the preset percentage, determining to reduce the gradient adjustment coefficient with a first gradient optimization coefficient; Based on the comparison result that the first difference percentage is less than or equal to the preset percentage, determining to reduce the gradient adjustment coefficient with a second gradient optimization coefficient.

[0060] Specifically, the value range of the preset percentage is set to [30%, 50%], and 40% is preferred in the embodiments of the present invention; the value range of the first gradient optimization coefficient is set to [0.925, 0.935], and 0.932 is preferred in the embodiments of the present invention; the value range of the second gradient optimization coefficient is set to [0.941, 0.956], and 0.945 is preferred in the embodiments of the present invention.

[0061] Specifically, the process of optimizing the rate correction coefficient according to the featheriness of the cracks in the stamping parts includes: Comparing the featheriness with a preset featheriness; Determine to optimize the rate correction coefficient based on the comparison result that the feather degree is less than or equal to the preset feather degree; Subtract the preset feather degree from the feather degree to obtain a second difference percentage; A number of rate optimization coefficients corresponding to the second difference percentage are set to increase the rate correction coefficient according to the rate optimization coefficients.

[0062] Specifically, compare the second difference percentage with a preset percentage; Based on the comparison result that the second difference percentage is greater than the preset percentage, determine to increase the rate correction coefficient with a first rate optimization coefficient; Based on the comparison result that the second difference percentage is less than or equal to the preset percentage, determine to increase the rate correction coefficient with a second rate optimization coefficient.

[0063] It can be understood that increasing the rate correction coefficient means reducing the rate gradient between the first rate and the second rate.

[0064] Specifically, the value range of the first rate optimization coefficient is set to [1.2, 1.4], and preferably 1.3 in the embodiments of the present invention; the value range of the second rate optimization coefficient is set to [1.01, 1.19], and preferably 1.12 in the embodiments of the present invention.

[0065] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. A stamping machine control method based on complex blanking, characterized in that Including: Dividing the stamping part into several regions according to the initial contact area of the punch, determining the transition region between the bright zone and the fracture zone of the cut surface for a single said region, and determining the qualification of the die clearance of the stamping machine based on the height ratio of the said transition region; Determining the height stability characterization values of several said transition regions based on the determination result of the qualified die clearance to adjust the pressure gradient of the stamping machine using a gradient adjustment coefficient; Or, based on the determination result of the unqualified die clearance, adjusting the thickness of the equal-height shim at the corresponding position according to the root circle radius of the cut surface burr; Collecting the average value of the fillet curvature of the cut surface, determining the rate gradient of the stamping machine based on the average value of the fillet curvature, judging to adjust the first rate at the initial stage of stamping with a rate adjustment coefficient or adjust the second rate at the middle stage of stamping with a rate correction coefficient according to the curvature fluctuation frequency of the fillet, or, based on the overall flaw detection results of several workpieces, determining to optimize the gradient adjustment coefficient or optimize the rate correction coefficient according to the featheriness of the stamping part crack.

2. The stamping machine control method based on complex blanking according to claim 1, characterized in that, The process of determining the qualification of the die clearance of the stamping machine according to the said transition region includes: Respectively determining the first preset angle range of the bright zone and the second preset angle range of the fracture zone according to the material parameters of the stamping part; Determining the first distribution range of the bright zone based on the first preset angle range, and determining the second distribution range of the fracture zone based on the second preset angle range; Determining the region between the first distribution range and the second distribution range as the transition region, and determining the ratio of the height of the transition region to the total height of the cut surface as the height ratio; Comparing the height ratio with a first preset ratio; Based on the comparison result that the height ratio is greater than the first preset ratio, determining that the die clearance of the stamping machine is unqualified; Based on the comparison result that the height ratio is less than or equal to the first preset ratio, determining that the die clearance of the stamping machine is qualified.

3. The stamping machine control method based on complex blanking according to claim 2, characterized in that The process of adjusting the thickness of the equal-height shim under the condition of determining that the die clearance of the stamping machine is unqualified includes: Establishing a radius distribution histogram according to the root circle radius of the cut surface burr, and connecting the midpoint positions of the tops of the rectangles of the radius distribution histogram to establish a radius curve; Coinciding the radius curve with the standard curve with the coordinate origin as the reference; Determining the first ratio of the coincident area to the area enclosed by the standard curve and the coordinate axes, and comparing the first ratio with a second preset ratio; Based on the comparison result that the first ratio is less than the second preset ratio, determining to reduce the thickness of the equal-height shim; Wherein, subtracting the second preset ratio from the first ratio to obtain a corresponding difference value, setting several thickness adjustment coefficients corresponding to the corresponding difference value to reduce the thickness of the equal-height shim according to the thickness adjustment coefficient.

4. The stamping machine control method based on complex blanking according to claim 2, wherein Also including: Under the condition of determining that the die clearance is qualified, determining the height stability characterization value of the transition region, wherein, Taking the transition region of the cut surface corresponding to a single region as the reference region, and horizontally extending along the cut surface to close to establish several transition rings; Determine the second ratio of the overlapping area of each of the transition rings to the area of any one of the transition rings, and determine the maximum value of the second ratio as the height stability characterization value.

5. The stamping machine control method based on complex blanking according to claim 4, wherein, It further includes determining whether the pressure center of the stamping die is offset according to the height stability characterization value, wherein, Compare the height stability characterization value with a preset characterization value; Based on the comparison result that the height stability characterization value is less than the preset characterization value, determine that the pressure center of the stamping die is offset.

6. The stamping machine control method based on complex blanking according to claim 5, characterized in that, It further includes adjusting the pressure gradient under the condition that the pressure center is determined to be offset, wherein, Subtract the height stability characterization value from the preset characterization value to obtain a characterization difference; Set a number of gradient adjustment coefficients corresponding to the characterization difference to reduce the pressure gradient based on the gradient adjustment coefficients.

7. The stamping machine control method based on complex blanking according to claim 6, characterized in that The process of determining whether the rate gradient of the stamping machine is qualified according to the average roundness curvature includes: Compare the average roundness curvature with a preset average curvature respectively; Based on the comparison result that the average roundness curvature is greater than the first preset average curvature or less than the second preset average curvature, determine that the rate gradient of the stamping machine is unqualified.

8. The stamping machine control method based on complex blanking according to claim 7, characterized in that Under the condition that the rate gradient is determined to be unqualified, the process of determining to adjust the first rate or the second rate includes: Taking the position of the cut surface corresponding to the end time of the initial stamping stage as a demarcation point, divide the fillet of the cut surface into an initial fillet and a middle fillet; Determine the corresponding average initial fillet curvature and average middle fillet curvature respectively; Set rate adjustment coefficients corresponding to the average initial fillet curvature to adjust the first rate respectively, and / or set rate correction coefficients corresponding to the average middle fillet curvature to adjust the second rate.

9. The stamping machine control method based on complex blanking according to claim 8, characterized in that, The process of determining to optimize the gradient adjustment coefficient according to the featheriness of the crack of the stamping part includes: Compare the featheriness with a preset featheriness; Based on the comparison result that the featheriness is greater than the preset featheriness, determine to optimize the gradient adjustment coefficient; Subtract the preset featheriness from the featheriness to obtain a first difference percentage; Set a number of gradient optimization coefficients corresponding to the first difference percentage to reduce the gradient adjustment coefficient according to the gradient optimization coefficients.

10. The stamping machine control method based on complex blanking according to claim 8, characterized in that, The process of determining to optimize the rate correction coefficient according to the featheriness of the crack of the stamping part includes: Compare the featheriness with a preset featheriness; Based on the comparison result that the featheriness is less than or equal to the preset featheriness, determine to optimize the rate correction coefficient; Subtract the featheriness from the preset featheriness to obtain a second difference percentage; Set a number of rate optimization coefficients corresponding to the second difference percentage to increase the rate correction coefficient according to the rate optimization coefficients.

Images