A stamping machine control method based on complex blanking

Abstract

The present invention relates to the field of stamping machine control technology, and in particular to a stamping machine control method based on complex blanking, comprising: dividing a stamping part into a plurality of areas according to the initial contact area of a punch, determining a transition area for each of the areas to determine the eligibility of a die gap of the stamping machine; determining a high stability characterization value based on a determination result that the die gap is qualified to adjust the pressure gradient of the stamping machine, or, based on a determination result that the die gap is unqualified, adjusting the thickness of a contour gasket according to the root radius of a burr on a cut surface; determining a mean value of fillet curvature based on the adjusted stamping process to determine whether a rate gradient of the stamping machine is qualified; and adjusting a first rate at the initial stage of stamping or a second rate in the middle stage of stamping based on a determination result that the rate is unqualified; performing flaw detection on a workpiece after stamping, and determining an optimized gradient adjustment coefficient or the rate correction coefficient based on the feather degree. The present invention improves the processing accuracy of stamping parts.

Description

Technical Field

[0001] The present invention relates to the field of punching machine control technology, and in particular to a punching machine control method based on complex blanking. Background Art

[0002] Modern manufacturing is in urgent need of high-precision, high-surface-quality stamping parts, especially in the manufacture of complex-shaped parts such as battery trays for new energy vehicles and aerospace structural components. Traditional stamping processes face bottlenecks such as excessive edge burrs and insufficient surface finish. Complex blanking (e.g., multiple sharp corners, irregular holes, and variable cross-section profiles) leads to uneven material flow, which causes the strain rate in sharp corners to exceed critical values, triggering microcrack propagation and increasing burr height. Simultaneously, local stresses at the cutting edges of complex-contour dies reach over 800 MPa, shortening the life of carbide dies by 40%. The burr rate increases by 3-5 times after edge passivation. The insufficient elongation of high-strength steel during complex blanking leads to edge fiber fracture and increased roughness. Traditional stamping equipment struggles to adapt to complex blanking requirements due to insufficient rigidity, coarse speed control, and a lack of dynamic compensation.

[0003] Chinese patent application publication number: CN101421095A discloses a stamping machine, a control device and a control method for the stamping machine, wherein the stamping machine comprises: a motor; a rotating body driven by the motor to rotate and converting the rotational motion into reciprocating motion; and a slider connected to the conversion mechanism and performing reciprocating motion. When the motor is rotated at a constant command speed, the actual torque of the motor varies with the rotation angle of the rotating body, wherein the control device of the stamping machine comprises: an angle detection device for detecting the rotation angle of the rotating body; a torque determination device for determining the required motor torque corresponding to the characteristics of the stamping machine based on the value of the rotation angle input from the angle detection device; and a speed adjustment device for increasing the rotation command speed of the motor from the constant command speed when the rotation angle of the rotating body is an angle at which the required motor torque is less than a predetermined motor torque reference value.

[0004] The following problems also exist in the existing technology: the existing technology lacks real-time detection and dynamic regulation of the stamping process of complex blanking, which leads to insufficient smoothness of the cut surface of the complex-shaped stamping parts after stamping, resulting in low processing accuracy of the stamping parts. Summary of the Invention

[0005] To this end, the present invention provides a stamping machine control method based on complex blanking, which is used to overcome the problem that the stamping process of complex blanking in the existing technology lacks real-time detection and dynamic regulation, resulting in insufficient smoothness of the cut surface of the complex-shaped stamping parts after stamping, resulting in low processing accuracy of the stamping parts.

[0006] To achieve the above objectives, the present invention provides a punching machine control method based on complex blanking, comprising:

[0007] Dividing the stamped part into several regions according to the initial contact area of the punch, determining the transition area between the bright band and the fracture band of the cut surface for each region, and determining the acceptability of the die clearance of the stamping machine based on the height ratio of the transition area;

[0008] Based on the determination result of the qualified die gap, the height stability characterization values of the transition regions are determined to adjust the pressure gradient of the punching machine using the gradient adjustment coefficient.

[0009] Or, based on the determination result that the mold gap is unqualified, the thickness of the contour gasket at the corresponding position is adjusted according to the root circle radius of the burr on the cut surface;

[0010] The mean value of the fillet curvature of the cut surface is collected to determine the rate gradient of the punching machine based on the mean value of the fillet curvature, and to determine the first rate in the initial stage of stamping to be adjusted by the rate adjustment coefficient or the second rate in the middle stage of stamping to be adjusted by the rate correction coefficient according to the curvature fluctuation frequency of the fillet, or, based on the overall flaw detection results of several workpieces, to determine the optimization of the gradient adjustment coefficient or the optimization of the rate correction coefficient according to the featheriness of the cracks in the stamping parts.

[0011] Furthermore, the process of determining the eligibility of the die clearance of the punching machine according to the transition region includes:

[0012] Determining a first preset angle range of the bright zone and a second preset angle range of the broken zone according to material parameters of the stamping part;

[0013] Determine a first distribution range of the bright band based on the first preset angle range, and determine a second distribution range of the broken band based on the second preset angle range;

[0014] Determine the area between the first distribution range and the second distribution range as a transition area, and determine the ratio of the height of the transition area to the total height of the cross-section as the height ratio;

[0015] Comparing the height ratio with a first preset ratio;

[0016] Determining that the die clearance of the punching machine is unqualified based on a comparison result that the height ratio is greater than the first preset ratio;

[0017] Based on the comparison result that the height ratio is less than or equal to the first preset ratio, it is determined that the die gap of the punching machine is qualified.

[0018] Furthermore, under the condition that the die clearance of the punching machine is determined to be unqualified, the process of adjusting the thickness of the contour gasket includes:

[0019] A radius distribution histogram is established according to the root circle radius of the burr on the cut surface, and a radius curve is established by connecting the midpoint positions of the top ends of the rectangles of the radius distribution histogram;

[0020] Overlapping the radius curve with the standard curve based on the coordinate origin;

[0021] Determining a first ratio of the overlapping area to the area enclosed by the standard curve and the coordinate axis, and comparing the first ratio with a second preset ratio;

[0022] Determining to reduce the thickness of the contour gasket based on a comparison result that the first ratio is less than the second preset ratio;

[0023] The second preset ratio is subtracted from the first ratio to obtain a corresponding difference, and a number of thickness adjustment coefficients corresponding to the corresponding difference are set to reduce the thickness of the contour gasket according to the thickness adjustment coefficients.

[0024] Furthermore, under the condition that the mold gap is determined to be qualified, the process of determining the height stability characterization value of the transition region includes:

[0025] Taking the transition area of the cut surface corresponding to a single area as the reference area, horizontally extending along the cut surface until closed to establish a plurality of transition rings;

[0026] A second ratio of the overlapping area of each of the transition rings to the area of any of the transition rings is determined, and the maximum value of the second ratio is determined as a high stability characterization value.

[0027] Furthermore, the process of determining whether the pressure center of the stamping die is offset according to the height stability characterization value includes:

[0028] comparing the height stability characterization value with a preset characterization value;

[0029] The pressure center offset of the stamping die is determined based on a comparison result that the height stability characterization value is less than the preset characterization value.

[0030] Furthermore, the process of adjusting the pressure gradient under the condition of determining the pressure center offset includes:

[0031] Subtracting the preset characterization value from the high stability characterization value to obtain a characterization difference value;

[0032] A plurality of gradient adjustment coefficients corresponding to the characterizing difference are set to reduce the pressure gradient based on the gradient adjustment coefficients.

[0033] Furthermore, the process of determining whether the rate gradient of the punching machine is qualified according to the mean value of the fillet curvature includes:

[0034] Comparing the mean value of the fillet curvature with the preset mean value of the curvature;

[0035] Based on the comparison result that the rounded corner curvature mean is greater than a first preset curvature mean or less than a second preset curvature mean, it is determined that the velocity gradient of the punching machine is unqualified.

[0036] Furthermore, under the condition that the rate gradient is determined to be unqualified, the process of determining whether to adjust the first rate or the second rate includes:

[0037] Taking the position of the cut surface corresponding to the initial end time of stamping as the dividing point, the fillet of the cut surface is divided into an initial fillet and a mid-term fillet;

[0038] Determine the corresponding initial fillet curvature mean and mid-term fillet curvature mean respectively;

[0039] The rate adjustment coefficient corresponding to the initial rounded corner curvature mean value is set to adjust the first rate, and / or the rate correction coefficient corresponding to the mid-term rounded corner curvature mean value is set to adjust the second rate.

[0040] Furthermore, the process of determining and optimizing the gradient adjustment coefficient according to the featheriness of the stamping crack includes:

[0041] comparing the featheriness with a preset featheriness;

[0042] Determining to optimize the gradient adjustment coefficient based on a comparison result that the feather degree is greater than a preset feather degree;

[0043] subtracting the featheriness from the preset featheriness to obtain a first difference percentage;

[0044] A plurality of gradient optimization coefficients corresponding to the first difference percentage are provided to reduce the gradient adjustment coefficient according to the gradient optimization coefficients.

[0045] Furthermore, the process of determining and optimizing the rate correction coefficient according to the featheriness of the stamping crack includes:

[0046] comparing the featheriness with a preset featheriness;

[0047] Determining to optimize the rate correction coefficient based on a comparison result that the feather degree is less than or equal to a preset feather degree;

[0048] subtracting the preset featheriness from the featheriness to obtain a second difference percentage;

[0049] A plurality of rate optimization coefficients corresponding to the second difference percentage are set to increase the rate correction coefficient according to the rate optimization coefficients.

[0050] Compared with the prior art, the beneficial effect of the present invention is that the present invention judges the eligibility of the mold gap based on the determination of the height ratio of the transition area of any cross-section area. If the height ratio is too large, it means that the mold gap is too large, the crack expands too early, the material is not fully plastically deformed, and breaks, which increases the elastic recovery of the material, resulting in a smaller size of the blank. If the height ratio is too small, it means that the mold gap is too small, the upper and lower cracks do not overlap, and a secondary shear band is generated, resulting in a sudden change in the crack expansion path and causing local deformation. For unqualified mold gaps, the height of the contour gasket is adjusted to ensure the eligibility of the mold gap. For qualified mold gaps, the height stability of the transition area is determined. The characterization value determines whether the transition area of the cut surface remains in the same position range. If the transition area remains in the same position range, it means that the pressure center and the geometric center are not offset. If it does not remain in the same position range, it means that the pressure center is offset, which will cause eccentric loads and uneven force on the stamping parts, thereby affecting the processing accuracy of the stamping parts; and excessive pressure gradient will cause a stronger torque to be generated in the high-pressure area, breaking the torque balance, forcing the pressure center to move toward the high-pressure side, and the pressure center deviates from the geometric center, resulting in low processing accuracy of the stamping parts. By determining the degree of offset in the transition area, the pressure gradient can be accurately adjusted to improve the processing accuracy of the stamping parts.

[0051] Furthermore, the present invention obtains the mean value of the fillet curvature according to the adjusted stamping process. If the mean value is too small, it will lead to uneven material flow and tearing in the collapsed angle area. If the mean value is too large, the proportion of the bright band will be reduced and the slope of the fracture band will increase, thereby affecting the assembly accuracy. A low first rate at the initial stage of stamping will lead to a low material flow rate, causing the material to stay at the fillet for a longer time, resulting in sufficient relaxation of the elastic deformation part, reduced yield strength, and easier flow of the material to the fillet area, thereby increasing the curvature of the fillet; if the first rate at the initial stage of stamping is too high, the strain rate at the fillet will rise sharply, the yield strength of the material will increase, the flow resistance will increase, and the material will be at the fillet. It is difficult to spread fully, and the actual fillet radius is reduced; when the second rate in the middle stage of stamping is too low, the flow speed of the material in the fillet area slows down, and the mold surface cannot be filled in time, resulting in material accumulation at the fillet and the fillet curvature is too large. When the second rate in the middle stage of stamping is too high, the material will produce "overload shear" in the fillet area, resulting in the local strain rate exceeding the material limit, the material fibers at the fillet are excessively stretched, and the actual curvature radius is reduced, thereby affecting the processing accuracy of the stamping parts. The present invention further improves the processing accuracy of the stamping parts by precisely adjusting the first rate or the second rate according to the specific situation.

[0052] Furthermore, the present invention determines the featheriness of the crack, that is, the degree of crack bifurcation, through the flaw detection results after stamping. The greater the pressure gradient, the faster the stress intensity factor at the crack tip increases, which increases the probability of crack bifurcation. A large difference between the initial stamping rate and the mid-stamping rate will cause the local strain rate of the material to exceed the critical value, the crack propagation rate will increase, and the radial degree of the crack will also increase. 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 parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 Schematic diagram of a cross section of a stamping part according to an embodiment of the present invention;

[0054] Figure 2 This is a flow chart of a punching machine control method based on complex blanking according to an embodiment of the present invention;

[0055] Figure 3 This is a flow chart of the qualification of the mold gap according to an embodiment of the present invention;

[0056] Figure 4 A flowchart for determining whether the pressure center of a stamping die is offset according to an embodiment of the present invention;

[0057] Figure 5 A flow chart of determining whether the velocity gradient of a punching machine is qualified according to an embodiment of the present invention;

[0058] In the figure: 1. Fault zone, 2. Transition zone, 3. Bright zone. DETAILED DESCRIPTION

[0059] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0060] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0061] See also Figure 1-Figure 5 As shown, Figure 1 Schematic diagram of a cross section of a stamping part according to an embodiment of the present invention; Figure 2 This is a flow chart of a punching machine control method based on complex blanking according to an embodiment of the present invention; Figure 3 This is a flow chart of the qualification of the mold gap according to an embodiment of the present invention; Figure 4 A flowchart for determining whether the pressure center of a stamping die is offset according to an embodiment of the present invention; Figure 5 This is a flow chart for determining whether the velocity gradient of a punching machine is qualified according to an embodiment of the present invention.

[0062] An embodiment of the present invention provides a stamping machine control method based on complex blanking, comprising:

[0063] Step S1: Divide the stamped part into several regions according to the initial contact area of the punch, determine the transition area between the bright band and the fracture band of the cut surface for each region, and determine the eligibility of the die clearance of the stamping machine based on the height ratio of the transition area;

[0064] Step S2, based on the result of the determination that the mold gap is qualified, determining a plurality of height stability characterization values of the transition region to adjust the pressure gradient of the punching machine using a gradient adjustment coefficient,

[0065] Or, based on the determination result that the mold gap is unqualified, the thickness of the contour gasket at the corresponding position is adjusted according to the root circle radius of the burr on the cut surface;

[0066] Step S3, collecting the mean value of the fillet curvature of the cut surface, determining the rate gradient of the punching machine based on the mean value of the fillet curvature, determining to adjust the first rate in the initial stage of stamping with a rate adjustment coefficient or to adjust the second rate in 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 cracks in the stamping parts.

[0067] Specifically, the complex-shaped stamping parts are divided into several areas according to the initial contact area of the punch. During the processing of the stamping parts, the punch and the stamping parts are only in partial contact with the stamping parts in the initial contact stage, forming several circular contact areas centered on the cutting edge. Taking the center of the circular contact area as the reference point, the area of the circular contact area can be enlarged to divide the cut surface into several cut surface areas corresponding to the initial contact area. The area division can be used to accurately locate the positions with large differences in material flow resistance according to subsequent analysis results.

[0068] Specifically, the pressure gradient is the gradient between the center pressure and the edge pressure of the mold, and the root circle radius of the burr refers to the arc radius of the burr root contour on the cross section.

[0069] Specifically, the process of determining the eligibility of the die clearance of the punching machine according to the transition region includes:

[0070] Determining a first preset angle range of the bright zone and a second preset angle range of the broken zone according to material parameters of the stamping part;

[0071] Determine a first distribution range of the bright band based on the first preset angle range, and determine a second distribution range of the broken band based on the second preset angle range;

[0072] Determine the area between the first distribution range and the second distribution range as a transition area, and determine the ratio of the height of the transition area to the total height of the cross-section as the height ratio;

[0073] Comparing the height ratio with a first preset ratio;

[0074] Determining that the die clearance of the punching machine is unqualified based on a comparison result that the height ratio is greater than the first preset ratio;

[0075] Based on the comparison result that the height ratio is less than or equal to the first preset ratio, it is determined that the die gap of the punching machine is qualified.

[0076] It can be understood that the preset angle range of the bright band and the fracture band is determined according to the plasticity of the material. 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 band is [1°, 3°], and the second preset angle range of the fracture band is [5°, 8°]. For high-strength steel with an elongation less than 15%, such as Q460, the first preset angle range of the bright band is [3°, 5°], and the second preset angle range of the fracture band is [8°, 15°].

[0077] It can be understood that the bright band is the area formed by shear deformation of the material near the die edge during the stamping process. Its surface is smooth and perpendicular to the stamping direction. Under ideal conditions, the bright band is completely perpendicular to the plane of the sheet metal and has an inclination angle of 0°. However, due to die wear or uneven material flow, the bright band may have a slight inclination; the fracture zone is the area formed by the expansion of material cracks. Its surface is rough and has an inclination angle of 5°-15° to the sheet surface. The specific angle is determined according to the material parameters.

[0078] Specifically, the distribution ranges of the corresponding bright band and fracture zone can be determined respectively according to the angle range, and the area between the distribution ranges of the bright band and the fracture zone is determined as the transition area.

[0079] 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 of the transition area is in the range of 10% to 15%, and for low-plasticity materials such as stainless steel and high-carbon steel, the height proportion of the transition area is in the range of 20% to 30%. In the embodiment of the present invention, for high-plasticity materials, that is, materials with an elongation greater than or equal to 30%, the first preset proportion is preferably 12%, and for low-plasticity materials, that is, materials with an elongation less than 15%, the second preset proportion is preferably 25%.

[0080] Specifically, under the condition that the die clearance of the punching machine is determined to be unqualified, the process of adjusting the thickness of the contour gasket includes:

[0081] A radius distribution histogram is established according to the root circle radius of the burr on the cut surface, and a radius curve is established by connecting the midpoint positions of the top ends of the rectangles of the radius distribution histogram;

[0082] Overlapping the radius curve with the standard curve based on the coordinate origin;

[0083] Determining a first ratio of the overlapping area to the area enclosed by the standard curve and the coordinate axis, and comparing the first ratio with a second preset ratio;

[0084] Determining to reduce the thickness of the contour gasket based on a comparison result that the first ratio is less than the second preset ratio;

[0085] Determining that there is no need to adjust the thickness of the contour gasket based on a comparison result that the first ratio is greater than or equal to the second preset ratio;

[0086] The second preset ratio is subtracted from the first ratio to obtain a corresponding difference, and a number of thickness adjustment coefficients corresponding to the corresponding difference are set to reduce the thickness of the contour gasket according to the thickness adjustment coefficients.

[0087] It can be understood that a small root circle radius of the burr indicates that the root of the burr is sharp and easy to break, but microcracks are likely to remain after removal. A large root circle radius indicates that the root of the burr is smooth, the removal efficiency is high but a greater cutting force is required. The standard curve is a curve in which the distribution of the root circle radius meets the process requirements.

[0088] Specifically, the value range of the second preset proportion is set to [0.7, 0.85], and 0.8 is preferred in the embodiment of the present invention.

[0089] Specifically, the excessive height proportion of the transition area is mainly caused by the excessive mold gap, which will cause the root circle radius of the burr to be too large, resulting in a small overlapping area between the radius curve and the standard curve. Therefore, the mold gap can be adjusted according to the distribution curve of the root circle radius of the burr.

[0090] Specifically, subtracting the second preset ratio from the first ratio to obtain a ratio difference, and comparing the ratio difference with the preset difference;

[0091] Determining to reduce the thickness of the contour gasket by a first thickness adjustment coefficient based on a comparison result that the proportion difference is greater than or equal to the preset difference;

[0092] Based on the comparison result that the proportion difference is less than the preset difference, it is determined to reduce the thickness of the contour gasket by a second thickness adjustment coefficient.

[0093] Specifically, the value range of the preset difference is set to [0.02, 0.05], and the preferred embodiment of the present invention is 0.03; the value range of the first thickness adjustment coefficient is set to [0.85, 0.89], and the preferred embodiment of the present invention is 0.87; the value range of the second thickness adjustment coefficient is set to [0.9, 0.94], and the preferred embodiment of the present invention is 0.92.

[0094] Specifically, under the condition that the mold gap is determined to be qualified, the process of determining the height stability characterization value of the transition region includes:

[0095] Taking the transition area of the cut surface corresponding to a single area as the reference area, horizontally extending along the cut surface until closed to establish a plurality of transition rings;

[0096] A second ratio of the overlapping area of each of the transition rings to the area of any of the transition rings is determined, and the maximum value of the second ratio is determined as a high stability characterization value.

[0097] It can be understood that, under ideal conditions, the transition rings of the transition area corresponding to any divided area are extended to be closed based on the transition rings, and the rings should be located on the same horizontal plane within the same range.

[0098] Specifically, the process of determining whether the pressure center of the stamping die is offset according to the height stability characterization value includes:

[0099] comparing the height stability characterization value with a preset characterization value;

[0100] Determining a pressure center offset of the stamping die based on a comparison result that the height stability characterization value is less than the preset characterization value;

[0101] Based on the comparison result that the high stability characterization value is greater than or equal to the preset characterization value, it is determined that the pressure center of the stamping die is not offset.

[0102] Specifically, the criterion for determining whether the pressure center is offset is whether the pressure center is consistent with the geometric center. If they are consistent, it is determined that there is no offset; if they are inconsistent, it is determined that there is offset; the value range of the preset characterization value is set to [0.6, 0.8], and 0.7 is preferred in the embodiment of the present invention.

[0103] Specifically, the process of adjusting the pressure gradient under the condition of determining the pressure center offset includes:

[0104] Subtracting the preset characterization value from the high stability characterization value to obtain a characterization difference value;

[0105] A plurality of gradient adjustment coefficients corresponding to the characterizing difference are set to reduce the pressure gradient based on the gradient adjustment coefficients.

[0106] Specifically, the characterization difference value is compared with a preset characterization difference value;

[0107] Determining to reduce the pressure gradient by a first gradient adjustment coefficient based on a comparison result that the characterization difference is greater than the preset characterization difference;

[0108] Based on a comparison result that the characterizing difference is less than or equal to the preset characterizing difference, it is determined to reduce the pressure gradient by a second gradient adjustment coefficient.

[0109] Specifically, the value range of the preset characterization difference is set to [0.03, 0.06], and the embodiment of the present invention preferably is 0.04; the value range of the first gradient adjustment coefficient is set to [0.9, 0.92], and the embodiment of the present invention preferably is 0.91; the value range of the second gradient adjustment coefficient is set to [0.93, 0.96], and the embodiment of the present invention preferably is 0.94.

[0110] Specifically, the process of determining whether the rate gradient of the punching machine is qualified according to the mean value of the fillet curvature includes:

[0111] Comparing the mean value of the fillet curvature with the preset mean value of the curvature;

[0112] Determining that the velocity gradient of the punching machine is unqualified based on a comparison result that the mean value of the fillet curvature is greater than a first preset mean value of curvature or less than a second preset mean value of curvature;

[0113] The velocity gradient of the punching machine is determined to be qualified based on the comparison result that the rounded corner curvature mean is less than or equal to the first preset curvature mean and greater than or equal to the second preset curvature mean.

[0114] Specifically, the value ranges of the first preset mean curvature and the second preset mean curvature are determined according to the material type. For example, for pure aluminum with a thickness range of 0.5mm-1.5mm, the value range of the first preset mean curvature is 0.10mm-0.15mm, and the value range of the second preset mean curvature is 0.05mm-0.08mm; for mild steel with a thickness range of 0.8mm-2.0mm, the value range of the first preset mean curvature is 0.15mm-0.20mm, and the value range of the second preset mean curvature is 0.10mm-0.12mm; for high carbon steel with a thickness range of 2.0mm-4.0mm, the value range of the first preset mean curvature is 0.25mm-0.30mm, and the value range of the second preset mean curvature is 0.18mm-0.22mm.

[0115] Specifically, 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:

[0116] Taking the position of the cut surface corresponding to the initial end time of stamping as the dividing point, the fillet of the cut surface is divided into an initial fillet and a mid-term fillet;

[0117] Determine the corresponding initial fillet curvature mean and mid-term fillet curvature mean respectively;

[0118] The rate adjustment coefficient corresponding to the initial rounded corner curvature mean value is set to adjust the first rate, and / or the rate correction coefficient corresponding to the mid-term rounded corner curvature mean value is set to adjust the second rate.

[0119] Specifically, the initial rounded corner curvature mean is compared with the preset curvature mean, and the mid-term rounded corner curvature mean is compared with the preset curvature mean;

[0120] Determining to increase the first rate based on a comparison result that the initial rounded corner curvature mean is greater than the first preset curvature mean;

[0121] determining to increase the second rate based on a comparison result that the mid-term fillet curvature mean is greater than the first preset curvature mean;

[0122] Determining to reduce the first rate based on a comparison result that the initial rounded corner curvature mean is less than the second preset curvature mean;

[0123] Determining to reduce the second rate based on a comparison result that the mid-term fillet curvature mean is less than the second preset curvature mean;

[0124] Among them, several rate adjustment coefficients corresponding to the initial difference are set to increase or decrease the first rate according to the rate adjustment coefficient, and several rate correction coefficients corresponding to the mid-term difference are set to increase or decrease the second rate according to the rate correction coefficient. The initial difference is the difference between the initial fillet curvature mean and the first preset curvature mean or the difference between the second preset curvature mean and the initial fillet curvature mean, and the mid-term difference is the difference between the mid-term fillet curvature mean and the first preset curvature mean or the difference between the second preset curvature mean and the mid-term fillet curvature mean.

[0125] Specifically, the mean value of the fillet curvature is the average value of the fillet curvature. The fillet profile is directly measured using an optical profilometer to output a curvature distribution curve. 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 mean value of the fillet curvature. For example, if N is 5, and the curvatures are 0.12mm, 0.15mm, 0.13mm, 0.16mm and 0.18mm respectively, the mean value of the fillet curvature is 0.148mm.

[0126] Specifically, the dividing point between the initial stamping stage and the middle stamping stage of the stamping parts is determined by the material deformation rate. The stage when the equivalent strain is less than 0.2 is determined as the initial stamping stage, and the stage when the equivalent strain is greater than or equal to 0.2 is determined as the middle stamping stage. Elastic deformation occurs in the initial stamping stage to produce microcracks, plastic deformation occurs in the middle stamping stage, and the upper and lower cracks expand toward each other to form a mixed fracture zone. In the late stamping stage, the cracks completely penetrate the fracture and no longer deform.

[0127] Specifically, under the condition of determining to increase the first rate, the initial rounded corner curvature mean value is subtracted from the first preset curvature mean value to obtain a first initial difference value;

[0128] comparing the first initial difference with a preset initial difference;

[0129] determining to increase the first rate by a first rate adjustment coefficient based on a comparison result that the first initial difference is greater than the preset initial difference;

[0130] Based on a 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 by a second rate adjustment coefficient.

[0131] Specifically, the value range of the preset initial difference is set to [0.03mm, 0.04mm], and the embodiment of the present invention preferably prefers 0.03mm; the value range of the first rate adjustment coefficient is set to [1.1, 1.22], and the embodiment of the present invention preferably prefers 1.15; the value range of the second rate adjustment coefficient is set to [1.05, 1.09], and the embodiment of the present invention preferably prefers 1.05.

[0132] Specifically, under the condition of determining to increase the second rate, the mid-term fillet curvature mean value is subtracted from the first preset curvature mean value to obtain a first mid-term difference value;

[0133] comparing the first mid-term difference with a preset mid-term difference;

[0134] determining to increase the second rate by a first rate correction factor based on a comparison result that the first mid-term difference is greater than the preset mid-term difference;

[0135] The second rate is increased by a second rate correction coefficient based on a comparison result that the first mid-term difference is less than or equal to the preset mid-term difference.

[0136] Specifically, the value range of the preset mid-term difference is set to [0.01mm, 0.02mm], and the embodiment of the present invention preferably is 0.02mm; the value range of the first rate correction coefficient is set to [1.08, 1.13], and the embodiment of the present invention preferably is 1.1; the value range of the second rate correction coefficient is set to [1.03, 1.07], and the embodiment of the present invention preferably is 1.04.

[0137] Specifically, under the condition of determining to reduce the first rate, the second preset curvature mean value is subtracted from the initial rounded corner curvature mean value to obtain a second initial difference value;

[0138] comparing the second initial difference with a preset initial difference;

[0139] determining to reduce the first rate by a third rate adjustment coefficient based on a comparison result that the second initial difference is greater than the preset initial difference;

[0140] Based on a comparison result that the second initial difference is less than or equal to the preset initial difference, it is determined to reduce the first rate by a fourth rate adjustment coefficient.

[0141] Specifically, the value range of the third rate adjustment coefficient is set to [0.88, 0.92], and the preferred embodiment of the present invention is 0.89; the value range of the fourth rate adjustment coefficient is set to [0.93, 0.95], and the preferred embodiment of the present invention is 0.93.

[0142] Specifically, under the condition of determining to reduce 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 value;

[0143] comparing the second mid-term difference with a preset mid-term difference;

[0144] determining to increase the second rate by a third rate correction factor based on a comparison result that the second mid-term difference is greater than the preset mid-term difference;

[0145] The second rate is increased by a fourth rate correction factor based on a comparison result that the second mid-term difference is less than or equal to the preset mid-term difference.

[0146] Specifically, the value range of the third rate correction coefficient is set to [0.89, 0.91], and 0.9 is preferred in the embodiment 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 embodiment of the present invention.

[0147] Specifically, the process of determining and optimizing the gradient adjustment coefficient according to the featheriness of the stamping crack includes:

[0148] comparing the featheriness with a preset featheriness;

[0149] Determining to optimize the gradient adjustment coefficient based on a comparison result that the feather degree is greater than a preset feather degree;

[0150] subtracting the featheriness from the preset featheriness to obtain a first difference percentage;

[0151] A plurality of gradient optimization coefficients corresponding to the first difference percentage are provided to optimize the gradient adjustment coefficient according to the gradient optimization coefficients.

[0152] Specifically, the feather degree refers to the density of the stripes of radial cracks. The preset feather degree is the average feather degree of 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 0.5mm-1.5mm, the preset feather degree value range is 3 lines / mm-5 lines / mm, and the embodiment of the present invention preferably has 4 lines / mm; for mild steel with a thickness range of 0.8mm-2.0mm, the preset feather degree value range is 5 lines / mm-10 lines / mm, and the embodiment of the present invention preferably has 6 lines / mm.

[0153] Specifically, comparing the first difference percentage with a preset percentage;

[0154] Determining to reduce the gradient adjustment coefficient by a first gradient optimization coefficient based on a comparison result that the first difference percentage is greater than the preset percentage;

[0155] Based on the comparison result that the first difference percentage is less than or equal to the preset percentage, it is determined to reduce the gradient adjustment coefficient by a second gradient optimization coefficient.

[0156] Specifically, the value range of the preset percentage is set to [30%, 50%], and the embodiment of the present invention preferably is 40%; the value range of the first gradient optimization coefficient is set to [0.925, 0.935], and the embodiment of the present invention preferably is 0.932; the value range of the second gradient optimization coefficient is set to [0.941, 0.956], and the embodiment of the present invention preferably is 0.945.

[0157] Specifically, the process of determining and optimizing the rate correction coefficient according to the featheriness of the stamping crack includes:

[0158] comparing the featheriness with a preset featheriness;

[0159] Determining to optimize the rate correction coefficient based on a comparison result that the feather degree is less than or equal to a preset feather degree;

[0160] subtracting the preset featheriness from the featheriness to obtain a second difference percentage;

[0161] A plurality of rate optimization coefficients corresponding to the second difference percentage are set to increase the rate correction coefficient according to the rate optimization coefficients.

[0162] Specifically, comparing the second difference percentage with a preset percentage;

[0163] determining to increase the rate correction coefficient by the first rate optimization coefficient based on a comparison result that the second difference percentage is greater than the preset percentage;

[0164] Based on the comparison result that the second difference percentage is less than or equal to the preset percentage, it is determined to increase the rate correction coefficient by a second rate optimization coefficient.

[0165] It can be understood that increasing the rate correction coefficient means reducing the rate gradient between the first rate and the second rate.

[0166] Specifically, the value range of the first rate optimization coefficient is set to [1.2, 1.4], and the preferred value in the embodiment of the present invention is 1.3; the value range of the second rate optimization coefficient is set to [1.01, 1.19], and the preferred value in the embodiment of the present invention is 1.12.

[0167] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A punching machine control method based on complex blanking, characterized in that: include: Dividing the stamped part into several regions according to the initial contact area of the punch, determining the transition area between the bright band and the fracture band of the cut surface for each region, and determining the acceptability of the die clearance of the stamping machine based on the height ratio of the transition area; Based on the determination result of the qualified die gap, the height stability characterization values of the transition regions are determined to adjust the pressure gradient of the punching machine using the gradient adjustment coefficient. Or, based on the determination result that the mold gap is unqualified, the thickness of the contour gasket at the corresponding position is adjusted according to the root circle radius of the burr on the cut surface; Collecting the mean value of the fillet curvature of the cut surface, determining the rate gradient of the punching machine based on the mean value of the fillet curvature, determining to adjust the first rate in the initial stage of punching with a rate adjustment coefficient or to adjust the second rate in the middle stage of punching 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 cracks in the stamped parts; The process of determining the eligibility of the die gap of the punch press based on the transition area includes: Determining a first preset angle range of the bright zone and a second preset angle range of the broken zone according to material parameters of the stamping part; Determine a first distribution range of the bright band based on the first preset angle range, and determine a second distribution range of the broken band based on the second preset angle range; Determine the area between the first distribution range and the second distribution range as a transition area, and determine the ratio of the height of the transition area to the total height of the cross-section as the height ratio; Comparing the height ratio with a first preset ratio; Determining that the die clearance of the punching machine is unqualified based on a comparison result that the height ratio is greater than the first preset ratio; Determining that the die clearance of the punching machine is qualified based on a comparison result that the height ratio is less than or equal to the first preset ratio; Under the condition that the die clearance of the punching machine is determined to be unqualified, the process of adjusting the thickness of the contour gasket includes: A radius distribution histogram is established according to the root circle radius of the burr on the cut surface, and a radius curve is established by connecting the midpoint positions of the top ends of the rectangles of the radius distribution histogram; Overlapping the radius curve with the standard curve based on the coordinate origin; Determining a first ratio of the overlapping area to the area enclosed by the standard curve and the coordinate axis, and comparing the first ratio with a second preset ratio; Determining to reduce the thickness of the contour gasket based on a comparison result that the first ratio is less than the second preset ratio; The second preset ratio is subtracted from the first ratio to obtain a corresponding difference, and a number of thickness adjustment coefficients corresponding to the corresponding difference are set to reduce the thickness of the contour gasket according to the thickness adjustment coefficients.

2. The punching machine control method based on complex blanking according to claim 1, characterized in that: Also includes: Under the condition that the mold gap is determined to be qualified, the height stability characterization value of the transition region is determined, wherein, Taking the transition area of the cut surface corresponding to a single area as the reference area, horizontally extending along the cut surface until closed to establish a plurality of transition rings; A second ratio of the overlapping area of each of the transition rings to the area of any of the transition rings is determined, and the maximum value of the second ratio is determined as a high stability characterization value.

3. The punching machine control method based on complex blanking according to claim 2, characterized in that: The method further includes determining whether the pressure center of the stamping die is offset according to the height stability characterization value, wherein: comparing the height stability characterization value with a preset characterization value; The pressure center offset of the stamping die is determined based on a comparison result that the height stability characterization value is less than the preset characterization value.

4. The punching machine control method based on complex blanking according to claim 3 is characterized in that: The method further includes adjusting the pressure gradient under the condition of determining the pressure center offset, wherein: Subtracting the preset characterization value from the high stability characterization value to obtain a characterization difference value; A plurality of gradient adjustment coefficients corresponding to the characterizing difference are set to reduce the pressure gradient based on the gradient adjustment coefficients.

5. The punching machine control method based on complex blanking according to claim 4, characterized in that: The process of determining whether the rate gradient of the punching machine is qualified according to the mean value of the fillet curvature includes: Comparing the mean value of the fillet curvature with the preset mean value of the curvature; Based on the comparison result that the rounded corner curvature mean is greater than a first preset curvature mean or less than a second preset curvature mean, it is determined that the velocity gradient of the punching machine is unqualified.

6. The punching machine control method based on complex blanking according to claim 5, 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 initial end time of stamping as the dividing point, the fillet of the cut surface is divided into an initial fillet and a mid-term fillet; Determine the corresponding initial fillet curvature mean and mid-term fillet curvature mean respectively; The rate adjustment coefficient corresponding to the initial rounded corner curvature mean value is set to adjust the first rate, and / or the rate correction coefficient corresponding to the mid-term rounded corner curvature mean value is set to adjust the second rate.

7. The punching machine control method based on complex blanking according to claim 6, characterized in that: The process of determining and optimizing the gradient adjustment coefficient according to the featheriness of the stamping crack includes: comparing the featheriness with a preset featheriness; Determining to optimize the gradient adjustment coefficient based on a comparison result that the feather degree is greater than a preset feather degree; subtracting the featheriness from the preset featheriness to obtain a first difference percentage; A plurality of gradient optimization coefficients corresponding to the first difference percentage are provided to reduce the gradient adjustment coefficient according to the gradient optimization coefficients.

8. The punching machine control method based on complex blanking according to claim 7, characterized in that: The process of determining and optimizing the rate correction coefficient according to the featheriness of the stamping crack includes: comparing the featheriness with a preset featheriness; Determining to optimize the rate correction coefficient based on a comparison result that the feather degree is less than or equal to a preset feather degree; subtracting the preset featheriness from the featheriness to obtain a second difference percentage; A plurality of rate optimization coefficients corresponding to the second difference percentage are set to increase the rate correction coefficient according to the rate optimization coefficients.

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