Stamping equipment and method for metal workpiece

Abstract

The invention relates to the technical field of metal plate stamping machining, and discloses a stamping device and method for a metal workpiece, and the stamping device comprises a turret punch press and a plate feeding positioning system. The plate feeding and positioning system comprises a feeding driving mechanism, a clamping device, an auxiliary supporting mechanism and a pressing device. The auxiliary supporting mechanism comprises a supporting guide rail, a roller supporting assembly, a receding driving device and a position sensor, the roller supporting assembly comprises a plurality of independent supporting units, and each supporting unit comprises a fixedly-installed lower roller and an upper roller capable of vertically ascending and descending through a lifting support. In the rapid moving stage of the plate, the upper and lower rollers are matched to apply light pressure to the plate, the free span of the thin and long plate is limited within the distance range between the adjacent rollers, and inertial bending deformation is restrained. In the precise positioning stage, the receding driving device drives the lifting support to be lifted upwards, the upper roller is separated from the upper surface of the plate, restraining force interference is eliminated, and the accuracy of the positioning reference is ensured.

Description

Technical Field

[0001] This invention relates to the field of metal sheet stamping technology, and more specifically, to a stamping device for metal workpieces. Background Technology

[0002] In the field of metal stamping, turret punch presses are widely used in multi-station continuous stamping of sheet metal. With the increasing demands for machining accuracy in the manufacturing industry, the precise positioning of sheet metal on turret punch presses has become a crucial factor affecting product quality.

[0003] In existing technologies, the sheet metal servo feeding mechanism achieves precise positioning of the sheet metal through a ball screw pair and a servo motor. After the clamping device clamps the sheet metal, the servo motor drives the ball screw to move the sheet metal quickly to the vicinity of the target position. Then, it decelerates for precise positioning. A laser rangefinder detects the edge position deviation of the sheet metal and feeds it back to the control system for compensation, achieving a positioning accuracy of ±0.01 mm.

[0004] However, when continuously feeding and processing slender sheets, especially those with an aspect ratio exceeding 8:1, the sheet moves rapidly under single-point clamping of the clamping device. The free end of the sheet undergoes inertial bending deformation under acceleration, causing the sheet edge to shift relative to its ideal straight position. The laser rangefinder detects the edge position of the sheet in its bent state, resulting in the positioning reference actually being the curved outline of the sheet. When the subsequent pressing device flattens and locks the sheet, it returns to a straight state, causing a drift in the relative position of the sheet. This causes the actual punching position to deviate from the design coordinates, exceeding the hole tolerance requirements, affecting the assembly accuracy and product quality. Summary of the Invention

[0005] This invention provides a stamping device for metal workpieces, solving the technical problem in related technologies where the positioning reference shifts due to inertial bending deformation of slender plates during rapid movement.

[0006] This invention discloses a stamping equipment for metal workpieces, comprising: a turret punch press and a sheet metal feeding and positioning system; the turret punch press includes a frame, a turret, a hydraulic stamping system, and a control system; the sheet metal feeding and positioning system includes a feeding drive mechanism, a clamping device, an auxiliary support mechanism, and a pressing device; the feeding drive mechanism includes a servo motor, a ball screw pair, and a linear guide rail, the output shaft of the servo motor is connected to one end of the ball screw, the nut seat of the ball screw is fixed on the slide of the linear guide rail, and the clamping device is mounted on the slide; the auxiliary support mechanism includes a support guide rail, a roller support assembly, a retraction drive device, and a position sensor; the support guide rail is fixed to the side of the worktable and extends along the feeding direction; the roller support assembly includes multiple independent support units, each support unit including a lower roller bracket, a lower roller, a lifting bracket, and an upper... The system comprises rollers, a guide device, and a preload spring. The lower roller bracket is arranged parallel to the support rail along the feeding direction. The lower roller is mounted on the lower roller bracket via bearings and securely supports the lower surface of the sheet material. The lifting bracket is connected to the support rail via a guide device, which restricts the lifting bracket to vertical movement only. The upper roller is mounted on the lower end of the lifting bracket via bearings. The upper roller is located above the sheet material channel and is vertically opposite the lower roller. One end of the preload spring presses against the upper surface of the lifting bracket, and the other end presses against the support rail, placing the lifting bracket in a downward-pressing preloaded state. The upper roller applies light pressure to the upper surface of the sheet material under the action of the preload spring. A retraction drive device is connected to the lifting bracket, driving the lifting bracket to rise vertically, causing the upper roller to disengage from the upper surface of the sheet material.

[0007] Furthermore, the guiding device includes a guide shaft and a linear bearing. The guide shaft is arranged in a vertical direction, and the linear bearing is mounted on the lifting bracket and sleeved on the outside of the guide shaft.

[0008] Furthermore, the retraction drive device is a pneumatic push rod, the piston rod of the pneumatic push rod extends vertically upward, and the extended end of the piston rod faces the lower surface of the lifting bracket. When the air passage of the pneumatic push rod is connected to compressed air, the piston rod extends upward to push the lifting bracket to overcome the pressure of the pre-tightening spring and lift it upward, so that the upper roller is lifted off the upper surface of the plate.

[0009] Furthermore, both the upper and lower rollers are made of ceramic material, and are mounted by precision bearings, which are deep groove ball bearings filled with low-viscosity grease.

[0010] Furthermore, the length of the support guide rail is set to 60% to 70% of the total feeding stroke, covering the front section of the feeding stroke, while the rear section is left empty to avoid the positioning detection and stamping processing areas.

[0011] Furthermore, the multiple support units are arranged at equal intervals along the support guide rail, and the gap height formed between the upper roller and the lower roller is slightly greater than the thickness of the plate. When the plate enters between the upper and lower rollers, the lower surface of the plate is supported by the fixed lower roller, and the upper roller applies light pressure to the upper surface of the plate under the action of the pre-tightening spring, forming a constraint between the upper and lower parts.

[0012] Furthermore, the position sensor is a proximity switch, which is installed on the side of the support rail to detect the lifting position of the lifting bracket. When the lifting bracket is in the working position, the proximity switch detects the metal parts of the lifting bracket and outputs a signal to the control system. When the lifting bracket is raised to the retracted position, the proximity switch loses its detection object, and the control system determines that the auxiliary support mechanism is in the retracted state.

[0013] Furthermore, the lower roller bracket is fixedly connected to the workbench by bolts, and the upper surface of the lower roller is flush with or slightly higher than the workbench surface.

[0014] Furthermore, the pressing device includes a pneumatic pressing cylinder and a pressing plate. The piston rod of the pneumatic pressing cylinder is connected to the pressing plate. The pneumatic pressing cylinder is fixedly connected to the frame of the turret punch press. When the pneumatic pressing cylinder drives the pressing plate to press down, it presses the sheet metal onto the worktable.

[0015] This invention discloses a stamping method for metal workpieces, which uses the aforementioned metal workpiece stamping equipment to perform the following steps: Step 1, the clamping device clamps the front area of ​​the sheet metal, the control system confirms that the auxiliary support mechanism is in the working position, and the lifting bracket of the roller support assembly is in a depressed state under the action of the pre-tension spring; Step 2, the servo motor starts to drive the ball screw, the clamping device drives the sheet metal to start moving rapidly, the lower surface of the sheet metal is supported by the fixedly installed lower roller, and the upper roller installed on the lifting bracket applies light pressure to the upper surface of the sheet metal under the action of the pre-tension spring; Step 3, during the rapid feeding process, multiple roller support assemblies provide multi-point support along the length of the sheet metal, the free span of the sheet metal is limited to the distance between adjacent rollers, and the sheet metal maintains a relatively straight state and moves smoothly under the constraint of the upper and lower rollers; Step 4, when the sheet metal moves rapidly... When the plate approaches the target position, the servo system begins to decelerate, and the front end of the plate disengages from the coverage area of ​​the support guide rail. Step five: The control system issues a retraction command, and the retraction drive device drives the lifting bracket upwards. The upper roller disengages from the upper surface of the plate, while the lower roller remains in a fixed position to continue supporting the plate. Step six: The plate enters the precision positioning stage. The laser rangefinder detects the edge position of the plate, and the upper surface of the plate is no longer constrained by the upper roller. Step seven: The control system compensates for the detection deviation. After completing the precision positioning, the clamping device releases the plate. Step eight: The pressing device presses down to lock the plate, while the upper roller remains in the retraction position. The punch descends to complete the stamping process. Step nine: After stamping, the pressing device lifts up, the retraction drive device retracts, and the lifting bracket returns to its working position under the action of the pre-tension spring. The upper roller returns to its position above the plate channel, ready to support the next feeding.

[0016] This invention solves the technical problem of positioning reference offset caused by inertial bending deformation during rapid movement of slender plates in a single-point clamping system by setting a retractable auxiliary support mechanism, and achieves the following technical effects: During the rapid feeding phase, multiple roller support assemblies provide multi-point support along the length of the sheet material. Fixed lower rollers support the lower surface of the sheet, while liftable upper rollers apply light pressure to the upper surface, reducing the free span of the slender sheet from its overall length to the distance between adjacent rollers. According to the cantilever beam bending deformation theory, deflection is proportional to the cube of the free span. By shortening the free span, the bending deformation caused by inertial forces during rapid movement of the sheet is significantly reduced, suppressing the inertial bending deformation of the sheet.

[0017] The rollers are made of ceramic material and are equipped with low-friction precision bearings. The rotational resistance of a single roller is controlled at a low level, and the cumulative resistance of multiple roller support components is small. This provides shape support without affecting the precise control of feeding.

[0018] Before the sheet metal enters the positioning and detection stage, the retraction drive device drives the lifting bracket to rise vertically upwards, causing the upper roller to quickly detach from the upper surface of the sheet metal, while the lower roller remains in a fixed position, thus relieving the upper surface of the sheet metal of constraint. This vertical lifting method results in a simple linear motion trajectory, a short retraction stroke, and a reduced retraction time, improving production cycle time. This retraction mechanism eliminates the interference of the upper roller's contact pressure on the laser rangefinder sensor's detection results, and also eliminates the upper roller's obstruction of the pressing device's clamping of the sheet metal, ensuring the accuracy of the positioning reference and the stability of the stamping process.

[0019] By using upper and lower rollers in a fast feeding phase to constrain inertial bending deformation, and by vertically lifting the upper roller in a precision positioning phase to eliminate the constraint force on the upper surface, the punching position accuracy is improved, thus meeting the assembly accuracy requirements of the workpiece. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a stamping equipment for metal workpieces. Figure 1 ; Figure 2 yes Figure 1 Enlarged view of point A; Figure 3 This is a schematic diagram of the structure of a stamping equipment for metal workpieces. Figure 2 ; Figure 4 This is a schematic diagram of the structure of a stamping equipment for metal workpieces. Figure 3 ; Figure 5 This is a schematic diagram of the structure of a stamping equipment for metal workpieces. Figure 4 ; Figure 6 yes Figure 5 Enlarged view of point A; Detailed Implementation

[0021] In the field of metal workpiece stamping, turret punch presses are widely used in multi-station continuous stamping of sheet metal. Existing sheet metal servo feeding mechanisms achieve precise positioning of the sheet metal through ball screw pairs and servo motors. After the clamping device clamps the sheet metal, the servo motor drives the ball screw to move the sheet metal quickly to the vicinity of the target position. Subsequently, it decelerates for precise positioning. A laser rangefinder sensor detects the edge position deviation of the sheet metal and feeds it back to the control system for compensation, achieving a positioning accuracy of ±0.01mm.

[0022] However, when continuously feeding and processing slender sheets, especially those with an aspect ratio exceeding 8:1, the sheet moves rapidly under single-point clamping of the clamping device. The free end of the sheet undergoes inertial bending deformation under acceleration, causing the sheet edge to shift relative to its ideal straight position. The laser rangefinder detects the edge position of the sheet in its bent state, resulting in the positioning reference actually being the curved outline of the sheet. When the subsequent pressing device flattens and locks the sheet, it returns to a straight state, causing a drift in the relative position of the sheet. This causes the actual punching position to deviate from the design coordinates, exceeding the hole tolerance requirements, affecting the assembly accuracy and product quality.

[0023] The root cause of this technical problem is that the slender sheet lacks morphological constraints in the middle part during rapid movement of single-point clamping. Inertial forces cause the sheet to bend and deform, and the positioning detection system cannot distinguish between the deformation state and the actual position of the sheet, resulting in inconsistency between the positioning reference and the stamping state.

[0024] like Figure 1-6 As shown, according to an embodiment of this invention, a stamping device for metal workpieces is provided. The stamping device for metal workpieces includes a turret punch press and a sheet metal feeding and positioning system.

[0025] The turret punch press comprises a frame 1, a turret 2, a hydraulic stamping system, and a control system. The frame 1 is a welded steel structure, providing overall support and a rigid foundation. The turret 2 is rotatably mounted on the frame 1, and multiple punches are installed on its outer circumference. Automatic switching between different punches is achieved through the intermittent rotation of the turret 2. The hydraulic stamping system includes a hydraulic pump station, hydraulic cylinders, and pressure control valves, driving the punches to perform stamping operations. The control system coordinates the timing of various processes, including turret indexing, sheet metal feeding, and stamping actions.

[0026] The sheet metal feeding and positioning system has auxiliary support mechanisms 3 on both sides of the feeding channel. These mechanisms provide support and constraint during the rapid movement of the sheet metal to suppress inertial bending deformation, and retract and disengage during positioning detection and stamping processes to eliminate interference with precision positioning. The sheet metal feeding and positioning system includes a feeding drive mechanism 8, a clamping device, auxiliary support mechanisms 3, and a pressing device. The feeding drive mechanism 8 consists of a servo motor, a ball screw pair, and a linear guide rail. The output shaft of the servo motor is connected to one end of the ball screw via a coupling, and the nut seat of the ball screw is fixed to the slide of the linear guide rail via a connecting plate. The clamping device is mounted on the connecting plate and reciprocates along the linear guide rail following the slide, realizing the clamping and feeding of the sheet metal.

[0027] The auxiliary support mechanism 3 includes a support guide rail, a roller support assembly, a retraction drive device, and a position sensor. The support guide rail is a rectangular cross-section steel profile, fixed to the side of the worktable, extending along the feeding direction, and its length covers the front section of the feeding stroke. It should be understood that the length of the support guide rail is set to 60% to 70% of the total feeding stroke, with the front section used to support the rapid movement phase of the sheet metal, and the rear section left empty to avoid the positioning detection and stamping processing areas.

[0028] The roller support assembly consists of multiple independent support units arranged at equal intervals along the support guide rail. Each support unit includes a lower roller bracket, a lower roller 5, a lifting bracket 6, an upper roller 4, a guide device 7, bearings, and a preload spring. The lower roller bracket is arranged parallel to the support guide rail along the feeding direction. The lower roller 5 is mounted on the lower roller bracket via precision bearings. The upper surface of the lower roller 5 is flush with or slightly higher than the worktable surface and can rotate freely around a horizontal axis to support the lower surface of the sheet material. Furthermore, the lower roller bracket is bolted to the worktable. The lifting bracket 6 is connected to the support guide rail via the guide device 7, which consists of a guide shaft and a linear bearing. The guide shaft is vertically oriented, and the linear bearing is mounted on the lifting bracket 6 and sleeved on the outside of the guide shaft, restricting the lifting bracket 6 to move only vertically. The upper roller 4 is mounted on the lower end of the lifting bracket 6 via precision bearings. The upper roller 4 is located above the sheet material channel and is vertically opposite the lower roller 5, forming a gap between them for sheet material passage. The gap height is slightly greater than the sheet material thickness. Both the upper and lower rollers are made of ceramic material, with a smooth surface and high hardness, allowing them to rotate freely around a horizontal axis. The pre-tension spring is a compression spring, sleeved on the guide shaft, with its lower end pressing against the upper surface of the lifting bracket 6 and its upper end pressing against the support guide rail, so that the lifting bracket 6 is in a downward-pushing pre-tensioned state. When the plate enters between the upper and lower rollers, the lower surface of the plate is supported by the fixed lower roller 5, while the upper roller 4 applies slight pressure to the upper surface of the plate under the action of the pre-tension spring, forming a gentle constraint between the upper and lower rollers.

[0029] In some embodiments, the spacing between the support units along the support rail is 150 to 200 millimeters. This spacing setting ensures that during rapid movement of the slender plate, the free span of the plate is limited to the distance between two adjacent support units, which is significantly smaller than the overall length of the plate.

[0030] In some embodiments, the preload of the preload spring is set to apply a light pressure of two to three Newtons to the sheet metal on each roller. This pressure serves only to guide and prevent the sheet metal from bending significantly, without affecting the free movement of the sheet metal.

[0031] Furthermore, in order to reduce the resistance of the rollers to the movement of the sheet metal, the roller bearings are deep groove ball bearings, and the bearings are filled with low-viscosity grease, so that the rotational resistance of a single roller is less than 0.5 Newtons.

[0032] The retraction drive is a pneumatic push rod, with its piston rod extending vertically upwards. Furthermore, the pneumatic push rod is fixed to the worktable via a mounting base, with the extended end of the piston rod facing the lower surface of the lifting bracket 6. When compressed air is connected to the pneumatic push rod, the piston rod extends upwards, pushing the lifting bracket 6 upwards against the pressure of the pre-tension spring, causing the upper roller 4 to detach from the upper surface of the sheet material. The retraction height is five to ten millimeters, at which point the sheet material continues to be supported by the fixed lower roller 5 or falls naturally onto the worktable. When the pneumatic push rod's air path is disconnected, the piston rod retracts under the pressure of the pre-tension spring, the lifting bracket 6 moves downwards to return to its working position, and the upper roller 4 returns to the position above the sheet material channel, lightly contacting the sheet material. The lower roller 5 remains stationary throughout the entire process.

[0033] In some embodiments, the pneumatic push rod is a double-acting cylinder with two air circuits connected to the control air circuit respectively. The piston rod can be quickly extended and retracted by switching the air circuits through a solenoid valve. Since the retraction stroke is only five to ten millimeters, the retraction time can be controlled within 0.1 to 0.2 seconds.

[0034] The position sensor is a proximity switch, installed on the side of the support rail, to detect the lifting position of the lifting bracket 6. When the lifting bracket 6 is in the working position, the proximity switch detects the metal parts of the lifting bracket 6 and outputs a signal. The control system receives this signal and determines that the auxiliary support mechanism 3 is in the working state. When the lifting bracket 6 is raised to the retracted position, the proximity switch loses its detection object, and the control system determines that the auxiliary support mechanism 3 is in the retracted state.

[0035] The pressing device includes a pneumatic pressing cylinder and a pressing plate, with its piston rod connected to the pressing plate. Furthermore, the pneumatic pressing cylinder is fixedly connected to the frame 1 of the turret punch press via a flange and bolts. When stamping is required, the pneumatic pressing cylinder drives the pressing plate downwards, pressing the sheet metal firmly onto the worktable surface, providing reaction force support for the downward stamping of the punch.

[0036] It should be noted that the auxiliary support mechanism 3 and the feeding drive mechanism 8 are coordinated through a control system. During the rapid feeding stage of the sheet material, the auxiliary support mechanism 3 is in the working position, with the fixed lower roller 5 supporting the lower surface of the sheet material and the liftable upper roller 4 applying light pressure to the upper surface of the sheet material to limit bending deformation. Before the sheet material enters the precision positioning stage, the auxiliary support mechanism 3 performs a retraction action, with the upper roller 4 rising upwards and disengaging from the upper surface of the sheet material, while the lower roller 5 remains fixed, so that the upper surface of the sheet material is no longer subject to constraint. At this time, the laser range sensor detects the edge of the sheet material, and the detection process is not affected by the contact force of the upper roller 4.

[0037] The working principle of the metal workpiece stamping equipment is as follows: After the sheet metal is clamped by the clamping device, the servo motor starts and drives the sheet metal to move rapidly along the feeding direction. During the movement, the lower surface of the sheet metal is supported by the fixedly installed lower roller 5, and the upper roller 4 installed on the lifting bracket 6 applies light pressure to the upper surface of the sheet metal under the action of the pre-tension spring. Multiple support units provide multi-point support along the length of the sheet metal, limiting the free cantilever length of the sheet metal to the span range between adjacent support units. According to the bending deformation theory of cantilever beams, the deflection of the beam is proportional to the cube of the free cantilever length. By shortening the free span, the bending deformation of the sheet metal under the action of inertial force is significantly reduced. When the sheet metal moves rapidly to the vicinity of the target position, the front end of the sheet metal has already left the coverage area of ​​the support guide rail. At the same time, the control system issues a retraction command, and the pneumatic push rod drives the lifting bracket 6 to lift upward. The upper roller 4 lifts upward from the upper surface of the sheet metal by 5 to 10 millimeters within 0.1 to 0.2 seconds, while the lower roller 5 remains in a fixed position to continue supporting the sheet metal or the sheet metal falls naturally onto the worktable. At this point, the sheet metal enters the precision positioning stage. The laser rangefinder detects the edge position of the sheet metal. Since the upper roller 4 has retracted, the upper surface of the sheet metal is not subject to any constraint. The position of the sheet metal is controlled only by the feeding drive mechanism 8 and the positioning reference, and the detection result is not affected by the contact force of the rollers. After precision positioning is completed, the pressing device presses down to lock the sheet metal, and the punch moves down to complete the stamping process. Throughout the process, the upper roller 4 remains in a retracted state, and the lower roller 5 remains in a fixed position, without causing any interference to the sheet metal.

[0038] The steps to be performed; According to an embodiment of this invention, the stamping equipment for the metal workpiece performs the following steps during operation: Step 1: The board is fed into the feeding drive mechanism 8 by the feeding device. The clamping device clamps the front area of ​​the board with a set pressure. The control system confirms that the auxiliary support mechanism 3 is in the working position through the position sensor. The lifting bracket 6 of the roller support assembly is in the downward state under the action of the pre-tightening spring. The upper roller 4 is in the position above the board channel, and the lower roller 5 is fixed at the same level or slightly higher than the worktable.

[0039] Step 2: The servo motor starts to drive the ball screw, and the clamping device drives the plate to move quickly. The lower surface of the plate is supported by the fixedly installed lower roller 5, and the upper roller 4 installed on the lifting bracket 6 applies light pressure to the upper surface of the plate under the action of the pre-tightening spring, forming a constraint between the upper and lower parts.

[0040] Step 3: During the rapid feeding process, multiple roller support components provide multi-point support along the length of the plate. The free span of the plate is limited to the distance between adjacent rollers. Under the constraint of the upper and lower rollers, the plate moves smoothly in a relatively straight state. The rollers rotate synchronously with the plate, and the rotational resistance of a single roller is less than 0.5 Newtons.

[0041] Step 4: When the board moves quickly to the vicinity of the target position, the servo system begins to decelerate. At this time, the front end of the board has left the coverage area of ​​the support guide rail, and the board enters the area without the constraint of the upper roller 4.

[0042] Step 5: Simultaneously, the control system issues a retraction command, the pneumatic push rod quickly extends to push the lifting bracket 6 upward, the upper roller 4 detaches from the upper surface of the board by 5 to 10 millimeters within 0.1 to 0.2 seconds, and the lower roller 5 remains in a fixed position to continue supporting the board or the board falls naturally onto the worktable.

[0043] Step six: The board enters the precision positioning stage and approaches the fixed stop pin. The servo system makes fine adjustments, and the laser rangefinder detects the edge position of the board. At this time, the upper surface of the board is not constrained by the upper roller 4, and the detected position is completely controlled by the feeding drive mechanism 8.

[0044] Step 7: The control system compensates for the detection deviation and, after completing the precise positioning, the clamping device releases the plate.

[0045] Step 8: The pressing device presses down to lock the sheet metal. At this time, the upper roller 4 is still in the retracted position, and the pressing plate can completely press the sheet metal. The punch moves down to complete the stamping process.

[0046] Step 9: After stamping is completed, the pressing device is raised, and the sheet metal is ready for the next feeding step. The pneumatic push rod retracts, the lifting bracket 6 returns to the working position under the action of the pre-tightening spring, the upper roller 4 returns to the position above the sheet metal channel, and the lower roller 5 remains in a fixed position, ready to support the next feeding.

[0047] In some embodiments, step three further includes: the control system monitors the cumulative resistance of multiple roller support components, and when the cumulative resistance is less than five Newtons, it is determined that the roller support components are operating normally and do not affect the servo positioning accuracy.

[0048] In some embodiments, step five further includes: after the position sensor detects that the lifting bracket 6 has been raised to the position, it outputs a confirmation signal to the control system. The control system only allows the laser rangefinder to start detection after receiving the confirmation signal, ensuring that the upper roller 4 has completely detached from the upper surface of the plate during the detection process.

[0049] The metal workpiece stamping equipment provided in this embodiment achieves the technical effect of completely eliminating the morphological constraints during the rapid movement stage of the sheet metal and the upper surface constraints during the precision positioning stage by setting a retractable auxiliary support mechanism 3 in the sheet metal feeding and positioning system.

[0050] During the rapid feeding phase, multiple roller support assemblies provide multi-point support along the length of the sheet material. The fixedly installed lower roller 5 supports the lower surface of the sheet material, while the upper roller 4, mounted on the lifting bracket 6, applies light pressure to the upper surface, reducing the free span of the slender sheet material from its overall length to the distance between adjacent rollers. According to the cantilever beam bending deformation theory, deflection is proportional to the cube of the free span. When the free span is shortened to one-tenth of its original value, the bending deflection decreases to one-thousandth of its original value. This mechanism overcomes the problem of excessively long free cantilever in slender sheet materials under single-point clamping conditions, reducing the bending deformation caused by inertial forces during rapid movement from 0.15 mm to below 0.015 mm, significantly suppressing inertial bending deformation.

[0051] The rollers are made of ceramic material and paired with low-friction precision bearings. The rotational resistance of a single roller is controlled to within 0.5 Newtons, and the cumulative resistance of multiple roller support components is less than 5 Newtons, which is negligible compared to the driving force of the servo motor. The combination of ceramic rollers and low-friction precision bearings overcomes the factor that introduces additional frictional resistance into the support mechanism, affecting positioning accuracy. It provides shape support without affecting the precise control of feeding.

[0052] Before the sheet metal enters the positioning and detection stage, the retraction drive device drives the lifting bracket 6 to rise vertically upwards, causing the upper roller 4 to quickly disengage from the upper surface of the sheet metal by five to ten millimeters, while the lower roller 5 remains in a fixed position, thus removing the constraint force from the upper surface of the sheet metal. This vertical lifting method replaces the swinging method, resulting in a simple linear motion trajectory, short retraction stroke, and a simple and reliable mechanism. Because the retraction stroke is only five to ten millimeters, the retraction time is shortened to within 0.1 to 0.2 seconds, significantly faster than the 0.3 seconds of the swinging method, thus improving the production cycle time. The retraction mechanism, where the lifting bracket is raised vertically upwards by the retraction drive device, overcomes the interference of the upper roller 4's contact pressure on the laser rangefinder sensor's detection results. It also overcomes the obstruction of the upper roller 4 from the pressing device's clamping of the sheet metal, ensuring that the upper surface of the sheet metal is not affected by any constraint force during laser rangefinder detection and pressing, thus ensuring the accuracy of the positioning reference and the stability of the stamping state. Since the lower roller 5 is fixedly installed and does not participate in the retraction action, the retraction drive device only needs to overcome the pressure of the preload spring to achieve the rapid disengagement of the upper roller 4, which simplifies the design of the retraction mechanism and improves the reliability of the retraction action.

[0053] By using upper and lower rollers in conjunction to constrain and suppress inertial bending deformation during the rapid feeding stage, and by vertically lifting the upper roller 4 during the precision positioning stage to eliminate the constraint force on the upper surface, this implementation method completely solves the problem of positioning reference offset caused by inertial bending deformation when slender plates are clamped and moved rapidly at a single point. This improves the punching position accuracy from a deviation of 0.1-2 mm to within a tolerance range of 0.05 mm, thus meeting the assembly accuracy requirements of the workpiece.

[0054] In addition, the auxiliary support mechanism 3 adopts a modular design, and the support units can be flexibly configured according to different plate sizes and processing requirements. The length of the support guide rail and the number of support units can be adjusted according to the feeding stroke, which has good adaptability and expandability.

Claims

1. A stamping device for metal workpieces, characterized in that, include: Turret punch press and sheet metal feeding and positioning system; The turret punch press includes a frame, a turret, a hydraulic stamping system, and a control system; The sheet material feeding and positioning system includes a feeding drive mechanism, a clamping device, an auxiliary support mechanism, and a pressing device. The feeding drive mechanism includes a servo motor, a ball screw pair, and a linear guide. The output shaft of the servo motor is connected to one end of the ball screw. The nut seat of the ball screw is fixed on the slide of the linear guide. The clamping device is installed on the slide. The auxiliary support mechanism includes a support rail, a roller support assembly, a retraction drive device, and a position sensor; The support guide rail is fixed to the side of the workbench and extends along the feeding direction; The roller support assembly includes multiple independent support units, each support unit including a lower roller bracket, a lower roller, a lifting bracket, an upper roller, a guide device, and a preload spring; The lower roller bracket is arranged parallel to the support rail along the feeding direction. The lower roller is mounted on the lower roller bracket through bearings, and the lower roller fixes and supports the lower surface of the plate. The lifting support is connected to the support rail via a guide device, which restricts the lifting support to move only vertically up and down. The upper roller is mounted on the lower end of the lifting bracket via a bearing. The upper roller is located above the plate channel and is arranged opposite to the lower roller in the vertical direction. One end of the pre-tension spring presses against the upper surface of the lifting bracket, and the other end presses against the support guide rail, so that the lifting bracket is in a downward-pushing pre-tensioned state. The upper roller applies light pressure to the upper surface of the plate under the action of the pre-tension spring. The retraction drive device is connected to the lifting bracket and drives the lifting bracket to rise vertically, causing the upper roller to detach from the upper surface of the plate.

2. The stamping equipment for metal workpieces according to claim 1, characterized in that, The guiding device includes a guide shaft and a linear bearing. The guide shaft is arranged in a vertical direction, and the linear bearing is mounted on the lifting bracket and sleeved on the outside of the guide shaft.

3. The stamping equipment for metal workpieces according to claim 1, characterized in that, The retraction drive device is a pneumatic push rod. The piston rod of the pneumatic push rod extends vertically upward, and the extended end of the piston rod faces the lower surface of the lifting bracket. When the air passage of the pneumatic push rod is connected to compressed air, the piston rod extends upward and pushes the lifting bracket to overcome the pressure of the pre-tightening spring and lift it upward, so that the upper roller is lifted off the upper surface of the plate.

4. The stamping equipment for metal workpieces according to claim 1, characterized in that, Both the upper and lower rollers are made of ceramic material and are mounted by precision bearings, which are deep groove ball bearings filled with low-viscosity grease.

5. The stamping equipment for metal workpieces according to claim 1, characterized in that, The length of the support guide rail is set to 60% to 70% of the total feeding stroke, covering the front section of the feeding stroke, while the rear section is left empty to avoid the positioning detection and stamping processing areas.

6. The stamping equipment for metal workpieces according to claim 1, characterized in that, The multiple support units are arranged at equal intervals along the support guide rail. The gap between the upper roller and the lower roller is slightly greater than the thickness of the plate. When the plate enters between the upper and lower rollers, the lower surface of the plate is supported by the fixed lower roller, and the upper roller applies light pressure to the upper surface of the plate under the action of the pre-tightening spring, forming a constraint between the upper and lower parts.

7. The stamping equipment for metal workpieces according to claim 1, characterized in that, The position sensor is a proximity switch, which is installed on the side of the support rail to detect the lifting position of the lifting bracket. When the lifting bracket is in the working position, the proximity switch detects the metal parts of the lifting bracket and outputs a signal to the control system. When the lifting bracket is raised to the retracted position, the proximity switch loses its detection object, and the control system determines that the auxiliary support mechanism is in the retracted state.

8. The stamping equipment for metal workpieces according to claim 1, characterized in that, The lower roller bracket is fixedly connected to the workbench by bolts, and the upper surface of the lower roller is flush with or slightly higher than the workbench surface.

9. The stamping equipment for metal workpieces according to claim 1, characterized in that, The pressing device includes a pneumatic pressing cylinder and a pressing plate. The piston rod of the pneumatic pressing cylinder is connected to the pressing plate. The pneumatic pressing cylinder is fixedly connected to the frame of the turret punch press. When the pneumatic pressing cylinder drives the pressing plate to press down, it presses the plate onto the worktable.

10. A stamping method for a metal workpiece, characterized in that, The following steps are performed using the stamping equipment for the metal workpiece according to any one of claims 1 to 9: Step 1: The clamping device clamps the front area of ​​the plate, the control system confirms that the auxiliary support mechanism is in the working position, and the lifting bracket of the roller support assembly is in the downward state under the action of the pre-tightening spring. Step 2: The servo motor starts to drive the ball screw, and the clamping device drives the plate to move quickly. The lower surface of the plate is supported by the fixed lower roller, and the upper roller installed on the lifting bracket applies light pressure to the upper surface of the plate under the action of the pre-tightening spring. Step 3: During the rapid feeding process, multiple roller support components provide multi-point support along the length of the plate. The free span of the plate is restricted to the distance between adjacent rollers. Under the combined constraint of the upper and lower rollers, the plate maintains a relatively straight state and moves smoothly. Step 4: When the board moves rapidly to the vicinity of the target position, the servo system begins to decelerate, and the front end of the board leaves the coverage area of ​​the support guide rail. Step 5: The control system issues a retraction command, and the retraction drive device drives the lifting bracket to rise upward. The upper roller moves upward and detaches from the upper surface of the board, while the lower roller remains in a fixed position to continue supporting the board. Step six: The board enters the precision positioning stage. The laser rangefinder detects the edge position of the board, and the upper surface of the board is no longer constrained by the upper roller. Step 7: The control system compensates for the detection deviation and, after completing the precise positioning, the clamping device releases the plate. Step 8: The pressing device presses down to lock the sheet metal, while the upper roller remains in the retracted position, and the punch moves downward to complete the stamping process; Step nine: After stamping is completed, the pressing device is raised, the retraction drive device retracts, the lifting bracket returns to the working position under the action of the pre-tightening spring, and the upper roller returns to the position above the plate channel, ready to support the next feeding.

Images