A degree compensation numerical control bending machine

Abstract

This utility model discloses a deflection-compensated CNC bending machine, including a bending machine frame. A sliding mechanism is slidably mounted on the bending machine frame, and a driving mechanism for driving the sliding mechanism to move up and down is configured on the bending machine frame. An electrical control system is provided on one side of the bending machine frame. A lower die is mounted on the bending machine frame via a deflection compensation component, and an upper die is mounted on the sliding mechanism via several adjusting clamps. This utility model uses a deflection compensation component to achieve dual compensation through a "static pre-arching + dynamic shape memory alloy compensation" deflection compensation component: the mounting frame is pre-arched according to the commonly used bending force to provide basic static compensation; high-performance shape memory alloys such as NiTiNO generate shrinkage stress of more than 500MPa when heated, which can be independently adjusted according to the real-time bending force to accurately offset the deflection deformation of the lower die and the mounting frame, avoid bending angle deviation, and ensure consistent dimensions of batch processed products.

Description

Technical Field

[0001] This utility model mainly relates to the field of CNC bending machine technology, specifically a deflection compensation CNC bending machine. Background Technology

[0002] In industrial production, CNC bending machines are core equipment for bending sheet metal. Their processing accuracy directly determines the forming quality and assembly adaptability of the product, especially in mass production scenarios, where product dimensional consistency is a key indicator of equipment performance. However, existing CNC bending machines generally face the problem of insufficient processing accuracy due to deflection deformation during actual operation. When the bending machine applies bending force to the sheet metal, the mounting frame supporting the lower die and the lower die itself will undergo elastic deflection deformation due to the force. As the hardness and thickness of the sheet metal increase, the required bending force increases, and the amount of deflection deformation also increases. This deformation causes the working surface of the lower die to be unable to remain flat, resulting in deviations in the bending angle of the sheet metal. This can lead to manual correction or, in severe cases, product scrapping, seriously affecting production efficiency and product qualification rate. To mitigate deflection issues, traditional CNC bending machines employ a static pre-arch design. This involves pre-processing the mounting frame into an arched structure with a fixed curvature to counteract deflection under specific bending forces. However, this approach is only suitable for single-specification sheet metal or fixed bending force scenarios. When processing sheet metal of different materials and thicknesses, leading to variations in bending force, the fixed pre-arch curvature cannot be dynamically adjusted, resulting in a significant decrease in compensation effectiveness and poor versatility. Another approach uses mechanical push rods or hydraulic push rods for dynamic compensation. However, the compensation accuracy of these solutions depends on the displacement control precision of the push rods and is limited by mechanical clearance and response speed, making it difficult to achieve real-time and precise compensation of deflection. Especially during processing with frequent changes in bending force, compensation lag or overcompensation can easily occur, leading to fluctuations in the bending angle. Utility Model Content

[0003] This utility model provides a significantly different solution to the problem of overly simplistic existing technical solutions. It primarily offers a deflection-compensating CNC bending machine to address the issues raised in the background section. Traditional CNC bending machines, relying on static pre-arching designs and mounting frames to fix pre-formed arcs to offset specific bending force deformation, are only suitable for single sheet metal specifications or fixed bending forces. When the sheet metal material or thickness changes, leading to altered bending forces, the compensation effect drops sharply, and versatility is poor. Furthermore, dynamic compensation via mechanical / hydraulic push rods depends on the accuracy of push rod displacement, and is limited by mechanical clearance and response speed, making it difficult to accurately offset deformation in real time. Frequent changes in bending force can easily lead to compensation lag or over-compensation, resulting in fluctuations in the bending angle.

[0004] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: A deflection-compensated CNC bending machine includes a bending machine frame, a sliding mechanism slidably mounted on the bending machine frame, a drive mechanism for driving the sliding mechanism to move up and down on the bending machine frame, and an electrical control system on one side of the bending machine frame. A lower die is mounted on the bending machine frame via a deflection compensation component, and an upper die is mounted on the sliding mechanism via several adjusting clamps. A CNC back gauge mechanism is provided inside the bending machine frame.

[0005] More preferably, the deflection compensation component includes a mounting frame installed on the bending machine frame, a control host on one side of the mounting frame, and several evenly spaced holes on the mounting frame, each hole containing an isolation box; each isolation box contains a high-performance shape memory alloy, each high-performance shape memory alloy is connected to a connecting block, and a support frame is provided on the connecting block; the lower die is installed on the support frame; and a pressure sensor for detecting real-time bending force is provided on the mounting frame, the pressure sensor being electrically connected to the control host.

[0006] More preferably, the sliding mechanism consists of a mounting plate and sliders, the sliders being symmetrically distributed about the vertical center line of the mounting plate, and the bending machine frame being provided with a sliding track adapted to the sliders.

[0007] More preferably, the drive mechanism consists of a hydraulic pump, a proportional valve, a hydraulic cylinder, a servo motor, an encoder, and a hydraulic station. The piston rod of the hydraulic cylinder is connected to the mounting plate, and the drive mechanism is symmetrically distributed about the vertical center line of the mounting plate.

[0008] More preferably, the front end of the bending machine frame is provided with a linear guide rail, and multiple movable brackets are slidably mounted on the linear guide rail.

[0009] More preferably, the CNC back gauge mechanism comprises a servo motor, a ball screw, a guide rail, a stop finger, a bracket, an encoder, a machine base, and a protective cover. The servo motor is connected to the ball screw via a coupling, and the ball screw is connected to the bracket via a nut. The guide rail is mounted on the bracket, and the stop finger is slidably mounted on the guide rail and fixed with screws. The machine base is mounted on the bending machine frame, and both the ball screw and the servo motor are mounted on the machine base, with the bracket slidably connected to the machine base. The encoder is built into the servo motor, and the protective cover covers the exterior of precision components such as the screw and guide rail to prevent the intrusion of metal dust, oil, and other foreign matter.

[0010] Compared with the prior art, the beneficial effects of this utility model are as follows: This CNC bending machine employs a deflection compensation component, which utilizes a dual compensation design of "static pre-arching + dynamic shape memory alloy compensation." The mounting frame features a pre-arched structure based on commonly used bending forces, providing basic static compensation. Simultaneously, high-performance shape memory alloys, such as NiTiO3, generate shrinkage stress exceeding 500MPa when heated. This stress can be independently adjusted according to real-time bending force groups to offset the deflection deformation of the lower die and mounting frame, preventing bending angle deviations caused by die deformation and improving product dimensional consistency during batch processing.

[0011] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0012] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the rear view structure of this utility model; Figure 3 This is a schematic diagram of the full cross-sectional structure of the flexural compensation component of this utility model; Figure 4 In this utility model Figure 3 A magnified structural diagram at point A in the diagram.

[0013] Numbering on the map: 1. Bending machine frame; 2. Sliding mechanism; 3. Drive mechanism; 4. Electrical control system; 5. Linear guide rail; 6. Movable bracket; 7. Deflection compensation component; 701. Mounting bracket; 702. Support frame; 703. Control host; 704. Isolation box; 705. High-performance shape memory alloy; 706. Connecting block; 8. Lower die; 9. Adjusting clamp; 10. Upper die; 11. CNC back gauge mechanism. Detailed Implementation

[0014] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in different forms and is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the disclosure of the utility model more thorough and comprehensive.

[0015] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0016] Please refer to the appendix carefully. Figure 1-4 A deflection-compensated CNC bending machine includes a bending machine frame 1, a sliding mechanism 2 slidably mounted on the bending machine frame 1, a drive mechanism 3 for driving the sliding mechanism 2 to move up and down on the bending machine frame 1, an electrical control system 4 on one side of the bending machine frame 1, a lower die 8 mounted on the bending machine frame 1 via a deflection compensation component 7, an upper die 10 mounted on the sliding mechanism 2 via several adjusting clamps 9, and a CNC back gauge mechanism 11 inside the bending machine frame 1.

[0017] In this embodiment, as Figure 3 and Figure 4 As shown, the deflection compensation component 7 includes a mounting bracket 701 installed on the bending machine frame 1. A control host 703 is provided on one side of the mounting bracket 701. The mounting bracket 701 has several evenly spaced holes, and an isolation box 704 is installed in each hole. Each isolation box 704 has a high-performance shape memory alloy 705 inside. Each high-performance shape memory alloy 705 is connected to a connecting block 706. A support frame 702 is provided on the connecting block 706. The lower mold 8 is installed on the support frame 702. The mounting bracket 701 is provided with a pressure sensor for detecting the real-time bending force. The pressure sensor is electrically connected to the control host 703. The high-performance shape memory alloy 705 can be made of nickel-titanium alloy, with its phase transformation temperature Af point set at 50℃±10℃, recoverable strain not less than 5%, and recoverable stress not less than 500MPa.

[0018] Mounting bracket 701 is made of high-strength, high-modulus alloy steel, and its initial geometry is not completely straight. Instead, it is pre-machined into a precisely calculated, smooth micro-arched shape based on the expected deflection under the most commonly used bending force. This pre-arched shape provides basic, static deflection compensation. When electrically heated, each group of high-performance shape memory alloy 705 is independently controlled, arranged laterally along the worktable, covering the entire compensation area. The groups are electrically insulated from each other. When electrically heated, an austenitic phase transformation occurs, resulting in length contraction and generating huge shrinkage stress (up to 500 MPa or more), thereby performing corresponding deflection compensation. The isolation chamber 704 is made of high-temperature resistant ceramic fiber or high-silica composite material. The control host 703 has a built-in compensation control module, which receives the signal from the pressure sensor and calculates the heating current or heating time required for each group of high-performance shape memory alloy 705 according to the preset bending force compensation mapping model (formula: Δα=k1⋅F+k2⋅σs+k3⋅t+C, where Δα is the angle compensation amount; F is the actual bending force; σs is the material yield strength; t is the sheet thickness; k1, k2, k3 are linear coefficients; C is a constant term). The module then performs pulse width modulation (PWM) control on each group through an independent circuit.

[0019] In this embodiment, as Figure 1 and Figure 2As shown, the sliding mechanism 2 consists of a mounting plate and sliders. The sliders are symmetrically distributed about the vertical centerline of the mounting plate, and the bending machine frame 1 is equipped with sliding tracks adapted to the sliders. The symmetrical distribution of the sliders about the vertical centerline of the mounting plate allows the sliding mechanism 2 to evenly transfer the weight of the mounting plate and the upper die 10 to each slider during its up-and-down movement, avoiding tilting or shaking of the mechanism due to force offset. Combined with the symmetrical drive design of the drive mechanism 3, the lateral force during the sliding process can be further reduced, ensuring that the upper die 10 maintains a stable posture during bending operations and reducing bending accuracy deviations caused by mechanism shaking.

[0020] In this embodiment, as Figure 1 and Figure 2 As shown, the CNC back gauge mechanism 11 consists of a servo motor, a ball screw, a guide rail, a stop finger, a bracket, an encoder, a machine base, and a protective cover. The servo motor is connected to the ball screw via a coupling, and the ball screw is connected to the bracket via a nut. The guide rail is mounted on the bracket, and the stop finger is slidably mounted on the guide rail and fixed with screws.

[0021] The machine base is mounted on the bending machine frame 1. The ball screw and servo motor are both mounted on the machine base, and the bracket is slidably connected to the machine base. The encoder is built into the servo motor, and the protective cover covers the outside of precision components such as the screw and guide rail to prevent metal dust, oil and other foreign objects from entering.

[0022] The material stop is mounted on the guide rail using a combination of sliding installation and screw fixing: the sliding installation design allows for quick adjustment of the material stop's position on the guide rail according to the bending requirements of different sheet materials; the screw fixing ensures that the material stop is stably locked after being adjusted into place, preventing displacement due to vibration during operation.

[0023] The servo motor is directly connected to the ball screw via a coupling. Combined with an encoder built into the servo motor, real-time monitoring and control of the ball screw's rotation angle are achieved. The encoder converts the servo motor's speed and angle signals into electrical signals, which are then fed back to the control system for precise control of the ball screw's feed rate. Simultaneously, the ball screw is stably connected to a bracket via a nut. When the ball screw rotates, it drives the bracket to slide smoothly along the machine base, ultimately achieving high-precision adjustment of the stop finger's position. This reduces the stop positioning error during sheet metal bending and improves the consistency of bending dimensions.

[0024] In this embodiment, as Figure 1 and Figure 2 As shown, the drive mechanism 3 consists of a hydraulic pump, a proportional valve, a hydraulic cylinder, a servo motor, an encoder, and a hydraulic station. The piston rod of the hydraulic cylinder is connected to the mounting plate, and the drive mechanism 3 is symmetrically distributed about the vertical center line of the mounting plate. The servo motor is directly mechanically connected to the hydraulic pump, and the hydraulic pump draws oil from the oil tank of the hydraulic station to generate high-pressure oil.

[0025] High-pressure hydraulic fluid is delivered to a proportional valve (or servo valve) via an oil pipe. The proportional valve acts as the "control switch" of the hydraulic system. The numerical control (NC) system sends command signals to control the opening size and direction of the proportional valve, thereby precisely regulating the flow and direction of the hydraulic fluid entering the hydraulic cylinder.

[0026] Controlled hydraulic fluid pushes the piston rod of the hydraulic cylinder to extend or retract, thereby driving the slider of the bending machine to move up and down to complete the bending action. An encoder is typically mounted at the tail of the servo motor to detect the motor's speed and angle in real time, feeding the signal back to the CNC system to form a closed-loop control of the motor speed. A linear encoder is mounted on the frame, and its signal output is electrically connected to the electrical control system. It can detect the actual position of the slider in real time and feed the position signal back to the CNC system for comparison and correction with the target position, forming a closed-loop control of the slider position.

[0027] It should be noted that the CNC bending machine used in this utility model is a mature existing technology, therefore, the components and control system are not described in detail here.

[0028] In this embodiment, as Figure 1 and Figure 2 As shown, the front end of the bending machine frame 1 is provided with a linear guide rail 5, and multiple movable brackets 6 are slidably mounted on the linear guide rail 5. The linear guide rail 5 provides a stable sliding guide for the multiple movable brackets 6, and the multiple movable brackets 6 can slide flexibly along the linear guide rail 5. By adjusting the position of the movable brackets 6, when processing long workpieces, the middle or end of the workpiece can be reliably supported by adjusting the position of the brackets.

[0029] The specific operating procedure for this utility is as follows: After the equipment is started, the electrical control system 4 first performs a self-check on each core component, including the hydraulic station, servo motor, and encoder of the drive mechanism 3, the servo motor and ball screw of the CNC back gauge mechanism 11, and the control host 703 of the deflection compensation component 7, to ensure that each component is fault-free and properly connected. At the same time, the slider of the sliding mechanism 2 automatically resets to the initial position, and the stop finger of the CNC back gauge mechanism 11 also returns to the reference positioning point, preparing for subsequent operations.

[0030] Subsequently, the operator inputs parameters such as the material, thickness, bending angle, and bending length of the sheet material to be processed through the CNC interface of the electrical control system 4. The system automatically calculates the required bending force, the downward distance of the upper die 10, the blocking position of the CNC back gauge mechanism 11, and the compensation amount of the deflection compensation component 7 based on the parameters. For the CNC back gauge mechanism 11, the system controls its servo motor to start, drives the ball screw to rotate through the coupling, and the nut on the ball screw drives the bracket to slide along the machine base. The encoder built into the servo motor provides real-time feedback of the speed and angle signals, ensuring that the blocking finger moves accurately to the preset position and is then locked in place by screws.

[0031] For the deflection compensation component 7, the control host 703 presets the heating parameters of the high-performance shape memory alloy 705 according to the calculated bending force, and the mounting bracket 701 itself has formed a static foundation compensation based on the micro-arched pre-structure designed for common bending forces, which lays the groundwork for dynamic compensation.

[0032] Next, the operator places the sheet metal into the lower mold 8 and slides the movable bracket 6 along the linear guide rail 5 at the front end of the bending machine frame 1 according to the length of the sheet metal. The bracket is adjusted to the middle or lower end of the sheet metal to form reliable support, preventing the middle of the sheet metal from sagging due to excessive length. This ensures that the sheet metal remains in a horizontal position to reduce positioning errors. At the same time, one end of the sheet metal is aligned with the stop finger of the CNC back gauge mechanism 11, which has been precisely positioned. The stop finger restricts the longitudinal position of the sheet metal, ensuring that the starting position of each bend is consistent, thus guaranteeing the dimensional consistency of batch processing.

[0033] Then, the bending operation begins. The electrical control system 4 sends a bending command to the drive mechanism 3. The servo motor directly drives the hydraulic pump to start. The hydraulic pump draws oil from the hydraulic station tank and generates high-pressure oil. The high-pressure oil is transported to the proportional valve through the oil pipe. The CNC system sends a signal to the proportional valve to precisely control the opening size and direction of the proportional valve, adjust the flow rate and direction of the oil entering the hydraulic cylinder, push the piston rod of the hydraulic cylinder to extend, and then drive the mounting plate of the sliding mechanism 2 to move downward. Since the drive mechanism 3 is symmetrically distributed about the vertical center line of the mounting plate, and the slider of the sliding mechanism 2 is also symmetrically distributed and adapted to the sliding track of the frame, the mounting plate can drive the upper mold 10 to move downward smoothly without tilting or shaking, ensuring that the upper mold 10 and the lower mold 8 are accurately aligned.

[0034] When the upper mold 10 contacts the sheet metal and applies bending force, the lower mold 8 and the mounting bracket 701 are prone to deflection deformation under the bending force. At this time, the deflection compensation component 7 starts dynamic compensation. The control host 703, based on real-time bending force data, groups the high-performance shape memory alloy 705 in the holes of the mounting bracket 701 for heating. Each group is electrically insulated and independently controlled. The high-performance shape memory alloy 705, such as NiTiN, undergoes an austenitic phase transformation when heated, shrinks in length, and generates a shrinkage stress of more than 500MPa. This stress is transmitted to the support frame 702 through the connecting block 706, thereby accurately offsetting the deflection deformation of the lower mold 8. At the same time, the mounting bracket 701 is made of high-strength alloy steel, and its preset pre-arched structure provides static compensation. This works in conjunction with the dynamic compensation to ensure that the mold remains flat during the bending process and to avoid bending angle deviation of the sheet metal due to mold deformation.

[0035] During the bending operation, dual closed-loop control ensures motion accuracy. The encoder at the tail of the servo motor in the drive mechanism 3 detects the motor speed and angle in real time and feeds the signal back to the electrical control system 4, forming a closed-loop control of the motor speed to avoid fluctuations in the hydraulic pump output oil pressure. The key auxiliary component, the grating ruler installed on the frame, directly detects the actual position of the hydraulic cylinder or sliding mechanism 2 and feeds back the high-precision position signal to the system. It is compared and corrected with the preset downward distance to ensure that the downward depth of the upper mold 10 is accurate, thereby ensuring that the bending angle of the sheet metal meets the parameter requirements.

[0036] After bending and forming, the process enters the finishing and resetting stage. The electrical control system 4 sends a reset command to the drive mechanism 3, the proportional valve reverses the direction of the oil, the hydraulic cylinder piston rod retracts, and drives the sliding mechanism 2 and the upper mold 10 to move upward and reset. The operator loosens the fixing screw of the stop finger of the CNC back gauge mechanism 11, slides and adjusts the stop finger, and then takes out the processed plate. During the operation, the protective cover of the CNC back gauge mechanism 11 always covers the ball screw, guide rail and other precision components, preventing the intrusion of metal dust, oil and other foreign objects, and avoiding the wear of components from affecting the positioning accuracy.

[0037] The present invention has been described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A deflection-compensated CNC bending machine, comprising a bending machine frame (1), characterized in that: A sliding mechanism (2) is slidably mounted on the bending machine frame (1). A driving mechanism (3) for driving the sliding mechanism (2) to move up and down is configured on the bending machine frame (1). An electrical control system (4) is provided on one side of the bending machine frame (1). A lower die (8) is mounted on the bending machine frame (1) through a deflection compensation component (7). An upper die (10) is mounted on the sliding mechanism (2) through several adjusting clamps (9). A CNC back gauge mechanism (11) is provided inside the bending machine frame (1).

2. The deflection-compensating CNC bending machine according to claim 1, characterized in that: The deflection compensation component (7) includes a mounting bracket (701) installed on the bending machine frame (1). A control host (703) is provided on one side of the mounting bracket (701). The mounting bracket (701) has several evenly spaced holes, and an isolation box (704) is installed in each hole. Each isolation box (704) is provided with a high-performance shape memory alloy (705). Each high-performance shape memory alloy (705) is connected to a connecting block (706). A support frame (702) is provided on the connecting block (706). The lower mold (8) is installed on the support frame (702). The mounting bracket (701) is provided with a pressure sensor for detecting real-time bending force. The pressure sensor is electrically connected to the control host (703).

3. A deflection-compensating CNC bending machine according to claim 1, characterized in that: The sliding mechanism (2) consists of a mounting plate and a slider. The sliders are symmetrically distributed about the vertical center line of the mounting plate, and the bending machine frame (1) is provided with a sliding track that is compatible with the slider.

4. A deflection-compensating CNC bending machine according to claim 1, characterized in that: The drive mechanism (3) consists of a hydraulic pump, a proportional valve, a hydraulic cylinder, a servo motor, an encoder, and a hydraulic station. The piston rod of the hydraulic cylinder is connected to the mounting plate, and the drive mechanism (3) is symmetrically distributed about the vertical center line of the mounting plate.

5. A deflection-compensating CNC bending machine according to claim 1, characterized in that: The front end of the bending machine frame (1) is provided with a linear guide rail (5), and multiple movable brackets (6) are slidably installed on the linear guide rail (5).

6. A deflection-compensating CNC bending machine according to claim 1, characterized in that: The CNC back gauge mechanism (11) consists of a servo motor, a ball screw, a guide rail, a stop finger, a bracket, an encoder, a machine base, and a protective cover. The servo motor is connected to the ball screw via a coupling, and the ball screw is connected to the bracket via a nut. The guide rail is mounted on the bracket, and the stop finger is slidably mounted on the guide rail and fixed with screws. The machine base is mounted on the bending machine frame (1), and both the ball screw and the servo motor are mounted on the machine base, with the bracket slidably connected to the machine base. The encoder is built into the servo motor, and the protective cover covers the outside of the screw, guide rail, and precision components to prevent metal dust, oil, and foreign matter from entering.

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