A three-dimensional free-form forming device and method based on induction heating and quenching

Abstract

The present invention relates to the field of free bending forming technology, and specifically discloses three-dimensional free forming equipment and methods based on induction heating and quenching. In the six-axis free bending forming technical equipment, the introduction of induction heating modules and quenching heat treatment modules has brought a major innovation to the production process. Through the integrated induction heating device, the profile or pipe components are quickly heated, which effectively reduces the deformation resistance of the material and significantly enhances the forming plasticity of the material. Combined with the six-axis free bending equipment's ability to finely control multiple degrees of freedom, the outlet of the bending die is equipped with an annular quenching device, which enables us to perform cooling treatment immediately after the component is formed. This process ensures that the finished component has a higher level of strength and hardness. This advanced free bending system that integrates induction heating and quenching processes seamlessly combines the forming of the material with the subsequent strengthening treatment, thereby greatly improving the performance of the material and the quality of the finished product.

Description

Technical Field

[0001] The present invention relates to the field of free bending forming, in particular to a three-dimensional free forming device and method based on induction heating and quenching. Background Art

[0002] Three-dimensional free-form bending technology has been a significant technological innovation in the international plastics processing field in recent years. Compared to traditional bending methods, this technology primarily achieves flexible, precise, and integral forming of complex three-dimensional axial components by controlling the position and posture of the forming mechanism in three-dimensional space. Faced with the miniaturization, lightweighting, and compactness of spacecraft, weaponry, and new energy vehicles, three-dimensional free-form bending technology offers high flexibility and excellent part adaptability. It can meet the forming needs of complex components made of various materials and shapes without changing molds, offering significant advantages in integrally forming a series of high-performance, complex, and special-shaped components required for equipment in various fields. However, the free-form forming of profiles / tubes made of difficult-to-deform materials remains challenging. To address these challenges, a three-dimensional free-form forming device and method based on induction heating and quenching is now being developed. This device reduces the material's deformation resistance by increasing the forming temperature, enabling the one-step integral forming of complex, difficult-to-deform axial profiles / tubes. The device is also equipped with a cooling device to accommodate the quenching heat treatment required for some materials.

[0003] Based on this, a three-dimensional free-form forming device and method based on induction heating and quenching are now provided, which can eliminate the disadvantages of existing devices. Summary of the Invention

[0004] The purpose of the present invention is to provide a three-dimensional free-forming device and method based on induction heating and quenching, which solves the problem that bending forming in the prior art is still quite difficult.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] This three-dimensional free-form forming machine, based on induction heating and quenching, is based on a six-axis free-form bending machine, with the addition of an induction heating module and a quenching heat treatment module. The induction heating device rapidly heats the formed component, reducing deformation resistance and improving its forming performance. Combined with the six-axis free-form bending machine's precise control of multiple degrees of freedom, it enables precise forming of complex curved components made of difficult-to-deform materials (such as titanium alloys and high-strength steel) such as profiles and tubes. Furthermore, a ring-shaped quenching device at the bending die exit ensures high strength and hardness levels in the finished component.

[0007] On the basis of the above technical solutions, the present invention also provides the following optional technical solutions:

[0008] A forming method of a three-dimensional free-form forming device based on induction heating and quenching, comprising the following steps:

[0009] Design coil shape: Design the electromagnetic induction heating coil according to the shape of the profile. The shape of the induction heating coil will change the distribution and intensity of the magnetic field. In order to ensure that the workpiece is heated evenly during the induction heating process, it is necessary to design a reasonable coil shape for profiles / tubes with different cross-sectional shapes. Use finite element simulation software to simulate the heating conditions of the workpiece during induction heating to ensure the rationality of the induction heating coil design;

[0010] Setting the heating power: The distance between the bending die and the front end of the guide mechanism of a six-axis free bending machine is the forming section, typically only about 120-250mm in length. Before forming, set the heating power of the electromagnetic induction heating coil. Once set, insert the profile / tube into the propulsion device, close the clamping mechanism, and maintain the bending die at its origin. Start the electromagnetic induction heating preheating for 5 seconds, then activate the Z-axis servo motor to control the propulsion device to feed the workpiece through the bending die at a speed of 10mm / s. During this period, use an infrared temperature gun to measure the surface temperature of the workpiece in the forming section. Only when it reaches the required heating temperature range can the subsequent forming experiment be carried out.

[0011] Developing a forming program: Six-axis free-bending equipment has six degrees of freedom. Therefore, compared to three-axis free-bending equipment, its forming program analysis requires corresponding solutions for the motion paths of the A / B / C axes and the X / Y / Z axes (some profiles require a V-axis servo motor to control the mandrel to prevent defects such as wrinkling in the profile / tube). First, fit the UR relationship. Through single-bend experiments with different eccentricities U, the bend radius R is measured and fitted using the following formula;

[0012]

[0013] Ap is the length of the plastic deformation zone, u is a constant for a certain specification of pipe, and D is the pipe diameter.

[0014] After obtaining the UR relationship, the bending program is used to analyze the component. Assuming that the first bending radius is R and the bending angle is λ, the corresponding eccentricity U can be obtained and the remaining parameters can be solved:

[0015]

[0016] X is the moving length of the bending die in the x direction, Y is the moving length of the bending die in the y direction, θ is the central angle, is the deflection angle of the bending die around the x-axis, is the deflection angle of the bending die around the y-axis, S is the arc length of the bending forming section, is the torsion angle of the bending die around the z-axis (the above formula is used for spiral parts), and t is the time taken for the workpiece to be formed when it is fed at a speed of 10 mm per second.

[0017] By analogy, the three-dimensional free bending program of curved components is analyzed;

[0018] Import program: import the complete program of the analytical component (reserve 5 seconds to keep the propulsion device stationary so that the workpiece can be preheated) into the six-axis free bending forming control system;

[0019] Three-dimensional free bending forming: The induction heating coil and the three-dimensional free bending program are started at the same time. After heating for 5 seconds, the Z-axis servo motor is started, driving the propulsion device to push the workpiece forward at a feed rate of 10mm / s. The workpiece is heated to the specified temperature range by the induction coil in the forming area. The X / Y-axis servo motor drives the bending die to move along the x / y direction. Since the bending die of the six-axis free bending forming equipment is an active motion structure, the bending die must remain perpendicular to the workpiece axis during bending. Therefore, the bending die needs to be actively deflected. Therefore, the A / B / C / axis servo motor needs to drive the bending die to deflect a certain angle around the x / y / z axis. After the forming section is completed, the bending die returns to the origin.

[0020] Cooling and quenching: During the forming process, the cylindrical nozzle of the annular quenching device continuously sprays water mist to the die mouth of the bending die to cool the workpiece. The quenching cooling rate can be changed by the water mist flow rate or the quenching medium;

[0021] Shape inspection: Compare the formed component with the digital model, and optimize the forming process according to the actual situation so that the shape of the bent component can fit the digital model.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention organically combines six-axis free bending forming technology with hot forming technology, which not only enables the precise manufacturing of high-strength, difficult-to-deform type / tube bending components, but also significantly improves the forming limit and reduces or even eliminates springback. The coordinated control between the motion trajectory of the bending die, the profile heating temperature, and the cooling rate can achieve integrated and comprehensive regulation of the shape of complex-shaped, high-strength type / tube components. Therefore, the application of this forming technology can change the traditional manufacturing model of segmented bending and then welding of key load-bearing components in my country's aviation, land warfare equipment, automobiles and other fields, and improve the forming quality of type / tube components and the level of digital forming and manufacturing. In addition, the application of such components can significantly reduce the overall weight of the product while enhancing the load-bearing performance of key components. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a diagram of the six-axis free-bending induction heating and quenching equipment;

[0025] Figure 2 This is the motion control diagram of the six-axis free bending equipment; Figure 3 The coil shape diagrams of different forms of the same profile cross section; Figure 4The coil shape diagrams for different profile cross sections; Figure 5 It is a ring quenching device; Figure 6 This is the formed workpiece diagram for Case 1, with a wall thickness of t; Figure 7 Figure 2 shows the formed workpiece in case 2, with a wall thickness of t.

[0026] Notes on figure numbers: 1X-axis servo motor, 2Y-axis servo motor, 3Z-axis servo motor, 4A-axis servo motor, 5B-axis servo motor, 6C-axis servo motor, 7 bending die, 8 guiding mechanism, 9 induction heating coil, 10 annular quenching device, 11 pressing mechanism, 12 propulsion device, 13V-axis servo motor, 14 columnar nozzle, 15 type / pipe. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0028] Example (1) Design of coil shape: forming as Figure 5 The induction heating coil (9) of the curved member shown is shaped as Figure 3 In the figure, assuming that the profile material is TA18, the TA18 material parameters are imported into the finite element simulation software to simulate the cross-sectional temperature distribution of the workpiece when heated by the induction coil;

[0029] (2) Setting the heating power: insert the profile / tube 15 into the propulsion device 12, close the clamping mechanism 11, keep the bending die 7 at the origin position, start the electromagnetic induction heating and preheat for 5 seconds, then start the Z-axis servo motor 3 to control the propulsion device 12 to feed the workpiece through the bending die 7 at a speed of 10 mm / s. During this period, use an infrared temperature measuring gun to measure the surface temperature of the workpiece in the forming section. If the temperature is around 650°C, then this heating power is the forming heating power.

[0030] (3) Drafting procedure: First, measure the bending radius with different U values ​​and fit the UR relationship according to the following formula:

[0031]

[0032] Solve the Ap and u values. Since this part is a single-bend part, the bending angle λ1=90°. The remaining parameters are:

[0033]

[0034] (The distance between the front end of the mold guide mechanism 8 and the bending mold 7 is A=200)

[0035]

[0036] (Time required for the curved section)

[0037] (4) Importing the program: importing the solved operating parameters into the program;

[0038] (5) Bending: The induction heating device and the three-dimensional free bending program are started simultaneously. After heating for 5 seconds, the Z-axis servo motor 3 drives the propulsion device 12 to feed the profile at a speed of 10 mm / s. The bending die 7 moves in the Y-axis direction by U1 and deflects around the X-axis by an angle θ1. After the forming section is completed, the bending die 7 returns to the origin.

[0039] (6) Cooling and quenching: When the bending die 7 starts to move, the annular quenching device 10 is started to quench the profile;

[0040] (7) Shape inspection: Scan the formed component and compare it with the digital model, and optimize the bending process according to the actual situation.

[0041] Example 2: (1) Design coil shape: forming as Figure 6 The induction heating coil 9 of the curved member shown is shaped as Figure 3 In the figure, assuming that the profile material is TC4, the TC4 material parameters are imported into the finite element simulation software to simulate the cross-sectional temperature distribution of the workpiece when heated by the induction coil;

[0042] (2) Setting the heating power: put the profile / tube into the pushing device 12, close the clamping mechanism 11, keep the bending die 7 at the origin position, start the electromagnetic induction heating and preheat for 5 seconds, then start the Z-axis servo motor 3 to control the pushing device 12 to feed the workpiece through the bending die 7 at a speed of 10 mm / s. During this period, use an infrared temperature measuring gun to measure the surface temperature of the workpiece in the forming section. If the temperature is around 750°C, then this heating power is the forming heating power.

[0043] (3) Drafting procedure: First, measure the bending radius with different U values ​​and fit the UR relationship according to the following formula:

[0044]

[0045] Solve for Ap and u values, set the bending angle λ = 90°, and the remaining parameters:

[0046]

[0047] (The distance between the die guide front end 8 and the bending die 7 is A=200)

[0048]

[0049] (4) Importing the program: importing the solved operating parameters into the program;

[0050] (5) Bending: Start the induction heating device and the three-dimensional free bending program at the same time. After heating for 5 seconds, the Z-axis servo motor 3 drives the propulsion device 12 to feed the profile at a speed of 10 mm / s. The bending die 7 moves in the Y-axis direction by U1, and deflects the angle θ around the X-axis and twists around the Z-axis. , after the forming section is completed, the bending die 7 returns to the origin;

[0051] (6) Cooling and quenching: When the bending die 7 starts to move, the annular quenching device 10 is started to quench the profile;

[0052] (7) Shape inspection: Scan the formed component and compare it with the digital model, and optimize the bending process according to the actual situation.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A forming method of a three-dimensional free-form forming device based on induction heating and quenching, characterized in that: The equipment used includes a six-axis free bending forming device, which is equipped with: an electromagnetic induction heating module, which is used to heat the pipe (15) before forming to reduce the deformation resistance of the material and improve its forming performance; a quenching heat treatment module, which is arranged at the outlet of the bending die (7) and includes an annular quenching device (10) for cooling the component immediately after the forming process is completed to ensure that it has high strength and hardness; The method comprises the following steps: step 1: designing the shape of the induction heating coil (9) for the shape of the cross section of the pipe (15), and verifying the uniformity of the heating of the workpiece by the designed coil through finite element simulation; step 2: setting the heating power, and preheating the workpiece to a desired temperature range before forming; step 3: using a six-axis free bending forming system to solve the motion paths of the A / B / C axis and the X / Y / Z axis of the bent member, and relying on the multi-degree-of-freedom control of the six-axis free bending device to achieve precise forming; In step three: The motion path solution for the A / B / C axis and the X / Y / Z axis is: Fitting the U-R relationship, through the single bending experiment with different eccentricity U, the bending radius R is measured and fitted by the following formula: Ap is the length of the plastic deformation zone, u is a constant for a certain specification of pipe, and D is the pipe diameter; After obtaining the U-R relationship, the bending program is used to analyze the component. Assuming that the first bending radius is R and the bending angle is λ, the corresponding eccentricity U can be obtained and the remaining parameters can be solved: X is the moving length of the bending die (7) in the x direction, Y is the moving length of the bending die (7) in the y direction, is the central angle, is the deflection angle of the bending die (7) around the x-axis, is the deflection angle of the bending die (7) around the y-axis, S is the arc length of the bending forming section, is the torsion angle of the bending die (7) around the z axis. The above formula is used for the screw part. t is the time when the workpiece is fed at a speed of 10 mm per second.

2. The forming method of the three-dimensional free-form forming equipment based on induction heating and quenching according to claim 1, characterized in that: The water mist flow rate or quenching medium of the columnar nozzle (14) in the annular quenching device (10) can be adjusted to change the quenching cooling rate, thereby achieving control over the strength and hardness level of the formed component.

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