Mirror image additive manufacturing method of composite material component

Abstract

A mirror image additive manufacturing method for a composite material component is characterized in that the position of a virtual central plane of the component is determined, and double laying heads symmetrical along the central plane are arranged on the two sides of the central plane; the double laying heads are respectively provided with heat sources; the double laying heads synchronously move along the laying track and mutually provide opposite supporting force, the angle of the supporting force is valued in the angle range between the normal direction of the central plane and the normal direction of the surface of the component, and when the normal direction of the central plane and the normal direction of the surface of the component are not collinear, the virtual central plane is updated according to the geometric center position of the current laid component; and the material spreading speeds of the double spreading heads are independently controlled. In order to solve the problems of large deformation and poor performance caused by unbalanced residual stress inevitably formed by traditional single-side heating, single-side pressurizing and single-direction laying, the invention provides a method for introducing opposite-vertex double laying heads on two sides of the component, so that small and balanced distribution of stress is ensured, and the manufacturing precision and quality of the composite material component are effectively improved.

Description

Technical Field

[0001] The present invention relates to a manufacturing technology for composite components, especially the additive manufacturing technology for automatic laying of composite laminates. Specifically, it is a mirror additive manufacturing technology for composite components. Background Art

[0002] Thermoplastic composites are lightweight, high-strength, impact-resistant, high-temperature resistant, and recyclable, and are the key to a leapfrog improvement in the comprehensive performance of new-generation equipment. The manufacturing of thermoplastic composite components mainly consists of three manufacturing steps: "laying - consolidation - processing". Laying is the step of stacking raw materials layer by layer to obtain the shape, which directly determines the final quality and accuracy of the component. Existing laying methods rely on special molds and lay layer by layer following the mold. However, this method uses the principle of unilateral heating, unilateral pressurization, and unidirectional laying, and non-equilibrium residual stresses will inevitably be generated on both sides of the thermoplastic composite laminate, resulting in large deformation and poor performance of the component, restricting the high-quality production and efficient development of equipment.

[0003] In response to the above problems, relevant domestic and foreign units have proposed two aspects of reference technologies in recent years. They are the tool-less automatic fiber placement technology (Tool-less AFP) proposed by the German Aerospace Center / the Advanced Technology Laboratory of the US NIAR, and the double-sided mirror laser melting deposition additive manufacturing method (CN119304210A) proposed by the Aviation Manufacturing Research Institute of China. First, for the tool-less automatic fiber placement technology, a traditional automatic fiber placement head and a supporting roller opposite to it are used, and the automatic laying is completed suspended in space by two robotic arms, enabling tool-less automatic laying. However, due to drastic temperature changes and non-equilibrium material distribution, although there are support wheels to ensure the laying trajectory, there are still extremely large thermal stresses and consolidation deformations under tool-less conditions, and it is difficult to achieve precise additive manufacturing in principle. Second, in the field of non-composite material forming, the double-sided mirror laser melting deposition additive manufacturing method discloses depositing materials layer by layer in a mirror-image manner of the trajectory on both sides of a flat substrate. This method solves problems such as large deformation of the parts formed by the single-sided laser powder feeding direct deposition additive manufacturing method, and relatively high material and post-processing costs. However, for composite material forming, a laying head is required to provide pressure, and the actual composite components are mainly curved surfaces. The above disclosed method uses a vertical flat substrate as the mirror surface and prints layer by layer in a mirror-image manner of the plane trajectory on both sides. There is no contact pressure between the print head and the substrate, and it is difficult to form high-quality continuous fiber-reinforced composite curved surface components.

[0004] The present invention aims to solve the problems of large deformation and poor performance in the existing additive manufacturing methods for composite materials, and proposes a mirror additive manufacturing method for composite material components. This method first determines the position of the virtual central plane of the component. On both sides of the central plane, two laying heads are set with the pressing direction along the normal direction of the central plane and symmetric with respect to the central plane. Heat sources are respectively set on the two laying heads to apply the required temperature field for manufacturing to the materials on both sides of the central plane at the same time. The two laying heads move synchronously along the laying trajectory and provide counter-support forces to each other. The laying heads lay materials layer by layer from the central plane to both sides. The mirror additive manufacturing mode of the present invention can make the temperature and materials on both sides of the central plane of the composite material component symmetrically distributed, greatly reduce the non-equilibrium residual stress caused by temperature difference and anisotropy, and achieve the manufacturing of composite material components with small deformation and high performance. Summary of the Invention

[0005] The object of the present invention is to invent a mirror additive manufacturing method for composite material components in view of the problems of large deformation and poor performance of composite components in traditional additive manufacturing methods. It breaks through the limitation of the traditional method that unilateral heating, unilateral pressing, and unidirectional laying are difficult to avoid non-equilibrium residual stress. Through the principle of two symmetrically distributed, synchronously moving, and mutually counter-supporting laying heads on both sides of the central plane of the component, it realizes the symmetric distribution of temperature and materials along the central plane, greatly reduces the non-equilibrium residual stress caused by temperature difference and anisotropy, and provides a new feasible technical solution for the manufacturing of composite material components with small deformation and high performance.

[0006] The technical solution of the present invention is as follows:

[0007] A mirror additive manufacturing method for composite material components, characterized in that for a composite laminate component, first determine the position of the virtual central plane of the component. If the component is an asymmetric laminate with a layer loss structure, take the thickness center as the point on the central plane. With the central plane as the symmetry plane, on both sides of the central plane, two laying heads symmetric with respect to the central plane are set. Heat sources are respectively set on the two laying heads to heat the materials being laid on both sides at the same time. According to the geometric structure difference, the heat sources on both sides are regulated to apply the required temperature field for manufacturing to the materials on both sides of the central plane at the same time. The laying heads lay materials layer by layer from the central plane to both sides. The two laying heads move synchronously along the laying trajectory and provide counter-support forces to each other, so that the laid component has better structural stiffness. The angle of the support force is within the range of the angle between the normal direction of the central plane and the normal direction of the component surface. When the normal direction of the central plane and the normal direction of the component surface are not collinear, the virtual central plane is updated according to the geometric center position of the currently laid component. The material laying speeds of the two laying heads are independently controlled.

[0008] Before the double laying head lays the first layer of material from the center plane to both sides, a weakly rigid central thin layer is clamped at the position of the virtual center plane to provide initial support for the laying of the first layer of material; the central thin layer is preformed from the same matrix material as the component, and the forming method preferably uses a 3D printing method without a mold.

[0009] The double laying heads are respectively provided with distance sensors to measure the actual position of the laid material in real time, calculate the deviation δ between the actual position and the theoretical position of the component, and further perform reverse compensation for the deviation along the normal direction of the center plane. The compensation amount C is positively correlated with the value of the deviation δ.

[0010] The double laying heads can be carried by one or a combination of structures such as a double-spindle horizontal machine tool, a double-spindle vertical machine tool, a double-spindle circular arc track horizontal machine tool, and a double robotic arm machine tool system.

[0011] The heat source can be one or a combination of two of laser, infrared, microwave, hot air, and energized heat source.

[0012] The beneficial effects of the present invention are:

[0013] By the method of the present invention, effective control of the residual stress and deformation of the thermoplastic composite component can be achieved, the forming quality and precision of the composite component are improved, and at the same time, expensive special molds are avoided, which has high practical value and broad application prospects. Description of the Drawings

[0014] Figure 1 It is a schematic diagram of a specific embodiment of the present invention with a certain aircraft skin part. Detailed Embodiment

[0015] The present invention will be further described below in conjunction with the drawings and embodiments.

[0016] As Figure 1 shown.

[0017] Figure 1 Shown is a skin component of a certain aircraft fuselage section. The skin is made of carbon fiber reinforced polyether ether ketone CF / PEEK composite material, and the ply structure is [0° / 45° / 90° / -45°] 4s , a total of 32 layers of CF / PEEK prepreg, with a thickness of 5 mm, and is manufactured by the mirror additive manufacturing method of the present invention. The specific steps are as follows:

[0018] Step 1: First, determine the position of the virtual center plane of the skin component, obtain the center plane, and obtain a digital model of the center plane thin layer with a thickness of 0.5 mm through surface offset. Print a center plane thin layer with a thickness of 0.5 mm using PEEK resin;

[0019] Step 2: On both sides of the printed thin layer of the central plane, a dual-robot system is used to apply dual laying heads with the pressure direction along the normal direction of the central plane and symmetric with respect to the central plane. Heat sources are respectively arranged on the dual laying heads. The heat sources adopt laser heat sources. According to the bilateral laying conditions of the component, the heat sources on both sides are regulated to apply the temperature field required for manufacturing to the materials on both sides of the central plane simultaneously.

[0020] Step 3: Obtain the initial G code for mirror additive manufacturing according to the shape and laying trajectory of the skin part. Use the dual-robot system to drive the dual laying heads to move synchronously along the laying trajectory and provide counter-support forces for each other. The laying heads lay materials layer by layer from the central plane to both sides.

[0021] Step 4: Distance sensors are respectively arranged on the dual laying heads to measure the actual position of the laid materials in real time, calculate the deviation δ between the actual position and the theoretical position of the component, and further perform reverse compensation for the deviation along the normal direction of the central plane. The compensation amount C is positively correlated with the value of the deviation δ. By continuously measuring the deviation value, the G code of the dual robots is updated to achieve precise regulation of the shape during the mirror additive manufacturing process of the component.

[0022] The parts not involved in the present invention are the same as the prior art and are implemented using the prior art.

Claims

1. A mirror-image additive manufacturing method for a composite material component, characterized in that: First, determine the position of the virtual center plane of the component; then, set up two laying heads symmetrically along the center plane on both sides of the center plane; third, set up heat sources at the two laying heads respectively to simultaneously apply the temperature field required for manufacturing to the materials on both sides of the center plane; Fourth, the dual laying heads are made to move synchronously along the laying trajectory and provide mutual top support force, and the angle of the support force is taken within the angle range between the center plane normal and the component surface normal; when the center plane normal and the component surface normal are not colinear, the virtual center plane is updated according to the geometric center position of the currently laid component.

2. The method according to claim 1, characterized in that The material laying speeds of the dual laying heads are controlled independently.

3. The method according to claim 1, characterized in that Before the double laying heads lay the first layer of materials from the center plane to both sides, at least one mechanism is used to position and clamp the weak rigidity center thin layer at the location of the virtual center plane to provide initial support for the laying of the first layer of materials, or after laying the first layer of materials, at least one mechanism is used to position and clamp the laid first layer of materials; the center thin layer is preformed from the same base material as the component.

4. The method according to claim 1, characterized in that: The double laying heads are respectively provided with distance sensors to measure the actual position of the laid materials in real time, calculate the deviation δ between the actual position and the theoretical position of the component, and further reversely compensate the deviation of the laying trajectory along the normal of the center plane, and the compensation amount C is positively correlated with the value of the deviation δ.

5. The method according to claim 1, characterized in that The double placement head is mounted in one or a combination of structures selected from a double-spindle horizontal machine tool, a double-spindle vertical machine tool, a double-spindle circular track horizontal machine tool, and a double-manipulator arm machine tool system.

6. The method according to claim 1, characterized in that The heat source is one of laser, infrared, microwave, hot air, and electric heat source, or a combination of two of them.

7. The method according to claim 1, characterized in that For composite laminate components, the position of the virtual center plane of the component is first determined. If the component is an asymmetric laminate with a layer loss structure, the thickness center is taken as the point on the center plane, and the center plane is taken as the symmetry plane.

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