Floating clamping machining process method for aerospace plate parts

Abstract

A floating clamping machining process method for aerospace plate parts is characterized by comprising the steps that firstly, a stress groove is machined, and the stress change condition, namely deformation force, of a part machining gap clamping point is measured through a floating clamping device; secondly, in the rough machining stage of the part, when the stress of the clamping point of the part exceeds a set threshold value, the floating clamping device of the clamping point is loosened in a machining gap, and the part is clamped after the stress of the part is rebalanced; and finally, before the finish machining stage, an initial residual stress field is deduced based on the measured deformation force, and the finish machining allowance is simulated, analyzed and optimized based on the initial residual stress field. According to the method, the stress of the part is released in the machining process of the spaceflight plate type part, the finish machining allowance is optimized according to the inferred initial residual stress, and machining deformation control over the spaceflight plate type part can be achieved.

Description

Technical Field

[0001] The invention relates to the field of aerospace processing technology, in particular to a processing technology, specifically to a floating clamping processing technology method for aerospace plate parts. Background Art

[0002] The new generation of aerospace vehicles pursues more extreme comprehensive performance, and has put forward higher strength and integration requirements for large structural parts. The structure is more complex, the precision requirements are higher, and especially the processing deformation control is more stringent. Large aerospace plate structural parts are large in size, thin in wall, and have a high amount of material removal. After the parts are processed, they are prone to severe deformation such as bending, twisting, and bending and twisting under the action of the residual stress field. If the parts are deformed, they can only be assembled with stress, which will seriously affect the comprehensive performance and safety of the aerospace vehicle.

[0003] In existing research, workpiece deformation reduction is based on empirical analysis methods and offline prediction data of processing rules. Traditional processing process planning is completed before processing and remains unchanged throughout the entire processing process, mostly limited to static planning. However, due to the uncertainty factors in the processing process, the processing deformation cannot be accurately predicted, and controlling the processing deformation based on the prediction results is not ideal. During the processing process, with the coupling of cutting force, cutting heat and clamping force, the distribution of initial residual stress changes continuously, and the predetermined processing sequence cannot cope with the changing workpiece state to achieve the purpose of controlling deformation. Therefore, how to adaptively adjust the processing technology according to the state of the workpiece during processing and control deformation still needs further in-depth research. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the existing aerospace plate parts processing deformation control precision is high, and the parts are prone to serious deformation such as bending, twisting and bending and twisting combination after the residual stress is released, and to invent a floating clamping processing method for aerospace plate parts. The present invention releases the part stress during the processing of aerospace plate parts, and optimizes the finishing allowance based on the inferred initial residual stress, so as to realize the processing deformation control of aerospace plate parts.

[0005] The technical solution of the present invention is: A floating clamping processing method for aerospace plate parts, characterized by: First, the stress groove area is determined; Secondly, the stress groove is processed and the force change of the clamping point of the part processing gap is measured using a floating clamping device, that is, the deformation force; Third, during the rough machining stage of the part, when the force on the clamping point of the part exceeds the set threshold, the floating clamping device of the clamping point is released in the machining gap, and the part is clamped after the stress of the part is rebalanced; Finally, before the finishing stage, the initial residual stress field is inferred based on the measured deformation force, and finally the finishing allowance is optimized based on the simulation analysis of the initial residual stress field.

[0006] The stress groove area is calculated by finite element analysis software to calculate the deformation of the part after removing the material in the area. If the part is deformed and the area where the material is removed does not interfere with the part, this area is defined as a stress groove. The rule for determining the stress groove is to maximize the deformation of the part after removing the material.

[0007] The threshold is the force exerted on the clamping point after the part is deformed less than the machining allowance by the finite element analysis software, and this is defined as the threshold.

[0008] The optimization of finishing allowance based on initial residual stress field simulation analysis is to input the initial residual stress field through finite element analysis software, calculate the machining deformation of parts under different finishing allowances, and select the finishing allowance with the smallest deformation as the finishing allowance.

[0009] Beneficial effects of the present invention: 1. The present invention proposes a floating clamping deformation release method based on threshold value, which can realize the processing deformation control of aerospace plate parts by releasing the part deformation during processing.

[0010] 2. Traditional machining process planning is completed before machining and is an offline process planning method. The present invention uses online machining process optimization to optimize the finishing allowance based on the inferred initial residual stress, thereby realizing machining deformation control of aerospace plate parts.

[0011] 3. The floating clamping processing deformation control process for aerospace plate parts proposed in the present invention is highly universal and practical, effectively reduces the deformation of parts after processing, improves the qualified rate of aerospace plate parts, greatly improves production efficiency for enterprises and creates huge economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a flow chart of an example implementation of the present invention.

[0013] Figure 2 This is a typical aerospace plate structural component clamping layout diagram of the present invention.

[0014] Figure 3 This is a stress groove distribution diagram of a typical aerospace plate structure in an example of the present invention.

[0015] Figure 4 This is a diagram showing the optimization results of the finishing allowance of a typical aerospace plate structural part according to an example of the present invention. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0017] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of implementation. The change or adjustment of their relative relationship should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0018] like Figure 1-4 shown.

[0019] A floating clamping processing method for aerospace plate parts, such as Figure 1 As shown, it includes the following steps: First, determine the stress groove area; the processing stress groove can be determined by finite element analysis software. First, calculate the deformation of the part after removing the material in the area. If the part deforms and the area where the material is removed does not interfere with the part, this area is defined as a stress groove. The rule for determining the stress groove is to maximize the deformation of the part after removing the material.

[0020] Secondly, the stress groove is processed and the force change of the clamping point of the part processing gap is measured using a floating clamping device, that is, the deformation force; Third, during the rough machining stage of the parts, when the force on the clamping point of the part exceeds the set threshold, the floating clamping device of the clamping point is released in the machining gap, and the part is clamped after the stress of the part is re-balanced; the threshold can be output by the finite element analysis software after applying a deformation less than the machining allowance to the part, and this is defined as the threshold.

[0021] Finally, before the finishing stage, the initial residual stress field is inferred based on the measured deformation force, and finally the finishing allowance is optimized based on the simulation analysis of the initial residual stress field. The optimization of the finishing allowance based on the simulation analysis of the initial residual stress field is to input the initial residual stress field through finite element analysis software, calculate the machining deformation of the part under different finishing allowances, and select the finishing allowance with the smallest deformation as the finishing allowance.

[0022] Below Figure 2 The typical aerospace aluminum alloy structural part processing deformation control process is shown as an example to illustrate. The process includes the following steps.

[0023] 1. Take the processing of typical aerospace plate structural parts as an example. The part material is 2A14 aluminum alloy, the part blank size is 1410mm×1420mm×35mm, and the part geometry and deformation force measurement equipment position information are as follows: Figure 2 According to the 6+X positioning method (6+X positioning method ZL201610518135.6), during the processing, two fixing fixtures are used in the middle area of ​​the part, and eight deformation force measuring devices (i.e. floating clamping devices, which can be implemented by using Chinese patent ZL2014107680148) are used to fix the part at the corners.

[0024] 2. Processing stress grooves. For the aerospace plate structural parts, the area where the material is removed and does not interfere with the parts is selected as the stress groove area. Then, the finite element analysis software is used to apply a random residual stress field to the parts and calculate the deformation of the parts after the material in the area is removed. If the parts do not deform significantly, the stress groove area can be increased until the parts deform significantly. Finally, the stress groove area of ​​the aerospace plate parts is 17 through cavities of different sizes, such as Figure 3 shown.

[0025] 3. Rough machining stress release. First, calculate the deformation release threshold. After applying a deformation less than the machining allowance to the part through finite element analysis software, output the force on the clamping point, take the maximum force among the 8 clamping points, and define this as the threshold for deformation release. The threshold for deformation release of the part in this example is set to 100N. During the rough machining process, monitor the force of the floating clamping device. When the deformation force is greater than 100N, release the clamping device of the floating clamping point in the cutting gap to release the part stress, and then re-clamp the part to continue machining. Repeat the above operations until the rough machining is completed.

[0026] 4. Optimize the finishing allowance. Before the finishing stage begins, the initial residual stress field (ZL202111331411.5) is inferred based on the deformation force measured in the stress groove stage. Then, through the finite element analysis software, the initial residual stress field is input to calculate the final machining deformation of the part under different finishing allowances, and the finishing allowance with the smallest deformation is selected as the optimization result. The optimization result of the finishing allowance of the example part is: 2.5mm for surface A and 1.5mm for surface B. Figure 4 shown.

[0027] The above embodiments are only preferred implementation modes of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and equivalent substitutions without departing from the principles of the present invention. These technical solutions after improvements and equivalent substitutions to the claims of the present invention all fall within the protection scope of the present invention.

[0028] The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

Claims

1. A floating clamping processing method for aerospace plate parts, characterized by: First, the stress groove area is determined; Secondly, the stress groove is processed and the force change of the clamping point of the part processing gap is measured using a floating clamping device, that is, the deformation force; Third, during the rough machining stage of the part, when the force on the clamping point of the part exceeds the set threshold, the floating clamping device of the clamping point is released in the machining gap, and the part is clamped after the stress of the part is rebalanced; Finally, before the finishing stage, the initial residual stress field is inferred based on the measured deformation force, and finally the finishing allowance is optimized based on the simulation analysis of the initial residual stress field.

2. The process according to claim 1, characterized in that: The stress groove area is calculated by finite element analysis software to calculate the deformation of the part after removing the material in the area. If the part is deformed and the area where the material is removed does not interfere with the part, this area is defined as a stress groove; the rule for determining the stress groove is to maximize the deformation of the part after removing the material.

3. The process according to claim 1, characterized in that: The threshold is the force exerted on the clamping point after the part is deformed less than the machining allowance by the finite element analysis software, and this is defined as the threshold.

4. The process according to claim 1, characterized in that: The optimization of finishing allowance based on initial residual stress field simulation analysis is to input the initial residual stress field through finite element analysis software, calculate the machining deformation of the part under different finishing allowances, and select the finishing allowance with the smallest deformation as the finishing allowance.

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