High-precision web anti-deformation processing method for frame structure

Abstract

The present application relates to the technical field of machining, in particular to a high-precision web anti-deformation machining method for frame-like structural parts, according to the characteristics of the frame-like structural parts, the weak rigid region of the part web is selected, and the maximum deformation of the web in the weak rigid region of the structural part is calculated by using finite element simulation, the maximum deformation is taken as a reference, the web in the weak rigid region of the frame-like structural part is verified by lifting the tool, the thickness of the web after verification is measured, and the actual deformation of the structural part is identified by comparing with the theoretical condition, so that the web can be accurately machined by lifting the tool during formal finishing. By the method, the high-precision requirement of large structural part manufacturing can be met, the deformation affecting the part machining is prevented, and the machining quality is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of machining, in particular to a high-precision web anti-deformation machining method for frame structure. BACKGROUND

[0002] Frame structure is an important aircraft structure, and its typical structure is a structure with large length and width and small thickness. In recent years, aircraft structures have been developing towards large-scale and high-precision, which has increased the difficulty of numerical control machining.

[0003] Due to the overall structure and large size of the frame structure, after rough machining, the internal stress of the structure material is unevenly distributed, and the pressure transmission distance is too large, which can cause insufficient rigidity of the web area of the structure and deformation. In the existing machining process, process bosses are usually set around the structure for clamping and pressing, and the weak rigidity area of the structure often deforms. The farther the distance from the process boss, the worse the pressing effect, so it is more prone to deformation. The cutting point of the numerical control machine tool is a theoretical value, and the web is warped, so the web will be overcut after cutting, the web thickness is too small, and the part fails. The precision error of the numerical control machine tool itself in the Z direction and the clamping error of the tool clamping will affect the machining precision of the web thickness of the part. SUMMARY

[0004] To solve the above technical problems, the present application provides a high-precision web anti-deformation machining method for frame structure, which can meet the high-precision requirements of large-scale structure manufacturing, prevent deformation from affecting part machining, and ensure machining quality.

[0005] The present application is achieved by adopting the following technical solutions:

[0006] A high-precision web anti-deformation machining method for frame structure, comprising the following steps:

[0007] Step S1. Selecting the weak rigidity area of the web according to the structure characteristics of the part and the arrangement of the process pressing boss pressing hole;

[0008] Step S2. Calculating the maximum deformation δ of the weak rigidity area web of the part:

[0009]

[0010] Wherein, C1, C2, C3, C4, C5 and C6 are constant terms; H is the theoretical thickness of the weak rigidity area web after rough machining; a is the machining allowance of the weak rigidity area web of the frame structure before finishing machining; and L is the maximum length of the selected frame structure contour.

[0011] Step S3. According to the maximum deformation δ, Z-direction tool lifting anti-deformation verification machining is carried out in the frame of the weak rigid region, i.e. in the verification machining region.

[0012] Step S4. After the verification machining, the actual web thickness of the verification machining region is measured.

[0013] Step S5. According to the measurement of step S4, the program offset amount of subsequent formal machining is determined.

[0014] In the step S1, the selection method of the weak rigid region of the part web is to select the web with the minimum sum of distances from each boss pressing hole position.

[0015] The step S2 specifically comprises: constructing a part model in finite element simulation, limiting the pressing hole position as a fixed position, applying a tool force F to the weak rigid region of the web, and obtaining the calculation method of the maximum deformation δ of the weak rigid region of the web through finite element simulation.

[0016] In the step S3, when Z-direction tool lifting anti-deformation verification machining is carried out, the machine tool Z-direction actual origin value is set as Z-direction initial origin + Z-direction tool lifting amount; wherein the Z-direction tool lifting amount = maximum deformation δ of the weak rigid region of the web + 0.1mm.

[0017] The size of the verification machining region is 30mm*20mm, and the tolerance is ±5mm.

[0018] The step S5 specifically refers to: if the actual web thickness of the verification machining region is less than the theoretical thickness, tool lifting machining is carried out in subsequent formal machining; if the actual web thickness is greater than the theoretical thickness, tool lowering machining is carried out in subsequent formal machining.

[0019] When tool lifting machining is carried out, the machine tool Z-direction actual origin is set as Z-direction initial origin + program Z-direction offset amount, and the Z-direction offset amount is the absolute value of the theoretical thickness of the part web minus the actual web thickness of the verification machining region.

[0020] When tool lowering machining is carried out, the machine tool Z-direction actual origin is set as Z-direction initial origin - program Z-direction offset amount, and the Z-direction offset amount is the absolute value of the theoretical thickness of the part web minus the actual web thickness of the verification machining region.

[0021] Compared with the prior art, the beneficial effects of the present application are as follows:

[0022] 1、After the rough machining of the structural part is completed, according to the characteristics of the frame type structural part, the weak rigid region of the part web is selected, and the maximum deformation of the web in the weak rigid region of the structural part is calculated by using finite element simulation, and the maximum deformation is used as a reference to verify the machining of the web in the weak rigid region of the frame type structural part, and the thickness of the web after verification machining is measured and compared with the theoretical situation to identify the actual deformation of the structural part, which can accurately lift the knife processing during the formal finishing of the web to ensure the high-precision size requirement of the web after finishing.

[0023] The method effectively avoids the influence of deformation on the high-precision thickness size of the web caused by uneven stress distribution and excessive transmission distance of the pressing force, and eliminates the web out-of-tolerance problem caused by tool clamping, machine Z-direction error and the like based on the actual situation of the workpiece, improves the web thickness machining precision, and improves the qualification rate of the frame type structural part, and prevents the frame type structural part from being scrapped.

[0024] 2、Before the web in the weak rigid region of the frame type structural part is finished, the Z-direction offset is set, and the knife lifting verification machining is carried out, which can effectively avoid the quality problem of web thickness out-of-tolerance caused by deformation in the actual machining process of the part, machine Z-direction precision error and tool sleeve clamping error.

[0025] 3、The maximum deformation δ of the frame type structural part in the weak rigid region is calculated by using finite element simulation or typical structure deformation calculation method, the Z-direction lifting amount can be set targetly, and the influence of the actual deformation amount on the web thickness in the web finishing process of the part can be effectively verified. If the Z-direction lifting amount is set too large, the rigidity of the part web during verification is greater than that during the finishing of the part web, and the influence of the actual deformation amount on the web thickness in the finishing process of the part web cannot be verified. If the Z-direction lifting amount is set too small, the web is prone to be too small due to the deformation of the part web being greater than the Z-direction lifting amount. BRIEF DESCRIPTION OF DRAWINGS

[0026] The application will be further described in detail below with reference to the drawings and specific embodiments of the application, in which:

[0027] Figure 1 It is a schematic diagram for selecting the weak rigid region of the part web in the application;

[0028] Figure 2 It is a schematic diagram of the verification machining region in the application. DETAILED DESCRIPTION

[0029] Example 1

[0030] As a basic embodiment of the application, the application comprises a frame type structural part high-precision web anti-deformation machining method, comprising the following steps:

[0031] Step S1. According to the part structure characteristics and the arrangement of the process compression boss compression hole, the weak rigid region of the part web is selected.

[0032] Step S2. The maximum deformation δ of the weak rigid region web of the part is calculated.

[0033]

[0034] Wherein, C1, C2, C3, C4, C5, C6 are constant terms; H is the theoretical thickness of the weak rigid region frame web after rough machining; a is the machining allowance of the weak rigid region web of the frame structure before finishing machining; L is the maximum length of the selected frame structure contour.

[0035] Step S3. According to the maximum deformation δ, Z-direction tool lifting anti-deformation verification machining is carried out in the frame of the weak rigid region, that is, in the verification machining area.

[0036] Step S4. After verification machining, the actual web thickness of the verification machining area is measured.

[0037] Step S5. According to the measurement of step S4, the program offset of subsequent formal machining is determined.

[0038] Example 2

[0039] As a preferred embodiment of the present application, the present application comprises a high-precision web anti-deformation machining method for frame structure, comprising the following steps:

[0040] Step S1. According to the part structure characteristics and the arrangement of the process compression boss compression hole, the weak rigid region of the part web is selected, and the selection method is: selecting the web with the minimum sum of distances from each boss compression hole.

[0041] Step S2. The part model is constructed in finite element simulation, and the compression hole is rigidly limited. The tool stress F is applied to the weak rigid region of the web. The maximum deformation δ of the weak rigid region web of the part is calculated by the maximum deformation δ calculation method of the part weak rigid region web obtained in the finite element simulation:

[0042]

[0043] Wherein, C1, C2, C3, C4, C5, C6 are constant terms; H is the theoretical thickness of the weak rigid region frame web after rough machining; a is the machining allowance of the weak rigid region web of the frame structure before finishing machining; L is the maximum length of the selected frame structure contour.

[0044] Step S3. According to the maximum deformation δ, Z-direction tool lifting anti-deformation verification machining is carried out in the frame of the weak rigid region, that is, in the verification machining area.

[0045] Step S4. After the verification machining, measure the actual web thickness of the verification machining area.

[0046] Step S5. Determine the program offset amount of the subsequent formal machining according to the measurement of step S4.

[0047] Example 3

[0048] As another preferred embodiment of the present application, the present application comprises a high-precision web anti-deformation machining method for frame-like structural members, comprising the following steps:

[0049] Step S1. Select the weak-rigidity area of the web of the part according to the structural features of the part and the arrangement of the process compression boss compression hole positions.

[0050] Step S2. Calculate the maximum deformation δ of the web of the weak-rigidity area of the part:

[0051]

[0052] wherein C1, C2, C3, C4, C5, and C6 are constant terms; H is the theoretical thickness of the frame web after rough machining; a is the machining allowance of the web of the weak-rigidity area of the frame-like structural member before finish machining; and L is the maximum length of the profile of the frame-like structural member selected.

[0053] Step S3. Perform Z-direction tool lifting anti-deformation verification machining in the frame of the weak-rigidity area, i.e., the verification machining area, according to the maximum deformation δ. That is, before finish machining of the web, set the actual Z-direction origin value = the initial Z-direction origin + the Z-direction tool lifting amount. Wherein the Z-direction tool lifting amount = the maximum deformation δ of the web of the weak-rigidity area of the frame-like structural member + 0.1 mm.

[0054] Step S4. After the verification machining, measure the actual web thickness of the verification machining area.

[0055] Step S5. Determine the program offset amount of the subsequent formal machining according to the measurement of step S4. If the actual thickness of the web of the verification machining area is less than the theoretical thickness, tool lifting machining is needed in the subsequent formal machining; if the actual thickness of the web is greater than the theoretical thickness, tool lowering machining is needed in the subsequent formal machining.

[0056] Example 4

[0057] As another preferred embodiment of the present application, the present application comprises a high-precision web anti-deformation machining method for frame-like structural members, comprising the following steps:

[0058] Step S1. Select the weak-rigidity area of the web of the part according to the structural features of the part and the arrangement of the process compression boss compression hole positions. The selection method of the weak-rigidity area of the web of the part is to select the web with the minimum sum of distances from each boss compression hole position.Figure 1 The point A of the selected area is selected to minimize the sum of distances to each pressing hole.

[0059] Step S2. Construct a part model in finite element simulation, and define the rigidity at the pressing hole, and apply a tool force F to the weak rigid area of the web. The calculation method of the maximum deformation δ of the weak rigid area of the web in the finite element simulation is obtained.

[0060] The typical frame structure part shown in the drawings is taken as an example. Figure 1 The part structure parameters are taken as independent variables, and the maximum deformation result is taken as dependent variable δ. The response surface model is constructed by using the test design method, and finally the calculation method of the maximum deformation δ of the weak rigid area of the web of the frame structure part is constructed by linear regression analysis:

[0061]

[0062] Wherein, C1, C2, C3, C4, C5, C6 are constant terms; H is the theoretical thickness of the weak rigid area of the web after rough machining; a is the machining allowance of the weak rigid area of the web of the frame structure part before finishing machining; L is the maximum length of the outline of the frame structure part selected.

[0063] Step S3. According to the maximum deformation δ calculated by the above method, Z-direction tool lifting anti-deformation verification machining is carried out in the frame of the weak rigid area of the web. That is, before finishing the web, the actual origin value of the machine tool Z direction is set as Z-direction initial origin+Z-direction tool lifting amount. Wherein, the Z-direction tool lifting amount = the maximum deformation δ of the weak rigid area of the web of the frame structure part+0.1mm. Referring to the drawings Figure 2 The size of the verification machining area is 30mm*20mm, and the tolerance is ±5mm.

[0064] Step S4. After the verification machining is completed, the actual web thickness of the verification machining area is measured. At this time, the theoretical thickness of the web of the verification machining area = the final thickness of the web+Z-direction tool lifting amount.

[0065] Step S5. The program offset amount of subsequent formal machining is determined according to the measurement of step S4. If the actual web thickness of the verification machining area is less than the theoretical thickness, tool lifting machining is carried out in subsequent formal machining; if the actual web thickness is greater than the theoretical thickness, tool lowering machining is carried out in subsequent formal machining.

[0066] The Z-direction offset amount is the absolute value of the difference between the theoretical thickness of the part web and the actual web thickness of the verification machining area.

[0067] When tool lifting machining is carried out, the actual origin of the machine tool Z direction is set as Z-direction initial origin+program Z-direction offset amount. When tool lowering machining is carried out, the actual origin of the machine tool Z direction is set as Z-direction initial origin-program Z-direction offset amount.

[0068] Embodiment 5

[0069] As a further preferred embodiment of the present application, the present application comprises a high-precision web deformation prevention processing method for frame-like structural members, comprising the following steps:

[0070] Step S1. Select the weak-rigidity region of the web according to the structural features of the part and the arrangement of the process compression boss compression hole sites. After the rough machining of the frame-like structural member is completed, due to the uneven stress distribution inside the frame-like structural member and the excessively large compression force transmission distance, the frame grids far from the process boss begin to deform to varying degrees. In order to ensure smooth processing and not to damage the part, the region with the weakest rigidity and the most prone to deformation on the frame-like structural member is selected as the verification processing region. The selection principle is that the sum of the distances from the weak-rigidity region of the web to each boss compression hole site is the minimum value. Refer to the drawings shown in the description. Select region A, and the sum of the distances to each compression hole site is the minimum value. Figure 1

[0071] Step S2. Calculate the maximum deformation δ of the weak-rigidity region web of the part according to the structural features of the structural member and the processing equipment parameters:

[0072]

[0073] Wherein, C1, C2, C3, C4, C5, C6 are constant terms; H is the theoretical thickness of the weak-rigidity region web after rough machining of the frame-like structural member; a is the processing allowance of the weak-rigidity region web of the frame-like structural member before finish machining; L is the maximum length of the profile of the frame-like structural member selected.

[0074] When the material of the frame-like structural member is aluminum alloy, through finite element analysis at an equivalent cutting force of about 100N to 300N, taking the part structural parameters as the independent variable and the maximum deformation result as the dependent variable, and supplemented by actual trial cutting, it can be obtained that C1=-0.270, C2=0.005, C3=-0.003, C4=0.328, C5=-3.1×10 -7 , C6=-0.409. If the thickness H of the weak-rigidity region web of the frame grid with processing allowance is 4mm, the processing allowance a is 2mm, and the maximum length L of the frame grid is 275mm, then the maximum deformation δ=0.35mm.

[0075] Step S3. According to the maximum deformation δ, set the Z-direction tool lifting amount, and perform Z-direction tool lifting deformation prevention verification processing in the frame grid with weak-rigidity region web. Wherein, the Z-direction tool lifting amount = the maximum deformation δ of the weak-rigidity region web of the frame-like structural member + 0.1mm.

[0076] Step S4. After the verification processing is completed, measure the actual web thickness of the verification processing region. ​

[0077] Step S5. Determine the program offset for the subsequent formal machining based on the measurement of step S4.

[0078] In summary, the person skilled in the art, after reading the present application document, according to the technical solutions and technical concepts of the present application, without creative mental effort, various corresponding transformation schemes can be made, which all belong to the scope of protection of the present application.

Claims

1. A high-precision web deformation prevention processing method for frame-type structural members, characterized by: Comprising the following steps: Step S1. According to the part structure features and the arrangement of the pressing boss pressing hole positions, the weak rigid region of the part web plate is selected; the selection method of the weak rigid region of the part web plate is: selecting the web plate with the minimum sum of distances from each boss pressing hole position; Step S2. In the finite element simulation, the part model is constructed, and the pressing hole position is limited as a fixed position, the tool stress F is applied to the weak rigid region of the web plate, through the finite element simulation, the calculation method of the maximum deformation δ of the weak rigid region of the web plate is obtained, and the maximum deformation δ of the weak rigid region of the part web plate is calculated: Wherein, C1, C2, C3, C4, C5, C6 are constant terms; H Theoretical thickness of the rough machining of the weak rigid area frame web; a The machining allowance of the weak rigid area web before the finishing machining of the frame structure; L The maximum length of the selected frame structure profile; Step S3. According to the maximum deformation δ, Z-direction tool lifting anti-deformation verification machining is carried out in the frame of the weak rigid region, i.e. in the verification machining area; when the Z-direction tool lifting anti-deformation verification machining is carried out, the actual origin value of the machine tool Z-direction is set as Z-direction initial origin+Z-direction tool lifting amount; wherein, the Z-direction tool lifting amount = the maximum deformation δ of the weak rigid region of the web plate+0.1mm; Step S4. After the verification machining is completed, the actual web plate thickness of the verification machining area is measured; Step S5. According to the measurement of step S4, the program offset amount of subsequent formal machining is determined: if the actual web plate thickness of the verification machining area is less than the theoretical thickness, tool lifting machining is carried out in the subsequent formal machining; if the actual web plate thickness is greater than the theoretical thickness, tool lowering machining is carried out in the subsequent formal machining.

2. The high-precision web deformation prevention processing method for a frame structure according to claim 1, characterized in that: The size of the verification machining area is 30mm×20mm, and the tolerance is ±5mm.

3. The high-precision web deformation prevention processing method of a frame structure according to claim 1, characterized in that: When tool lifting machining is carried out, the actual origin of the machine tool Z-direction is set as Z-direction initial origin+program Z-direction offset amount, and the Z-direction offset amount is the absolute value of the theoretical thickness of the part web plate minus the actual web plate thickness of the verification machining area.

4. The high-precision web deformation prevention processing method of a frame structure part according to claim 1, characterized in that: When tool lowering machining is carried out, the actual origin of the machine tool Z-direction is set as Z-direction initial origin-program Z-direction offset amount, and the Z-direction offset amount is the absolute value of the theoretical thickness of the part web plate minus the actual web plate thickness of the verification machining area.

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