A method of preventing welding distortion in a wing frame and skin

Abstract

The present application relates to a kind of methods for preventing wing skeleton and skin from welding deformation, belong to welding technical field, solve the problem that existing laser welding technology is used for welding wing skeleton and skin when easily welding deformation.A kind of methods for preventing wing skeleton and skin from welding deformation, comprising the following steps: S1, design the tooling fixture for welding wing skeleton and wing skeleton and skin;S2, the parts of the wing skeleton to be welded are assembled on substrate;S3, after assembly, chord plane measurement is carried out;S4, using laser welding method, the joint of wing skeleton is welded;S5, the chord plane measurement of wing skeleton obtained by welding is carried out, and is corrected.The present application effectively controls and reduces the deformation problem of wing skeleton and skin in the process of laser welding by optimizing tooling fixture, assembly procedure, welding sequence, chord plane measurement and correction, and welding deformation can be controlled below ±0.5%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding, in particular to a method for preventing welding deformation of a wing framework and a skin. BACKGROUND

[0002] As an advanced welding technology, laser welding has many advantages in wing manufacturing, such as high energy density, precise heat input control, and small heat-affected zone. However, this technology also has some difficulties in the process of wing laser welding, especially regarding welding deformation.

[0003] The welding deformation of laser welding when applied to wing manufacturing mainly comes from the following reasons: (a) high energy density: laser welding has high energy density, and the energy is concentrated in a small area, which can cause the temperature of the welding point and its surrounding area to rise rapidly, resulting in thermal expansion; (b) temperature gradient: during the welding process, due to the action of the laser beam, the temperature distribution of the welding area and the surrounding material is uneven, forming a significant temperature gradient; this uneven temperature field can cause uneven thermal expansion of the material, and further cause thermal stress and thermal deformation; (c) structure and material properties: the materials commonly used in wing manufacturing, such as titanium alloy and aluminum alloy, have low thermal conductivity and high thermal expansion coefficient, which makes them more prone to deformation during laser welding; and the wing framework is usually composed of longitudinal and transverse beams and ribs, all of which are thin-walled parts, with many welding joint positions and poor rigidity of thin-walled parts, resulting in an increase in critical positions prone to welding deformation.

[0004] As can be seen, welding deformation is a common problem in the process of wing welding, which can cause a series of hazards to the performance and safety of the aircraft. Therefore, it is urgent to provide a method that can effectively control and prevent welding deformation of the wing framework and the skin, which is of great significance to ensure the welding quality of the aircraft wing and guarantee the safety and reliability of the aircraft. SUMMARY

[0005] In view of the above analysis, the present application aims to provide a method for preventing welding deformation of a wing framework and a skin, to solve the problem of easy welding deformation when using existing laser welding technology to weld the wing framework and the skin.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] The present application provides a method for preventing welding deformation of a wing framework and a skin, comprising the following steps:

[0008] S1, designing a tooling fixture for welding the wing framework and the wing framework and the skin;

[0009] The wing framework comprises M longitudinal members distributed in parallel along a first direction and N transverse members distributed in parallel along a second direction, each transverse member containing M-1 transverse ribs, the M longitudinal members and N×(M-1) transverse ribs are connected to form a grid structure through 2×N×(M-1) joints, M≥3, N≥3; the first direction is different from the second direction;

[0010] The tool clamp of the wing framework comprises a base plate, a positioning mechanism and a clamping mechanism arranged on the base plate; the clamping mechanism comprises three types of pressing mechanisms, side pressing mechanisms and pushing mechanisms;

[0011] S2, assembling the parts of the wing framework to be welded on the base plate, controlling the relative positions of the parts and the welding deformation through the reasonably designed positioning mechanism, pressing mechanism, side pressing mechanism and pushing mechanism; specifically comprising the following steps:

[0012] S21: cooperating the first longitudinal member with the positioning mechanism to position; arranging one side pressing mechanism at each of the 1 / 5-2 / 5 and 3 / 5-4 / 5 sections of the first longitudinal member between any two adjacent joints, and arranging one pressing mechanism at the 2 / 5-3 / 5 section;

[0013] S22: sequentially assembling N transverse ribs on the base plate from one end to the other end of the first longitudinal member, and arranging two side pressing mechanisms at the 1 / 3-2 / 3 section of each transverse rib;

[0014] S23: assembling the second longitudinal member on the base plate, and arranging side pressing mechanisms at the 1 / 5-4 / 5 section of the second longitudinal member between any two adjacent joints;

[0015] Alternately repeating S22 and S23 to assemble the remaining M-3 longitudinal members and N×(M-2) transverse ribs;

[0016] S24: assembling the Mth longitudinal member on the base plate, arranging one side pressing mechanism at each of the 1 / 5-2 / 5 and 3 / 5-4 / 5 sections of the Mth longitudinal member between any two adjacent joints, arranging one pressing mechanism at the 2 / 5-3 / 5 section, and arranging one pushing mechanism outside the Mth longitudinal member and opposite to each joint;

[0017] S3: after assembly, measuring the chord plane;

[0018] S4: using laser welding, sequentially welding the 2×N×(M-1) joints of the wing framework from one end to the other end along the first direction and from one side to the other side along the second direction according to the welding sequence, to control the welding deformation;

[0019] S5: measuring the chord plane of the wing framework obtained by welding to correct the shape.

[0020] Further, each pressing mechanism comprises a pressing strip, two ends of the pressing strip are respectively arranged on two sides of the first longitudinal member or the Mth longitudinal member, and the first longitudinal member or the Mth longitudinal member is pressed and fixed on the base plate.

[0021] Further, each side pressing mechanism comprises a pressing piece, one end of the pressing piece is pressed on the surface of any longitudinal member or transverse rib, and the other end is fixed on the base plate, so that the longitudinal member or the transverse rib is pressed and fixed on the base plate.

[0022] Further, each pushing mechanism comprises a pushing block and a mounting seat, the pushing block comprises a top rod and an end pressing part which are connected with each other, the mounting seat is fixed on the base plate, the top rod is fixed in the mounting seat through rotary connection, and the end pressing part is driven to abut against the side wall of the Mth longitudinal member by rotating the top rod.

[0023] Further, the positioning mechanism comprises W positioning pins, the W positioning pins are matched with the W lugs contained in the first longitudinal member to limit the position of the first longitudinal member relative to the base plate in the first direction, and W≥2.

[0024] Further, the wing skeleton and skin jig comprises:

[0025] In S1, the wing skeleton and skin jig comprises a base plate, a skeleton side pressing mechanism and a skin pressing mechanism arranged on the base plate.

[0026] In S6, the wing skeleton and skin to be welded are assembled on the wing skeleton and skin jig, and the relative position and welding deformation of the wing skeleton and skin are controlled through the skeleton side pressing mechanism and the skin pressing mechanism, and the method comprises the following steps:

[0027] In S61, the wing skeleton is assembled on the base plate, and one skeleton side pressing mechanism is arranged on the 1 / 5-2 / 5 and 3 / 5-4 / 5 sections of the first longitudinal member and the Mth longitudinal member of the wing skeleton between any two adjacent joints.

[0028] In S62, the upper skin and the lower skin are arranged on the front surface and the back surface of the wing skeleton, and 2×(M+N-4) skin pressing mechanisms are arranged on the outer side of the upper skin and the lower skin and along the M-2 longitudinal members and N-2 transverse ribs in the wing skeleton which are in contact with the upper skin and the lower skin.

[0029] In S7, chord plane measurement is performed on the assembled wing skeleton and skin.

[0030] In S8, a combination of the wing skeleton and the upper and lower skins is obtained by laser welding, and the welding sequence is as follows to control the welding deformation:

[0031] S81: sequentially weld the contact parts of the second transverse member, the third transverse member, …, the N-1th transverse member and the skin along the first direction from one end to the other end; for each transverse member, symmetrically weld along the second direction from one side to the other side;

[0032] S82: sequentially weld the contact parts of the second longitudinal member, the M-1th longitudinal member, the third longitudinal member, the M-2th longitudinal member, …, the 1 / 2*Mth longitudinal member or the 1 / 2*(M+1)th longitudinal member and the skin along the second direction from one side to the other side; for each longitudinal member, symmetrically weld along the first direction from one end to the other end;

[0033] S83: bottom tack weld the contact parts of the first longitudinal member, the Mth longitudinal member, the first transverse member and the Nth transverse member and the skin on the outer side of the wing frame;

[0034] S9: chord plane measure the assembly.

[0035] Further, each skin pressing mechanism comprises a pressing strip, a slot with a size of the contact part of the longitudinal member or the transverse member inside the wing frame and the skin and penetrating through the upper and lower surfaces of the pressing strip is formed on the pressing strip, and the pressing strip is used to fix and press the wing frame together with the upper skin or the lower skin covering the surface of the wing frame on the base plate along the first direction or the second direction.

[0036] Further, the chord plane measurement results of S5 and S3 are compared, the chord plane measurement results of S9 and S7 are compared, the deformation point position and the deformation amount are obtained, the wing frame and the assembly are corrected, and the slight deformation in the laser welding process is further eliminated to ensure the dimensional accuracy.

[0037] Further, the device for chord plane measurement comprises at least one of a laser scanner and a laser tracker; and / or,

[0038] Further, the correction method comprises one or a combination of mechanical correction, thermal correction, cold correction and numerical control correction.

[0039] Further, the tooling fixture for welding the wing frame and the wing frame and the skin further comprises a rotating mechanism coaxially arranged on both sides of the base plate.

[0040] S4 further comprises welding the front weld of each joint of the wing frame first; then turning over the tooling fixture through the rotating mechanism to weld the back weld of each joint; and then adjusting the tooling fixture through the rotating mechanism to weld the side weld of each joint to reduce the welding deformation.

[0041] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0042] The present application provides a method for preventing the deformation of wing skeleton and skin during welding, which is optimized from multiple aspects (fixture, assembly process, welding sequence, chord plane measurement and shape correction), effectively controls and significantly reduces the deformation of wing skeleton and skin during laser welding, and the welding deformation can be controlled below ±0.5%;

[0043] (1) The present application effectively controls the movement and misplacement during welding and significantly reduces the welding deformation by optimizing the fixture and assembly process, including positioning scheme, clamping scheme (clamping mechanism type, clamping point position and number, assembly sequence).

[0044] a. Positioning scheme: when assembling the parts of the wing skeleton, first cooperate with the positioning mechanism on the fixture and the first longitudinal member to determine its position along the first direction relative to the base plate, and take this position as the reference position when installing other members to ensure the relative position of each member during assembly.

[0045] b. Clamping scheme: by selecting appropriate clamping mechanism type (including pressing mechanism, side pressing mechanism, pushing mechanism, skeleton side pressing mechanism, skin pressing mechanism), setting appropriate number of clamping mechanisms at appropriate positions, and using appropriate assembly sequence to rigidly fix each part, ensure uniform distribution of clamping force and avoid unnecessary constraints in the welding area; at the same time, by providing appropriate support points for the parts to be welded by the base plate, effectively control the movement and misplacement during welding, and significantly reduce the welding deformation.

[0046] (2) The present application reduces the accumulation of welding stress and deformation by optimizing the welding sequence.

[0047] Specifically, when welding the parts of the wing skeleton, the preferred welding sequence (including welding from one end to the other end along the first direction, and from one side to the other side along the second direction) is adopted; when welding the wing skeleton and skin, first adopt the preferred welding sequence (including welding M-2 longitudinal members from both sides to the middle along the second direction, and symmetrically welding each longitudinal member from both ends to the middle along the first direction) for penetration welding, and then adopt the preferred welding sequence (including welding the outermost longitudinal member first, and then welding the outermost transverse member) for bottom locking welding; the above welding sequence can make the weld shrink freely and reduce the accumulation of welding stress, thereby preventing deformation, cracking and other problems caused by residual stress generated during welding.

[0048] (3) The present application further eliminates the slight deformation during welding by chord plane measurement and shape correction.

[0049] Specifically, by respectively measuring chord plane of the wing framework and the combination of the wing framework and upper and lower skin before and after welding, the deformation point position and deformation amount are obtained by comparison, and the wing framework and the combination of the wing framework and upper and lower skin are corrected to ensure the dimensional accuracy of the wing framework and the skin after welding.

[0050] The various technical solutions described above can also be combined with each other in the present application to achieve more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purposes and other advantages of the present application can be achieved and obtained through the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings are included to provide a further understanding of the embodiments and no limitation on the present application is intended to be represented thereby, it being intended that the application can be practiced with or without the exact configurations illustrated in the drawings.

[0052] Figure 1 A schematic view (partly) of a wing framework provided for an embodiment of the present application;

[0053] Figure 2 A schematic view (partly) of a wing framework provided for an embodiment of the present application on a tool fixture;

[0054] Figure 3 In (a), (b), (c), (d), (e) and (f), (a) is a schematic view of a wing framework provided for an embodiment of the present application; Figure 2 In (a), (b), (c), (d), (e) and (f), (a) is a schematic view of a wing framework provided for an embodiment of the present application; Figure 2 In (a), (b), (c), (d), (e) and (f), (a) is a schematic view of a wing framework provided for an embodiment of the present application; Figure 2 In (a), (b), (c), (d), (e) and (f), (a) is a schematic view of a wing framework provided for an embodiment of the present application; Figure 2 In (a), (b), (c), (d), (e) and (f), (a) is a schematic view of a wing framework provided for an embodiment of the present application; Figure 2 In (a), (b), (c), (d), (e) and (f), (a) is a schematic view of a wing framework provided for an embodiment of the present application;

[0055] Figure 4 A schematic view (partly) of a wing framework and a skin provided for an embodiment of the present application;

[0056] Figure 5 A schematic view (partly) of a wing framework and a skin provided for an embodiment of the present application on a tool fixture;

[0057] Figure 6 A site map of welding deformation obtained by comparing a chord plane three-dimensional model of a wing framework before and after welding provided for an embodiment of the present application;

[0058] Figure 7 A photo (partly) of a weld seam of a wing framework and a skin locking bottom welding provided for an embodiment of the present application;

[0059] Figure 8The X-ray non-destructive testing photo (partial) of the weld seam of the wing frame and skin lock bottom welding provided by the embodiment of the present application;

[0060] Reference signs:

[0061] 100-wing frame; 11-first main beam; 12-second main beam; 13-third main beam; 14-first cross rib; 15-second cross rib; 16-third cross rib; 17-fourth cross rib; 18-vent hole; 200-tool clamp of the wing frame; 21-positioning pin; 22a-pressing mechanism; 22b-side pressing mechanism; 22c-pushing mechanism; 23a-first rotating mechanism; 23b-second rotating mechanism; 24-connection end; 25-butted joint; 26-step groove; 300-skin; 400-tool clamp of the wing frame and skin; 41-skin pressing mechanism; 42-frame side pressing mechanism; 43a-first clamp rotating mechanism; 43b-second clamp rotating mechanism. DETAILED DESCRIPTION

[0062] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which form a part of this application, and together with the embodiments of the present application serve to explain the principles of the present application, and are not intended to limit the scope of the present application.

[0063] The present application provides a method for preventing welding deformation of a wing frame and skin, comprising the following steps:

[0064] Step S1, designing a tool clamp for welding the wing frame and the wing frame and skin;

[0065] The wing frame comprises: M longitudinal members distributed in parallel along a first direction and N transverse members distributed in parallel along a second direction, each transverse member containing M-1 cross ribs, the M longitudinal members and N×(M-1) cross ribs being connected by 2×N×(M-1) joints to form a grid structure, M≥3, N≥3; the first direction is different from the second direction.

[0066] The tool clamp of the wing frame comprises: a base plate, a positioning mechanism arranged on the base plate, and a clamping mechanism; wherein the clamping mechanism comprises three types of pressing mechanism, side pressing mechanism and pushing mechanism.

[0067] Preferably, the included angle between the first direction and the second direction is 85°-95°; illustratively, the included angle between the first direction and the second direction is a right angle.

[0068] Preferably, the longitudinal members and the cross ribs are rod-shaped members; more preferably, the longitudinal members and the cross ribs are hollow rod-shaped members.

[0069] Optionally, the cross-sectional shape of the longitudinal members and the cross ribs can be one or a combination of, but not limited to, I-shaped and Π-shaped.

[0070] Preferably, the wall thickness of the longitudinal members and the cross ribs is 2mm-10mm; more preferably, the wall thickness of the longitudinal members and the cross ribs is 2mm-3mm.

[0071] Preferably, the material of the longitudinal members and the cross ribs is one or a combination of titanium alloy, aluminum alloy, and steel.

[0072] Preferably, all the longitudinal members and the cross ribs of the wing skeleton are manufactured by 3D printing method; wherein, when the model of 3D printing is established, the M longitudinal members are designed to include 2xNx(M-1) connecting end heads along the second direction to accurately butt joint with the two end faces of each cross rib to form 2xNx(M-1) butt joints; the inner side edges of the longitudinal members and the cross members located at the outermost side of the wing skeleton are designed to include step grooves with the same thickness as the skin; and air holes are reserved on the longitudinal members and the cross ribs located inside the wing skeleton to make each grid structure communicate;

[0073] Preferably, the above-mentioned 3D printing method further comprises: after the 3D printing is completed, machining finishing is performed on all the longitudinal members and the cross ribs (mainly the surfaces to be welded) to further improve the accuracy when the butt joints of the longitudinal members and the cross members located at the outermost side of the wing skeleton and the skin are aligned. The machining finishing method can be selected as needed, including but not limited to one or a combination of milling, grinding, scraping, lapping, superfinishing, and polishing.

[0074] Exemplarily, referring to Figure 3 (d), the third main beam 13 includes a connecting end head 24 along the second direction to accurately butt joint with the left end face of the fourth cross rib 17 to form a butt joint 25.

[0075] It is worth noting that, compared with the T-shaped joints between the longitudinal members and the cross ribs, the longitudinal members obtained by 3D printing and machining finishing are connected to the two ends of the cross ribs one by one to form butt joints, which at least achieves the following beneficial effects: (1) due to the symmetry of the butt joints formed by the two ends of the cross rib, more uniform stress distribution can be provided in the welding area, reducing the risk of cracks and other welding defects caused by stress concentration; (2) the heat distribution is relatively uniform when the butt joint is welded, which helps to reduce the generation of welding defects such as pores and incomplete fusion; (3) the welding strength of the butt joint is higher, and the weld width is smaller, which does not require additional filler material or special edge design, and may be more economical in material use, which is conducive to achieving the requirements of lightweight and high strength of the wing.

[0076] Exemplarily, referring to Figure 3(e), the inner side of the transverse member at the uppermost end of the wing skeleton and the rightmost longitudinal member comprises a stepped groove 26, the height of the stepped groove is the same as the thickness of the skin, so that the upper and lower skins are overlapped on the stepped groove 26 to form a flush joint.

[0077] It is worth noting that, compared with the direct lap joint of the upper and lower skins on the surface of the wing skeleton, the present application at least achieves the following beneficial effects by designing the stepped groove on the outermost side of the wing skeleton around the periphery for the skin to lap on the stepped groove to form a flush joint: (1) the contact area of the wing skeleton and the skin around the periphery is larger, which is conducive to improving the welding strength of the all-around lock-bottom welding, and the welding seam width is smaller, which is conducive to achieving the balance of light weight and high strength; (2) due to the larger contact area of the wing skeleton and the skin around the periphery, the heat distribution is relatively uniform during welding, which helps to reduce the generation of welding defects such as pores and incomplete fusion; (3) by using the positioning function of the stepped groove, no additional positioning mechanism is needed, and the positioning of the skin and the wing skeleton can be quickly realized, and the relative position and structural stability of the skin and the wing skeleton can be maintained during welding, reducing the risk of cracks and other welding defects caused by stress concentration.

[0078] Exemplarily, referring to Figure 1 , all longitudinal members and cross ribs inside the wing skeleton (such as the second main beam 12 and the third cross rib 16) are reserved with air holes to make each grid structure communicate.

[0079] It can be understood that the shape of the base plate is determined by the shape of the wing skeleton, and can be designed as needed as long as it can support and support the to-be-welded parts of the wing skeleton. Exemplarily, referring to Figure 2 , the shape of the base plate is a grid-shaped thin plate, and each grid inside includes a hollow structure.

[0080] It should be noted that the positioning mechanism on the base plate includes W positioning pins, W≥2; the W lugs contained in the first longitudinal member cooperate with the W positioning pins to define the position of the first longitudinal member relative to the base plate in the first direction, which will serve as the reference position when other components are installed, thereby ensuring the relative position of each component during assembly.

[0081] Preferably, the positioning mechanism is arranged outside the to-be-welded area to avoid the welding seam position and ensure the accessibility of the welding tool; in one possible design, referring to Figure 2 , the outer side of the first longitudinal member (i.e. the first main beam 11) comprises two lugs arranged at intervals in the first direction, each lug is matched with the positioning pin 21 on the base plate, that is, the positioning pin 21 passes through the inner hole on the lug to accurately position the first longitudinal member in the first direction on the position of the positioning pin on the base plate.

[0082] It should be noted that the clamping mechanism on the base plate includes one or a combination of the three types of pressing mechanism, side pressing mechanism and pushing mechanism, and the number and position of each type of clamping mechanism can be designed as needed.

[0083] Preferably, the clamping mechanism includes a combination of the three types of pressing mechanism, side pressing mechanism and pushing mechanism.

[0084] Preferably, each pressing mechanism includes a pressing strip, the two ends of which can be located on both sides of the longitudinal member or cross rib and fix and press the longitudinal member or cross rib along the entire width direction on the base plate, so as to control the relative position of the parts to be welded in the wing skeleton and the thermal deformation during welding.

[0085] As an optional embodiment, the two ends of the pressing strip are fixed on the base plate by threaded connection; for example, see Figure 2 and Figure 3 (a), the pressing mechanism 22a includes a pressing strip with holes at both ends for screws or bolts to pass through and screw into the base plate.

[0086] Preferably, each side pressing mechanism includes a pressing sheet, one end of which can be located on the surface of the longitudinal member or cross rib, and the other end is fixed on the base plate, for fixing and pressing the longitudinal member or cross rib along part or all of the width on the base plate, so as to control the relative position of the parts to be welded in the wing skeleton and the thermal deformation during welding.

[0087] As an optional embodiment, the pressing sheet is fixed on the base plate by threaded connection; for example, see Figure 2 and Figure 3 (b), the side pressing mechanism 22b includes a pressing sheet with holes at the part not in contact with the longitudinal member or cross rib for screws or bolts to pass through and screw into the base plate.

[0088] It can be understood that the number of holes on the pressing sheet can be designed as needed; for example, the pressing sheet includes two holes to achieve effective fixation while ensuring uniform distribution of clamping force and avoiding deformation due to local over-tightening.

[0089] In a possible design, the pressing sheet is further provided with a blind groove for accommodating the protruding part on the longitudinal member or cross rib, so as to adapt to the non-planar shape of the parts to be welded in the wing skeleton and facilitate installation operation; the shape of the blind groove is determined by the shape of the protruding part on the longitudinal member or cross rib.

[0090] Preferably, each pushing mechanism comprises a pushing block and a mounting seat, the pushing block comprises a top rod and an end pressing part connected with each other, the mounting seat is fixed on the base plate, the top rod is fixed in the mounting seat through a rotating connection, and the end pressing part is driven to abut against the side wall of the longitudinal member or the transverse rib by rotating the top rod, so that the relative position of the to-be-welded part in the wing framework and the thermal deformation during welding are controlled.

[0091] Preferably, the top rod and the mounting seat are connected through threads; for example, see Figure 2 and Figure 3 (c), the pushing mechanism 22c is connected with the mounting seat through threads arranged on the outer surface of the top rod and threads in the hole of the mounting seat.

[0092] The tooling fixture for the wing framework and the skin comprises a base plate, a framework side pressing mechanism arranged on the base plate, and a skin pressing mechanism.

[0093] Preferably, each framework side pressing mechanism comprises a pressing sheet, one end of the pressing sheet is capable of pressing on the surface of the outermost longitudinal member or transverse member of the wing framework, and the other end of the pressing sheet is fixed on the base plate; so that the relative position of the wing framework and the tooling fixture and the thermal deformation are controlled; for example, see Figure 5 The framework side pressing mechanism 42 is used for fixing and pressing the wing framework on the base plate.

[0094] Preferably, each skin pressing mechanism comprises a pressing strip, a groove with a size capable of accommodating the contact surface between the longitudinal member or transverse member inside the wing framework and the skin and penetrating through the upper and lower surfaces of the pressing strip is arranged on the pressing strip; the skin pressing mechanism is used for fixing and pressing the wing framework, the upper skin and / or the lower skin covering the surface of the wing framework on the base plate along the first direction and / or the second direction. The skin pressing mechanism can control the relative position of the wing framework and the upper and lower skins on the base plate, and meanwhile, for the penetration welding of the long weld, the skin pressing mechanism is arranged along the weld between the wing framework and the upper and lower skins, so that the thermal deformation of the wing framework and the skin during welding can be effectively controlled and reduced.

[0095] As an optional embodiment, the pressing strip is fixed on the base plate through threads; for example, a plurality of holes are arranged on the end of the pressing strip and / or along the two sides of the groove, so that the screws or bolts can pass through and be screwed into the base plate and / or the skin.

[0096] Preferably, the tooling fixture for welding the wing framework and the wing framework and the skin further comprises rotating mechanisms coaxially arranged on both sides of the base plate; the two rotating mechanisms are connected with the welding workbench, the wing framework and the skin are conveniently welded at different angles by rotating the tooling fixture, and the accessibility of the welding gun is improved.

[0097] Preferably, the two rotating mechanisms Figure 2the first and second rotating mechanisms 23a and 23b in the first embodiment, Figure 5 the first and second clamp rotating mechanisms 43a and 43b in the second embodiment are coaxially arranged on both sides of the base plate and the rotating axes are perpendicular to the first direction; more preferably, the two rotating structures are coaxially arranged at the middle positions of both sides of the base plate and the rotating axes are perpendicular to the first direction.

[0098] Step S2, assemble the parts of the wing skeleton to be welded on the base plate, control the relative positions of the parts and the welding deformation by the rationally designed positioning mechanism, pressing mechanism, side pressing mechanism and pushing mechanism; specifically including the following steps:

[0099] S21: cooperate the first longitudinal member with the positioning mechanism to position; set one side pressing mechanism at 1 / 5-2 / 5 and 3 / 5-4 / 5 sections of the first longitudinal member between any two adjacent joints (take any one joint of the two adjacent joints as the reference), and set one pressing mechanism at 2 / 5-3 / 5 section;

[0100] In a possible design, cooperate the W lugs contained in the first longitudinal member with the W positioning pins on the base plate to position, so as to limit the position of the first longitudinal member relative to the base plate along the first direction; W≥2.

[0101] Preferably, set one side pressing mechanism at 1 / 4 and 3 / 4 of the first longitudinal member between any two adjacent joints (take any one joint of the two adjacent joints as the reference), and set one pressing mechanism at 1 / 2.

[0102] S22: sequentially assemble N cross ribs on the base plate along one end to the other end of the first longitudinal member, and set two side pressing mechanisms at 1 / 3-2 / 3 section of each cross rib (take any one end of both ends of each cross rib as the reference);

[0103] Preferably, set one side pressing mechanism at 1 / 3 and 2 / 3 of each cross rib (take any one end of both ends of each cross rib as the reference).

[0104] S23: assemble the second longitudinal member on the base plate, and set side pressing mechanisms at 1 / 5-4 / 5 section of the second longitudinal member between any two adjacent joints (take any one joint of the two adjacent joints as the reference);

[0105] Specifically, place the second longitudinal member on the base plate and abut the ends of the N cross ribs in S22, and set side pressing mechanisms at 1 / 5-4 / 5 section of the second longitudinal member between any two adjacent joints;

[0106] In a possible design, a side-pressing mechanism is arranged at a 2 / 5-3 / 5 section of the second longitudinal member between any two adjacent joints (with reference to any one of the two adjacent joints);

[0107] In a possible design, a side-pressing mechanism is arranged at a 2 / 5-3 / 5 section of the second longitudinal member between any two adjacent joints (with reference to any one of the two adjacent joints);

[0108] Alternately repeating S22 and S23 to assemble the remaining M-3 longitudinal members and N×(M-2) cross members;

[0109] Specifically, the third longitudinal member is assembled according to S23, the N cross members between the third longitudinal member and the fourth longitudinal member are assembled according to S22, and so on; the M-1th longitudinal member is assembled according to S23, and the N cross members between the M-1th longitudinal member and the Mth longitudinal member are assembled according to S22.

[0110] S24: assembling the Mth longitudinal member on the substrate, arranging a side-pressing mechanism at a 1 / 5-2 / 5 section and a 3 / 5-4 / 5 section of the Mth longitudinal member between any two adjacent joints (with reference to any one of the two adjacent joints), arranging a pressing mechanism at a 2 / 5-3 / 5 section, and arranging a pushing mechanism outside the Mth longitudinal member and opposite to each joint;

[0111] More preferably, a side-pressing mechanism is arranged at a 1 / 4 section and a 3 / 4 section of the Mth longitudinal member between any two adjacent joints (with reference to any one of the two adjacent joints), and a pressing mechanism is arranged at a 1 / 2 section.

[0112] Referring to Figure 2 A pushing mechanism 22c is arranged outside the Mth longitudinal member and opposite to each joint.

[0113] In S2, each pressing mechanism comprises a pressing strip, and two ends of the pressing strip are arranged on two sides of the first longitudinal member or the Mth longitudinal member, respectively, to press and fix the first longitudinal member or the Mth longitudinal member on the substrate;

[0114] Each side-pressing mechanism comprises a pressing sheet, one end of the pressing sheet is pressed on a surface of any longitudinal member or cross member, and the other end is fixed on the substrate to press and fix the longitudinal member or the cross member on the substrate;

[0115] Each pushing mechanism comprises a pushing block and a mounting seat, the pushing block comprises a top rod and an end pressing portion which are connected to each other, the mounting seat is fixed on the substrate, the top rod is fixed in the mounting seat through a rotary connection, and the end pressing portion is driven to abut against a side wall of the Mth longitudinal member by rotating the top rod.

[0116] Step S3, after assembly, chord plane measurement is performed;

[0117] S31: select a suitable chord plane measurement device;

[0118] Preferably, the chord plane measurement device comprises at least one of a laser scanner and a laser tracker.

[0119] S32: use the chord plane measurement device to scan along the chord length direction of the wing skeleton, and record the data points.

[0120] S33: input the collected data into computer-aided design (CAD) software, perform data analysis, and generate a chord plane three-dimensional model of the wing skeleton before welding.

[0121] Step S4, using laser welding, according to the welding sequence: welding the 2xNx(M-1) joints of the wing skeleton from one end to the other end along the first direction and from one side to the other side along the second direction in sequence to control the welding deformation; specifically comprising the following steps:

[0122] Step S41: using inert gas to protect the weld from the front and the back;

[0123] Specifically, the tooling fixture assembled with the wing skeleton parts to be welded is placed on the laser welding platform and fixed, and inert gas is used to protect the weld from the front and the back; in one possible design, the tooling fixture is assembled and fixed with the laser welding platform through the rotating mechanisms on both sides of the tooling fixture; wherein the front protection can use the existing technology of drag cover protection method (nozzle + drag cover, inert gas is sprayed from the drag cover).

[0124] Preferably, a sealing cover is built in situ on the back of each weld using flexible sealing material, and an inert gas inlet and outlet are provided on the sealing cover to protect the weld from the back.

[0125] In one possible design, a sealing cover is formed by bonding sealing tape on the longitudinal members and / or cross ribs near the back of each weld, and holes are formed on the sealing cover to form the inert gas inlet and outlet; this method has the advantages of easy availability of materials, simple operation, and good back gas protection effect, and the tape can be quickly removed after welding.

[0126] Further, the positions of the gas inlet and outlet are designed according to the specific gravity of the selected inert gas and air; preferably, the inert gas is argon, the gas inlet is located at the lower part of the sealing cover, and the gas outlet is located at the upper part of the sealing cover; argon is heavier than air, and it is easier to obtain a higher concentration by filling argon from a lower position, and the argon protection effect is better.

[0127] Step S42: all the welding joints are tack welded under the front and back protection of inert gas on the welding seam;

[0128] Preferably, the welding joints are butt joints; the M longitudinal members include 2×N×(M-1) connecting end heads along the second direction, which can be butt-jointed with two end faces of N×(M-1) cross ribs to form 2×N×(M-1) butt joints; the butt joints have high strength and small welding seam, which can reduce the welding heat input and thus reduce the welding thermal deformation.

[0129] Specifically, the welding track is found first, i.e. the laser spot is ensured to be located at the middle position of the welding seam; then all the welding joints of the wing skeleton are tack welded.

[0130] Preferably, the middle part of the welding joint is selected for tack welding; since the length of the welding joint of the longitudinal member and the cross rib of the wing skeleton is relatively short, the middle part of the joint is selected for tack welding, which can effectively ensure the uniformity of the heat input, reduce the welding deformation and stress concentration.

[0131] The length of the tack welding can be determined according to the length of the welding joint; preferably, the length of the tack welding is 1 / 5-1 / 3 of the length of the welding joint; for example, the length of the welding joint is 30 mm, and the length of the tack welding is 10 mm. If the length of the tack welding is too long, the welding area may be overheated and excessively melted, and if the length is insufficient, the welding point may not be firmly connected.

[0132] Optionally, the process parameters of the tack welding are as follows: the laser power is 700-900 W, the defocusing amount is -1.0 mm to -3.0 mm, and the welding speed is 0.5-2.5 m / min; preferably, the process parameters of the tack welding are as follows: the laser power is 750-850 W, the defocusing amount is -1.5 mm to -2.5 mm, and the welding speed is 1.0-2.0 m / min; for example, the laser power is 800 W, the defocusing amount is -2 mm, and the welding speed is 1.5 m / min.

[0133] Step S43: all the welding joints are formally welded under the front and back protection of inert gas on the welding seam;

[0134] Preferably, the welding sequence is as follows: the 2×N×(M-1) joints of the wing skeleton are welded in sequence from one end to the other end along the first direction and from one side to the other side along the second direction, so as to control the welding deformation.

[0135] The above welding sequence can make the welding seam shrink freely, reduce the accumulation of welding stress, and thus minimize the welding deformation caused by the residual stress generated in the laser welding process; at the same time, the welding operation is facilitated, and the straightness of the welding joints located on the same straight line is effectively ensured.

[0136] For example, see Figure 1 The eight welded joints are welded sequentially in the order of (①-⑧). That is, from top to bottom, along the second horizontal beam (including the second horizontal reinforcement 15 and the first horizontal reinforcement 14) from left to right, first weld the butt joint ① between the second horizontal reinforcement 15 and the third main beam 13, and the butt joint ② between the second horizontal reinforcement 15 and the second main beam 12; then weld the butt joint ③ between the first horizontal reinforcement 14 and the second main beam 12, and the butt joint ④ between the first horizontal reinforcement 14 and the first main beam 11; then, along the third horizontal beam (including the fourth horizontal reinforcement 17 and the third horizontal reinforcement 16) from left to right, first weld the butt joint ⑤ between the fourth horizontal reinforcement 17 and the third main beam 13, and the butt joint ⑥ between the fourth horizontal reinforcement 17 and the second main beam 12; then weld the butt joint ⑦ between the third horizontal reinforcement 16 and the second main beam 12, and the butt joint ⑧ between the third horizontal reinforcement 16 and the first main beam 11.

[0137] If ① and ④ are welded first, ② and ③ may not be able to be joined into a straight line due to different directions of thermal deformation.

[0138] Preferably, the welding sequence in steps S43 and S42 is the same. By following a consistent welding sequence for tack welding and final welding, it is helpful to better control the heat input and heat distribution during the welding process, thereby reducing welding deformation.

[0139] Preferably, the arc ignition and extinguishing distance during formal welding is 3mm to 7mm; more preferably, the arc ignition and extinguishing distance is 5mm. On the one hand, if the arc ignition and extinguishing distance is too short, the distance between the laser welding gun nozzle and the workpiece surface will be reduced, and the heat of the laser will be transferred to the workpiece more concentratedly, which will lead to local overheating and increase the risk of welding deformation. On the other hand, if the arc ignition and extinguishing distance is too short, the stability of the laser may be reduced, and the laser oscillation may be increased, which will lead to uneven weld formation and increase the risk of welding deformation.

[0140] Optionally, the formal welding process parameters are: laser power of 1700W to 2100W, defocusing amount of -3.5mm to -6.5mm, and welding speed of 0.5m / min to 2.5m / min; preferably, the formal welding process parameters are: laser power of 1850W to 1950W, defocusing amount of -4.5mm to -5.5mm, and welding speed of 1.0m / min to 2.0m / min. For example, the laser power is 1900W, the defocusing amount is -5mm, and the welding speed is 1.5m / min.

[0141] As an optional implementation, step S4 can adopt the following welding sequence: first, weld the front weld of each joint of the wing frame; then, flip the tooling fixture by rotating the mechanism to weld the back weld of each joint; then, adjust the tooling fixture by rotating the mechanism to weld the side weld of each joint to reduce welding deformation.

[0142] In a possible design, for the area that is difficult to reach or difficult to observe during the welding process, i.e. the dead angle position, nonlinear programming or the use of flexible welding equipment, such as welding robots, can be adopted to adjust the welding gun angle according to the actual situation to ensure the reachability of the welding gun.

[0143] Step S5, chord plane measurement is performed on the wing framework obtained by welding.

[0144] The chord plane measurement device and step mentioned in S3 are adopted to perform chord plane measurement on the wing framework.

[0145] The deformation point position and deformation amount are obtained by comparing the chord plane measurement results of S5 and S3, the wing framework is corrected, and the slight deformation in the laser welding process is further eliminated to ensure the dimensional accuracy.

[0146] Optionally, the correction method includes one or a combination of mechanical correction, thermal correction, cold correction, and numerical control correction. The mechanical correction includes but is not limited to manual correction, pressure correction, and stretching correction; the thermal correction includes but is not limited to local heating and overall heating; the cold correction includes but is not limited to cooling shrinkage and cold stretching; and the numerical control correction includes but is not limited to numerical control correction and robot correction.

[0147] Step S6, the wing framework to be welded and the skin are assembled on the fixture clamp of the wing framework and the skin, and the relative position and welding deformation of the wing framework and the skin are controlled through the framework side pressing mechanism and the skin pressing mechanism; specifically including the following steps:

[0148] S61: Assembling the wing framework on the base plate, and arranging one framework side pressing mechanism at each of the 1 / 5-2 / 5 and 3 / 5-4 / 5 segments of the first longitudinal member and the Mth longitudinal member of the wing framework between any two adjacent joints (taking any one of the two adjacent joints as the reference).

[0149] S62: Covering the upper skin and the lower skin on the front and back surfaces of the wing framework, and arranging 2×(M+N-4) skin pressing mechanisms on the outer side of the upper skin and the lower skin and along the contact part of the M-2 longitudinal members and the N-2 transverse members inside the wing framework and the upper skin and the lower skin.

[0150] In a possible design, each skin pressing mechanism includes a pressing strip, a groove with a size equal to the contact surface of the corresponding longitudinal member or transverse member inside the wing framework and the skin and penetrating through the upper and lower surfaces of the pressing strip is formed on the pressing strip, and the pressing strip fixes and presses the wing framework, the upper skin and / or the lower skin covering the surface of the wing framework, and the wing framework together on the base plate along the first direction and / or the second direction.

[0151] Step S7, chord plane measurement is performed on the assembled wing skeleton and skin;

[0152] Chord plane measurement is performed on the wing skeleton and skin by using the device and step mentioned in S3.

[0153] Step S8, the combination of the wing skeleton and the upper and lower skins is obtained by laser welding; specifically, the following welding sequence is adopted to control the welding deformation:

[0154] S81: sequentially weld the contact portions of the second transverse member, the third transverse member, …, the N-1th transverse member and the skin from one end to the other end along the first direction; for each transverse member, weld symmetrically from one side to the other side along the second direction;

[0155] S82: sequentially weld the contact portions of the second longitudinal member, the M-1th longitudinal member, the third longitudinal member, the M-2th longitudinal member, …, to the 1 / 2*Mth longitudinal member or the 1 / 2*(M+1)th longitudinal member and the skin from both sides to the middle along the second direction; for each longitudinal member, weld symmetrically from both ends to the middle along the first direction;

[0156] S83: bottom lock welding is performed on the contact portions of the first longitudinal member, the Mth longitudinal member, the first transverse member and the Nth transverse member and the skin on the outer side of the wing skeleton;

[0157] Preferably, the first longitudinal member and the Mth longitudinal member are welded first, and then the first transverse member and the Nth transverse member are welded. Among them, the longitudinal member with greater rigidity is welded first, and then the transverse member with smaller rigidity is welded, so as to ensure the stability and precision of the overall structure.

[0158] Preferably, in S8, inert gas is used for front protection and back protection of the weld; wherein, by means of the wing skeleton and the upper and lower skins with air holes, a closed and connected gas path environment is formed, the inert gas enters from one end of the wing skeleton and is discharged from the other end of the wing skeleton, thereby protecting the weld from the back.

[0159] In S8, the front protection can adopt the existing technology of drag shield protection method (nozzle + drag shield, inert gas is sprayed from the drag shield).

[0160] Preferably, the following process parameters are used:

[0161] In S81 and S82, the laser power is 2000W-2200W, the defocusing amount is -4mm-6mm, and the welding speed is 0.02m / min-0.03m / min; exemplarily, the laser power is 2100W, the defocusing amount is -5mm, and the welding speed is 0.025m / min;

[0162] In S83, the lock bottom welding includes positioning welding and formal welding;

[0163] The positioning welding has a laser power of 700-900 W, a defocusing amount of -1.0 mm to -3.0 mm, and a welding speed of 0.5-2.5 m / min; preferably, the laser power is 750-850 W, the defocusing amount is -1.5 mm to -2.5 mm, and the welding speed is 1.0-2.0 m / min; exemplarily, the laser power is 800 W, the defocusing amount is -2 mm, and the welding speed is 1.5 m / min.

[0164] The positioning welding has a length of 5-15 mm and a weld spacing of 25-35 mm; exemplarily, the positioning welding has a length of 10 mm and a weld spacing of 30 mm.

[0165] The formal welding has a laser power of 900-1100 W, a defocusing amount of -3 mm to -7 mm, and a welding speed of 0.5-2.5 m / min; preferably, the formal welding has a laser power of 950-1050 W, a defocusing amount of -4 mm to -6 mm, and a welding speed of 1.0-2.0 m / min; exemplarily, the laser power is 1000 W, the defocusing amount is -5 mm, and the welding speed is 1.5 m / min.

[0166] Preferably, in S4 and S8, the front protection gas flow is 20-40 L / min, and the back protection gas flow is 4-6 L / min; more preferably, the front protection gas flow is 20-30 L / min; exemplarily, the front protection gas flow is 25 L / min, and the back protection gas flow is 5 L / min.

[0167] Preferably, in S4 and S8, after the welding is completed, the inert gas protection is stopped after being cooled for 15-20 min; after the welding is completed, the gas protection (mainly the back gas protection) can protect the weld metal from being eroded by harmful gases in the air during the cooling process, and maintain the purity and performance of the weld metal.

[0168] It is worth noting that, in S4 and S8, the above-mentioned preferred welding parameters and inert gas flow have a positive effect on reducing welding deformation.

[0169] For the welding parameters, (a) when the laser power is too large, it can cause the heat-affected zone of the welding area to increase, leading to more heat input into the material and increasing the risk of welding deformation; too small laser power can cause insufficient welding and reduce the performance of the weld; (b) when the defocusing amount is too large, the energy of the laser beam may not be concentrated in the welding area, leading to uneven heat input; this uneven heat distribution can increase the temperature gradient in the welding area and its vicinity and generate larger thermal stress, thereby increasing the risk of welding deformation; while too small defocusing amount can affect the welding quality and efficiency; (c) welding speed: too slow welding speed can cause excessive heat input in the welding area, which can lead to excessive heat-affected zone and increase the risk of welding deformation; too fast welding speed can cause insufficient heat input per unit area, which can make the weld not fully penetrated, affecting the formation of the weld and the welding quality.

[0170] For the inert gas flow, (a) when the gas flow is too large, the cooling effect of the gas on the molten pool will be enhanced, which can cause the temperature of the molten pool to be too low, making the flowability of the welding material worse and increasing the risk of welding deformation; too large gas flow can cause the protective gas flow to be turbulent, which can destroy the protective effect, in which case the molten pool can be invaded by oxygen, nitrogen and other gases in the air, increasing the risk of welding defects such as porosity, which indirectly affects the welding deformation; (b) too small gas flow can cause the gas in the molten pool to not be able to completely overflow, and after the molten pool solidifies, holes can be formed on the surface or inside the weld, these porosity defects can cause local stress concentration of the welded structure, increasing the risk of deformation; when the gas flow is too small, the stiffness of the protective gas is not enough, which can cause the molten pool to be invaded by oxygen, nitrogen and other gases in the air, increasing the risk of welding defects such as porosity, which indirectly affects the welding deformation.

[0171] Step S9, chord plane measurement is performed on the assembly.

[0172] The chord plane measurement device and steps mentioned in S3 above are used to perform chord plane measurement on the assembly.

[0173] The chord plane measurement results of S9 and S7 are compared to obtain the deformation point position and deformation amount, and the assembly of the wing skeleton and the skin is corrected to further eliminate the slight deformation in the laser welding process and ensure the dimensional accuracy.

[0174] Preferably, in steps S2 and S6, the assembly includes: trial assembly, repair of the trial assembly, marking of the assembly tolerance requirements, and marking of the components; pickling to remove the oxide skin and improve the welding quality; formal assembly: after pickling, the components are assembled in sequence according to the matching marks on the components, and clamped with tooling fixtures to ensure that the assembly tolerance requirements are met.

[0175] Preferably, in steps S2 and S6, the assembly tolerance requirement includes that the butt joint gap and step at each point of each joint is not greater than 0.1 mm, and the butt joint gap and step of the cumulative length of not more than 30 mm within a local arbitrary 100 mm is not greater than 0.2 mm.

[0176] Preferably, before assembly, the welding area is pretreated until the metal luster is exposed, and the surface roughness Ra of the welding surface is ≤3.2 μm.

[0177] Specifically, the pretreatment mainly includes processing the welding area by machining finishing; specifically, the welding surface is processed by machining to ensure flatness, smoothness, no burr, and maintain the edges and corners, and the surface roughness Ra of the processed welding surface is ≤3.2 μm; the welding area is cleaned by mechanical processing to remove surface oil stains, non-metallic impurities, etc., until the metal luster is exposed; wherein the welding area includes the welding surface and both sides of the weld; the non-metallic impurities include oxides.

[0178] Optionally, the welding area includes 10 mm to 30 mm on both sides of the weld; preferably, 20 mm on both sides of the weld.

[0179] Optionally, the machining method includes but is not limited to milling, grinding, scraping, grinding, superfinishing, and polishing.

[0180] Optionally, the mechanical processing method includes mechanical polishing, and the tool for mechanical polishing includes but is not limited to a steel wire brush, sandpaper, and a file.

[0181] It can be understood that by pretreating the welding area (including the welding surface), the quality and reliability of the welded joint can be ensured.

[0182] The technical solutions of the present application are further described in detail below in combination with specific embodiments.

[0183] Embodiment 1

[0184] The embodiment provides a method for preventing welding deformation of a TA15 titanium alloy wing framework and a skin, including the following steps:

[0185] Step S1, designing a tool fixture for welding the wing framework and the wing framework and the skin;

[0186] Referring to Figures 1-5The wing skeleton 100 comprises a first main beam 11, a second main beam 12, and a third main beam 13 distributed in parallel along a first direction, and a first cross beam (not shown in the figure), a second cross beam, a third cross beam, and a fourth cross beam (not shown in the figure) distributed in parallel along a second direction; the second cross beam comprises a first cross rib 14 and a second cross rib 15 distributed in a straight line, and the third cross beam comprises a third cross rib 16 and a fourth cross rib 17 distributed in a straight line; the angle between the first direction and the second direction is 87°.

[0187] The main beams and the cross ribs are made of TA15 titanium alloy and are hollow rods with a wall thickness of 3 mm and a cross-sectional shape of an I-beam; the skin is made of TA15 titanium alloy with a wall thickness of 2 mm.

[0188] The tooling fixture 200 of the wing skeleton comprises a base plate, a positioning mechanism, a pressing mechanism, a side pressing mechanism, a pushing mechanism, and two rotating mechanisms 23a and 23b symmetrically and coaxially distributed at the middle positions of the two sides of the base plate.

[0189] The base plate is in the shape of a grid-shaped thin plate, and each grid comprises a quadrilateral or cross-shaped hollow structure;

[0190] The positioning mechanism comprises two positioning pins 21 on the base plate;

[0191] Each pressing mechanism 22a comprises a long strip-shaped pressing strip with two holes at the two ends for screws to pass through and be screwed into the base plate;

[0192] Each side pressing mechanism 22b comprises a long strip-shaped pressing strip with two holes at the part not in contact with the main beam or the cross rib for screws to pass through and be screwed into the base plate;

[0193] Each pushing mechanism 22c comprises a pushing block and a mounting seat, the pushing block comprises a top rod and an end pressing part connected to each other, the mounting seat is fixed to the base plate, the outer surface of the top rod is provided with threads matched with the threads of the inner hole of the mounting seat, and the end pressing part is driven to abut against the side wall of the main beam by rotating the top rod.

[0194] The tooling fixture 400 of the wing skeleton 100 and the skin 300 comprises a base plate, a skin pressing mechanism, a skeleton side pressing mechanism, and two fixture rotating mechanisms 43a and 43b symmetrically and coaxially distributed at the middle positions of the two sides of the base plate.

[0195] Each skin pressing mechanism 41 comprises a long strip-shaped pressing strip with a strip-shaped groove with a size just suitable for accommodating the contact surface of the main beam or the cross beam and the skin;

[0196] Each skeleton side pressing mechanism 42 comprises a long strip-shaped pressing strip with two holes at the part not in contact with the wing skeleton for screws to pass through and be screwed into the base plate.

[0197] Step S2, assemble the parts of the wing skeleton to be welded on the base plate;

[0198] S21: match the two lugs on the right side of the first main beam 11 with the two positioning pins 21 on the base plate, and position; set one side pressing mechanism 22b at 1 / 4 and 3 / 4 of the first main beam 11 between any two adjacent joints, and set one pressing mechanism 22a at 1 / 2;

[0199] S22: sequentially assemble 4 cross ribs on the base plate from the upper end to the lower end of the first main beam 11, and set one side pressing mechanism 22b at 1 / 3 and 2 / 3 of each cross rib, respectively;

[0200] S23: assemble the second main beam 12 on the base plate, and set two side pressing mechanisms 22b distributed face to face at 2 / 5 of the second main beam 12 between any two adjacent joints;

[0201] Repeat S22 to sequentially assemble 4 cross ribs between the second main beam 12 and the third main beam 13;

[0202] S24: assemble the third main beam 13 on the base plate, and set one side pressing mechanism 22b at 1 / 4 and 3 / 4 of the third main beam 13 between any two adjacent joints, and set one pressing mechanism 22a at 1 / 2; set one pushing mechanism 22c on the outer side of the third main beam 13 and opposite to each joint.

[0203] Step S3, after assembly, measure the chord plane of the wing skeleton by using a laser scanner; input the collected data into the Geomagic Control X software to generate a chord plane three-dimensional model of the wing skeleton before welding.

[0204] Step S4, use a laser welding device (device name: large-size three-dimensional multi-layer curved surface high-power high-precision laser welding equipment; manufacturer: Aerospace Sanjiang Laser) to sequentially weld 16 joints from top to bottom and from left to right, and for the 8 joints shown in (①-⑧) in order. Figure 1

[0205] During welding, argon is used to protect the weld seam, and a drag cover + nozzle is used for front protection, and 3M tape is used to bond the main beam and / or cross rib near the back of each weld seam, thereby building a sealed cover, and a hole is made in the lower part of the sealed cover and argon is introduced, and a hole is made in the upper part to form an argon outlet.

[0206] Positioning welding: laser power is 800W, defocusing amount is -2mm, and welding speed is 1.5m / min; select the middle of each joint for positioning welding, and the positioning welding length is 10mm.

[0207] ​Formal welding: laser power is 1900W, defocusing amount is-5mm, welding speed is 1.5m / min; the distance of starting and extinguishing arc is 5mm.

[0208] Step S5, chord plane measurement is performed on the wing skeleton obtained by welding, and the shape is corrected.

[0209] According to the above S3, chord plane measurement is performed on the wing skeleton, and through comparison, the deformation point position and deformation amount are obtained, and cold correction is performed by using a hot correction and rubber hammer knocking method to correct the residual small deformation.

[0210] Step S6, the wing skeleton to be welded and the skin are assembled on the tool fixture of the wing skeleton and the skin;

[0211] S61: the wing skeleton obtained in step S5 is assembled on the base plate, and one skeleton side pressing mechanism 42 is arranged at 1 / 4 and 3 / 4 of the first main beam 11 and the third main beam 13 between any two adjacent joints of the wing skeleton;

[0212] S62: the upper skin and the lower skin are covered on the front and back surfaces of the wing skeleton, and six skin pressing mechanisms 41 are arranged at the contact parts of the second main beam 12, the second cross beam and the third cross beam inside the wing skeleton and the upper skin and the lower skin.

[0213] Step S7, according to S3, chord plane measurement is performed on the assembled wing skeleton and skin;

[0214] Step S8, laser welding is performed according to the following welding sequence to obtain the combination of the wing skeleton and the upper and lower skins;

[0215] S81 and S82: the third cross beam, the second cross beam, the second main beam 12 and the contact parts of the upper skin and the lower skin are sequentially penetrated and welded according to the sequence ①-⑤ shown in Figure 4

[0216] S83: the third main beam 13, the first main beam 11, the upper first cross beam and the lower fourth cross beam (not shown in the figure) are sequentially welded according to the sequence ⑥-⑦ shown in Figure 4

[0217] In the welding, argon is used to protect the front and back surfaces of the weld, wherein the front surface is protected by using a drag cover + nozzle, and the back surface is protected by using the relatively closed and connected gas path environment formed by the wing skeleton and the upper and lower skins with the reserved air holes 18, and the argon enters from the fourth cross beam at the lower part of the wing skeleton and is discharged from the first cross beam at the upper part of the wing skeleton to protect the back surface of the weld;

[0218] In S81 and S82, the laser power is 2100W, the defocusing amount is-5mm, and the welding speed is 0.025m / min;​​

[0219] In S83, the positioning welding is performed with a laser power of 800 W, a defocusing amount of -2 mm, a welding speed of 1.5 m / min, a positioning welding length of 10 mm, and a welding seam spacing of 30 mm; the formal welding is performed with a laser power of 1000 W, a defocusing amount of -5 mm, and a welding speed of 1.5 m / min. The arcing and extinguishing distance is 5 mm.

[0220] In S4 and S8, the front protection shroud gas flow is 25 L / min; and the back protection flow is 5 L / min.

[0221] In step S9, the assembly is subjected to chord plane measurement and correction according to S5.

[0222] Implementation results:

[0223] 1. Chord plane measurement shows that the welding deformation of the wing skeleton, the assembly of the wing skeleton and the skin can be controlled below ±0.5%, as shown in FIG. 1; thus, it is shown that the method provided by the present application can significantly reduce the welding deformation, and further reduce the residual stress and cracking problems, and improve the welding quality; and since the welding deformation is very small, little or almost no correction is needed to meet the standard requirements, and cost reduction and efficiency improvement are achieved. Figure 6 2. Visual or with the aid of a magnifying glass of less than 10 times, the appearance quality of the weld is inspected, and the results show that the weld surface of the wing skeleton, the assembly of the wing skeleton and the skin has no defects such as oxidation, inclusion, porosity, crack, incomplete fusion, undercut, depression, etc., as shown in FIG. 2.

[0224] Figure 7

[0225] 3. X-ray nondestructive testing is performed, and the results show that the weld quality of the wing skeleton, the assembly of the wing skeleton and the skin completely meets the I-grade weld requirement of QJ20465-2016 (Titanium and Titanium Alloy Laser Welding Technical Requirements), as shown in FIG. 3. Figure 8

[0226] 4. The normal temperature tensile sample of the weld is prepared, and the joint normal temperature tensile mechanical property test is performed, and the results show that the normal temperature tensile strength of the weld of the wing skeleton, the assembly of the wing skeleton and the skin can reach more than 95% of the base material; for example, Figure 1 the tensile strength of the four joints ①-④ in the table is 900 Mpa-912 Mpa, and the tensile strength of the base material is about 930 Mpa.

[0227] ​​​The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preventing welding deformation of wing frame and skin, characterized in that, Includes the following steps: S1. Tooling fixtures designed for welding wing frames and wing frames and skins; The wing frame includes: M longitudinal members distributed parallel to a first direction and N transverse members distributed parallel to a second direction. Each transverse member contains M-1 transverse ribs. The M longitudinal members and N×(M-1) transverse ribs are connected by 2×N×(M-1) joints to form a grid structure. M≥3, N≥3; the first direction is different from the second direction. The tooling fixture for the wing frame includes: a base plate, a positioning mechanism and a clamping mechanism mounted on the base plate; the clamping mechanism includes three types: a pressing mechanism, a side pressing mechanism and a pushing mechanism. S2. Assemble the wing frame parts to be welded onto the base plate, using a rationally designed positioning mechanism, clamping mechanism, side pressing mechanism, and pushing mechanism to control the relative position of each part and welding deformation; specifically including the following steps: S21: The first longitudinal member is positioned in conjunction with the positioning mechanism; a side pressing mechanism is set in the 1 / 5 to 2 / 5 and 3 / 5 to 4 / 5 sections of the first longitudinal member located between any two adjacent joints, and a clamping mechanism is set in the 2 / 5 to 3 / 5 section; S22: Along one end of the first longitudinal member to the other end, N transverse ribs are sequentially assembled on the base plate, and two side pressing mechanisms are provided in the 1 / 3 to 2 / 3 section of each transverse rib. S23: Assemble the second longitudinal member on the base plate, and set a side pressure mechanism in the 1 / 5 to 4 / 5 section between any two adjacent joints of the second longitudinal member; Alternately repeat steps S22 and S23 to assemble the remaining M-3 longitudinal members and N×(M-2) transverse ribs; S24: Assemble the Mth longitudinal member on the base plate, and set a side pressing mechanism in the 1 / 5 to 2 / 5 and 3 / 5 to 4 / 5 sections of the Mth longitudinal member located between any two adjacent joints, set a clamping mechanism in the 2 / 5 to 3 / 5 section, and set a pushing mechanism on the outside of the Mth longitudinal member and directly opposite each joint. S3. After assembly, perform chord plane measurement; S4. Using laser welding, weld the 2×N×(M-1) joints of the wing frame in the following order: from one end to the other along the first direction and from one side to the other along the second direction, in order to control welding deformation. S5. Perform chord plane measurement and shape correction on the welded wing frame.

2. The method for preventing welding deformation of the wing frame and skin according to claim 1, characterized in that, Each of the clamping mechanisms includes a clamping bar, with both ends of the clamping bar placed on either side of the first longitudinal member or the Mth longitudinal member, to clamp and fix the first longitudinal member or the Mth longitudinal member onto the substrate.

3. The method for preventing welding deformation of the wing frame and skin according to claim 1, characterized in that, Each of the said side-pressing mechanisms includes a pressing plate, one end of which is pressed against the surface of any longitudinal member or transverse rib, and the other end is fixed to the base plate, thereby pressing and fixing the longitudinal member or transverse rib to the base plate.

4. The method for preventing welding deformation of the wing frame and skin according to claim 1, characterized in that, Each of the pushing mechanisms includes a push block and a mounting base. The push block includes a push rod and an end pressing part connected to each other. The mounting base is fixed to the base plate. The push rod is fixed in the mounting base by a rotatable connection. By rotating the push rod, the end pressing part is driven to abut against the side wall of the Mth longitudinal member.

5. The method for preventing welding deformation of the wing frame and skin according to claim 1, characterized in that, The positioning mechanism includes W positioning pins, which engage the W lugs of the first longitudinal member with the W positioning pins to define the position of the first longitudinal member relative to the substrate along the first direction; W≥2.

6. The method for preventing welding deformation of the wing frame and skin according to claim 1, characterized in that, Also includes: In S1, the tooling fixtures for the wing frame and skin include: a base plate, a frame side pressing mechanism, and a skin pressing mechanism disposed on the base plate; S6. Assemble the wing frame and skin to be welded onto the tooling fixtures for the wing frame and skin. Control the relative position and welding deformation of the wing frame and skin through the frame side pressing mechanism and the skin clamping mechanism; specifically including the following steps: S61: The wing skeleton is assembled on the base plate, and a skeleton side pressure mechanism is set in the 1 / 5 to 2 / 5 and 3 / 5 to 4 / 5 sections of the first longitudinal member and the Mth longitudinal member of the wing skeleton located between any two adjacent joints. S62: The upper and lower skins are covered on the front and back of the wing frame. Two × (M+N-4) skin clamping mechanisms are provided on the outside of the upper and lower skins and along the contact parts of M-2 longitudinal members and N-2 transverse members inside the wing frame with the upper and lower skins. S7. Perform chord plane measurements on the assembled wing frame and skin; S8. Laser welding is used to obtain the wing frame and upper and lower skin assembly; specifically, the following welding sequence is included to control welding deformation: S81: Weld the second transverse member, the third transverse member, ... the N-1th transverse member in contact with the skin in sequence from one end to the other along the first direction; For each transverse member, weld in the same direction from one side to the other along the second direction. S82: Along the second direction from both sides to the middle, weld the second longitudinal member, the M-1 longitudinal member, the third longitudinal member, the M-2 longitudinal member, ... up to the contact part between the 1 / 2*M longitudinal member or the 1 / 2*(M+1) longitudinal member and the skin. For each longitudinal member, weld symmetrically from both ends to the middle along the first direction. S83: The contact portions of the first longitudinal member, the Mth longitudinal member, the first transverse member, and the Nth transverse member on the outer side of the wing frame with the skin are to be locked with bottom welds. S9. Perform chord plane measurements on the assembled body and correct its shape.

7. The method for preventing welding deformation of the wing frame and skin according to claim 6, characterized in that, Each of the skin clamping mechanisms includes a clamping strip with a groove on the clamping strip that is the size of the contact surface between the longitudinal or transverse member inside the wing frame and the skin and extends through the upper and lower surfaces of the clamping strip. The clamping strip is used to fix and press the wing frame together with the upper or lower skin covering the surface of the wing frame onto the base plate along a first direction or a second direction.

8. The method for preventing welding deformation of the wing frame and skin according to claim 1 or 6, characterized in that, It also includes comparing the chord plane measurement results of S5 and S3, and comparing the chord plane measurement results of S9 and S7 to obtain the location and amount of deformation points, correcting the shape of the wing frame and assembly, further eliminating minor deformations during the laser welding process, and ensuring dimensional accuracy.

9. The method for preventing welding deformation of the wing frame and skin according to claim 1 or 6, characterized in that, The device for chordal plane measurement includes at least one of a laser scanner and a laser tracker; and / or, The calibration methods include one or a combination of mechanical calibration, hot calibration, cold calibration, and CNC calibration.

10. The method for preventing welding deformation of the wing frame and skin according to claim 1, characterized in that, The tooling fixture for welding the wing frame and the wing frame and skin also includes a rotating mechanism coaxially arranged on both sides of the base plate. S4 also includes first welding the front weld of each joint of the wing frame; then flipping the tooling fixture through a rotating mechanism to weld the back weld of each joint; and then adjusting the tooling fixture through a rotating mechanism to weld the side weld of each joint to reduce welding deformation.

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