End machining method of stiffened wall plate

Abstract

The invention belongs to the technical field of aircrafts, and discloses an end machining method for a stiffened wall plate. The stiffened wall plate comprises a skin and stringers arranged on the skin at intervals in the width direction of the skin, each stringer comprises a first stringer part and a second stringer part, and the first stringer parts are connected to the end face of the skin in the height direction of the skin; the end machining method of the stiffened wall plate comprises the following steps that a first grinding wheel sheet cuts a second truss part and at least part of a first truss part in the width direction of the stiffened wall plate at a first feeding distance; the milling cutter is used for milling and removing the remaining first truss part and skin in the width direction of the stiffened wall plate by a second feeding distance; the second feeding distance is smaller than the first feeding distance, so that a remaining step is formed at the end of the skin; the second grinding wheel grinds away the remaining steps, on one hand, the amount of powder scraps is small, the problem of layering separation does not need to be worried about, the end of the stiffened wall plate is machined more conveniently, and the machining efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of aircraft technology, and in particular to a method for processing the end of a stiffened panel. Background Technology

[0002] Stiffened panels are an important component of aircraft, characterized by their large size and complex structure.

[0003] The stiffened panel consists of a skin and stringers mounted on the skin, both formed by plying composite materials. After molding, the stiffened panel may have dimensional deviations at its ends and retain burrs or other attachments, necessitating partial cutting at the ends. In existing technologies, milling cutters are difficult to plan tool paths, easily leading to ply separation. Grinding with a grinding wheel generates a large amount of powder and debris. Furthermore, due to the thickness of the skin, the heat accumulates during die cutting with a grinding wheel, resulting in burnt parts and even potential heat-induced wheel distortion. This distortion not only causes the machining profile to deviate from the requirements but the resulting force can also cause the skin to separate on the machined surface, making the end machining of stiffened panels difficult and inefficient. Summary of the Invention

[0004] The purpose of this invention is to provide a method for processing the ends of stiffened wall panels, which makes the processing of the ends of stiffened wall panels more convenient and efficient.

[0005] To achieve this objective, the present invention adopts the following technical solution: A method for processing the end of a stiffened wall panel is provided. The stiffened wall panel includes a skin and stringers spaced apart on the skin along its width direction. The ply direction of the skin is the height direction. Each stringer includes a first stringer portion and a second stringer portion. The first stringer portion is connected to the skin, and the connection between the first stringer portion and the second stringer portion is smoothly transitioned. The second stringer portion is connected to the first stringer portion. The first stringer portion has the same ply direction as the skin, and the second stringer portion is perpendicular to the ply direction of the skin. The method for processing the end of the stiffened wall panel includes the following steps: S1. The first grinding wheel cuts the second truss and at least a portion of the first truss along the width direction of the reinforced wall panel with a first cutting distance; S2. The milling cutter mills away the remaining first truss and skin along the width direction of the stiffened wall panel at a second cutting distance; the second cutting distance is less than the first cutting distance to form a residual step at the end of the skin; S3. The second grinding wheel removes the remaining steps.

[0006] In some embodiments, in step S3, the second grinding wheel grinds away the remaining steps along the width direction of the reinforced wall panel at a third cutting distance, the third cutting distance being not less than the first cutting distance.

[0007] In some embodiments, in step S3, the thickness of the second grinding wheel and the thickness of the residual step are less than the third feed distance.

[0008] In some embodiments, during step S2, the axis of the milling cutter is parallel to the axis of the second truss.

[0009] In some embodiments, in step S2, the angle between the axis of the milling cutter and the axis of the second truss is α, and the angle α is an acute angle.

[0010] In some embodiments, the included angle α is not greater than 30°.

[0011] In some embodiments, the milling cutter is an end mill.

[0012] In some embodiments, in step S1, the depth to which the first grinding wheel cuts the first truss is not less than half the thickness of the second truss.

[0013] In some embodiments, in step S1, the first grinding wheel cuts the entire first truss.

[0014] In some embodiments, the first grinding wheel is mounted on the first flange, and the difference between the radius of the first grinding wheel and the radius of the first flange is greater than the sum of the depth to which the second stringer and the first grinding wheel cut the first stringer; And / or, the second grinding wheel is mounted on the second flange, and the difference between the radius of the second grinding wheel and the radius of the second flange is greater than the sum of the heights of the skin and the stringer.

[0015] The beneficial effects of this invention are: The end processing method of this stiffened wall panel involves first cutting the second stringer and at least the first stringer using a first grinding wheel. Since the stringers are spaced on the skin and are relatively small, a large portion of the first grinding wheel is exposed during cutting, providing better heat dissipation. Furthermore, the small size of the stringers results in less cutting powder and debris, preventing the accumulation of high-temperature dust that could clog the tool and burn the workpiece. Simultaneously, the first grinding wheel performs rotary cutting, avoiding any delamination of the first and second stringers during the cutting process. The remaining first stringer and skin are then milled away using a milling cutter. Since the milling direction is along the width of the stiffened wall panel, the delamination of the stringer and skin is minimized. The layer direction is perpendicular, and during milling, it will not cause the ply separation of the first stringer and the skin. Although the milling direction is parallel to the ply direction of the second stringer, the second cut distance is smaller than the first cut distance. Therefore, the milling cutter will only contact the part of the second stringer that needs to be cut and separated, so there is no need to worry about ply separation. Then, the remaining steps formed by the second grinding wheel due to the smaller second cut distance can be removed. Because the remaining steps are small, the amount of powder and debris generated is much less than that generated by the traditional grinding wheel directly cutting the skin. Therefore, the above method reduces the amount of powder and debris and eliminates the problem of ply separation, making the end processing of the stiffened panel more convenient and improving the processing efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the first grinding wheel cutting according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the milling process described in the embodiment of the present invention; Figure 3 This is a schematic diagram of the second grinding wheel removing the remaining steps as described in an embodiment of the present invention; Figure 4 yes Figure 3 Enlarged view of point A in the middle; Figure 5 This is a comparison diagram showing whether the axis of the milling cutter and the axis of the second girder are parallel or at an angle to each other, as described in the embodiments of the present invention. Figure 6 This is a schematic diagram of the skin and stringer ply direction according to an embodiment of the present invention; Figure 7 This is a flowchart of the end processing method for the stiffened wall panel described in an embodiment of the present invention.

[0017] In the picture: 1. Skin; 2. Truss; 21. First Truss; 22. Second Truss; 3. Residual Steps; 4. First Grinding Wheel; 5. Milling Cutter; 6. Second Grinding Wheel. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] like Figures 1 to 7 As shown, the present invention provides a method for processing the end of a stiffened wall panel, the stiffened wall panel including a skin 1 and a joint along the width direction of the skin 1 ( Figure 1 (in the Y direction) the stringers 2 are spaced apart on the skin 1, such as Figure 6 As shown, the layup direction of skin 1 is the height direction ( Figure 1 In the Z direction), the stringer 2 includes a first stringer 21 and a second stringer 22. The first stringer 21 is connected to the end face of the skin 1 along its height direction. The connection between the first stringer 21 and the second stringer 22 is smooth. The second stringer 22 is connected to the first stringer 21. The first stringer 21 has the same ply direction as the skin 1, and the second stringer 22 is perpendicular to the ply direction of the skin 1. Based on this, the end processing method of the stiffened wall panel includes the following steps: S1. The first grinding wheel 4 cuts the second truss 22 and at least part of the first truss 21 along the width direction of the reinforced wall panel with a first cutting distance; S2, the milling cutter 5 mills away the remaining first truss 21 and skin 1 along the width direction of the stiffened wall panel at a second cutting distance; the second cutting distance is less than the first cutting distance, so as to form a residual step 3 at the end of the skin 1; S3, the second grinding wheel 6 grinds away the remaining steps 3.

[0023] The end processing method of this stiffened wall panel involves first cutting the second truss 22 and at least part of the first truss 21 using a first grinding wheel 4. Since the trusses 2 are spaced on the skin 1 and are relatively small, a large portion of the first grinding wheel 4 is exposed during cutting, providing better heat dissipation. Furthermore, the small size of the trusses 2 results in less cutting powder and debris, preventing the accumulation of high-temperature dust that could clog the tool and burn the workpiece. Simultaneously, the first grinding wheel 4 performs rotary cutting, ensuring no delamination of the first truss 21 and the second truss 22 during the cutting process. The remaining first truss 21 and skin 1 are then milled away using a milling cutter 5. Since the milling direction of the milling cutter 5 is along the width direction of the stiffened wall panel, it and the first truss 21... Furthermore, since the layup direction of the skin 1 is perpendicular, the layup of the first stringer 21 and the skin 1 will not separate during the milling process. Although the milling direction is parallel to the layup direction of the second stringer 22, the second feed distance is smaller than the first feed distance. Therefore, the milling cutter 5 will only contact the part of the second stringer 22 that needs to be cut and separated, so there is no need to worry about the layup separation phenomenon. Then, the residual step 3 formed by the second grinding wheel 6 is ground off because the second feed distance is smaller than the first feed distance. Since the residual step 3 is small in size, the amount of powder and debris it produces is much less than the debris produced by the traditional grinding wheel directly cutting off the skin 1. Therefore, the above method reduces the amount of powder and debris and does not need to worry about the layup separation problem, making the end processing of the stiffened wall panel more convenient and improving the processing efficiency.

[0024] It should be noted here that both the first and second cutting distances extend inward from the edge of the reinforced wall panel as a reference (extending along the length of the reinforced wall panel, where the length direction is...). Figure 1 The distance in the X direction.

[0025] like Figure 6 As shown, due to the smooth transition at the connection between the first stringer 21 and the second stringer 22, there is an R-angle here, and its ply direction changes significantly. Milling this area with the milling cutter 5 may also cause ply delamination. Therefore, in some embodiments, the depth to which the first grinding wheel 4 cuts the first stringer 21 is not less than half the thickness of the second stringer 22. Figure 6As shown, during the forming of the first truss 21 and the second truss 22, a portion of the layup in the first truss 21 is formed by bending a portion of the layup in the second truss 22 (at the R-corner). Therefore, when the cutting depth of the first truss 21 is not less than half the thickness of the second truss 22, the connection between the first truss 21 and the second truss 22 is cut off by the first grinding wheel 4. This ensures that the bend (R-corner) is cut off, eliminating the need to use the milling cutter 5 to remove the connection and reducing the possibility of layup separation. It should be noted that if the first grinding wheel 4 cuts the first truss 21 too shallowly, errors may result in incomplete cutting of the connection between the first truss 21 and the second truss 22, leading to a risk of layup separation during milling by the milling cutter 5. Conversely, if the first grinding wheel 4 cuts the first truss 21 too deeply, the amount of cutting powder and debris increases, and the increased contact area of ​​the first grinding wheel 4 reduces heat dissipation, increasing the risk of deformation of the first grinding wheel 4.

[0026] Of course, in some alternative embodiments, the first grinding wheel 4 can cut the entire first truss 21.

[0027] In some embodiments, the diameter of the first grinding wheel 4 can be greater than the distance between two adjacent first stringers 21, so that when the first grinding wheel 4 is cutting, the two adjacent second stringers 22 and the two adjacent first stringers 21 can cut simultaneously, so that both sides of the first grinding wheel 4 are subjected to force at the same time, forming a force state similar to "bridge support", which can offset part of the radial component force, reduce sway and vibration, thereby reducing the risk of the first grinding wheel 4 breaking or deforming.

[0028] In some embodiments, the first grinding wheel 4 is mounted on the first flange, and the difference between the radius of the first grinding wheel 4 and the radius of the first flange is greater than the sum of the cutting depths of the second girder 22 and the first grinding wheel 4 into the first girder 21; thus, the portion to be cut is completely exposed within the radius of the first grinding wheel 4, thereby reducing the possibility of interference with the first flange during cutting. It should be noted that the mounting method of the first grinding wheel 4 and the first flange is prior art and will not be described in detail here.

[0029] like Figure 5 As shown, in some embodiments, in step S2, the axis of the milling cutter 5 may be parallel to the axis of the second truss 22.

[0030] In the current embodiment, in step S2, the angle between the axis of the milling cutter 5 and the axis of the second truss 22 is α, and the angle α is an acute angle. When the axis of the milling cutter 5 is parallel to the axis of the second stringer 22, the milling cutter 5 will simultaneously contact the entire second stringer 22 (since the second stringer 22 is only cut, not severed from the first stringer 21). At this time, the force on the milling cutter 5 will be the greatest, and the abrupt change in cutting depth when the milling cutter 5 contacts the second stringer 22 will lead to a sudden change in cutting force, which can easily cause large vibrations and adverse machining results. However, when the angle between the axis of the milling cutter 5 and the axis of the second stringer 22 is α, and α is an acute angle, and the axis of the milling cutter 5, the axis of the second stringer 22, and the skin surface 1 are at angles to each other, the milling cutter 5 will only gradually contact a portion of the second stringer 22. The milling cutter 5 will not simultaneously contact the entire second stringer 22. Compared to when the axis of the milling cutter 5 is parallel to the axis of the second stringer 22, the force on the milling cutter 5 and the degree of change will be reduced, thereby reducing the possibility of damage to the milling cutter 5 and also reducing the driving power of the milling cutter 5.

[0031] For example, the included angle α does not exceed 30°. If the angle is too large, when the milling cutter 5 contacts the skin 1, the milling cutter 5 will exert a downward force on the skin 1. This force is in the same direction as the ply direction of the skin 1. If this force is too large, it can easily lead to ply separation of the skin 1. In the current embodiment, the milling cutter 5 is an end mill, which makes it easier for the milling cutter 5 to contact the second stringer 22 and the skin 1 simultaneously. It should also be noted that the end mill has less thermal deformation than other milling cutters (such as face mills), resulting in higher workpiece precision, more controllable tool life and machining quality. This reduces the possibility of temperature rise during milling by the milling cutter 5, which could cause deformation of the end of the stiffened panel.

[0032] like Figures 2 to 4 As shown, in some embodiments, in step S3, the second grinding wheel 6 grinds away the remaining steps 3 along the width direction of the stiffened wall panel with a third feed distance. The third feed distance is not less than the first feed distance, in order to reduce the phenomenon that the remaining steps 3 are not completely removed due to mechanical errors, tool wear errors, machine tool overall errors, etc., and to ensure milling quality. The thickness of the remaining steps 3 can be controlled within the range of 0.3mm to 0.8mm, leaving a uniform allowance layer for subsequent processes.

[0033] It should be noted here that the mesh size of the first grinding wheel 4 and the second grinding wheel 6 is not specifically limited, and can vary depending on the type of reinforced wall panel.

[0034] like Figure 4As shown, specifically, the thickness of the second grinding wheel 6 and the thickness of the residual step 3 are less than the third feed distance. Therefore, when the second grinding wheel 6 is grinding, the residual step 3 can abut against the circumferential surface of the second grinding wheel 6, so that one end face of the second grinding wheel 6 is always exposed. This can improve the heat dissipation effect of the second grinding wheel 6, thereby reducing the possibility of deformation of the second grinding wheel 6 due to the finishing of the residual step 3, and avoiding the delamination phenomenon caused by the finishing of the residual step 3. At the same time, the above method can remove the residual step 3 in one go by the second grinding wheel 6, without the need for multiple grinding, thus improving efficiency.

[0035] In some embodiments, the second grinding wheel 6 is mounted on the second flange, and the difference between the radius of the second grinding wheel 6 and the radius of the second flange is greater than the sum of the heights of the skin 1 and the stringer 2. Similarly, when the second grinding wheel 6 is used for finishing, both the skin and the stringer 2 are fully exposed within the radius of the second grinding wheel 6, avoiding the possibility of interference with the second flange. It should be noted that the mounting method of the second grinding wheel 6 and the second flange is prior art and will not be elaborated further. In some embodiments, the second grinding wheel 6 can be the same as the first grinding wheel 4, thus eliminating the need for disassembly and replacement. In this case, the first flange and the second flange can use the same flange, further improving efficiency. Exemplarily, both the first grinding wheel 4 and the second grinding wheel 6 can be, but are not limited to, electroplated diamond thin-film grinding wheels, with a cutting line speed set to 25m / s to 35m / s. This speed range ensures efficient cutting while avoiding material softening and sticking due to frictional heat accumulation. Of course, the second grinding wheel 6 can be different from the first grinding wheel 4, depending on the type of reinforced wall panel, and will not be elaborated further.

[0036] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for processing the end of a stiffened wall panel, the stiffened wall panel comprising a skin (1) and long stringers (2) spaced apart on the skin (1) along the width direction of the skin (1), the ply direction of the skin (1) being the height direction, the long stringers (2) comprising a first stringer (21) and a second stringer (22), the first stringer (21) being connected to the skin (1), the second stringer (22) being connected to the first stringer (21), the first stringer (21) having the same ply direction as the skin (1), the second stringer (22) being perpendicular to the ply direction of the skin (1), and the connection between the first stringer (21) and the second stringer (22) being smoothly transitioned; characterized in that, The end processing method of the stiffened wall panel includes the following steps: S1. The first grinding wheel (4) cuts the second truss (22) and at least part of the first truss (21) along the width direction of the stiffened wall panel with a first cutting distance. S2, The milling cutter (5) mills away the remaining first truss (21) and the skin (1) along the width direction of the stiffened wall panel at a second cutting distance; the second cutting distance is less than the first cutting distance to form a residual step (3) at the end of the skin (1). S3, the second grinding wheel (6) grinds away the remaining steps (3).

2. The method for processing the end of a stiffened wall panel according to claim 1, characterized in that, In step S3, the second grinding wheel (6) grinds away the remaining steps (3) along the width direction of the reinforced wall panel at a third cutting distance, the third cutting distance being no less than the first cutting distance.

3. The method for processing the end of a stiffened wall panel according to claim 2, characterized in that, In step S3, the thickness of the second grinding wheel (6) and the thickness of the residual step (3) are less than the third feed distance.

4. The method for processing the end of a stiffened wall panel according to claim 1, characterized in that, In step S2, the axis of the milling cutter (5) is parallel to the axis of the second truss (22).

5. The method for processing the end of a stiffened wall panel according to claim 1, characterized in that, In step S2, the angle between the axis of the milling cutter (5) and the axis of the second truss (22) is α, and the angle α is an acute angle.

6. The method for processing the end of a stiffened wall panel according to claim 5, characterized in that, The included angle α is no greater than 30°.

7. The method for processing the end of a stiffened wall panel according to claim 5, characterized in that, The milling cutter (5) is an end mill (5).

8. The method for processing the end of a stiffened wall panel according to claim 1, characterized in that, In step S1, the first grinding wheel (4) cuts the first truss (21) to a depth not less than half the thickness of the second truss (22).

9. The method for processing the end of a stiffened wall panel according to claim 1, characterized in that, In step S1, the first grinding wheel (4) cuts all of the first truss (21).

10. The method for processing the end of a stiffened wall panel according to claim 1, characterized in that, The first grinding wheel (4) is mounted on the first flange, and the difference between the radius of the first grinding wheel (4) and the radius of the first flange is greater than the sum of the depth by which the second truss (22) and the first grinding wheel (4) cut the first truss (21); And / or, the second grinding wheel (6) is mounted on the second flange, and the difference between the radius of the second grinding wheel (6) and the radius of the second flange is greater than the sum of the heights of the skin (1) and the stringer (2).

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