Numerical control roll bending method for variable-curvature skin part of airplane

Abstract

The invention discloses a numerical control roll bending method for a variable-curvature skin part of an airplane, which comprises the following steps of: firstly, carrying out trial production of the skin part, and recording the down-regulation depth of an upper roller at each time and the distance between roll bending marking lines on the left side and the right side of the part and the center line of the part for rolling of a preformed blank and each roll bending process in the trial production process; during subsequent skin part blank machining, the part blank is cut to be completely consistent with the blank used in the first step in size and shape, and the center line of each blank is determined; according to the same method as the first step, a section template is not needed in the numerical control machining process, and in the blank pre-forming process and each roll bending process, roll bending equipment is programmed through data recorded in the first step, so that the roll bending equipment adjusts the down-regulation depth and the rolling arc length of an upper roller according to the program, and the blank does not need to be taken down; the equipment finally completes machining of the whole part according to the sequence of preforming, first-time roll bending, second-time roll bending and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of roll bending forming of aircraft variable curvature skin parts, and in particular to a numerical control roll bending method of aircraft variable curvature skin parts. Background Art

[0002] Aircraft wing leading edge skin parts are generally formed by traditional rolling methods. Such parts are mainly formed by multiple rolling from small to large curvatures. Generally, large leading edge parts require 9-13 rollings. When rolling large leading edge parts, at least 3 people are required to operate together, one to operate the machine tool, and two to stabilize the parts to align them with the rolling center line. Otherwise, the reference line of the raw material will deviate and not coincide with the central axis of the upper roller, resulting in unqualified parts and a waste of manpower. Because the rolling is carried out according to the rolling mark line, the reaction speed of each person in visually observing the reference line position is different, and the time to notify the machine operator to stop the machine tool will be different. Communication with the machine operator will cause errors, affecting the stability of product quality. In order to ensure the quality of parts, high skills and a lot of work experience are often required. Summary of the invention

[0003] The purpose of the present invention is to provide a numerical control rolling method for aircraft variable curvature skin parts, which is used to overcome the problems of large error, difficult operation, low efficiency, etc. in the prior art.

[0004] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0005] A numerical control rolling method for aircraft variable curvature skin parts, comprising:

[0006] The first step is to collect CNC rolling bending technical parameters

[0007] First, the raw material of the skin part is placed on the rolling device, and the center line of the skin part is adjusted so that the center line passes through the centers of the two lower rollers, and then the position of the upper roller is adjusted so that the lower part of the upper roller passes the highest point of the lower roller by a first preset distance, and the rolling device is turned on to roll the raw material to the left and right respectively to a second preset distance from the edge, so as to obtain a preformed raw material with a certain curvature;

[0008] Secondly, take off the preformed material, place the cut surface template on the preformed material, align the center lines of the two, and then roll the cut surface template to the left and right respectively, record the tangent position of the bottom arc of the cut surface template and the preformed material, and record it as the rolling mark line;

[0009] Once again, after recording the rolling mark line, put the preformed material on the rolling device again for the first rolling. The first rolling requires the material to roll multiple times. Each time it rolls, first lower the upper roller by a certain depth, then start the rolling device, so that the preformed material rolls left and right N times. Then continue to lower the upper roller, start the rolling device again, and roll the preformed material. Use the same method to continuously adjust the lowering depth of the upper roller, and make the preformed material roll left and right after each adjustment.

[0010] Perform the second rolling: take down the preformed rough material after the first rolling, roll the rough material with the cut surface template to determine the rolling mark line for this rolling, then place the rough material on the equipment and process the rough material in the same way as the first rolling;

[0011] Repeat the above steps to roll the raw material for a preset number of times to obtain the processed parts;

[0012] For the rolling of the preformed material and each rolling process, record the lowering depth of the upper roller each time, as well as the distance between the rolling marking lines on the left and right sides of the part and the center line of the part;

[0013] The second step is CNC machining

[0014] For subsequent rough material processing of skin parts:

[0015] Cut the part stock into the same size and shape as the stock used in the first step, and determine the center line of each stock;

[0016] During the preforming of the rough material and each rolling process, the data recorded in the first step is used to program the rolling equipment, so that the rolling equipment adjusts the lowering depth of the upper roller and the rolling arc length according to the program. There is no need to remove the rough material. The equipment finally completes the processing of the entire part in the order of preforming the rough material, the first rolling, the second rolling...

[0017] Furthermore, for the rough material of LY12-CZ-δ0.8, the downward adjustment range of the upper roller should be adjusted to 10 mm during the preforming rough material processing.

[0018] Furthermore, the first preset distance is 4-10 mm.

[0019] Furthermore, the second preset distance is 5-10 mm.

[0020] Furthermore, the section template is a tool for manufacturing or inspecting the inner surface of a part, and the bottom of the section template is an arc surface.

[0021] Furthermore, the value of N is 2-5 times.

[0022] Furthermore, the preset number of times is 9-12 times.

[0023] A numerical control processing device stores a computer program for implementing the numerical control rolling method of the aircraft variable curvature skin part.

[0024] Compared with the prior art, the present invention has the following technical features:

[0025] By using the method of the present invention, when rolling the skin sheet, the machine tool controls the rolling distance L and the distance H between the upper and lower rollers, and gradually rolls until it fits the part section template. It is no longer necessary to compare the section templates one by one and draw marking lines, which solves the problems of low efficiency and high labor intensity when rolling variable curvature skin parts; it is no longer necessary to repeatedly align the rolling center line and visually inspect the rolling marking line of the raw material, which solves the problems of large errors and poor part quality caused by human factors when rolling variable curvature skin parts. When using the method of the present invention, it is only necessary to input the data recorded in the trial production into the machine tool, and then rolling and bending can be performed one by one. By using this method, the processing efficiency of variable curvature skin parts is improved by about 80% compared with the existing method, and the quality of parts is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The schematic diagram of the processing process for collecting CNC rolling bending technical parameters in the first step;

[0027] Figure 2 It is a schematic diagram of the second step of CNC machining process;

[0028] Where: t-material thickness;

[0029] R0-the radius of curvature of the part during rolling;

[0030] d1, d2 – are the radii of the upper and lower rollers respectively;

[0031] a-half the distance between the two lower rollers;

[0032] H - distance between upper and lower rollers;

[0033] Figure 3 It is a schematic diagram of the raw material on the rolling bending equipment;

[0034] Figure 4 Schematic diagram of data recorded during each rolling process in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] In view of the above situation of the prior art, the purpose of the present invention is to provide a method for CNC rolling of aircraft variable curvature skin parts, so as to solve the problems of low efficiency, high labor intensity and poor surface quality of existing variable curvature skin parts during rolling, and improve processing efficiency.

[0036] The method of numerical control rolling bending of aircraft variable curvature skin parts includes rolling bending trial production of variable curvature skin parts, measuring the distance between the marking line and the rough material reference line after each rolling bending, and recording the relative distance H between the upper and lower rollers. During rolling bending, it is only necessary to align the rough material reference line with the axis of the upper roller once, and then roll and bend the parts one by one according to the data recorded in the trial production.

[0037] See attached Figure 1-4 The present invention provides a numerical control rolling method for aircraft variable curvature skin parts, comprising:

[0038] The first step is to collect CNC rolling bending technical parameters

[0039] First, place the raw material of the skin part on the rolling device, adjust the center line of the skin part so that it passes through the center of the two lower rollers, then adjust the position of the upper roller so that the lower part of the upper roller passes the highest point of the lower roller by 4-10mm, turn on the rolling device to roll the raw material to the left and right respectively to a distance of 5-10mm from the edge, so as to obtain a preformed raw material with a certain curvature; the amplitude of the upper roller downward adjustment should be determined according to the specific thickness and material of the raw material. Generally, for the raw material of LY12-CZ-δ0.8 material, it should be adjusted by 10mm;

[0040] Secondly, remove the preformed blank, place the section template on the preformed blank, align the center lines of the two, and then roll the section template to the left and right respectively, record the position of the tangent line between the arc at the bottom of the section template and the preformed blank, and record it as the rolling mark line; the section template is a tooling for manufacturing or inspecting the inner surface of the part, and the bottom of the section template is an arc surface;

[0041] Once again, after recording the rolling mark line, put the preformed material on the rolling device again for the first rolling. The first rolling requires the material to roll multiple times. Each time it rolls, first lower the upper roller to a certain depth, then start the rolling device, so that the preformed material rolls left and right three times. Then continue to lower the upper roller, start the rolling device again, and roll the preformed material. Use the same method to continuously adjust the lowering depth of the upper roller.

[0042] Perform the second rolling: take down the preformed rough material after the first rolling, roll the rough material with the cut surface template to determine the rolling mark line for this rolling, then place the rough material on the equipment and process the rough material in the same way as the first rolling;

[0043] Repeat the above steps and roll the raw material 9-12 times to obtain the processed parts;

[0044] In the first step, for the rolling of the preformed blank and each rolling process, record the lowering depth of the upper roller each time, as well as the distance between the rolling marking lines on the left and right sides of the part and the center line of the part;

[0045] The second step is CNC machining

[0046] For subsequent rough material processing of skin parts:

[0047] Cut the part stock into the same size and shape as the stock used in the first step, and determine the center line of each stock;

[0048] According to the same method as the first time, there is no need to use a cutting template during the CNC machining process. During the preforming of the raw material and each rolling process, the data recorded in the first step is used to program the rolling equipment, so that the rolling equipment adjusts the lowering depth of the upper roller and the rolling arc length according to the program. There is no need to remove the raw material. The equipment follows the order of preforming, first rolling, second rolling... When the preset number of times is reached or the part has been formed, the rolling is stopped to complete the processing of the entire part.

[0049] Example:

[0050] Step 1: Trial-produce variable curvature skin parts. After each rolling, measure and record the arc length L between the rolling mark line and the center line of the rough material, and the relative distance H between the upper and lower rollers. Figure 2 .

[0051] Step 2: Process the subsequent parts, make the base line of the rough material coincide with the axis of the upper roller, determine the curvature radius R of the first rolling, adjust the distance H between the upper and lower rollers, first roll forward for a distance of L1, then roll backward for a distance of L1+L2, and finally roll forward for a distance of L2 to make the base line of the rough material coincide with the axis of the upper roller again;

[0052] Step 3: gradually adjust the distance H between the upper and lower rollers, and roll the corresponding distance L until the part is finally formed.

[0053] This method fills the gap in the digital processing of aircraft variable curvature skin parts, so that the part processing process can be precisely controlled; this method overcomes the shortcomings of low efficiency and high labor intensity of existing aircraft skin roll forming, reduces labor intensity, and improves part processing efficiency; this method overcomes the shortcomings of discontinuous curvature and poor surface quality of parts during existing aircraft skin roll forming, achieves smooth transition of various regions of the part, and improves the surface quality of the part. This method overcomes the shortcomings of part defects caused by insufficient personal experience during existing aircraft skin roll forming, so that inexperienced workers and apprentices can also produce qualified parts.

Claims

1. A method for numerically controlling the rolling of aircraft variable curvature skin parts, characterized in that: include: The first step is to collect CNC rolling bending technical parameters First, the raw material of the skin part is placed on the rolling device, and the center line of the skin part is adjusted so that the center line passes through the centers of the two lower rollers, and then the position of the upper roller is adjusted so that the lower part of the upper roller passes the highest point of the lower roller by a first preset distance, and the rolling device is turned on to roll the raw material to the left and right respectively to a second preset distance from the edge, so as to obtain a preformed raw material with a certain curvature; Secondly, take off the preformed material, place the cut surface template on the preformed material, align the center lines of the two, and then roll the cut surface template to the left and right respectively, record the tangent position of the bottom arc of the cut surface template and the preformed material, and record it as the rolling mark line; Once again, after recording the rolling mark line, put the preformed material on the rolling device again for the first rolling. The first rolling requires the material to roll multiple times. Each time it rolls, the upper roller is first lowered by a certain depth, and then the rolling device is turned on to roll the preformed material left and right N times. Then the upper roller is further lowered, and the rolling device is turned on again to roll the preformed material. The same method is used to continuously adjust the lowering depth of the upper roller, and the preformed material is rolled left and right after each adjustment. Perform the second rolling: take down the preformed rough material after the first rolling, roll the rough material with the cut surface template to determine the rolling mark line for this rolling, then place the rough material on the equipment and process the rough material in the same way as the first rolling; Repeat the above steps to roll the raw material for a preset number of times to obtain the processed parts; For the rolling of the preformed material and each rolling process, record the lowering depth of the upper roller each time, as well as the distance between the rolling marking lines on the left and right sides of the part and the center line of the part; The second step is CNC machining For subsequent rough material processing of skin parts: Cut the part stock into the same size and shape as the stock used in the first step, and determine the center line of each stock; During the preforming of the rough material and each rolling process, the data recorded in the first step is used to program the rolling equipment, so that the rolling equipment adjusts the lowering depth of the upper roller and the rolling arc length according to the program. There is no need to remove the rough material. The equipment finally completes the processing of the entire part in the order of preforming the rough material, the first rolling, the second rolling...

2. The CNC rolling method for aircraft variable curvature skin parts according to claim 1 is characterized in that: For the rough material of LY12-CZ-δ0.8, the downward adjustment range of the upper roller should be adjusted to 10mm during the preforming rough material processing.

3. The CNC rolling method for aircraft variable curvature skin parts according to claim 1 is characterized in that: The first preset distance is 4-10 mm.

4. The CNC rolling method for aircraft variable curvature skin parts according to claim 1 is characterized in that: The second preset distance is 5-10 mm.

5. The method for numerically controlling the rolling of aircraft variable curvature skin parts according to claim 1, characterized in that: The cutting surface template is a tool for manufacturing or inspecting the inner surface of parts, and the bottom of the cutting surface template is an arc surface.

6. The CNC rolling method for aircraft variable curvature skin parts according to claim 1, characterized in that: The value of N is 2-5 times.

7. The CNC rolling method for aircraft variable curvature skin parts according to claim 1, characterized in that: The preset number of times is 9-12 times.

8. A numerical control processing device, wherein a computer program for implementing the numerical control rolling bending method of aircraft variable curvature skin parts according to any one of claims 1 to 7 is stored in the numerical control processing device.

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