Aircraft wing end face butt joint hole making method based on standard flat plate coordination

Abstract

The invention belongs to the technical field of aircraft manufacturing, and relates to an aircraft wing end face butt joint hole making method based on standard flat plate coordination. Comprising the following steps that S1, the milling amount of the butt joint end face is calculated, and milling of the butt joint end face is completed; s2, a standard flat plate is installed on the butt joint end face; s3, selecting one of the positioning holes of the standard flat plate as a reference hole, and creating a base coordinate system; s4, center coordinates of all the positioning holes in the base coordinate system are collected; s5, the coaxiality of the machine tool spindle and all the positioning holes in the standard flat plate is checked, and if the positioning holes are not coaxial with the machine tool spindle, the center coordinates of the corresponding positioning holes in the base coordinate system are adjusted till the positioning holes are coaxial; s6, reaming is conducted on all small holes in the butt joint end face; and S7, reaming the primary hole after reaming.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft manufacturing, and relates to a method for making butt holes on the end faces of aircraft wings based on standard flat plate coordination. Background Art

[0002] A large aircraft wing consists of outer wings, middle outer wings, and central wing components. Figure 1 , butt-jointed assembly is formed, and a process margin is left on the butt joint end faces of each wing, and there are initial butt holes on the butt joint end faces. The wings need to use the initial butt holes on the end faces for positioning and installation during assembly and component assembly. However, due to factors such as manufacturing errors and assembly stress, the positions of the initial butt holes on the wing end faces after the wing box is formed deviate from the theoretical positions of the digital model, and it is impossible to directly compile a CNC program based on the theoretical digital model to process the end face butt holes. In order to reduce risks, unify the coordination basis of the butt joint holes on the end faces of each butt joint wing, and ensure the coaxiality and precision requirements of the butt joint holes on each butt joint wing component, a standard plate is used to coordinate the positions of the butt joint holes, and then a machine tool is used to expand and ream the initial butt joint holes on the end faces of each wing.

[0003] At present, the hole making process method is to use "reamer + drill sleeve" to check the interference amount in the standard flat plate docking hole to align the hole center of the docking hole, and then replace the spindle tool in turn to expand and ream the holes one by one. This hole making method has the following problems: ① The docking hole center alignment operation completely depends on the operator's perception of the sliding tightness of the drill sleeve in the standard flat plate docking hole, and the alignment accuracy is not high. ② The time for hole center alignment depends entirely on the operator's skill level and experience, and the adjustment process takes a long time. ③ After the hole position is aligned, the spindle head needs to be kept stationary, and the docking hole expansion and reaming work is completed by replacing the spindle head tool to ensure that the spindle is concentric during the two operations of expansion and reaming. This method can only be used after one docking hole is processed, and then the next docking hole center alignment, expansion, and reaming operations can be performed, so it is necessary to replace the reamer-reamer drill-reamer tool at least 3 times to process a docking hole. The number of holes processed for the butt joint end faces of a single aircraft wing is 480 = middle and outer wings (77+43)×2 + central wings 77×2 + outer wings 43×2, and the spindle tool needs to be replaced 480×3=1440 times in total. The existing finishing equipment is not equipped with an automatic tool changer, and the entire hole making process is labor-intensive and inefficient. ④ During the manual tool change process, it is difficult for the operator to ensure that the tool handle can be horizontally inserted into the spindle chuck, which can easily cause wear on the spindle taper, reduce spindle accuracy, and shorten the service life of the machine tool. ⑤ The main process of hole making relies entirely on manual control by the operator, which has a high risk of error. Summary of the invention

[0004] The purpose of the present invention is to provide a method for making holes on the end faces of aircraft wings based on standard plate coordination, which makes up for the shortcomings of the existing methods for making holes on the end faces of wing wings, such as low hole center alignment accuracy, many tool changes during the hole making process, high labor intensity, and low processing efficiency, and provides a method with high precision and efficiency, improved labor intensity, and reduced risk of human error.

[0005] Technical Solution

[0006] A method for making a butt hole on an aircraft wing end face based on standard plate coordination comprises the following steps:

[0007] S1: Calculate the milling amount of the butt joint end face and complete the milling of the butt joint end face;

[0008] S2: Install a standard plate on the butt end;

[0009] S3: Select one of the positioning holes of the standard plate as a reference hole and create a base coordinate system;

[0010] S4: Collect the center coordinates of all positioning holes in the base coordinate system;

[0011] S5: Check the coaxiality of the machine tool spindle and each positioning hole on the standard plate. If there is a positioning hole that is not coaxial with the machine tool spindle, adjust the center coordinates of the corresponding positioning hole in the base coordinate system until they are coaxial;

[0012] S6: Expand all small holes on the butt end faces;

[0013] S7: Ream the initial hole after expansion.

[0014] Furthermore, in S1, the calculation formula of the milling amount is as follows:

[0015] Q = Q1 + (H1 + C - H2);

[0016] Among them, Q represents the total milling amount;

[0017] Q1 is the roughness value of the entire wing end surface, that is, the difference between the highest point and the lowest point;

[0018] H1 is the actual wall thickness of the part before processing;

[0019] C is the difference between the starting point percentage gauge pressure reading and the measuring point percentage reading when measuring the end surface roughness;

[0020] H2 is the theoretical wall thickness value required by the design after milling is completed.

[0021] After the milling amount is calculated empirically without any problems, the end milling cutter is installed on the spindle. The milling amount of each cutter is allocated according to the requirements of preliminary milling and fine milling. The milling is performed in batches in a clockwise direction according to the shape of the wing end face. During fine milling, the single milling amount is less than or equal to 0.3mm.

[0022] Furthermore, in S2, the standard plate is the basis for coordinating the positions of the docking holes of each wing end face. The standard plate is distributed with through holes concentric with the docking holes of the wing docking end face. The outer diameter of the through hole matches the outer diameter of the drill sleeve, and the inner diameter of the drill sleeve is consistent with the final hole size of the docking hole of the wing docking end face. The standard plate is fixed with bolts through the four corner positioning holes and the positioning holes on the product clamping fixture foot. The standard plate is provided with an end face shape inspection block. According to the clearance requirements between the block and the wing end face shape, the wing attitude is adjusted, and at the same time, the deviation between each docking hole and the center of the standard plate is ensured to be no more than ±1mm. Then, no less than 6 initial hole bolts are used to tighten and fix the standard plate and the wing docking end face.

[0023] Further, in S3, the docking hole at the lower left corner of the standard plate is selected as the reference hole, the center coordinates of the reference hole are collected using the machine tool measurement system, and the zero offset is set according to the center coordinates of the reference hole to establish a base coordinate system, and the coordinate origin of the base coordinate system is the center coordinates of the reference hole.

[0024] Furthermore, in S4, an RMP60 probe is installed on the spindle, and the probe is manually positioned to the approximate center position of each docking hole in the standard plate. The probe measuring ball contacts the inner surface of the docking hole of the standard plate in four directions: bottom, top, left, and right. The center coordinates of each docking hole relative to the base coordinates are automatically calculated, and the collected center coordinates are used as input for CNC programming of docking hole processing on the docking end faces of wing components.

[0025] Further, in S5, the coaxiality is checked as follows:

[0026] Install a reamer on the machine tool spindle, and install a drill sleeve matching the size of the docking hole on the reamer;

[0027] Move the machine tool spindle to the collected center coordinates of the docking hole, and control the drill sleeve to move back and forth in the docking hole. If the drill sleeve slides easily in the docking hole, it is considered that the corresponding docking hole is coaxial with the spindle, otherwise it is considered that they are not coaxial.

[0028] Further, in S5, the process of adjusting the center coordinate of the docking hole in the base coordinate system is as follows:

[0029] Slide the drill sleeve on the reamer to the surface of the standard flat plate docking hole, visually observe the position deviation between the drill sleeve and the standard flat plate docking hole, select the deviation axis to adjust the spindle until the drill sleeve can slide into the standard flat plate docking hole, and then adjust the X-axis or Y-axis respectively. Each time you adjust, move the drill sleeve back and forth in the docking hole. Determine the next adjustment direction and amount by sensing the tightness of the drill sleeve in the standard flat plate docking hole, until the drill sleeve easily slides into the standard flat plate docking hole, and the adjustment process is completed.

[0030] Further, in S6, the spindle tool is replaced with a reamer, and the hole is expanded after checking the coaxiality. The spindle speed is based on the formula n(r / min)=v÷πd·k, where n represents the spindle speed, v is the processing line speed, d is the tool diameter, and k is an empirical value introduced after practical verification during the actual processing process. The k value range is 0-1. The feed rate is calculated by the formula f=n·z·fz, where f represents the feed rate, n is the spindle speed, z is the feed amount per tooth, and fz is the feed revolutions per tooth.

[0031] The specific process of hole expansion is as follows:

[0032] First expansion:

[0033] Processing parameters: speed 541±10r / min, feed 86±5mm / min;

[0034] The allowance after processing is 2-3mm.

[0035] Second expansion:

[0036] Processing parameters: speed 489±10r / min, feed 156±5mm / min;

[0037] The allowance after processing is 0.3-0.8mm.

[0038] The above processing parameters are closely related to the part material, tool, aperture accuracy, machine tool spindle power, etc., and should be adjusted accordingly according to the actual situation during actual processing. They are for reference only. Among them, the remaining processing allowance after the second hole expansion is related to the final accuracy level of the docking hole, and should be adjusted accordingly according to the aperture accuracy.

[0039] Further, in S7, the spindle tool is replaced with a reamer, and the coaxiality is checked again before reaming. The specific parameters are as follows:

[0040] Speed ​​481±10r / min, feed 230±5mm / min;

[0041] The above processing parameters are closely related to the part material, tool, aperture accuracy, machine tool spindle power, etc. During actual processing, corresponding adjustments should be made according to the actual situation. They are for reference only.

[0042] Beneficial effects:

[0043] Compared with the prior art, the invention has the advantages of providing a method for making a butt hole on the end face of an aircraft wing based on standard plate coordination, which effectively improves the quality and efficiency of the butt end face processing of the aircraft wing, and mainly has the following advantages:

[0044] On the one hand, the present invention adopts a standard plate to coordinate the position relationship of the docking holes of each wing end surface, unifies the coordination basis, and maximizes the guarantee that the docking holes of each wing are concentric when docking.

[0045] On the one hand, the present invention adopts a CNC machine tool equipped with a workpiece measurement system to collect the center coordinates of the standard plate docking holes, provides CNC programming input for the wing docking end face hole making based on the coordination of the standard plate, improves the automation level of the wing component docking end face hole making, and at the same time makes up for the shortcomings of the original method of simply using a reamer + drill sleeve for hole position alignment, such as low hole position alignment efficiency and accuracy.

[0046] On the other hand, the present invention solves the problem of frequent tool changes in the previous hole-by-hole expanding and reaming processing method, and transforms the hole-by-hole expanding and reaming into a unified processing method of expanding first and then reaming. The number of tool changes for the docking end face hole making of a single aircraft wing component product has been reduced from 1,440 times to the current 52 times, and the tool change frequency has been reduced by 96.4%, which has greatly reduced the workload of personnel and has a positive significance for maintaining the spindle accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the wing components;

[0048] Figure 2 This is a schematic diagram of the hole center alignment of "reamer + drill sleeve";

[0049] Figure 3 It is the process flow chart of wing butt end surface processing;

[0050] Figure 4 This is the process flow chart for hole making on the wing butt end surface. DETAILED DESCRIPTION

[0051] The present invention provides a method for making a hole on the end face of an aircraft wing based on standard plate coordination, which is combined with Figure 3 , Figure 4 Taking the processing of the outer wing components as an example, the specific implementation mode of the present invention is further described in detail:

[0052] Step 1: After the wing components of the Chinese and foreign wings are assembled to form the wing box, they are hoisted by the factory crane to the special positioning tooling for wing finishing, and supported by the adjustable support parts or movable brackets on the positioning tooling.

[0053] Step 2: Install the standard plate, check the clearance between the upper and lower wall plates of the middle and outer wing butt joint end faces and the outer shape stopper on the standard plate. The clearance should meet the requirement of 4±0.75mm, and the deviation between the center of the butt joint hole of the middle and outer wing butt joint end faces and the center of the butt joint hole of the standard plate should be less than 1mm. Perform horizontal measurement, use a level to measure the set horizontal measurement points, calculate the height difference of the associated points, and determine that the horizontal posture of the middle and outer wings meets the design requirements.

[0054] Step 3: Use the clamps, supports, and bolts on the tooling to fix and clamp the wing components to prevent the wing from moving or shifting during processing, and remeasure the horizontal and upper and lower wall panels and the standard flat plate shape clearance.

[0055] Step 4: Install the dial indicator bracket and dial indicator on the end face of the machine tool spindle, move the machine tool spindle to position the dial indicator rod to the lower left corner of the wing end face and move the spindle to the dial indicator pressure reading of 5mm, move the machine tool spindle to move a circle according to the shape of the wing butt end face, and record the percentage readings at a certain distance around the circle, then move the dial indicator to the starting pressure gauge position, check whether the percentage reading is 5mm, and ensure that there is no deviation in the measurement. The recorded circumference dial indicator value and the initial flatness of the wing butt end face.

[0056] Step 5: Calculate the total milling amount according to the milling amount calculation formula Q=Q1+(H1+C-H2). After confirming that it is correct through empirical calculation, install the end mill on the machine tool spindle, move the machine tool spindle until the tip of the end mill contacts the lower left corner of the wing docking end face, manually turn the spindle until the tip of the cutter just scrapes off the paint layer on the end face surface, determine that the current milling cutter is flush with the docking end face, allocate each milling amount according to the single feed amount requirements for preliminary milling and fine milling, then set the processing parameters, and perform milling in batches in a clockwise direction. Measure the wall thickness of the part after each milling to verify whether the feed amount is correct and ensure that there is no wall thickness tolerance problem.

[0057] Step 6: Install the dial indicator bracket and dial indicator on the machine tool spindle, repeat the operation in step 4 above, and measure the unevenness value after the end face milling is completed. The requirement is ≤0.1mm.

[0058] Step 7: Hoist the standard plate, connect it with the four standard plate special positioning holes on the wing component positioning fixture through the four corner positioning holes of the standard plate with bolts, and use the initial positioning pins to tighten and fix the standard plate and the docking end surface of the wing product. The diameter of the selected initial positioning pin is 0.5mm smaller than the initial small hole of the wing docking end surface.

[0059] Step 8: Install the RMP60 probe on the machine tool spindle, move the machine tool spindle to position the probe to the approximate center position of the first docking hole in the lower left corner of the standard plate, start measurement to obtain the center coordinates of the hole, use the hole as the reference hole, set the base coordinates, and the center coordinates of the hole are the origin of the base coordinates.

[0060] Step 9: Repeat the above step 8 to collect the center coordinates of all holes on the standard plate and compile a CNC machining program.

[0061] Step 10: Install the reamer on the machine tool spindle and the drill sleeve on the reamer, such as Figure 2 As shown, run the CNC program to position the reamer on the spindle into the standard plate docking hole with a depth of half the depth of the standard plate. The drill sleeve on the sliding reamer moves back and forth in the standard plate docking hole to sense the tightness of the drill sleeve entering and exiting the standard plate docking hole. If it slides in and out easily, it is determined that the spindle is coaxial with the standard plate docking hole. If they are not coaxial, move the machine tool X / Y axis for adjustment and modify the center coordinates of the hole in the CNC program.

[0062] Step 11: Repeat the above step 10 to check whether the center coordinates of all docking holes are coaxial with the main axis.

[0063] Step 12: Install the reamer on the machine tool spindle, check the coaxiality and then reaming. The spindle speed is based on the formula n(r / min)=v÷πd·k, where n represents the spindle speed, v is the machining line speed, d is the tool diameter, and k is an empirical value introduced after practical testing during the actual machining process. The k value range is 0-1. The feed rate is calculated by the formula f=n·z·fz, where f represents the feed rate, n is the spindle speed, z is the feed per tooth, and fz is the feed revolutions per tooth.

[0064] The specific process of hole expansion is as follows, taking the φ18 specification butt hole as an example:

[0065] First expansion:

[0066] Processing parameters: speed 541r / min, feed 86mm / min;

[0067] The allowance after processing is 2-3mm.

[0068] First, expand the selected standard plate precision positioning hole. When expanding the hole, it is necessary to verify whether the spindle and the standard plate docking hole are coaxial and the tool parameter settings are correct. The specific verification method is as follows: Figure 4 Basically, there is no misalignment, and adjustments should be made if there is misalignment.

[0069] Step 13: Install the tool for the second hole expansion on the machine tool. The parameters for the second hole expansion are as follows:

[0070] Processing parameters: speed 489r / min, feed 156mm / min;

[0071] The allowance after processing is 0.3-0.8mm.

[0072] Step 14: Install the reamer on the machine tool, check the coaxiality again and then ream the hole. Taking the φ18 specification docking hole as an example, the specific parameters are as follows: speed 481r / min, feed 230mm / min.

[0073] Step 15: Use a plug gauge to check the hole diameter accuracy, and use a roughness comparison sample to check the hole wall finish. After checking that everything is correct, install the standard plate and the precision locating pins that are fixed and tightened on the butt ends of the middle and outer wings, and remove the initial locating pins.

[0074] Step 16: Repeat the methods described in steps 12, 13, and 14 to complete the expansion and reaming of the remaining docking holes of the middle and outer wing docking end faces except for the precision positioning.

Claims

1. A method for making a butt hole on an aircraft wing end surface based on standard plate coordination, characterized in that: The following steps are involved: S1: Calculate the milling amount of the butt joint end face and complete the milling of the butt joint end face; S2: Install a standard plate on the butt end; S3: Select one of the positioning holes of the standard plate as a reference hole and create a base coordinate system; S4: Collect the center coordinates of all positioning holes in the base coordinate system; S5: Check the coaxiality of the machine tool spindle and each positioning hole on the standard plate. If there is a positioning hole that is not coaxial with the machine tool spindle, adjust the center coordinates of the corresponding positioning hole in the base coordinate system until they are coaxial; S6: Expand all small holes on the butt end faces; S7: Ream the initial hole after expansion.

2. The method according to claim 1, characterized in that: In S1, the milling amount calculation formula is as follows: Q = Q1 + (H1 + C - H2); Among them, Q represents the total milling amount; Q1 is the roughness value of the entire wing end surface, which is the difference between the highest point and the lowest point; H1 is the actual wall thickness of the part before processing; C is the difference between the starting point percentage gauge pressure reading and the measuring point percentage reading when measuring the end surface roughness; H2 is the theoretical wall thickness value required by the design after milling is completed; After the milling amount is calculated empirically without any problems, the end milling cutter is installed on the spindle. The milling amount of each cutter is allocated according to the requirements of preliminary milling and fine milling. The milling is performed in batches in a clockwise direction according to the shape of the wing end face. During fine milling, the single milling amount is less than or equal to 0.3mm.

3. The method according to claim 2, characterized in that: In S2, the standard plate is the basis for coordinating the positions of the docking holes of each wing end face. The standard plate is distributed with through holes concentric with the docking holes of the wing docking end face. The outer diameter of the through hole matches the outer diameter of the drill sleeve, and the inner diameter of the drill sleeve is consistent with the final hole size of the docking hole of the wing docking end face. The standard plate is fixed to the locating holes on the foot of the product clamping fixture through the four corner locating holes by bolts. The standard plate is provided with an end face shape inspection block. According to the clearance requirements between the block and the wing end face shape, the wing attitude is adjusted. At the same time, it is ensured that the deviation between each docking hole and the center of the standard plate is not greater than ±1mm, and then no less than 6 initial hole bolts are used to tighten and fix the standard plate and the wing docking end face.

4. The method according to claim 2, characterized in that: In S3, the positioning hole at the lower left corner of the standard plate is selected as the reference hole, the center coordinates of the reference hole are collected using the machine tool measurement system, and the zero offset is set according to the center coordinates of the reference hole to establish a base coordinate system, and the coordinate origin of the base coordinate system is the center coordinates of the reference hole.

5. The method according to claim 2, characterized in that: In S5, the coaxiality is checked as follows: Install a reamer on the machine tool spindle, and install a drill sleeve matching the size of the positioning hole on the reamer; Move the machine tool spindle to the collected center coordinates of the locating hole, and control the drill sleeve to move back and forth in the locating hole. If the drill sleeve slides easily in the locating hole, it is considered that the corresponding locating hole is coaxial with the spindle, otherwise it is considered that they are not coaxial.

6. The method according to claim 2, characterized in that: In S5, the process of adjusting the center coordinate of the positioning hole in the base coordinate system is as follows: slide the drill sleeve on the reamer to the surface of the standard plate docking hole, visually observe the position deviation between the drill sleeve and the standard plate docking hole, select the deviation axis to adjust the spindle until the drill sleeve can slide into the standard plate docking hole, and then adjust the X-axis or Y-axis respectively. Each time the drill sleeve is adjusted, it moves back and forth in the docking hole once, and the next adjustment direction and adjustment amount are determined by sensing the tightness of the drill sleeve in the standard plate docking hole, until the drill sleeve easily slides into the standard plate docking hole, and the adjustment process is completed.

7. The method according to claim 2, characterized in that: In S6, the spindle tool is replaced with a reaming tool, and the hole is reamed after checking the coaxiality; the spindle speed calculation formula is: n(r / min)=v÷πd·k Where n represents the spindle speed, v is the machining speed, d is the tool diameter, k is an empirical value, and the k value range is 0-1; Feed rate calculation formula: f=n·z·fz Where f is the feed rate, n is the spindle speed, z is the feed per tooth, and fz is the feed revolutions per tooth; The specific process of hole expansion is as follows: First expansion: Processing parameters: speed 541±10r / min, feed 86±5mm / min; The remaining amount after processing is 2-3mm; Second expansion: Processing parameters: speed 489±10r / min, feed 156±5mm / min; The allowance after processing is 0.3-0.8mm.

8. The method according to claim 2, characterized in that: In S7, the spindle tool is replaced with a reamer, and the coaxiality is checked again before reaming. The specific parameters are as follows: Speed ​​481r / min±10, feed 230±5mm / min.

9. The method according to claim 8, characterized in that In S3, an RMP60 probe is installed on the spindle, and the probe is manually positioned to the approximate center position of each docking hole in the standard plate. The probe measuring ball contacts the inner surface of the docking hole of the standard plate in four directions: bottom, top, left, and right. The center coordinates of each docking hole relative to the base coordinates are automatically calculated, and the collected center coordinates are used as the input for the CNC programming of the docking hole processing of the docking end face of the wing component.

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