A method for precision control of a high-precision hole system in the web.

Abstract

This application provides a precision control method for a high-precision hole system in the web. The method includes: establishing a theoretical precision hole machining coordinate system under the part machining coordinate system; using the measurement function of the machine tool probe to adaptively compensate for the current state of the part to obtain the actual precision hole machining coordinate system; and machining the precision hole under the actual precision hole machining coordinate system. This application enables parts with precision holes having mutual positional requirements to be machined in any CNC machine tool with probe function in an unmanned manner by automatically changing the coordinate system, realizing adaptive precision compensation, and reducing the influence of web deformation on the position of the precision hole.

Description

Technical Field

[0001] This application belongs to the field of CNC machining technology, specifically relating to a precision control method for a high-precision hole system in a web. Background Technology

[0002] Machining the precision hole system in the web has always been a hot topic and a difficult point in machining. Its structural feature is that multiple precision holes of different sizes are distributed on the stiffeners or bosses of the web of the part, which are coordinated with each other. In the aerospace field, due to weight requirements, the thickness of the web is usually no more than 3mm. Because the web of the product is small and has poor rigidity, it is easy to deform during machining. When the deformation is large, it will affect the positional accuracy of the precision hole system in the web, and even cause the positional accuracy to exceed the tolerance, resulting in the product being unqualified.

[0003] In traditional machining, to eliminate the impact of deformation caused by the machining process on the positional accuracy of precision holes, precision hole machining is often treated as a separate process. After completing the machining of other structural parts, the part's posture is manually adjusted on a boring machine to ensure the flatness of the web is within a certain range before boring the holes to guarantee their positional accuracy. This machining method relies entirely on the operator's skill level, resulting in part quality being directly linked to the operator's skill level, thus posing a significant quality risk.

[0004] Meanwhile, this method requires operators to constantly manually adjust the parts to reduce the impact of web deformation on the position of precision holes, resulting in excessively long machine downtime, long part processing cycles, and low efficiency. As the research and production tasks of various types of military and civilian aircraft projects in the aviation manufacturing industry become increasingly heavy, the existing precision hole machining methods are gradually becoming a bottleneck restricting the rapid mass production of models. Summary of the Invention

[0005] Purpose of the invention: Since traditional processing methods rely entirely on the skill level of operators, the quality of parts is directly linked to the skill level of the operators, which poses a significant quality risk. Therefore, this application proposes an automated precision control method for high-precision hole systems in webs, which is of great significance for improving product quality, shortening processing cycles, and enhancing the level of automation in parts processing.

[0006] This application provides a method for controlling the precision of a high-precision hole system in a web, the method comprising:

[0007] Under the part machining coordinate system, establish a theoretical accuracy hole machining coordinate system;

[0008] The current state of the part is adaptively compensated by the measurement function of the machine tool probe to obtain the actual machining coordinate system of the precision hole;

[0009] The precision hole is manufactured in the actual machining coordinate system of the precision hole.

[0010] Preferably, establishing a theoretical accuracy hole machining coordinate system under the part machining coordinate system includes:

[0011] The internal shape of the part, the web plate, and the coordinate system references for machining the two precision holes have been completed.

[0012] The X-axis is established using two precision holes. One of the precision holes is set as the origin of the part, and any point on the web surface of the part is set as the XY plane of the theoretical precision hole machining coordinate system. The theoretical precision hole machining coordinate system is then established.

[0013] Preferably, after establishing the X-axis using two precision holes, setting one of the precision holes as the origin of the part, and setting any point on the web surface of the part as the XY plane of the theoretical precision hole machining coordinate system, the method further includes:

[0014] Verify the origin of the coordinate system. Under the theoretical precision hole machining coordinate system established above, measure the coordinates (X, Y) of the center of the reference precision hole that has been made by the upper station, and calculate the positional deviation (X0, Y0) between the measured value and the theoretical value. When the deviation value is within the allowable tolerance range, the origin of the coordinate system is considered to be without problems.

[0015] Preferably, the step of adaptively compensating for the current state of the part using the measurement function of the machine tool probe to obtain the actual machining coordinate system of the precision hole includes:

[0016] The deformation value of the web of the part is measured and automatically compensated to the theoretical precision hole machining coordinate system. The compensated theoretical precision hole machining coordinate system becomes the actual machining coordinate system of the precision hole.

[0017] Preferably, the web deformation value of the measured part is automatically compensated to the theoretical accuracy hole machining coordinate system, and the compensated theoretical accuracy hole machining coordinate system becomes the actual machining coordinate system of the accuracy hole, including:

[0018] In the direction of maximum deformation of the part, any point within φ50 of the end point of the part is selected as Z1; in the direction of minimum deformation of the part, any point within φ50 of the end point of the part is selected as Z2; and any point within φ50 of the geometric center of the part is selected as Z3. The Z values ​​of these three points are measured with a probe and recorded in the R variable.

[0019] The actual Z values ​​of the three points measured in the previous step are used to fit a plane, and the angle between the plane and the XY plane of the theoretical precision hole machining coordinate system is calculated.

[0020] By rotating the Z-axis of the theoretical precision hole machining coordinate system, the included angle is compensated to the theoretical precision hole machining coordinate system, and the actual machining coordinate system of the precision hole is established.

[0021] Preferably, the step of creating the precision hole in the actual machining coordinate system of the precision hole includes:

[0022] Use a φ2.1 alloy center drill to mark the φ10H8 precision hole;

[0023] Use a φ9*60 alloy drill bit to make a φ10H8 precision hole initial hole.

[0024] Use a φ9.8*80 flat-bottomed reamer to enlarge a φ10H8 precision hole;

[0025] A reamer is used to make a φ10H8 precision hole on a braiding machine, and a φ10*60 PVC machine reamer is used to make a φ10H8 precision hole.

[0026] A φ28H8 precision hole is made using a machine reamer; a φ28*60 PVC machine reamer is used to make a φ28H8 precision hole.

[0027] A φ15H8 precision hole is made using a machine reamer. A φ15*60 PVC machine reamer is used to make a φ15H8 precision hole.

[0028] Preferably, the method further includes:

[0029] Taking the origin of the actual machining coordinate system of the precision hole as the starting point, the machining of precision holes of each size starts from the nearest hole and proceeds from near to far.

[0030] Preferably, the method is applied to a CNC machine, which has a probe function.

[0031] The beneficial technical effects of this application are as follows:

[0032] This application enables parts with precision holes requiring mutual positional accuracy to be machined automatically in an unmanned manner by changing the coordinate system on any CNC machine tool with a probe function, achieving adaptive precision compensation and reducing the impact of web deformation on the position of precision holes. Attached Figure Description

[0033] Figure 1 This is a top view after converting the part machining coordinate system to the theoretical precision hole machining coordinate system;

[0034] Figure 2 It is a cross-sectional view of the position of the precision hole in the coordinate system for machining the theoretical precision hole;

[0035] Figure 3 It is a cross-sectional view showing the positions of the theoretical precision hole machining coordinate system and the actual precision hole machining coordinate system;

[0036] Figure 4 This is a top view of the precision hole machining on the part;

[0037] Wherein: 1-Part machining coordinate system, 2-Theoretical machining coordinate system for precision holes, 3-Part, 4-Probe, 5-22H8 precision hole, 6-φ16H8 precision hole, 7-Reference surface, 8-φ10H8 precision hole, 9-φ10H8 precision hole, 10-φ10H8 precision hole, 11-φ28H8 precision hole, 12-φ28H8 precision hole, 13-φ15H8 precision hole, 14-φ15H8 precision hole, 15-Actual machining coordinate system for precision holes, 16-Point Z1, 17-Point Z2, 18-Point Z3. Detailed Implementation

[0038] This invention provides a method for precision control of a high-precision hole system in a web. It is known that a high-precision hole system is a group of multiple precision holes of varying sizes and uneven distribution, designed to meet specific assembly or transmission requirements. These precision holes have strict positional requirements relative to each other. High-precision hole systems are commonly found on the webs of various large mechanical structural components.

[0039] This invention enables the automatic, unmanned machining of precision hole parts with strict positional requirements on any CNC machine tool equipped with a probe, automatically converting the coordinate system and achieving automatic precision compensation, thereby eliminating the influence of deformation on the position of the precision hole. In addition, it provides a process scheme and cutting parameters to ensure the hole diameter requirements.

[0040] In this embodiment of the invention, the invention is comprised of the following:

[0041] Please see Figures 1-4 This application provides a method for precision control of a high-precision hole system in the web, which consists of three parts.

[0042] The first step is to automatically establish a theoretical accuracy hole machining coordinate system under the part machining coordinate system.

[0043] 1) Given that the internal shape of the part, the web, and the coordinate system references for the two precision holes have been machined. Establish the X-axis using the two precision holes, set one of the precision holes as the origin of the part, and set any point on the web surface of the part as the XY plane of the theoretical precision hole machining coordinate system.

[0044] 2) Verify the origin of the coordinate system. Under the theoretical precision hole machining coordinate system established above, measure the coordinates (X, Y) of the center of the reference precision hole that has been made by the upper station, and calculate the positional deviation (X0, Y0) between the measured value and the theoretical value. When the deviation value is within the tolerance range, the origin of the coordinate system is considered to be without problems.

[0045] The second step involves using the measurement function of the machine tool probe to adaptively compensate for the current state of the part and establish the actual machining coordinate system for the precision hole. By measuring the current web deformation value of the part, the deformation value is automatically compensated to the theoretical precision hole machining coordinate system, and the compensated theoretical precision hole machining coordinate system becomes the actual machining coordinate system for the precision hole.

[0046] 1) Select any point within φ50 of the end point of the part as Z1 in the direction of the largest deformation of the part, select any point within φ50 of the end point of the part as Z2 in the direction of the smallest deformation of the part, and select any point within φ50 of the geometric center of the part as Z3. Use a probe to measure the Z value of these three points and record it in the R variable.

[0047] 2) Fit the actual Z values ​​of the three points measured in the previous step to a plane, and calculate the angle between the plane and the XY plane of the theoretical precision hole machining coordinate system;

[0048] 3) By rotating the Z-axis of the theoretical precision hole machining coordinate system, the included angle is compensated to the theoretical precision hole machining coordinate system, and the precision hole machining coordinate system is established.

[0049] The third step is to manufacture other precision holes in the actual machining coordinate system of the precision holes.

[0050] 1) Center drilling: Use a φ2.1 alloy center drill to drill points on the φ10H8 precision hole. Specific parameters: S = 2000 r / min, F = 200 mm / min, AP = 0.5 mm.

[0051] 2) Drilling a φ10H8 precision hole: Use a φ9*60 alloy drill bit to drill a φ10H8 precision hole. Specific parameters: S = 2000 r / min, F = 200 mm / min, AP = 3 mm.

[0052] 3) Use a φ9.8*80 flat-bottom reamer to enlarge the φ10H8 precision hole, with a margin of 0.1mm. Specific parameters: S = 2000r / min, F = 200mm / min, AP = 3mm.

[0053] 4) Use a reamer to make a φ10H8 precision hole. Use a φ10*60 PVC machine reamer to make a φ10H8 precision hole. Specific parameters: S=6000r / min, F=200mm / min;

[0054] 5) Use a machine reamer to make a φ28H8 precision hole. Use a φ28*60 PVC machine reamer to make a φ28H8 precision hole with a margin of 0.2mm. Specific parameters: S=6000r / min, F=200mm / min;

[0055] 6) Use a machine reamer to make a φ15H8 precision hole. Use a φ15*60 PVC machine reamer to make a φ15H8 precision hole with a margin of 0.1mm. Specific parameters: S=6000r / min, F=200mm / min.

[0056] It should be noted that each reaming program takes the origin of the actual machining coordinate system of the precision hole as the starting point. For each size of precision hole machining, it starts from the nearest hole and proceeds from near to far to avoid repeated machining paths and to obtain precision holes on the web, thereby reducing machine tool repetitive positioning errors.

[0057] This application enables parts with precision holes requiring mutual positional accuracy to be machined automatically in an unmanned manner by changing the coordinate system on any CNC machine tool with a probe function. It achieves adaptive accuracy compensation, reduces the impact of web deformation on the position of precision holes, adopts the minimum path principle during hole making, reduces the machine tool's repetitive positioning error, and further ensures the positional accuracy of the holes. At the same time, it provides parameters for machine-reamed holes to ensure that the diameter of the precision holes in the parts meets the design requirements.

[0058] In other embodiments of this application, the invention is further illustrated by taking the processing of partition-type parts on an automated production line composed of several CNC machine tools as an example. The CNC machine tools in the automated production line are five-axis CNC machining centers. Products enter and exit the machine tool via automatic pallet exchange. The pallets are automatically positioned and clamped on the worktable using a zero-point positioning system or other similar methods. Parts are connected to the pallets via tooling or directly. Measurement within the machine tool is performed using a probe.

[0059] The first step is to automatically establish the theoretical accuracy hole machining coordinate system 2 under the part machining coordinate system 1, such as... Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown.

[0060] 1) Establish a theoretical precision hole coordinate system. The probe 4 measures the center of the 22H8 precision hole 5 and the φ16H8 precision hole 6 respectively. The line connecting the two centers is set as the X-axis of the theoretical precision hole machining coordinate system 2. The direction of the φ16H8 precision hole 6 pointing to the 22H8 precision hole 5 is the positive direction of the X-axis. The probe 4 measures the center of the 22H8 precision hole 5 and sets it as the origin of the theoretical precision hole machining coordinate system 2. The probe 4 measures the Z value of the midpoint of the line connecting the two centers of the 22H8 precision hole 5 and the φ16H8 precision hole 6 on the web of the part 3, which is used as the Z0 surface of the theoretical precision hole machining coordinate system 2.

[0061] 2) Coordinate system origin verification: Under the theoretical precision hole machining coordinate system 2, use probe 4 to measure the coordinates (0,0) of the center of the φ22H8 precision hole 5 on part 3, and calculate the positional deviation (0.01, 0.005) between the measured value and the theoretical value. The deviation values ​​of X and Y are within 0.02mm, and there is no problem with the origin of the theoretical precision hole machining coordinate system 2.

[0062] The second step is to perform adaptive compensation on the theoretical precision hole machining coordinate system 2. Under the theoretical precision hole machining coordinate system 2, the deformation error of the web of the part is automatically compensated to the theoretical precision hole machining coordinate system, and the compensated theoretical precision hole machining coordinate system 2 becomes the precision hole machining coordinate system 15.

[0063] 1) The probe 4 measures the actual Z value of point Z116, where point Z116 is a point within φ50 of the end point of the part in the direction of the largest deformation of the part; the probe 4 measures the actual Z value of point Z217, where point Z318 is a point within φ50 of the end point of the part in the direction of the smallest deformation of the part; the probe 4 measures the actual Z value of point Z318, where point Z318 is a point within φ50 of the geometric center of the part.

[0064] 2) Using the measured Z values ​​of points Z116, Z217, and Z318 in step 1), fit a plane and calculate the angle θ between the plane and the XY plane in the theoretical precision hole machining coordinate system 2.

[0065] 3) By rotating the Z-axis of the theoretical precision hole machining coordinate system 2, the included angle θ is compensated to the theoretical precision hole machining coordinate system 2, and the precision hole machining coordinate system 15 is established.

[0066] Table 1 below compares the positional accuracy of the holes in both the theoretical accuracy hole machining coordinate system 2 and the theoretical accuracy hole machining coordinate system 2.

[0067] Table 1. Influence of adaptive compensation on orifice position accuracy

[0068]

[0069] The design of this partition-type part family requires a hole position accuracy of 0.1. Without using an adaptive compensation coordinate system, the hole position accuracy is not high due to the deformation of the web, and some precision holes exceed the tolerance. After using the adaptive compensation coordinate system, the hole position accuracy is significantly improved.

[0070] The third step is to produce other precision holes in the actual machining coordinate system 15 of the precision holes.

[0071] 1) Center drilling: Use a φ2.1*30 alloy center drill to drill points on φ10H8 precision holes 8, φ10H8 precision holes 9, and φ10H8 precision holes 10. Specific parameters: S = 2000 r / min, F = 200 mm / min, AP = 0.5 mm.

[0072] 2) Making φ10 precision holes with alloy drill bit: Use φ9*60 alloy drill bit to make φ10H8 precision holes 8, φ10H8 precision holes 9, and φ10H8 precision holes 10. Specific parameters: S = 2000r / min, F = 200mm / min, AP = 3mm.

[0073] 3) Enlarging φ10H8 precision holes: Use a φ9.8*80 flat bottom enlarging drill to enlarge φ10H8 precision holes 8, φ10H8 precision holes 9, and φ10H8 precision holes 10, with a single-sided allowance of 0.1mm. Specific parameters: S = 2000r / min, F = 200mm / min, AP = 3mm.

[0074] 4) Machine reamer for making φ10H8 precision holes: Use a φ10*60 machine PVC reamer to make φ10H8 precision holes 8, 9, and 10. Specific parameters: S = 6000r / min, F = 200mm / min.

[0075] 5) Machine reamer for making φ28H8 precision holes: Use a φ28*60 PVC machine reamer to make φ28H8 precision holes 11 and φ28H8 precision holes 12. Specific parameters: S=6000r / min, F=200mm / min, allowance 0.2mm on each side.

[0076] 6) Procedure for making φ15H8 precision holes with a machine reamer: Use a φ15*60 PVC machine reamer to make φ15H8 precision holes 13 and 14, with a margin of 0.1mm. Specific parameters: S=6000r / min, F=200mm / min.

[0077] Among them, taking the origin of the actual machining coordinate system 15 of the precision hole as the starting point, the machining of precision holes of each size starts from the nearest hole and proceeds from near to far to avoid repeated machining paths. The precision holes on the web are made in the following order: 9→8→10→11→12→13→14.

Claims

1. A method for precision control of a high-precision hole system in a web, characterized in that, The method includes: Under the part machining coordinate system, establish a theoretical accuracy hole machining coordinate system; The current state of the part is adaptively compensated by the measurement function of the machine tool probe to obtain the actual machining coordinate system of the precision hole; The precision hole is manufactured in the actual machining coordinate system of the precision hole; The step of using the measurement function of the machine tool probe to adaptively compensate for the current state of the part and obtain the actual machining coordinate system of the precision hole includes: The deformation value of the web plate of the part is measured and the deformation value is automatically compensated to the theoretical precision hole machining coordinate system. The compensated theoretical precision hole machining coordinate system becomes the actual machining coordinate system of the precision hole. The web deformation value of the measured part is automatically compensated to the theoretical accuracy hole machining coordinate system. The compensated theoretical accuracy hole machining coordinate system becomes the actual machining coordinate system of the accuracy hole, including: In the direction of maximum deformation of the part, any point within φ50 of the end point of the part is selected as Z1; in the direction of minimum deformation of the part, any point within φ50 of the end point of the part is selected as Z2; and any point within φ50 of the geometric center of the part is selected as Z3. The Z values ​​of these three points are measured with a probe and recorded in the R variable. The actual Z values ​​of the three points measured in the previous step are used to fit a plane, and the angle between the plane and the XY plane of the theoretical precision hole machining coordinate system is calculated. By rotating the Z-axis of the theoretical precision hole machining coordinate system, the included angle is compensated to the theoretical precision hole machining coordinate system, and the actual machining coordinate system of the precision hole is established.

2. The method according to claim 1, characterized in that, The establishment of a theoretical accuracy hole machining coordinate system under the part machining coordinate system includes: The internal shape of the part, the web plate, and the coordinate system references for machining the two precision holes have been completed. The X-axis is established using two precision holes. One of the precision holes is set as the origin of the part, and any point on the web surface of the part is set as the XY plane of the theoretical precision hole machining coordinate system. The theoretical precision hole machining coordinate system is then established.

3. The method according to claim 2, characterized in that, The method of establishing an X-axis using two precision holes, setting one of the precision holes as the origin of the part, and setting any point on the web surface of the part as the XY plane of the theoretical precision hole machining coordinate system, further includes: Verify the origin of the coordinate system. Under the theoretical precision hole machining coordinate system established above, measure the coordinates (X, Y) of the center of the reference precision hole that has been made by the upper station, and calculate the positional deviation (X0, Y0) between the measured value and the theoretical value. When the deviation value is within the allowable tolerance range, the origin of the coordinate system is considered to be without problems.

4. The method according to claim 1, characterized in that, The process of creating a precision hole in the actual machining coordinate system of the precision hole includes: Use a φ2.1 alloy center drill to mark the φ10H8 precision hole; Use a φ9*60 alloy drill bit to make a φ10H8 precision hole initial hole. Use a φ9.8*80 flat-bottomed reamer to enlarge a φ10H8 precision hole; A reamer is used to make a φ10H8 precision hole on a braiding machine, and a φ10*60 PVC machine reamer is used to make a φ10H8 precision hole. A φ28H8 precision hole is made using a machine reamer; a φ28*60 PVC machine reamer is used to make a φ28H8 precision hole. A φ15H8 precision hole is made using a machine reamer. A φ15*60 PVC machine reamer is used to make a φ15H8 precision hole.

5. The method according to claim 4, characterized in that, The method further includes: Taking the origin of the actual machining coordinate system of the precision hole as the starting point, the machining of precision holes of each size starts from the nearest hole and proceeds from near to far.

6. The method according to claim 1, characterized in that, The method is applied to CNC equipment, which has a probe function.

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