Automatic processing method for web of double-sided groove structure

Abstract

The invention discloses an automatic processing method for a web of a double-sided groove cavity structure, and compiles an automatic processing program for the web of the double-sided groove cavity structure, wherein the program comprises a first-station processing program, a first-station measurement program, a second-station semi-finishing processing program, a second-station semi-finishing measurement program, an error calculation compensation program, and a second-station finishing processing program. Through the invention, the automatic measurement of the thickness of the web of the double-sided groove cavity structure can be indirectly completed by using a measuring device installed on a numerically controlled machine tool, and the deviation value between the actual state and the theoretical state of the web of the double-sided groove cavity structure in the current state can be automatically calculated according to the measurement result, and the deviation value is adaptively compensated and processed to eliminate the deviation of the characteristic size accuracy caused by part clamping, tool measurement, etc.

Description

Technical Field

[0001] The invention relates to the technical field of numerical control machining, in particular to an automatic machining method for a web of a double-sided groove structure. Background Art

[0002] In the field of CNC machining, most parts have double-sided groove structures, and the web of the double-sided groove structure requires at least two finishing stations to collaborate to complete the machining. Due to factors such as part clamping, tool measurement, and machine tool accuracy, certain machining errors will occur. The web of the double-sided groove structure that is collaboratively processed by two stations must be stopped during the machining process to measure the thickness of the scrap plate, and the thickness deviation must be compensated before processing to ensure that the web thickness is qualified. Since the double-sided groove structure is generally a closed structure, the thickness measurement of its web is mostly completed using an ultrasonic thickness gauge, and the compensation of the deviation value needs to be calculated and entered manually.

[0003] As CNC parts gradually develop towards high added value and high precision, the traditional double-sided groove structure web processing method that relies on human intervention in the processing process to ensure the thickness accuracy of the web has led to the quality of parts being linked to the skill level of personnel, which poses a greater quality risk; at the same time, with the continuous advancement of industrial level, automation and intelligence have become important directions for the development of CNC processing. Therefore, how to eliminate the human intervention factor in the CNC processing of parts is the top priority for improving part quality and realizing the automation and intelligent production of CNC processed parts.

[0004] For the above problems, the current solution is to improve the clamping accuracy and tool measurement accuracy of each station of the parts as much as possible, and then obtain a relatively fixed compensation value through multiple processing tests, and directly solidify it into the process parameters. However, this method has certain limitations and shortcomings. First, the process parameters after solidification cannot be dynamically adjusted to adapt to the current processing state. The parts can only be processed on fixed machine tools, and the production process is not flexible enough; secondly, due to the limited number of test pieces for testing compensation values ​​for parts with the characteristics of "multiple varieties and small batches", the fixed compensation value is slightly insufficient in applicability, and the thickness of the double-sided groove cavity structure web cannot be accurately controlled; finally, with the wear of fixtures, machine tools, etc., their clamping and processing accuracy also decreases, and the solidified process parameters cannot be always applicable and need to be adjusted regularly. With the continuous development of in-machine measurement technology, a new solution is provided for the automated and precise processing of the double-sided groove cavity structure web, that is, using in-machine measurement technology to automatically measure the thickness of the double-sided groove cavity structure web, and then dynamically adjusting the compensation value according to the measurement results to achieve its automated and precise processing.

[0005] Due to the particularity of the double-sided groove structure, its web thickness cannot be directly measured using the existing in-machine measurement technology using the measuring device on the machine tool. Therefore, forming a processing method that indirectly completes the automatic measurement and compensation of the web thickness of the double-sided groove structure is of great significance to improving product quality and promoting the development of CNC machining towards automation and intelligence. Summary of the invention

[0006] The present invention provides an automatic processing method for a double-sided groove cavity structure web. Through the present invention, the automatic measurement of the thickness of the double-sided groove cavity structure web can be indirectly completed by using a measuring device installed on a CNC machine tool. The deviation value between the actual state and the theoretical state of the double-sided groove cavity structure web in the current state can be automatically calculated based on the measurement result, and the deviation value can be adaptively compensated and processed to eliminate the deviation of characteristic size accuracy caused by part clamping, tool measurement, etc. The present invention is composed of the following contents:

[0007] A method for automatically processing a web of a double-sided groove cavity structure, wherein the theoretical shape of the double-sided groove cavity structure is known, and the processing is performed by a numerically controlled machine tool, and the method is characterized in that the method comprises the following contents: 1) taking the upper end surface of the double-sided groove cavity structure as a reference surface, taking the upper surface of the web of the double-sided groove cavity structure as a first characteristic surface, and taking the lower surface of the web of the double-sided groove cavity structure as a second characteristic surface, and obtaining the theoretical distances between the reference surface and the first characteristic surface, and between the reference surface and the second characteristic surface according to the theoretical shape of the double-sided groove cavity structure; 2) compiling an automatic processing program for the web of the double-sided groove cavity structure, the program comprising a first-station processing program, a first-station measurement program, a second-station semi-finishing processing program, a second-station semi-finishing measurement program, an error calculation compensation program, and a second-station finishing processing program; 3) in the first-station processing program, finishing processing of the first characteristic surface and the reference surface is included; 4) in the first-station measurement program, a measurement program installed on a numerically controlled machine tool is used to calculate the error compensation program, and a second-station finishing processing program is used. The measuring device on the bed measures the actual distance from the reference plane to the first feature surface, and judges whether the finishing of the first feature surface is qualified based on the actual distance; 5) The theoretical semi-finishing allowance of the second feature surface is included in the semi-finishing program of the second station to form the semi-finishing surface of the second feature surface; 6) In the semi-finishing measurement program of the second station, the actual distance between the reference plane and the semi-finishing surface of the second feature surface is measured by the measuring device installed on the CNC machine tool; 7) In the error calculation and compensation program, the actual distance between the reference plane and the semi-finishing surface of the second feature surface is subtracted from the theoretical distance between the reference plane and the second feature surface to obtain the actual machining allowance of the second feature surface, and the difference between the actual machining allowance and the theoretical machining allowance of the second feature surface is compensated to the finishing process of the second feature surface; 8) In the finishing program of the second station, the finishing of the second feature surface is carried out according to the difference compensation.

[0008] The automatic processing method of the double-sided groove cavity structure web is characterized in that, in step 1), the thickness tolerance of the double-sided groove cavity structure web is proportionally distributed to the distance from the first characteristic surface to the reference plane and the distance from the second characteristic surface to the reference plane.

[0009] The automatic processing method of the web of the double-sided groove cavity structure is characterized in that, in step 4), the actual distance from the reference plane to the first characteristic surface is measured by selecting a reference point on the reference plane and selecting several characteristic points on the first characteristic surface according to their area sizes, and the Z-axis coordinate values ​​of the reference point and each characteristic point are measured respectively by a measuring device, and the average value of the difference between the Z-axis coordinate values ​​of each characteristic point and the reference point is the actual distance from the reference plane to the first characteristic surface.

[0010] The automatic processing method of the double-sided groove structure web is characterized in that, in step 8), the difference between the actual processing allowance and the theoretical processing allowance of the second characteristic surface is compensated to the Z-direction offset of the processing coordinate system of the second station.

[0011] The automatic machining method of the web of the double-sided groove structure is characterized in that, in step 8), the difference between the actual machining allowance and the theoretical machining allowance of the second characteristic surface is compensated to the finishing tool length of the second characteristic surface.

[0012] The automatic processing method of the double-sided groove structure web is characterized in that the first characteristic surface and the reference surface are processed by the same tool to eliminate errors introduced by different tools.

[0013] The automatic processing method of the double-sided groove structure web is characterized in that the semi-finishing and finishing of the second characteristic surface are processed by the same tool to eliminate the error introduced by different tools.

[0014] The advantages of the present invention are that it can use a convenient and universal probe to automatically complete the in-machine measurement and compensation processing of the double-sided groove cavity structure web in the machine tool, so that the accuracy of such products no longer depends on people or fixed process compensation parameters, and does not need to be processed on a fixed machine tool. While ensuring the processing accuracy of parts, the flexibility of the processing process is greatly improved; the tools used in the measurement process have the advantages of strong environmental adaptability, high precision, low cost, etc., which makes the present invention highly applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the transformation of the web thickness dimension of the double-sided groove cavity structure;

[0016] Figure 2 It is a schematic diagram of automatic measurement of the relative distance between the first characteristic surface and the reference surface;

[0017] Figure 3It is a schematic diagram of adaptive compensation processing of the relative distance between the second characteristic surface and the reference surface;

[0018] Explanation of numbers in the figure: 1 double-sided groove cavity structure web, 2 first characteristic surface, 3 second characteristic surface, 4 reference plane, 5 finishing first characteristic surface machining coordinate system, 6 first reference point, 7 first characteristic point, 8 second characteristic point, 9 second reference point, 10 finishing second characteristic surface machining coordinate system, 11 theoretical semi-finished surface of the second characteristic surface, 12 actual semi-finished surface of the second characteristic surface. DETAILED DESCRIPTION

[0019] Referring to the attached drawings, this embodiment takes the automatic processing process of a double-sided groove structure web as an example to further illustrate the scheme of the present invention. The double-sided groove structure web is composed of two mutually parallel planes, but it is applicable to double-sided structures composed of parallel curved surfaces, non-parallel planes, and non-parallel curved surfaces; the numerical control system is Sinumerik840D, but it is applicable to other numerical control systems; the measuring device in the machine tool is a wireless probe.

[0020] The first step is the absolute size conversion of the double-sided groove structure web 1, such as Figure 1 As shown. 1) The double-sided groove cavity structure web 1 is decomposed into two characteristic surfaces constituting the structure, namely the first characteristic surface 2 and the second characteristic surface 3; 2) The absolute size of the double-sided groove cavity structure web 1 - the web thickness δ is converted into the distance H1 from the first characteristic surface 2 to the reference surface 4 and the distance H2 from the second characteristic surface 3 to the reference surface 4, where δ = H2 - H1; 3) The tolerance band ± Δδ of the web thickness δ is compressed and modified to ± 0.9 × Δδ to offset the measurement error; 4) The compressed tolerance band is assigned to the distances H1 and H2, namely h1, h2 and h3, h4, where Δδ, h1, h2, h3, h4 must satisfy: h3-h2 ≤ 0.9 × Δδ, h4-h1 ≥ -0.9 × Δδ.

[0021] The second step is to compile the first station processing program, which includes the finishing process of the first feature surface 2 and the reference surface 4. The two surfaces are processed by the same tool.

[0022] The third step is to compile the first station measurement program, such as Figure 2 As shown in FIG. 1 , the program includes automatic measurement of the relative distance dimension H1 between the first feature surface 2 and the reference surface 4, specifically as follows: first, a first reference point 6 is selected on the reference surface 4, and three first feature points 7 are selected on the first feature surface 2; second, the Z-direction coordinate values ​​of the first reference point 6 and the three first feature points 7 in the finishing first surface machining coordinate system 5 are measured respectively by a measuring device installed on the machine tool; then, the Z-direction coordinate value difference between each first feature point 7 and the first reference point 6 is calculated respectively, and the maximum deviation H between each difference and the theoretical distance H1 is solved 1max and the minimum deviation H1min ; Finally, determine the maximum deviation H 1max and the minimum deviation H 1min Whether the tolerance requirement of the allocation is met, that is, whether h1>H 1max ≥H 1min >h2, if not satisfied, the automatic processing process ends.

[0023] The fourth step is to compile the semi-finishing program of the second station, such as Figure 3 As shown, the program includes the semi-finishing allowance δ1 of the second feature surface. The theoretical semi-finishing surface 11 of the second feature surface can be formed through the program. However, due to errors in tool setting, clamping, etc., the actual semi-finishing surface of the second feature surface formed after executing the program is 12.

[0024] The fifth step is to compile the semi-precision measurement program for the second station, such as Figure 3 As shown, the program includes measuring the distance from the reference plane 4 to the actual semi-finished surface 12 of the second feature surface, specifically as follows: at this time, the reference plane 4 is attached to the machine tool surface, and the machine tool surface and the reference plane 4 are in the same plane. A second reference point 11 is selected on the machine tool surface, and three second feature points 8 are selected on the actual semi-finished surface 12 of the second feature surface. The actual Z-axis coordinate values ​​of the second reference point 11 and the three second feature points 8 in the current machining coordinate system 10 are measured respectively, and the difference between the actual Z-axis coordinate value of each second feature point 8 and the actual Z-axis coordinate value of the second reference point 11 is calculated respectively, and the average value is calculated, which is the distance from the reference plane 4 to the actual semi-finished surface 12 of the second feature surface.

[0025] The sixth step is to compile an error calculation compensation program, such as Figure 3 As shown, in this program, the distance from the reference plane 4 to the actual semi-finished surface 12 of the second feature surface is subtracted from the theoretical distance H2 between the reference plane 4 and the second feature surface 3 to obtain the actual machining allowance δ1+ΔZ of the second feature surface, and the difference ΔZ between the actual machining allowance δ1 and the theoretical machining allowance is calculated to determine whether the deviation value ΔZ exceeds the theoretical position lower limit H2+h4 of the feature surface 3. If it does not exceed, the difference ΔZ is compensated to the Z-axis offset value of the second station machining coordinate system 10 to correct the machining coordinate system. If it exceeds, an alarm is issued.

[0026] The seventh step is to compile the finishing program for the second station, and use this program to complete the finishing of the second feature surface in the corrected machining coordinate system. In order to eliminate the errors introduced by different tools, it should be ensured that the semi-finishing and finishing of the second feature surface are completed by the same tool.

[0027] Finally, in the processing process of the double-sided groove cavity structure belly plate, the first station processing program and the first station measurement program are executed in sequence. After the tolerance requirements are met, it is turned over, and the second station semi-finishing program, the second station semi-finishing measurement program, the error calculation compensation program, and the second station finishing program are executed in sequence to complete the automatic processing of the double-sided groove cavity structure belly plate.

Claims

1. An automatic processing method for a web of a double-sided groove cavity structure, wherein the theoretical shape of the double-sided groove cavity structure is known and the processing is performed by a CNC machine tool, characterized in that The invention comprises the following contents: 1) taking the upper end surface of the double-sided groove cavity structure as the reference surface, taking the upper surface of the web of the double-sided groove cavity structure as the first characteristic surface, taking the lower surface of the web of the double-sided groove cavity structure as the second characteristic surface, and obtaining the theoretical distance between the reference surface and the first characteristic surface, and between the reference surface and the second characteristic surface according to the theoretical shape of the double-sided groove cavity structure; 2) compiling an automatic processing program for the web of the double-sided groove cavity structure, which comprises a first-station processing program, a first-station measurement program, a second-station semi-finishing program, a second-station semi-finishing measurement program, an error calculation compensation program, and a second-station finishing program; 3) performing the machining at the first station; The first station process includes finishing of the first feature surface and the reference surface; 4) in the first station measurement process, the actual distance from the reference surface to the first feature surface is measured by a measuring device installed on the CNC machine tool, and whether the finishing of the first feature surface is qualified is judged according to the actual distance; 5) in the second station semi-finishing process, the theoretical semi-finishing allowance of the second feature surface is included to form the semi-finishing surface of the second feature surface; 6) in the second station semi-finishing measurement process, the actual distance between the reference surface and the semi-finishing surface of the second feature surface is measured by a measuring device installed on the CNC machine tool; 7) in the error calculation compensation process, the error is calculated by the error calculation compensation process. The actual distance between the reference plane and the semi-finished surface of the second characteristic surface is subtracted from the theoretical distance between the reference plane and the second characteristic surface to obtain the actual machining allowance of the second characteristic surface, and the difference between the actual machining allowance and the theoretical machining allowance of the second characteristic surface is compensated in the finishing process of the second characteristic surface; 8) In the finishing program of the second station, the finishing of the second characteristic surface is carried out according to the difference compensation. In step 4), the actual distance from the reference plane to the first characteristic surface is measured by selecting a first reference point on the reference plane, selecting a plurality of characteristic points on the first characteristic surface according to their area sizes, and measuring the first reference point and the first characteristic point by a measuring device. The Z-axis coordinate values ​​of the datum point and each feature point, and the average value of the difference between the Z-axis coordinate values ​​of each feature point and the first datum point are the actual distance from the datum plane to the first feature plane. In step 6), the datum plane coincides with the machine tool surface, and the actual distance from the datum plane to the semi-finished surface of the second feature plane is measured by selecting a second datum point on the machine tool surface, selecting several feature points on the semi-finished surface of the second feature plane according to their area sizes, and measuring the Z-axis coordinate values ​​of the second datum point and each feature point respectively through a measuring device. The average value of the difference between the Z-axis coordinate values ​​of each feature point and the second datum point is the actual distance from the datum plane to the semi-finished surface of the second feature plane.

2. The automatic processing method of the double-sided groove structure web according to claim 1, characterized in that: In step 1), the thickness tolerance of the web of the double-sided groove cavity structure is proportionally allocated to the distance from the first characteristic surface to the reference surface and the distance from the second characteristic surface to the reference surface.

3. The automatic processing method of the double-sided groove structure web according to claim 1, characterized in that: In step 8), the difference between the actual machining allowance and the theoretical machining allowance of the second feature surface is compensated to the Z-direction offset of the machining coordinate system of the second station.

4. The automatic processing method of the double-sided groove structure web according to claim 1, characterized in that: In step 8), the difference between the actual machining allowance and the theoretical machining allowance of the second feature surface is compensated to the finishing tool length of the second feature surface.

5. The automatic processing method of the double-sided groove structure web according to claim 1, characterized in that: The first feature surface and the reference surface are processed by the same tool to eliminate the errors introduced by different tools.

6. The automatic processing method of the double-sided groove structure web according to claim 1, characterized in that: The semi-finishing and finishing of the second feature surface are processed by the same tool to eliminate the errors introduced by different tools.

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