Detection system and method for flexible online detection of internal threads of long steel pipe

Abstract

The invention relates to the field of steel pipe internal thread detection equipment, in particular to a detection system and method for flexible online detection of internal threads of a long steel pipe, and the method comprises the following steps: S1, measuring the reference position of the end of the steel pipe; s2, measuring the inner diameter of the end of the steel pipe and determining the inner circle axis position of the steel pipe; s3, measuring and determining the position of an internal thread spiral line; s4, on the basis that the position of the spiral line of the internal thread is determined, the measuring probe continues to move according to the actually-measured small diameter and thread pitch data and the control program of the detection system, the numerical values of at least three points are measured in a spiral groove of the internal thread, and then the pitch diameter of the internal thread is obtained through calculation; and S5, comparing and calculating a deviation value to obtain a detection result of the internal thread. According to the invention, judgment and feedback are realized through logic measurement and system calculation, the detection of the characteristics of internal threads, inner holes and the like can be realized, the internal threads of steel pipes with T-shaped threads and M-shaped triangular threads can be automatically detected, the detection range is wide, and the application is wide.

Description

Technical Field

[0001] The invention relates to the field of steel pipe internal thread detection equipment, in particular to a system and a detection method for flexible online detection of long steel pipe internal threads. Background Art

[0002] The inner contour processing of both ends of the steel pipe is divided into end face, inner hole and inner thread processing. The length range varies greatly, ranging from 1.5 meters to 10 meters, and the thread specifications include triangular threads, trapezoidal threads and other threads. The existing technology is to achieve it manually through the method of go and no-go gauges. Manual operation is labor-intensive, and the go and no-go gauge detection is also difficult to automate, and it is not convenient for later quality traceability. At the same time, manual detection requires the configuration of multiple inspection tools, which has high maintenance costs and no compatibility.

[0003] Because the length of steel pipes varies greatly, the standard equipment provided by standard testing equipment manufacturers is relatively expensive and cannot be promoted. The use of small three-coordinate equipment cannot meet all measurement requirements, has poor adaptability, and cannot achieve automation and online measurement.

[0004] Most of the existing quality inspection methods for internal threads of steel pipes are based on the manual use of go and stop gauges, which can only detect the "go" and "stop" of the thread, but cannot detect the specific values ​​of the thread parameters. In addition, there are too many inspection tools, and each inspection tool can only detect the perforating gun of one specification of thread, which has poor compatibility. The inspection process requires manual handling of the workpiece, and the inspection tools need to be carried back and forth and tightened, which requires high work intensity. Quality inspection is a post-inspection, which is disconnected from the processing link, and it is impossible to detect processing problems in time and compensate for processing parameters. If standard three-coordinate measuring equipment is used, the workpiece needs to be moved twice for positioning during the measurement process, the measurement speed is slow, the requirements for operators are also high, and online measurement cannot be achieved. Summary of the invention

[0005] In view of the problem in the prior art that it is inconvenient to detect the internal threads of steel pipes with large length variations, the present invention provides a system and method for flexible online detection of the internal threads of long steel pipes.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for flexible online detection of internal threads of long steel pipes, comprising the following steps:

[0008] S1, first measure the end reference position of the steel pipe;

[0009] S2, measure the inner diameter of the steel pipe end and determine the position of the inner axis of the steel pipe;

[0010] S3, measuring and determining the position of the internal thread helix, that is, starting from any outermost position of the internal thread helix, using the method of axial movement and radial measurement to determine the measured minor diameter and measured pitch of the internal thread;

[0011] S4, based on the determination of the position of the internal thread helix, the measuring probe continues to move according to the control program of the detection system according to the measured minor diameter and pitch data, and measures the internal thread pitch diameter from the internal thread helix groove;

[0012] S5, comparing the measured major diameter, minor diameter, middle diameter, and pitch of the internal thread with the standard parameters of the internal thread, and calculating the deviation value to obtain the detection result of the internal thread.

[0013] Preferably, in S2, when determining the position of the inner circle axis of the steel pipe, at least three measuring points are selected in the circumferential direction of the inner hole, and their measurement values ​​are obtained, and the axis position of the steel pipe is determined based on the auxiliary circle drawn based on the multiple measuring points.

[0014] Preferably, in S4, values ​​of at least three points evenly distributed in the spiral groove of the internal thread are measured, and then the mean diameter of the internal thread is obtained by calculation; wherein the control program is written according to the characteristic parameters of each thread.

[0015] Preferably, the calculation formula for the internal thread pitch diameter is:

[0016]

[0017] Where: D2 is the median diameter; M is the radial moving distance of the probe; I0 is the center distance between the two probe balls; d k is the probe ball diameter; P is the thread pitch; α is the tooth side angle.

[0018] Preferably, in S5, the deviation value is compared with the tolerance range of the internal thread standard parameters. When the deviation value is within the interval where the tolerance range is located, the quality of the internal thread of the steel pipe is qualified; otherwise, it is unqualified.

[0019] Preferably, when the deviation data is within the tolerance range, the part is qualified; when the deviation data is outside the tolerance range, the part is unqualified.

[0020] Preferably, when a part is unqualified, the deviation value is fed back to the processing machine tool by the controller, and the processing machine tool performs deviation compensation on the corresponding tool parameters.

[0021] A flexible online detection system for detecting the internal threads of a long steel pipe comprises a processing machine tool, a detection and transportation system, a first three-coordinate detection device and a second three-coordinate detection device, wherein the outlet of the processing machine tool is connected to the inlet of the detection and transportation system, and the first three-coordinate detection device and the second three-coordinate detection device are respectively arranged at the inlet and the outlet of the detection and transportation system; the first three-coordinate detection device and the second three-coordinate detection device both comprise a base, a three-coordinate moving mechanism, a measuring probe and a controller, the three-coordinate moving mechanism and the controller are arranged on the base, the measuring probe is arranged on the three-coordinate moving mechanism, the signal end of the measuring probe is connected to the input end of the controller, the control system is used to analyze the detection data and feed back the analysis results to the processing machine tool; the measuring probe comprises a measuring rod, a horizontal probe probe and a plurality of side probe probes, one end of the measuring rod is connected to the three-coordinate moving mechanism, and the other end is coaxially detachably connected to the horizontal probe probe, and the plurality of side probe probes are arranged along the circumference of the horizontal probe probe and are detachably connected to the horizontal probe probe.

[0022] A terminal device comprises a memory, a processor and a computer program stored in the memory and running on the processor, wherein the steps of the method are implemented when the processor executes the computer program.

[0023] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method are implemented.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention discloses a method for detecting the internal thread of a long steel pipe in a flexible online manner. The method first determines the position of the steel pipe by measuring the probe, then detects some thread parameters (major diameter, minor diameter, and middle diameter) of the internal thread of the steel pipe, and compares the detection data with the tolerance range of the internal thread standard parameters stored in the system to determine whether the thread quality is qualified. The method has the advantages of being adaptable to steel pipes of various specifications and different internal threads, no labor intensity and no risk, convenient quality tracing, and high detection efficiency.

[0026] The detection method has low requirements for the original position of the steel pipe, and can better adapt to the automatic measurement of the end internal thread under the state of great length range change. The signal end of the measuring probe is connected to the input and output end of a controller, so as to automatically obtain the detection data of each steel pipe. The tool compensation parameters of the processing equipment can also be corrected through the measurement results to improve the processing accuracy and stability of the CNC processing equipment. This method can realize highly flexible automatic operation, high detection efficiency, wide adaptability, no manual handling and operation, and has good promotion value.

[0027] The invention provides a flexible online detection of the internal thread of a long steel pipe, which can automatically detect the internal thread of the steel pipe. Through the automatic transportation system of the steel pipe running through the entire area, the transportation and positioning of different steel pipes and three-coordinate detection equipment can be realized, and flexible and automatic detection of different specifications can be realized. At the same time, the two three-coordinate detection devices are equipped with independent control systems and master control software after secondary development, which can realize the analysis of recorded data according to the relevant definitions of thread parameters, calculate and obtain various parameters of the thread, and automatically generate the detection results after the detection is completed.

[0028] The present invention can realize online automatic detection of long steel pipes through reasonable automation means and layout, and the processing range flexibility is not restricted by length changes.

[0029] This method provides the basic principles for measuring different threads. Software is developed based on the principles, which can directly measure the length of the inner contour of the workpiece, the verticality of the end face, and the thread parameters. The length and verticality are common detection methods for three-coordinate detection equipment, and the detection results are given intuitively, quantitatively and qualitatively, which is convenient for the subsequent thread quality traceability.

[0030] This method utilizes a set of detection tooling to match the detection requirements of steel pipes with various internal threads. There is no need to replace hardware. The detection of different internal threads can be achieved by calling different parameters through the program.

[0031] This automatic detection system equipment achieves flexible production at the lowest cost through reasonable structural layout and integration of secondary developed standard measuring equipment, and its input-output ratio has great market competitiveness.

[0032] The present invention can feed back the detection data to the processing numerical control equipment in time, and the numerical control equipment can adjust and correct the processing parameters in time, thus greatly reducing the failure rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A detection flow chart of a method for flexible online detection of internal threads of long steel pipes according to the present invention;

[0034] Figure 2 It is a schematic diagram for measuring the reference position of the steel pipe end;

[0035] Figure 3 It is a schematic diagram of inner diameter measurement;

[0036] Figure 4 It is a schematic diagram of thread position measurement;

[0037] Figure 5 This is a schematic diagram of measuring the middle diameter of the internal thread;

[0038] Figure 6 This is a schematic diagram of the internal thread measurement principle;

[0039] Figure 7 This is a layout diagram of a flexible online detection system for internal threads of long steel pipes according to the present invention;

[0040] Figure 8 It is a structural schematic diagram of a first three-coordinate detection device or a second three-coordinate detection device;

[0041] Fig. 9 Schematic diagram of the measurement probe structure.

[0042] In the figure, 1. processing machine tool; 2. first three-coordinate detection equipment; 3. detection and transportation system; 4. workpiece; 5. second three-coordinate detection equipment; 6. conveying and transportation system; 7. base; 8. measuring probe; 9. three-coordinate moving mechanism; 10. control system; 11. measuring rod; 12. horizontal probe probe; 13. side probe probe. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0044] The present invention discloses a method for detecting the internal thread of a long steel pipe in a flexible online manner. Figure 1 , including the following steps:

[0045] S1, first measure the end reference position of the steel pipe (such as Figure 2 As shown); because the outer surface of the steel pipe is an unprocessed surface, the position is inaccurate in the automatic detection system. The pipe end of the steel pipe is in the detection station, and the detection system needs to measure and determine the position first.

[0046] S2, measure the inner diameter of the steel pipe end and determine the position of the inner axis of the steel pipe (such as Figure 3 When determining the position of the inner circle axis of the steel pipe, at least three measuring points are selected in the circumferential direction of the inner hole, and their measurement values ​​are obtained. Auxiliary circles are drawn based on multiple measuring points to determine the position of the axis of the steel pipe.

[0047] S3, measure and determine the position of the internal thread helix, that is, start measuring from any position on the outermost side of the internal thread helix (such as Figure 4 As shown), the measured minor diameter and pitch of the internal thread are determined by axis movement and radial measurement;

[0048] S4, based on the determination of the position of the internal thread helix, the measuring probe continues to move according to the control program of the detection system according to the measured minor diameter and pitch data (such as Figure 5 As shown), the mean diameter of the internal thread is measured from the spiral groove of the internal thread; the values ​​of at least 3 points evenly distributed in the spiral groove of the internal thread are measured, and then the mean diameter of the internal thread is obtained by calculation; wherein the control program is written according to the characteristic parameters of each thread.

[0049] Reference Figure 6 , the calculation formula for the internal thread diameter is:

[0050]

[0051] Where: D2 is the median diameter; M is the radial moving distance of the probe; I0 is the center distance between the two probe balls; d k is the probe ball diameter; P is the thread pitch; α is the tooth side angle.

[0052] S5, compare the measured major diameter, minor diameter, middle diameter, and pitch of the internal thread with the internal thread standard parameters, and calculate the deviation value to obtain the internal thread test result. Compare the deviation value with the tolerance range of the internal thread standard parameters. When the deviation value is within the tolerance range, the internal thread quality of the steel pipe is qualified; otherwise, it is unqualified.

[0053] When the deviation data is within the tolerance range, the part is qualified; when the deviation data is outside the tolerance range, the part is unqualified. When the part is unqualified, the deviation value is fed back to the processing machine tool by the controller, and the processing machine tool performs deviation compensation on the corresponding tool parameters.

[0054] The present invention provides a method for flexible online detection of internal threads of long steel pipes, which can communicate with a CNC machine tool 1 in real time, and feed back the detection data to the CNC machine tool in a timely manner. The CNC machine tool can adjust and correct the tool compensation parameters in a timely manner, greatly reducing the processing defect rate of the thread lathe. The layout of the automation equipment of the present invention can realize flexible online detection of parts with a length of 1.5 meters to 10 meters through the movement of the transportation system, with low cost, high reliability and higher adaptability. Through certain logical measurements, and through system calculation to realize judgment and feedback, the detection of features such as internal threads and inner holes can be realized. Whether it is a T-thread or an M-type triangular thread, the internal threads of steel pipes can be automatically detected, with a wide detection range and wide application.

[0055] Example 1, detection of metric internal threads, imperial internal threads, and American internal threads:

[0056] A three-coordinate detection device is used to drive a detection probe for detection.

[0057] During testing, the probe goes deep into the inner hole of the product to be tested and measures 3 points in the circumferential direction of the internal thread. The system can determine the position of the internal thread based on the measurement data and detect the minor diameter of the thread at the same time; the probe moves forward half a pitch and measures 3 more points in the circumferential direction to measure the major diameter of the thread. The mean diameter of the thread is calculated through the software algorithm and compared with the standard value to obtain the test result.

[0058] Example 2, automatic detection of 2m-5m metric internal threads:

[0059] Automatic detection of internal threads of steel pipes is achieved. Through the automatic conveying system of the machine tool, chain-driven loading and unloading conveying, turning machine and buffer placement rack, the steel pipe is transported to the detection station through the conveyor line, measured by the three-coordinate detection equipment, calculated according to a certain logic by the computer system and software, analyzed according to the relevant definition of thread parameters, and various parameters of the thread are calculated and compared with the standard internal thread parameters. After the detection, the verification results are automatically generated.

[0060] The present invention also discloses a flexible online detection system for detecting the internal threads of long steel pipes. Figure 7 , 8 , including: a processing machine tool 1, a detection and transportation system 3, a first three-coordinate detection device 2 and a second three-coordinate detection device 5, the outlet of the processing machine tool 1 is connected to the entrance of the detection and transportation system 3, the first three-coordinate detection device 2 and the second three-coordinate detection device 5 are respectively arranged at the entrance and exit of the detection and transportation system 3; the first three-coordinate detection device 2 and the second three-coordinate detection device 5 have the same structure and size, the first three-coordinate detection device 2 and the second three-coordinate detection device 5 both include a base 7, a three-coordinate moving mechanism 9, a measuring probe 8 and a controller, the three-coordinate moving mechanism 9 and the controller are arranged on the base 7, the measuring probe 8 is arranged on the three-coordinate moving mechanism 9, the signal end of the measuring probe 8 is connected to the input end of the controller, and the control system 10 is used to analyze the detection data and feed back the analysis results to the processing machine tool 1.

[0061] Reference Fig. 9 The measuring probe 8 includes a measuring rod 11, a horizontal probe head 12 and a plurality of side probe heads 13. One end of the measuring rod 11 is connected to the three-coordinate moving mechanism 9, and the other end is coaxially and detachably connected to the horizontal probe head 12. The plurality of side probe heads 13 are arranged along the circumference of the horizontal probe head 12 and are detachably connected to the horizontal probe head 12. In this embodiment, the horizontal probe head 12 is threadedly connected to the measuring rod 11, and the plurality of side probe heads 13 are evenly threadedly connected to the circumference of the horizontal probe head 12. The plurality of side probe heads 13 are located in the same plane, and the plane is perpendicular to the axis of the measuring rod 11. The measuring probe 8 can complete detection in five different directions without changing the direction of the measuring rod 11, and can measure the inner contour features of the steel pipe.

[0062] When in use, first transport the workpiece 4 (steel pipe to be tested) to the testing position through the transportation system, stop and position it, and then use the first three-coordinate detection device 2 or the second three-coordinate detection device 5 to drive a measuring probe 8 for testing. With the use of automated equipment layout, there is no need for manual handling and participation, and the detection automation is realized. The end face and inner hole can be measured first by the three-coordinate detection device. After determining the position of the steel pipe axis, the parameters of the steel pipe internal thread (major diameter, minor diameter, and middle diameter) are measured. The measured values ​​of each parameter of the internal thread are compared with the standard parameters of the internal thread stored in the system, and the difference is calculated to give the test results. A measuring probe 8 can match various internal thread measurements of steel pipes of various specifications. There is no need to replace hardware. Different threads can be detected by calling different parameters through the program. After detection, it is transported by the conveying and transportation system 6 set after the second three-coordinate detection device 5 for subsequent processing.

[0063] The present invention also discloses a terminal device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, and the steps of the above method are implemented when the processor executes the computer program.

[0064] The present invention also discloses a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A method for flexible online detection of internal threads of long steel pipes, characterized in that: The following steps are involved: S1, first measure the end reference position of the steel pipe; S2, measure the inner diameter of the steel pipe end and determine the position of the inner axis of the steel pipe; S3, measuring and determining the position of the internal thread helix, that is, starting from any outermost position of the internal thread helix, using the method of axial movement and radial measurement to determine the measured minor diameter and measured pitch of the internal thread; S4, based on the determination of the position of the internal thread helix, the measuring probe continues to move according to the control program of the detection system according to the measured minor diameter and pitch data, and measures the internal thread pitch diameter from the internal thread helix groove; S5, comparing the measured major diameter, minor diameter, middle diameter, and pitch of the internal thread with the standard parameters of the internal thread, and calculating the deviation value to obtain the detection result of the internal thread.

2. The method for flexible online detection of internal threads of long steel pipes according to claim 1 is characterized in that: In S2, when determining the position of the inner circle axis of the steel pipe, at least three measuring points are selected in the circumferential direction of the inner hole, and their measurement values ​​are obtained. Auxiliary circles are drawn based on the multiple measuring points to determine the position of the axis of the steel pipe.

3. The method for flexible online detection of internal threads of long steel pipes according to claim 1 is characterized in that: In S4, the values ​​of at least three points evenly distributed in the spiral groove of the internal thread are measured, and then the middle diameter of the internal thread is obtained by calculation; wherein the control program is written according to the characteristic parameters of each thread.

4. The method for flexible online detection of internal threads of long steel pipes according to claim 3 is characterized in that: The calculation formula for the internal thread pitch diameter is: Where: D2 is the median diameter; M is the radial moving distance of the probe; I0 is the center distance between the two probe balls; d k is the probe ball diameter; P is the thread pitch; α is the tooth side angle.

5. The method for flexible online detection of internal threads of long steel pipes according to claim 1 is characterized in that: In S5, the deviation value is compared with the tolerance range of the internal thread standard parameters. When the deviation value is within the tolerance range, the quality of the internal thread of the steel pipe is qualified; otherwise, it is unqualified.

6. The method for flexible online detection of internal threads of long steel pipes according to claim 1 is characterized in that: When the deviation data is within the tolerance range, the part is qualified; when the deviation data is outside the tolerance range, the part is unqualified.

7. The method for flexible online detection of internal threads of long steel pipes according to claim 6 is characterized in that: When a part is unqualified, the deviation value is fed back to the processing machine tool by the controller, and the processing machine tool performs deviation compensation on the corresponding tool parameters.

8. A flexible online detection system for internal threads of long steel pipes, characterized in that: The invention comprises a processing machine tool (1), a detection and transportation system (3), a first three-coordinate detection device (2) and a second three-coordinate detection device (5); the outlet of the processing machine tool (1) is connected to the inlet of the detection and transportation system (3); the first three-coordinate detection device (2) and the second three-coordinate detection device (5) are respectively arranged at the inlet and the outlet of the detection and transportation system (3); the ends of the first three-coordinate detection device (2) and the second three-coordinate detection device (5) both comprise a base (7), a three-coordinate moving mechanism (9), a measuring probe (8) and a controller; the three-coordinate moving mechanism (9) and the controller are arranged on the base (7); the measuring probe (8) 8) is arranged on the three-coordinate moving mechanism (9), the signal end of the measuring probe (8) is connected to the input end of the controller, and the control system (10) is used to analyze the detection data and feed back the analysis results to the processing machine tool (1); the measuring probe (8) includes a measuring rod (11), a horizontal probe probe (12) and a plurality of side probe probes (13), one end of the measuring rod (11) is connected to the three-coordinate moving mechanism (9), and the other end is coaxially detachably connected to the horizontal probe probe (12), and the plurality of side probe probes (13) are arranged along the circumference of the horizontal probe probe (12) and are detachably connected to the horizontal probe probe (12).

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images