Laser cutting control system for superhard material compacts

Abstract

The application relates to the technical field of laser cutting, in particular to a laser cutting control system for a superhard material composite sheet, which comprises a monitoring module for acquiring an initial scanning path of a laser beam for the superhard material composite sheet, and demarcating a plurality of nodes in the initial scanning path, and dividing adjacent nodes into a scanning section; the monitoring module records the cutting speed of each scanning section and the cutting degree parameter of each node in the scanning process; a path control unit generates a supplementary scanning path based on the cutting degree parameter of each node; and a speed control unit determines the scanning speed of each scanning section in the supplementary scanning path based on the cutting degree parameter of the nodes at the two ends of the scanning section. The parallel configuration of the photoelectric detector array can effectively quantify and characterize the cutting degree of each node, so that the optimization of the path and speed determined based on the cutting degree of each node is more matched to the actual working condition, thereby effectively improving the forming precision of the superhard material composite sheet in the laser cutting process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser cutting, in particular to a laser cutting control system for superhard material composite sheet. BACKGROUND

[0002] The "superhard material composite sheet" generally refers to a composite material sintered by superhard material and cemented carbide substrate at high temperature and high pressure, and the superhard material mainly refers to diamond and cubic boron nitride. The superhard material composite sheet has important application value in the fields of oil drilling and precision machining due to its excellent characteristics such as high hardness and high wear resistance. However, its superhard characteristics also make it extremely difficult to be machined by traditional mechanical processing, and laser cutting technology has become the main processing method due to its non-contact and high precision characteristics.

[0003] For example, in the prior art, Chinese patent publication No. CN108453373A discloses a laser cutting machine control system, which comprises: a machine tool bed body comprising a top cover and a machine body, the top cover is uniformly provided with a first through hole, and the machine body is provided with a drawer; a cutting machine body is arranged on the left side of the top cover; a machine tool guide rail is arranged on the right side of the top cover, and the machine tool guide rail is uniformly provided with a second through hole; a mechanical arm is connected to one end of the cutting machine body, and the other end of the mechanical arm is provided with a laser cutting machine cutting head; a camera is arranged at the front end of the laser head of the laser cutting machine cutting head. The technical scheme improves the consistency of laser cutting, but requires continuous manual observation and parameter adjustment.

[0004] However, the above-mentioned technology has the following technical problems: first, the internal composite layer thickness deviation of the material is easy to cause the laser cutting quality deviation, resulting in inconsistent cutting depth and even local non-cutting-through phenomenon; second, the traditional laser cutting system adopts fixed scanning path and power parameters, and it is difficult to dynamically adjust the process parameters according to the real-time cutting state; third, the existing monitoring means mainly relies on offline detection or single parameter feedback, and cannot realize online evaluation and closed-loop control of cutting quality. SUMMARY

[0005] Therefore, the present application provides a laser cutting control system for superhard material composite sheet to solve at least one technical problem in the above background.

[0006] To achieve the above-mentioned purpose, the present application provides a laser cutting control system for superhard material composite sheet, which comprises a monitoring module and a control module.

[0007] The monitoring module is configured to acquire an initial scanning path of the laser beam on the superhard material composite sheet, and to demarcate a plurality of nodes in the initial scanning path, and to divide adjacent nodes into a scanning segment, and to record the cutting speed of each scanning segment and the cutting degree parameter of each node in the scanning process; the control module is connected with the monitoring module, and includes a path control unit and a speed control unit; the path control unit is configured to generate a supplementary scanning path based on the cutting degree parameter of each node in response to the cutting degree parameter of any node being abnormal after the laser beam scans the initial scanning path; and the speed control unit is configured to re-divide the supplementary scanning path into scanning segments, and to determine the scanning speed of each scanning segment in the supplementary scanning path based on the cutting degree parameter of the nodes at both ends of the scanning segment.

[0008] As a preferred technical solution of the laser cutting control system for the superhard material composite sheet, the monitoring module specifically includes a photodetector array arranged in parallel and spaced apart from the laser beam, and the photodetector array receives light generated by the laser beam after passing through the superhard material composite sheet in a direction parallel to the laser beam.

[0009] As a preferred technical solution of the laser cutting control system for the superhard material composite sheet, the monitoring module is configured to execute the following process to determine the cutting degree parameter:

[0010] acquire the average current of the photodetector array in the period corresponding to the node being cut, and determine the cutting degree parameter based on the average current of the photodetector array;

[0011] The cutting degree parameter is positively correlated with the average current of the photodetector array.

[0012] As a preferred technical solution of the laser cutting control system for the superhard material composite sheet, the monitoring module specifically executes the following operation to determine the cutting degree parameter:

[0013] The cutting degree parameter K = I1 / I2, where I1 is the average current of the photodetector array in the period corresponding to the node being cut, and I2 is the average current of the photodetector array when receiving light of the original laser beam in a direction parallel to the laser beam without passing through the superhard material composite sheet.

[0014] As a preferred technical solution of the laser cutting control system for the superhard material composite sheet, the determination of the path control unit on the abnormality of the cutting degree parameter includes comparing the cutting degree parameter with a corresponding threshold value, and determining that the cutting degree parameter is abnormal if it is less than the corresponding threshold value.

[0015] As a preferred technical scheme of the laser cutting control system for the superhard material composite sheet, the path control unit sets different thresholds for nodes with different laser beam passing times in the initial scanning path, and the greater the number of laser beam passing times of the node in the initial scanning path, the greater the threshold corresponding to the node.

[0016] As a preferred technical scheme of the laser cutting control system for the superhard material composite sheet, the path control unit responds to the cutting degree parameter anomaly of only one node to take the shortest path passing through the initial node and the node with the cutting degree parameter anomaly as the supplementary scanning path.

[0017] As a preferred technical scheme of the laser cutting control system for the superhard material composite sheet, the path control unit responds to the cutting degree parameter anomaly of more than one node to take the shortest path passing through each node with the cutting degree parameter anomaly as the supplementary scanning path.

[0018] As a preferred technical scheme of the laser cutting control system for the superhard material composite sheet, the speed control unit is further configured to dynamically adjust the scanning speed of the scanning section according to the difference between the cutting degree parameters of the nodes at both ends of the scanning section.

[0019] When the difference between the cutting degree parameters exceeds a preset threshold, the scanning speed is reduced and the number of laser beam repeated scanning of the scanning section in the supplementary scanning path is increased.

[0020] As a preferred technical scheme of the laser cutting control system for the superhard material composite sheet, the monitoring module sets the constraint condition of each node as:

[0021] The path lengths of the scanning sections are the same,

[0022] Or, the nodes are path inflection points.

[0023] Compared with the prior art, the beneficial effects of the present application are that through the parallel configuration collection of the photodetector array, the cutting degree of each node can be effectively quantified and characterized, and then the optimization of the path and speed determined based on the cutting degree of each node is more matched to the actual working condition, thereby effectively improving the forming precision of the superhard material composite sheet in the laser cutting process.

[0024] Further, the present application sets a monitoring module based on the photodetector array, quantitatively analyzes the light signal intensity after the laser penetrates the material as the cutting degree parameter, breaks through the hysteresis defect of traditional offline detection, and realizes online dynamic evaluation of the cutting depth. Combined with the node division and scanning section segmentation recording mechanism, the complex cutting path is discretized into an independently analyzable unit, the abnormal area is accurately positioned, and high-resolution data support is provided for subsequent parameter adjustment.

[0025] Further, the path control unit of the application intelligently generates a supplementary scanning path according to the spatial distribution characteristics of the abnormal nodes, avoiding energy redundancy caused by traditional fixed repeated scanning. By dynamically correlating the number and position of abnormal nodes with the supplementary path planning, the invalid scanning distance is reduced while ensuring the cutting integrity, thereby comprehensively improving the processing efficiency and reducing the energy consumption.

[0026] Further, the speed control unit of the application dynamically adjusts the scanning speed and the frequency of repeated scanning based on the gradient difference of the cutting degree parameters of adjacent nodes: for the cutting degree mutation area, energy precise compensation is realized by reducing the speed and superimposing multi-pass scanning, which effectively suppresses the cutting depth fluctuation caused by local material property difference and avoids the defects of overburning or insufficient cutting caused by single parameter adjustment.

[0027] Further, the photoelectric detector array of the application can be adapted to different wavelength lasers, and the path planning algorithm supports multiple cutting trajectory modes. The architecture design of the application facilitates system upgrading and modification, meets the processing needs of multi-specification superhard material composite sheets, and has wide industrial applicability. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The structure block diagram of the laser cutting control system for the superhard material composite sheet of the embodiment of the application is shown in the figure;

[0029] Figure 2 The schematic diagram of the superhard material composite sheet and the initial scanning path of the embodiment of the application is shown in the figure.

[0030] In the figure, 1 is a superhard material composite sheet; 2 is an initial node of a scanning path; 3 is an end node of a scanning path; and 4 is a superhard material tool bit. DETAILED DESCRIPTION

[0031] In order to make the purpose and advantages of the application more clear and obvious, the application will be further described below in combination with embodiments; it should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application.

[0032] The preferred embodiments of the application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the application and are not intended to limit the protection scope of the application.

[0033] It should be noted that in the description of the application, the terms "up", "down", "left", "right", "in", "out" and the like indicate the direction or positional relationship terms based on the direction or positional relationship shown in the drawings, which are only for the convenience of description and do not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the application.

[0034] Moreover, it needs to be explained that in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] Please refer to Figure 1 and Figure 2 The laser cutting control system for the superhard material composite piece in the embodiment of the present application and the schematic diagram of the superhard material composite piece and the initial scanning path in the embodiment of the present application are shown in FIGS. 1 and 2, respectively. The initial scanning path of the laser cutting device starts at the initial node 2 of the scanning path and ends at the end node 3 of the scanning path on the superhard material composite piece 1. In the process, a plurality of superhard material cutting heads 4 with the same shape are cut from the superhard material composite piece 1. In the above laser cutting process, the laser cutting control system for the superhard material composite piece is applied to control the laser cutting device. The laser cutting control system for the superhard material composite piece further comprises a monitoring module and a control module.

[0036] The monitoring module is used to obtain the initial scanning path of the laser beam on the superhard material composite piece, and to demarcate a plurality of nodes in the initial scanning path (the constraint condition for demarcating each node in the embodiment is that the path length of each scanning section is the same. In the implementation, the path inflection point can also be divided into nodes. The same path length can ensure uniformity, and the path inflection point is more prone to cutting problems. Targeted detection can improve the representation ability of the cutting degree parameter to the overall cutting process. In the implementation, the two node demarcation methods can be selected according to the actual working conditions). Adjacent nodes are divided into a scanning section. The monitoring module records the cutting speed of each scanning section and the cutting degree parameter of each node in the scanning process; the control module is connected with the monitoring module and comprises a path control unit and a speed control unit; the path control unit responds to the abnormal cutting degree parameter of any node after the laser beam scans the initial scanning path, and generates a supplementary scanning path based on the cutting degree parameter of each node; the speed control unit is configured to redivide the scanning section of the supplementary scanning path, and determine the scanning speed of each scanning section in the supplementary scanning path based on the cutting degree parameter of the nodes at both ends of the scanning section.

[0037] In detail, the core architecture of the laser cutting control system for the superhard material compact is composed of a monitoring module and a control module. The monitoring module integrates a high-precision photoelectric sensor array and a path planning algorithm. The hardware part of the monitoring module includes a linear array CCD detector group arranged in parallel on the side of the laser cutting head, which ensures that the scattered laser signal after penetrating the superhard material compact can be captured in real time. In the initialization stage, the monitoring module generates an initial scanning path based on the preset cutting contour. The path is divided into several equidistant nodes through discretization processing, and independent scanning segments are formed between adjacent nodes. During the scanning process, the monitoring module synchronously records the actual cutting speed of each scanning segment, and dynamically calculates the cutting degree parameter of each node by analyzing the current signal change rate of the photoelectric detector array in the corresponding time period, forming a three-dimensional data matrix containing the spatial position-cutting quality mapping relationship.

[0038] Specifically, the monitoring module specifically includes a photoelectric detector array arranged in parallel and spaced apart from the laser beam. The photoelectric detector array receives the light generated by the laser beam after penetrating the superhard material compact in a direction parallel to the laser beam. The monitoring module is configured to perform the following processes to determine the cutting degree parameter: obtaining the average current of the photoelectric detector array in the time period corresponding to the cutting node (i.e., the average of the current values of each photoelectric detector), and determining the cutting degree parameter based on the average current of the photoelectric detector array;

[0039] The cutting degree parameter is positively correlated with the average current of the photodetector array. In detail, for the quantitative evaluation of the cutting degree parameter, the monitoring module is built-in with a special signal processing chip, which performs the following standardization processing procedures: first, when the laser beam scans to the region corresponding to each node, a time window synchronization mechanism is triggered, the average current value (I1) of all activated detection units in this period is collected, and a dynamic comparison is made with the pre-stored reference current value (I2, obtained by calibrating the average current collected by the photodetector array when the laser is not cutting). The calculation of the cutting degree parameter K is realized by the formula K = I1 / I2, which represents the physical meaning of the beam blocking effect of the material cutting depth on the laser. Since the cutting depth of the superhard material composite sheet is positively correlated with the laser transmittance, when the cutting depth is high, more laser energy reaches the photodetector array, resulting in an increase in I1 and K value. Therefore, the system establishes an inverse mapping relationship between K value and cutting quality: the closer the K value is to 1 (i.e. I1 tends to I2), the more effective the cutting of the node region; the lower the K value, the less effective the cutting. Further, the control module is connected to the monitoring module through a high-speed data bus, and the path control unit and the speed control unit integrated in the control module form a closed-loop control chain. The path control unit retrieves the K value data of all nodes after the initial scanning is completed, and detects abnormalities point by point using a threshold comparison algorithm: for nodes with K values below the corresponding threshold, it is determined that the cutting degree parameter is abnormal. Subsequently, the path control unit generates a supplementary scanning path based on the spatial distribution characteristics of the abnormal nodes. It should be understood that the supplementary scanning path is included in the initial scanning path and should not appear new cutting positions, but only repeats part of the cutting path. In this embodiment, the superhard material composite sheet is a diamond composite sheet, and the corresponding relationship between the node and the threshold is that when the number of passes of the laser beam at the node is one, the corresponding threshold is 0.85, when the number of passes of the laser beam at the node is two, the corresponding threshold is 0.89, and when the number of passes of the laser beam at the node is three, the corresponding threshold is 0.95. In this embodiment, the number of passes of the laser beam at the node is not more than three, and in implementation, the threshold can be set to other values in combination with the specific material of the superhard material composite sheet and the cutting requirements.

[0040] Specifically, when a single abnormal node exists, a shortest straight line path connecting the starting point of the initial path and the node is generated; if multiple abnormal nodes exist, an optimal polyline path covering all abnormal nodes is calculated through a traversal algorithm to minimize the empty travel. After receiving the supplementary scanning path data, the speed control unit first performs adaptive segmentation on the path: according to the distance between adjacent abnormal nodes and the K value gradient difference, the supplementary path is divided into several variable-length scanning segments.

[0041] Specifically, the speed control unit is further configured to dynamically adjust the scanning speed of the scanning segment according to the difference between the cutting degree parameters of the two nodes at the ends of the scanning segment;

[0042] wherein, when the cutting degree parameter difference value exceeds a preset threshold value, the scanning speed is reduced and the number of repeated scanning of the laser beam in the supplementary scanning path for the scanning segment is increased. The determination of the path control unit for the cutting degree parameter anomaly includes comparing the cutting degree parameter with the corresponding threshold value, and if it is less than the corresponding threshold value, it is determined that the cutting degree parameter is abnormal. And the path control unit sets different threshold values for the nodes with different passing times of the laser beam in the initial scanning path, and the greater the passing times of the laser beam at the node in the initial scanning path, the greater the threshold value corresponding to the node. For each scanning segment, the speed control unit calculates the difference amount of K value between the start point and the end point, if the difference amount exceeds the preset gradient threshold value (0.2 in this embodiment), it is determined that there is a risk of sudden change of material properties in this segment, the scanning speed is automatically reduced to 50%-70% of the reference value, and the repeated scanning mechanism is triggered (the number of repetitions is proportional to the difference amount of K value); otherwise, the reference scanning speed is maintained. This dynamic speed regulation strategy not only avoids local overheating, but also ensures the accurate deposition of energy in the weak area of the material.

[0043] To eliminate environmental noise interference, the monitoring module further introduces a sliding mean filter algorithm in the data processing stage: segmenting the current signal corresponding to each node in the time domain, eliminating abnormal peaks caused by material spatter or detector transient saturation, and finally taking the weighted average value of the filtered data of each segment as the effective I1 value. In addition, the system automatically records the baseline current I2 when there is no material obstruction in the initialization stage, and performs online calibration regularly according to the laser power drift to ensure the long-term stability of K value calculation. This design makes the detection accuracy of the cutting degree parameter not affected by the aging of the laser or the fluctuation of environmental light, significantly improving the reliability of quality evaluation.

[0044] Through the synergistic effect of the above hardware layout and algorithm design, the monitoring module realizes two core functions: first, in the spatial dimension, it accurately associates the laser scanning position with the cutting quality data, forming a process database containing node coordinates, real-time K value and historical change curve; second, in the time dimension, it captures the instantaneous quality fluctuations caused by material heterogeneity in the cutting process through the millisecond-level signal acquisition rate, providing high refresh rate data support for real-time decision-making of the control module.

[0045] Specifically, the path control unit responds to the cutting degree parameter abnormality of only one node to take the shortest path passing through the initial node and the node with the cutting degree parameter abnormality as the supplemental scanning path. Responding to the cutting degree parameter abnormality of more than one node, the shortest path passing through each node with the cutting degree parameter abnormality is taken as the supplemental scanning path. In the above embodiment, the path control unit adopts a differentiated strategy to cope with different orders of magnitude of abnormal node distribution scenarios when performing supplemental scanning path planning. In this process, the path control unit calls the device kinematics model to verify the path feasibility in real time, and combines the maximum acceleration and steering angle limit mechanical parameters of the laser head to automatically optimize the theoretical straight line path into a smooth transition composite curve path, ensuring the trajectory stability of the laser scanning head under high-speed motion.

[0046] The hierarchical path generation mechanism realizes the following technical breakthroughs through the dual optimization of spatial distribution feature recognition and energy demand prediction: first, rapid directional compensation in the single node abnormal scenario, avoiding the efficiency loss caused by large-area repeated scanning; second, cluster path optimization in the multi-node abnormal scenario, significantly reducing the device empty travel time.

[0047] The flowcharts or block diagrams in the drawings illustrate the possible architectural, functional, and operational aspects of apparatuses, methods, and computer program products according to various embodiments of the present application. In this regard, each block in the flowcharts or block diagrams can represent a module, a program segment, or a portion of code that comprises one or more executable instructions for implementing the specified functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur in different orders than those noted in the figures. For example, two blocks noted in succession can actually be executed substantially in parallel, or they can be executed in reverse order, depending on the functionality involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based apparatus that performs specified functions or operations, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0048] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the present application, and the technical solutions after these changes or replacements will all fall within the protection scope of the present application.

[0049] The above merely describes the preferred embodiments of the present application and is not used to limit the present application; the present application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A laser cutting control system for superhard material composite sheets, characterized in that, include: The monitoring module is used to obtain the initial scanning path of the laser beam for the superhard material composite sheet, and to delineate several nodes in the initial scanning path, dividing adjacent nodes into a scanning segment. The monitoring module records the cutting speed of each scanning segment and the cutting degree parameters of each node during the scanning process. A control module, connected to the monitoring module, includes a path control unit and a speed control unit; The path control unit responds to any node's cutting degree parameter being abnormal after the laser beam has completed scanning the initial scanning path, and generates a supplementary scanning path based on the cutting degree parameters of each node. The speed control unit is configured to re-divide the supplementary scanning path into scanning segments and determine the scanning speed of each scanning segment in the supplementary scanning path based on the cutting degree parameter of the nodes at both ends of the scanning segment. Specifically, the monitoring module includes a photodetector array arranged parallel to and spaced apart from the laser beam. The photodetector array receives the light generated by the laser beam after passing through the superhard material composite sheet in a direction parallel to the laser beam. The monitoring module is configured to perform the following process to determine the cutting degree parameter: The average current of the photodetector array during the time period of cutting the corresponding node is obtained, and the cutting degree parameter is determined based on the average current of the photodetector array. The cutting degree parameter is positively correlated with the average current of the photodetector array; The monitoring module specifically performs the following calculations to determine the cutting degree parameter: The cutting degree parameter K = I1 / I2, where I1 is the average current of the photodetector array during the time period corresponding to the cutting node, and I2 is the average current of the photodetector array when it receives the light of the original laser beam that has not passed through the superhard material composite sheet in a direction parallel to the laser beam. The speed control unit is further configured to dynamically adjust the scanning speed of the scanning segment based on the difference in the cutting degree parameters of the nodes at both ends of the scanning segment. When the difference in the cutting degree parameter exceeds a preset threshold, the scanning speed is reduced and the number of laser beam re-scans of that scanning segment is increased in the supplementary scanning path.

2. The laser cutting control system for superhard material composite sheets according to claim 1, characterized in that, The path control unit determines the abnormality of the cutting degree parameter by comparing the cutting degree parameter with the corresponding threshold. If it is less than the corresponding threshold, the cutting degree parameter is determined to be abnormal.

3. The laser cutting control system for superhard material composite sheets according to claim 2, characterized in that, The path control unit sets different thresholds for nodes with different numbers of passes through the laser beam in the initial scanning path, and the greater the number of times the laser beam passes through a node in the initial scanning path, the greater the threshold corresponding to the node.

4. The laser cutting control system for superhard material composite sheets according to claim 1, characterized in that, The path control unit responds to an anomaly in the cutting degree parameter of only one node by using the shortest path passing through the initial node and the node with the anomaly in the cutting degree parameter as a supplementary scan path.

5. The laser cutting control system for superhard material composite sheets according to claim 4, characterized in that, The path control unit responds to anomalies in the cutting degree parameters of more than one node by using the shortest path passing through each node with anomalies in the cutting degree parameters as a supplementary scanning path.

6. The laser cutting control system for superhard material composite sheets according to claim 1, characterized in that, The monitoring module defines the constraints for each node as follows: The path length of each scan segment is the same. Alternatively, the node can be a path inflection point.

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