Control Method of Eco-friendly Stainless Steel Laser Cutting Device with Drastically Reduced Scattering of Dust and Harmful Gas

Abstract

A control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to embodiments of the present invention is such that a local exhaust unit integrally provided at the bottom of the cutting unit is synchronized with the movement of the cutting unit to immediately collect foreign substances and harmful gases at the point where cutting occurs, actively controls the amount of exhaust by predicting the degree of generation according to the material characteristics of the workpiece and the cutting path, and can quantitatively determine the cause of defects in the workpiece, the cutting unit, or the local exhaust unit based on the ratio of the measured concentration to the normal concentration.

Description

Technology Field

[0001] The present invention relates to an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion, and a method for controlling the same. Background Technology

[0002] Fiber laser cutting devices are widely used in industrial settings as a means to precisely cut metal plates such as stainless steel and carbon steel. In particular, high-power gantry-type laser cutting devices of 60KW or higher are being introduced in large-scale plate processing fields such as shipbuilding, construction, and heavy industry, and productivity is being significantly improved as large-area cutting with a working area of ​​30,000mm × 4,000mm becomes possible.

[0003] However, the process of cutting metal plates with high-power lasers generates large amounts of metal dust and harmful gases. In particular, when cutting stainless steel, large amounts of harmful gases such as nitrogen oxides (NOx) and ozone (O₃) are generated along with dust containing heavy metal oxides such as chromium and nickel, and if these substances are dispersed throughout the entire workspace, they can cause serious harm to the health of workers.

[0004] As a prior art to solve these problems, a technology for removing dust and harmful gases by installing fixed suction devices on both sides of a cutting workbench has been disclosed, as referenced in Korean Registered Patent No. 10-0994201, etc. However, this fixed suction device method has a fundamental limitation in that suction efficiency is significantly reduced due to changes in the distance between the point of generation and the point of suction in gantry-type equipment where the cutting head moves across a large work area to perform cutting. In particular, while the amount of dust and harmful gases generated increases rapidly when cutting ultra-thick plates with a thickness of 90mm or more, or in sections where the cutting speed drops sharply, it is difficult to respond to this in real time using only fixed suction devices.

[0005] Furthermore, most conventional dust collection methods operate solely with a constant suction force regardless of the amount of dust and harmful gases generated, which presents a problem in that they cannot actively respond to rapid fluctuations in pollutant emissions caused by changes in cutting paths or material properties. In particular, when cutting high-reflectivity materials such as stainless steel, the direction and range of dust dispersion change as the flow rate of auxiliary gases (N₂, O₂) varies; however, no technology has yet been presented to reflect these changes in the suction direction and angle in real time.

[0006] Furthermore, as the criteria for determining whether there are abnormalities in the exhaust condition are unclear, it is difficult to quickly identify and respond to the causes of abnormalities, such as defects in the workpiece, cutting head defects, and local exhaust device defects.

[0007] Therefore, there is an urgent need to develop a control method for a stainless steel laser cutting device that can immediately capture dust and harmful gases at the point of generation in conjunction with a cutting head, actively control the exhaust volume and intake direction according to the cutting path and material characteristics, and quantitatively determine the cause of abnormalities. The problem to be solved

[0008] Embodiments of the present invention aim to provide a control method for an eco-friendly stainless steel laser cutting device capable of effectively reducing the scattering of dust and harmful gases generated during high-power laser cutting by integrally providing a local exhaust unit at the bottom of the cutting unit to perform local exhaust synchronized with the movement of the cutting unit, and actively controlling the exhaust volume by predicting the degree of generation of foreign substances and harmful gases according to the material characteristics of the workpiece and the cutting path.

[0009] Furthermore, embodiments of the present invention aim to provide a control method for an eco-friendly stainless steel laser cutting device that can rapidly identify the cause of abnormalities and take appropriate countermeasures by equipping a measuring unit in the local exhaust unit to measure the concentration of residual foreign substances and harmful gases, and quantitatively determining defects in the workpiece, defects in the cutting unit, or defects in the local exhaust unit based on the ratio of the measured concentration to the normal concentration.

[0010] Furthermore, embodiments of the present invention aim to provide a control method for an eco-friendly stainless steel laser cutting device that prevents contamination of the entire workspace and ensures a safe working environment for the worker by actively inducing airflow so that foreign substances and harmful gases do not scatter upwards but flow only downwards by adjusting the pressure difference between the local exhaust section and the bottom exhaust section.

[0011] Furthermore, embodiments of the present invention aim to provide a control method for an eco-friendly stainless steel laser cutting device that can maximize collection efficiency by finely adjusting the height and angle of the local suction part according to the reflectance data of the workpiece and the flow rate data of the auxiliary gas, thereby responding in real time to changes in the direction of dust dispersion caused by changes in the auxiliary gas flow rate during the cutting of high-reflectance stainless steel.

[0012] Furthermore, embodiments of the present invention aim to provide a control method for an eco-friendly stainless steel laser cutting device capable of immediately responding to a surge in dust and harmful gas generation in a change section by recognizing in advance a section where the thickness or material of the workpiece changes along the processing path of the cutting section and preemptively switching the exhaust volume of the local exhaust section and the suction power of the lower dust collection section before entering the change section. means of solving the problem

[0013] According to embodiments of the present invention, a local exhaust unit is integrally provided at the bottom of the cutting unit, and the exhaust volume is actively controlled by predicting the degree of generation of foreign substances and harmful gases according to the material characteristics of the workpiece and the cutting path, and the cause of abnormality can be quantitatively determined based on the ratio of the measured concentration to the normal concentration.

[0014] Specifically, it may include a bed portion forming an exterior, a cutting portion movably provided on the bed portion for processing a workpiece, a local exhaust portion disposed at the bottom of the cutting portion for removing foreign substances and harmful gases generated during the cutting portion operation, a measuring portion disposed at the local exhaust portion for measuring the concentration of foreign substances and harmful gases, and a bottom exhaust portion disposed on the bed portion for removing foreign substances and harmful gases generated during the cutting portion operation. It may include a processing step of processing a workpiece through the cutting portion and a local exhaust step of removing foreign substances and harmful gases generated during the processing step through the local exhaust portion. The above local exhaust step may include a local prediction step for predicting the degree of generation of foreign substances and harmful gases according to the processing path of the cutting part considering the material characteristics of the workpiece; a local response step for controlling the exhaust volume of the local exhaust part according to the degree of generation of foreign substances and harmful gases predicted in the local prediction step; a local measurement step for measuring the concentration of remaining foreign substances and harmful gases through the measuring part after the local response step; and a local judgment step for determining a defect in the workpiece, a defect in the cutting part, or a defect in the local exhaust part if the concentration of foreign substances and harmful gases measured in the local measurement step differs from the normal concentration by a predetermined amount or more.

[0015] Additionally, the local exhaust unit may include a local suction unit for inhaling foreign substances and harmful gases, a local filter unit positioned in front of the local suction unit for filtering foreign substances, and a local imaging unit for photographing the local filter unit. The local determination step may determine a defect in the local filter unit or the local suction unit by photographing the local filter unit to determine blockage of the local filter unit when the local exhaust unit is determined to be defective.

[0016] Additionally, the local prediction step may include a prediction path step for receiving cutting speed data according to the cutting path of the cutting section, a prediction thickness step for receiving thickness data of the workpiece, and a prediction execution step for predicting the amount of foreign substances and harmful gases generated per section based on the cutting speed data and the thickness data. The local response step may control the exhaust volume of the local exhaust section to be amplified in real time according to the amount generated per section predicted in the prediction execution step.

[0017] Additionally, it may further include an exhaust control step to prevent foreign substances and harmful gases from scattering to the outside of the local exhaust section and the lower exhaust section. The exhaust control step can guide foreign substances and harmful gases to the local exhaust section or the lower exhaust section by adjusting the pressure difference between the local exhaust section and the lower exhaust section.

[0018] Additionally, the lower exhaust unit may include a lower dust collection unit positioned at the bottom of the bed unit to suck in foreign substances and harmful gases, a lower measuring unit that measures the pressure difference between the lower dust collection unit and the local exhaust unit, and a lower adjusting unit that adjusts the suction power of the lower dust collection unit according to the pressure difference measured by the lower measuring unit. The exhaust control step may include a pressure measuring step that measures the pressure difference between the local exhaust unit and the lower dust collection unit through the lower measuring unit; a pressure adjusting step that, if the pressure difference measured in the pressure measuring step is less than a preset reference pressure difference, increases the suction power of the lower dust collection unit through the lower adjusting unit to induce an airflow so that foreign substances and harmful gases flow into the bottom; and a pressure maintaining step that, if the pressure difference measured in the pressure measuring step is greater than or equal to a preset reference pressure difference, reduces the suction power of the lower dust collection unit through the lower adjusting unit to maintain the pressure difference between the local exhaust unit and the lower dust collection unit at the preset pressure difference.

[0019] Additionally, the local exhaust unit may further include a local height unit for adjusting the height of the local suction unit and a local angle unit for adjusting the angle of the local suction unit. The local response step may include a response receiving step for receiving reflectance data of the workpiece and flow rate data of the auxiliary gas, and a response adjustment step for finely adjusting the height and angle of the local suction unit by controlling the local height unit and the local angle unit according to the reflectance data and the flow rate data of the auxiliary gas.

[0020] In addition, the local exhaust step may further include a section recognition step for recognizing in advance a section where the thickness or material of the workpiece changes along the processing path of the cutting section, and a section switching step for switching the local height section and the local angle section to positions corresponding to the thickness or material of the changing section before the cutting section enters the changing section recognized in the section recognition step, and for preemptively switching the exhaust volume of the local exhaust section and the suction power of the lower dust collection section to an exhaust volume corresponding to the changing section. The section switching step may calculate a deviation by comparing the concentration of foreign substances and harmful gases measured by the measuring section after the cutting section enters the changing section with the predicted concentration corresponding to the changing section, and if the calculated deviation exceeds a preset allowable deviation, the preemptive switching point may be corrected and applied when entering the next changing section. Effects of the invention

[0021] Embodiments of the present invention provide a control method for an eco-friendly stainless steel laser cutting device that can effectively reduce the scattering of dust and harmful gases generated during high-power laser cutting by integrally providing a local exhaust unit at the bottom of the cutting unit to perform local exhaust synchronized with the movement of the cutting unit, and by actively controlling the amount of exhaust by predicting the degree of generation of foreign substances and harmful gases according to the material characteristics of the workpiece and the cutting path.

[0022] In addition, embodiments of the present invention provide a control method for an eco-friendly stainless steel laser cutting device that can rapidly identify the cause of an abnormality and take appropriate countermeasures by equipping a measuring unit in the local exhaust unit to measure the concentration of residual foreign substances and harmful gases, and quantitatively determining defects in the workpiece, defects in the cutting unit, or defects in the local exhaust unit based on the ratio of the measured concentration to the normal concentration.

[0023] In addition, embodiments of the present invention can provide a control method for an eco-friendly stainless steel laser cutting device that prevents contamination of the entire workspace and ensures a safe working environment for the worker by actively inducing airflow so that foreign substances and harmful gases do not scatter upwards but only flow downwards by adjusting the pressure difference between the local exhaust section and the bottom exhaust section.

[0024] In addition, embodiments of the present invention can provide a control method for an eco-friendly stainless steel laser cutting device that can maximize collection efficiency by finely adjusting the height and angle of the local suction part according to the reflectance data of the workpiece and the flow rate data of the auxiliary gas, thereby responding in real time to changes in the direction of dust scattering due to changes in the auxiliary gas flow rate when cutting high-reflection stainless steel.

[0025] In addition, embodiments of the present invention can provide a control method for an eco-friendly stainless steel laser cutting device capable of immediately responding to a surge in dust and harmful gas generation in a change section by recognizing in advance a section where the thickness or material of the workpiece changes along the processing path of the cutting section and preemptively switching the exhaust volume of the local exhaust section and the suction power of the lower dust collection section before entering the change section. Brief explanation of the drawing

[0026] FIG. 1 is a perspective view of an eco-friendly stainless steel laser cutting device that significantly reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 2 is a drawing showing the cutting section of an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 3 is a diagram showing the operation of the cutting section of an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 4 is a drawing showing the local exhaust and measuring sections of an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 5 is a drawing showing the lower exhaust section of an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 6 is a flowchart of a control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 7 is a flowchart of the local exhaust step of a control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 8 is a flowchart of the local prediction step and local response step of a control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. FIG. 9 is a flowchart of the exhaust control step of a control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion according to one embodiment of the present invention. Specific details for implementing the invention

[0027] Below, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention.

[0028] However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the invention in the drawings, parts unrelated to the description have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0029] In this specification, redundant descriptions of identical components are omitted.

[0030] Furthermore, when a component is described in this specification as being 'connected' or 'connected' to another component, it should be understood that it may be directly connected to or connected to the other component, or that there may be other components in between. On the other hand, when a component is described in this specification as being 'directly connected' or 'directly connected' to another component, it should be understood that there are no other components in between.

[0031] Furthermore, the terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention.

[0032] Additionally, in this specification, singular expressions may include plural expressions unless the context clearly indicates otherwise.

[0033] Furthermore, in this specification, terms such as 'comprising' or 'having' are intended merely to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0034] Additionally, in this specification, the term "and / or" includes a combination of the plurality of described items or any of the plurality of described items. In this specification, "A or B" may include "A," "B," or "both A and B."

[0035] FIG. 1 is a drawing showing the overall configuration of a laser cutting device according to one embodiment of the present invention. FIG. 2 is a drawing showing the cutting section of a laser cutting device according to one embodiment of the present invention.

[0036] FIG. 3 is a diagram showing the operation of the cutting section of a laser cutting device according to an embodiment of the present invention. FIG. 4 is a diagram showing the local exhaust section and the measuring section of a laser cutting device according to an embodiment of the present invention. FIG. 5 is a diagram showing the lower exhaust section of a laser cutting device according to an embodiment of the present invention.

[0037] Specifically, FIG. 3(a) shows a real-time height automatic adjustment system, and FIG. 3(b) shows an intelligent automatic obstacle avoidance function.

[0038] Referring to FIG. 1, the laser cutting device (U) may include a bed section (1), a cutting section (2), a local exhaust section (3), a measuring section (4), and a bottom exhaust section (5).

[0039] The bed section (1) forms the exterior of the laser cutting device (U) and can provide a workspace on which a workpiece is placed. The bed section (1) is manufactured with a welded forming structure, and residual stress is completely removed through internal stress removal via high-temperature heat treatment at 600°C and secondary vibration aging treatment, so precision can be maintained even during long-term use. In addition, the precision of the bed section (1) is guaranteed through precision machining using a large gantry milling machine processing center, and a plurality of support pins that support the workpiece are arranged in a grid shape on the upper surface, allowing for stable placement of workpieces ranging from large plates to small components. A bottom exhaust section (5) is positioned at the bottom of the bed section (1) to collect foreign substances and harmful gases generated during the cutting operation downward.

[0040] Referring to FIGS. 1 and 2, the cutting unit (2) is movably provided on the bed unit (1) to process a workpiece. The cutting unit (2) may be provided as a laser cutting head that performs cutting by irradiating a laser beam onto a workpiece, and may be provided so as to be movable in the X-axis and Y-axis directions across the entire working area of ​​the bed unit (1) by a gantry structure. The cutting unit (2) is equipped with an optical system that focuses the laser beam internally, and adopts a completely sealed structure to protect the internal optical lens from fine dust and foreign substances generated during processing. In addition, the cutting unit (2) can perform an automatic focusing function that automatically adjusts the focal length according to changes in the thickness of the workpiece, thereby providing uniform and smooth cut surface quality for workpieces of various materials and thicknesses, such as stainless steel, carbon steel, and aluminum.

[0041] Referring to FIG. 3, the cutting section (2) can move while maintaining a constant distance from the surface of the material according to the curvature or height change of the workpiece. As shown in FIG. 3(a), the cutting section (2) can move along the cutting path while actively adjusting the height of the cutting section (2) according to the curvature shape of the workpiece by detecting the distance from the surface of the workpiece in real time through a non-contact height sensor.

[0042] In addition, as shown in FIG. 3(b), the cutting unit (2) may be equipped with an active collision prevention function that detects in advance the warping of the plate material or the protrusion of foreign matter during processing to prevent collision, and can prevent damage to the cutting unit (2) and minimize equipment downtime by immediately driving to avoid an unexpected situation. Through this, consistent cutting quality can be maintained regardless of changes in the shape of the workpiece.

[0043] Referring to FIG. 4, the local exhaust unit (3) is positioned at the bottom of the cutting unit (2) to remove foreign substances and harmful gases generated during the operation of the cutting unit (2). Since the local exhaust unit (3) is integrally equipped with the cutting unit (2) and synchronized with the movement of the cutting unit (2), foreign substances and harmful gases can be immediately collected at the point where cutting occurs. Unlike conventional fixed suction devices, the local exhaust unit (3) maintains a constant distance between the point of generation and the point of suction even while the cutting unit (2) moves over a large-area work area, so the suction efficiency is not reduced and the scattering of dust and harmful gases can be effectively blocked. The local exhaust unit (3) may include a local suction unit (31), a local filter unit (32), a local imaging unit (33), a local height unit (34), and a local angle unit (35).

[0044] The local suction unit (31) can inhale foreign substances and harmful gases. The local suction unit (31) is positioned on the lower side of the cutting unit (2) to directly inhale dust and harmful gases generated during cutting at the point of generation, and the exhaust volume can be controlled in real time according to the material characteristics of the workpiece and the degree of foreign substances and harmful gases generated according to the cutting path.

[0045] The local filter unit (32) is positioned in front of the local suction unit (31) to filter foreign substances. The local filter unit (32) may be equipped with a high-temperature dust filtering unit that filters foreign substances including high-temperature metal dust, and by filtering the inhaled dust and foreign substances, it can prevent contamination of the downstream piping and dust collector and improve the durability of the entire exhaust system.

[0046] The local imaging unit (33) can photograph the local filter unit (32). The local imaging unit (33) is equipped with a shooting means such as a camera to visually check the blockage status of the local filter unit (32). In the local judgment step (S240), if the local exhaust unit (3) is judged to be defective, the local filter unit (32) can be determined to be blocked and used to distinguish between the local filter unit (32) and the local suction unit (31). Through this, the abnormality of the exhaust system can be diagnosed remotely without the operator having to directly inspect the filter status.

[0047] The local height section (34) can adjust the height of the local suction section (31). The local height section (34) can finely adjust the height of the local suction section (31) according to the reflectance data of the workpiece and the flow rate data of the auxiliary gas to optimize the collection efficiency, and can preemptively switch to a position corresponding to the change section before the cutting section (2) enters the section where the thickness or material of the workpiece changes.

[0048] The local angle section (35) can adjust the angle of the local suction section (31). When cutting high-reflection stainless steel, if the direction of dust scattering changes depending on the flow rate of the auxiliary gas (N₂, O₂), the local angle section (35) can finely adjust the angle of the local suction section (31) to enable collection corresponding to the changed scattering direction. Since the local height section (34) and the local angle section (35) receive reflectance data and auxiliary gas flow rate data in the corresponding adjustment step (S222) and are controlled in conjunction, they can maximize collection efficiency by responding in real time to changes in the direction of dust scattering due to changes in material characteristics.

[0049] The measuring unit (4) is positioned in the local exhaust unit (3) to measure the concentration of foreign substances and harmful gases. The measuring unit (4) measures the concentration of foreign substances and harmful gases remaining in the local measurement step (S230) of the local exhaust step (S200), and the measured concentration data can be used to quantitatively determine defects in the workpiece, defects in the cutting unit (2), or defects in the local exhaust unit (3) by calculating the ratio with the normal concentration in the local judgment step (S240). Through this, the determination of the cause of abnormalities, which previously relied on the operator's experience, can be performed quickly and accurately based on quantified standards.

[0050] Referring to FIG. 5, the bottom exhaust unit (5) is positioned in the bed unit (1) to remove foreign substances and harmful gases generated during the cutting unit (2) operation. FIG. 5 shows the detailed configuration of the bottom exhaust unit (5) corresponding to part 'A' in FIG. 1. The bottom exhaust unit (5) forms a hybrid airflow control system together with the local exhaust unit (3), and by adjusting the pressure difference between the local exhaust unit (3) and the bottom exhaust unit (5), the airflow can be actively induced so that foreign substances and harmful gases do not scatter outwardly to the upper side but only flow inward to the bottom. The bottom exhaust unit (5) may include a bottom dust collection unit (51), a bottom measuring unit (52), and a bottom control unit (53).

[0051] The lower dust collection unit (51) is positioned at the bottom of the bed unit (1) and can suck in foreign substances and harmful gases. The lower dust collection unit (51) can form a suction force from the bottom to the top of the bed unit (1) to collect dust and harmful gases falling to the bottom of the workpiece, and can be provided in a large capacity to handle a large amount of dust generated during high-power laser cutting.

[0052] The lower measuring unit (52) can measure the pressure difference between the lower dust collection unit (51) and the local exhaust unit (3). The pressure difference data measured by the lower measuring unit (52) is transmitted in real time to the lower control unit (53) and used to control the suction power of the lower dust collection unit (51), thereby allowing the pressure balance between the local exhaust unit (3) and the lower exhaust unit (5) to be continuously monitored.

[0053] The lower control unit (53) can adjust the suction power of the lower dust collection unit (51) according to the pressure difference measured by the lower measuring unit (52). When the measured pressure difference is less than a preset reference pressure difference, the lower control unit (53) increases the suction power of the lower dust collection unit (51) to induce an airflow so that foreign substances and harmful gases flow into the lower area, and when it is greater than the reference pressure difference, it reduces the suction power to maintain the pressure difference at the reference pressure difference. By doing so, the pressure difference between the local exhaust unit (3) and the lower exhaust unit (5) can be actively controlled to prevent foreign substances and harmful gases from scattering to the upper part of the workspace and to ensure a safe working environment for the worker.

[0054] FIG. 6 is a flowchart illustrating a control method for a laser cutting device according to an embodiment of the present invention. FIG. 7 is a flowchart illustrating a local exhaust step of a control method for a laser cutting device according to an embodiment of the present invention.

[0055] Referring to FIGS. 6 and 7, the control method (S) of a laser cutting device may include a processing step (S100), a local exhaust step (S200), and an exhaust control step (S300).

[0056] In the processing step (S100), the workpiece can be processed through the cutting unit (2). In the processing step (S100), the cutting unit (2) can perform cutting by moving the working area of ​​the bed unit (1) along a pre-set cutting path and irradiating the workpiece with a laser beam. The cutting unit can precisely focus the laser beam supplied from a high-power fiber laser source onto the surface of the workpiece through an optical system, and can improve the quality of the cut surface and prevent oxidation of the cut area by spraying an auxiliary gas (N₂, O₂, etc.) through a cutting nozzle. At this time, the cutting unit (2) provides information on the cutting path, cutting speed, and thickness of the workpiece in real time to the local exhaust step (S200) in conjunction with motion data of the FSCUT control system, and based on this, the exhaust volume of the local exhaust unit (3) can be actively controlled. The processing step (S100) is performed under processing conditions in which the laser output, cutting speed, type and flow rate of auxiliary gas are optimized according to the material and thickness of the workpiece, and this processing condition data can be used to predict the amount of foreign substances and harmful gases generated by section in the subsequent local prediction step (S210).

[0057] In the local exhaust stage (S200), foreign substances and harmful gases generated during the processing stage (S100) can be removed through the local exhaust unit (3). The local exhaust stage (S200) is a stage in which the local exhaust unit (3), which is integrally equipped with the cutting unit, is synchronized with the movement of the cutting unit (2) to immediately collect foreign substances and harmful gases at the point where cutting occurs. Unlike conventional fixed suction methods, the distance between the point of occurrence and the point of suction is always maintained constant even while the cutting unit moves over a large-area work area, so the suction efficiency is not reduced. The local exhaust stage (S200) may include a local prediction stage (S210), a local response stage (S220), a local measurement stage (S230), and a local judgment stage (S240).

[0058] In the local prediction step (S210), the degree of generation of foreign substances and harmful gases according to the processing path of the cutting section (2) can be predicted by considering the material characteristics of the workpiece. The local prediction step (S210) receives cutting speed data and workpiece thickness data according to the cutting path of the cutting section (2), and based on this, can predict in advance the amount of foreign substances and harmful gases generated by section. When cutting high-reflection materials such as stainless steel, a large amount of dust containing heavy metal oxides such as chromium and nickel, as well as harmful gases such as nitrogen oxides (NOx) and ozone (O₃), are generated. In particular, the amount of foreign substances and harmful gases tends to increase rapidly in sections where the thickness of the plate is thick or where the cutting speed decreases sharply. By reflecting these characteristics and providing foundational data that allows for the preemptive adjustment of the exhaust volume of the local exhaust section (3) before the actual increase in foreign substances and harmful gases occurs, the local prediction step (S210) can enable proactive exhaust control based on prediction rather than reactive response.

[0059] In the local response step (S220), the exhaust volume of the local exhaust unit (3) can be controlled according to the degree of foreign matter and harmful gas generation predicted in the local prediction step (S210). Since the local response step (S220) controls the exhaust volume of the local exhaust unit (3) to be amplified in real time according to the predicted generation amount per section, the suction force can respond immediately even in sections where the amount of foreign matter and harmful gas generation increases rapidly due to thickening of the workpiece or slowing down of the cutting speed, thereby effectively blocking the scattering of dust and harmful gas. In addition, the local response step (S220) receives reflectance data of the workpiece and flow rate data of the auxiliary gas and finely adjusts the height and angle of the local suction unit (31), thereby maximizing the collection efficiency by responding in real time to changes in the direction of dust scattering due to changes in the auxiliary gas flow rate when cutting high-reflection stainless steel.

[0060] In the local measurement step (S230), the concentration of remaining foreign substances and harmful gases can be measured through the measurement unit (4) after the local response step (S220). By measuring the concentration of remaining foreign substances and harmful gases in real time even after exhaust control is performed through the local response step (S220), the local measurement step (S230) can verify the actual effect of exhaust control and provide reference data for quantitatively identifying the cause of abnormalities in the subsequent local judgment step (S240). Since the measurement unit (4) is placed in the local exhaust unit and moves together with the cutting unit, the concentration of foreign substances and harmful gases at the point where cutting occurs can be accurately measured, and the measured concentration data can be used to determine whether there is an abnormality by comparing it with the normal concentration.

[0061] In the local judgment step (S240), if the concentration of foreign substances and harmful gases measured in the local measurement step (S230) differs from the normal concentration by more than a predetermined amount, it can be determined that the workpiece is defective, the cutting part (2) is defective, or the local exhaust part (3) is defective.

[0062] FIG. 8 is a flowchart showing the local prediction step and the local correspondence step of a control method for a laser cutting device according to one embodiment of the present invention.

[0063] Referring to FIGS. 7 and 8, the local determination step (S240) can determine a defect in the local filter unit (32) or the local suction unit (31) by photographing the local filter unit (32) through the local imaging unit (33) when the local exhaust unit (3) is determined to be defective. Specifically, when the local exhaust unit (3) is determined to be defective in the local determination step (S240), the local imaging unit (33) can photograph the local filter unit (32) and analyze the acquired image data. If a blockage of the local filter unit (32) is confirmed, it is determined that the local filter unit (32) needs to be replaced or cleaned, and if there is no blockage in the local filter unit (32), it is determined that the local suction unit (31) itself is defective, such as a decrease in the suction power of the local suction unit (31). By doing this, the cause of the defect in the local exhaust unit (3) is subdivided into the local filter unit (32) and the local suction unit (31), thereby preventing unnecessary parts replacement and improving maintenance efficiency.

[0064] Referring to FIG. 8(a), the local prediction step (S210) may include a prediction path step (S211), a prediction thickness step (S212), and a prediction execution step (S213).

[0065] In the predicted path step (S211), cutting speed data according to the cutting path of the cutting unit (2) can be received. The predicted path step (S211) receives the entire cutting path data of the cutting unit (2) and cutting speed data for each path section from the FSCUT control system, and in particular, can identify sections where the cutting speed decreases rapidly, such as corner sections and arc sections on the cutting path. In sections where the cutting speed decreases, laser energy per unit time is concentrated on the workpiece, so the amount of foreign matter and harmful gas generated increases, and the predicted path step (S211) can utilize this information on speed changes as key input data for predicting the amount generated per section.

[0066] In the predicted thickness step (S212), thickness data of the workpiece can be received. The predicted thickness step (S212) receives thickness data for each section of the workpiece to be processed, and can reflect the characteristic that as the thickness of the workpiece increases, the amount of metal melted during laser cutting increases, thereby increasing the amount of dust and harmful gases generated. In particular, when cutting an ultra-thick plate with a thickness of 90 mm or more, the amount of dust and harmful gases generated increases rapidly, so the thickness data received in the predicted thickness step (S212) can be used as important reference data for controlling the amplification of exhaust volume in the corresponding section.

[0067] In the prediction execution step (S213), the amount of foreign substances and harmful gases generated per section can be predicted based on cutting speed data and thickness data. The prediction execution step (S213) can calculate in advance the amount of foreign substances and harmful gases generated per section along the entire cutting path by comprehensively analyzing the cutting speed data received in the prediction path step (S211) and the thickness data received in the prediction thickness step (S212). The calculated prediction data for the amount generated per section is transmitted to the local response step (S220) and used to optimize the exhaust volume of the local exhaust unit (3) for each section. Through this, the exhaust volume is preemptively amplified in sections where the amount of foreign substances and harmful gases generated increases rapidly, thereby preventing the scattering of dust and harmful gases in advance.

[0068] Referring to FIG. 8(b), the local response step (S220) may include a response receiving step (S221) and a response adjustment step (S222).

[0069] In the response receiving step (S221), reflectance data of the workpiece and flow rate data of the auxiliary gas can be received. The response receiving step (S221) can receive laser reflectance data by material of the workpiece to be processed and real-time flow rate data of the auxiliary gas (N₂, O₂, etc.) sprayed through the cutting nozzle. Since high-reflectance materials such as stainless steel have high laser reflectance, the direction and range of dust scattering during cutting differ from those of general materials, and the direction of dust scattering also changes depending on changes in the flow rate of the auxiliary gas, the response receiving step (S221) can collect such material characteristics and processing condition data in real time and provide them to the response adjustment step (S222).

[0070] In the response adjustment step (S222), the local height section (34) and the local angle section (35) are controlled according to reflectance data and auxiliary gas flow rate data to finely adjust the height and angle of the local suction section (31). The response adjustment step (S222) analyzes the dust scattering direction based on the reflectance data and auxiliary gas flow rate data received in the response reception step (S221), and maximizes collection efficiency by adjusting the height and angle of the local suction section (31) in real time to a position optimized for the analyzed scattering direction. Through this, it is possible to actively respond to changes in the dust scattering direction due to changes in the auxiliary gas flow rate when cutting high-reflection stainless steel, and effectively reduce the scattering of dust and harmful gases along with controlling the exhaust volume of the local exhaust section (3).

[0071] FIG. 9 is a flowchart showing the exhaust control step of a control method for a laser cutting device according to one embodiment of the present invention.

[0072] Referring to FIGS. 6 and FIGS. 9, the exhaust control step (S300) is a step for preventing foreign substances and harmful gases from scattering to the outside of the local exhaust section (3) and the lower exhaust section (5), and can guide foreign substances and harmful gases to the local exhaust section (3) or the lower exhaust section (5) by adjusting the pressure difference between the local exhaust section (3) and the lower exhaust section (5). The exhaust control step (S300) is performed in conjunction with the local exhaust step (S200), and by actively controlling the pressure difference between the upward suction force of the local exhaust section (3) and the downward suction force of the lower exhaust section (5), an airflow can be formed so that foreign substances and harmful gases do not scatter to the upper outside of the work space but are concentratedly drawn into the local exhaust section (3) or the lower exhaust section (5). The exhaust control step (S300) may include a pressure measurement step (S310), a pressure control step (S320), and a pressure maintenance step (S330).

[0073] In the pressure measurement step (S310), the pressure difference between the local exhaust unit (3) and the lower dust collection unit (51) can be measured through the lower measurement unit (52). The pressure measurement step (S310) measures the difference between the suction pressure of the local exhaust unit (3) and the suction pressure of the lower dust collection unit (51) in real time through the lower measurement unit (52) provided in the lower exhaust unit (5), and the measured pressure difference data can be used as reference data to adjust the suction power of the lower dust collection unit (51) in the pressure control step (S320) and the pressure maintenance step (S330). The pressure measurement step (S310) is continuously repeated while the processing step (S100) and the local exhaust step (S200) are performed, allowing for real-time monitoring of changes in the pressure difference.

[0074] In the pressure control step (S320), if the pressure difference measured in the pressure measurement step (S310) is less than a preset reference pressure difference, the suction power of the lower dust collection unit (51) can be increased through the lower control unit (53) to induce an airflow so that foreign substances and harmful gases flow into the lower area. If the pressure difference measured in the pressure measurement step (S310) is less than the reference pressure difference, it may mean that the suction power of the lower dust collection unit (51) is relatively insufficient, so foreign substances and harmful gases do not flow sufficiently into the lower area and there is a high risk of scattering outwardly upward. Therefore, the pressure control step (S320) can actively induce an airflow so that foreign substances and harmful gases do not scatter outwardly but flow into the lower area by increasing the suction power of the lower dust collection unit (51) through the lower control unit (53) to strengthen the airflow in the downward direction.

[0075] In the pressure maintenance stage (S330), if the pressure difference measured in the pressure measurement stage (S310) is greater than or equal to a preset reference pressure difference, the suction force of the lower dust collection unit (51) is reduced through the lower control unit (53) to maintain the pressure difference between the local exhaust unit (3) and the lower dust collection unit (51) at the reference pressure difference. If the pressure difference measured in the pressure measurement stage (S310) is greater than the reference pressure difference, it may indicate a state where the suction force of the lower dust collection unit (51) is excessive, causing unnecessary energy consumption or problems such as the workpiece lifting off the bed. Therefore, in the pressure maintenance stage (S330), by appropriately reducing the suction force of the lower dust collection unit (51) through the lower control unit (53) to maintain the pressure difference between the local exhaust unit (3) and the lower dust collection unit (51) at the reference pressure difference, the energy efficiency of the entire exhaust system can be optimized and a stable airflow control state can be maintained.

[0076] Referring to FIG. 7, the local exhaust step (S200) may further include a section recognition step (S250) and a section switching step (S260).

[0077] In the section recognition step (S250), sections where the thickness or material of the workpiece changes along the processing path of the cutting section (2) can be recognized in advance. The section recognition step (S250) can analyze the entire cutting path performed in the processing step (S100) to identify in advance sections where the characteristics of foreign substances and harmful gases change, such as sections where the thickness of the workpiece changes or sections where the type of material changes. For example, when sections with different thicknesses are mixed within the same workpiece, or when cutting a workpiece with a combination of different materials, the section recognition step (S250) can determine in advance the location, entry point, and thickness or material characteristics of each changing section to prepare reference data for preemptive switching in the section switching step (S260).

[0078] In the section switching step (S260), before the cutting section (2) enters the change section recognized in the section recognition step (S250), the local height section (34) and the local angle section (35) are switched to positions corresponding to the thickness or material of the change section, and the exhaust volume of the local exhaust section (3) and the suction power of the lower dust collection section (51) can be preemptively switched to an exhaust volume corresponding to the change section. The section switching step (S260) allows the cutting section (2) to achieve optimal exhaust performance immediately after entering the change section by switching the exhaust conditions to a state optimized for the change section in advance before entering the change section. Additionally, the section switching step (S260) calculates a deviation by comparing the concentration of foreign substances and harmful gases measured by the measuring section (4) after the cutting section (2) enters the change section with the predicted concentration corresponding to the change section, and if the calculated deviation exceeds a preset allowable deviation, the preemptive switching time can be corrected and applied when entering the next change section. Through this, the section switching step (S260) performs a self-correction function that continuously optimizes the switching point for each changed section during the process of performing repetitive cutting operations, so that dust and harmful gas dispersion can be stably reduced even when continuously cutting workpieces of various thicknesses and material conditions.

[0079] Although representative embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications can be made to the above-described embodiments without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof. Explanation of the symbols

[0080] U: Cutting device 1: Bed section 2: Cutting section 3: Local exhaust section 4: Measuring section 5: Bottom exhaust section S: Control method S100: Processing step S200: Local exhaust stage S300: Exhaust control stage

Claims

Claim 1 A processing step comprising: a bed portion forming an exterior; a cutting portion movably provided on the bed portion to process a workpiece; a local exhaust portion disposed at the bottom of the cutting portion to remove foreign substances and harmful gases generated during the operation of the cutting portion; a measuring portion disposed on the local exhaust portion to measure the concentration of foreign substances and harmful gases; and a bottom exhaust portion disposed on the bed portion to remove foreign substances and harmful gases generated during the operation of the cutting portion, wherein the processing step comprises processing a workpiece through the cutting portion; and a local exhaust step comprising removing foreign substances and harmful gases generated during the processing step through the local exhaust portion; wherein the local exhaust step comprises: a local prediction step for predicting the degree of generation of foreign substances and harmful gases according to the processing path of the cutting portion considering the material characteristics of the workpiece; a local response step for controlling the exhaust volume of the local exhaust portion according to the degree of generation of foreign substances and harmful gases predicted in the local prediction step; and a local measurement step for measuring the concentration of remaining foreign substances and harmful gases through the measuring portion after the local response step. A control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion, characterized by including: a local judgment step in which, if the concentration of foreign substances and harmful gases measured in the local measurement step differs from the normal concentration by more than a predetermined amount, it is determined that there is a defect in the workpiece, a defect in the cutting part, or a defect in the local exhaust part. Claim 2 A control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion, wherein, in claim 1, the local exhaust unit comprises a local suction unit for inhaling foreign substances and harmful gases, a local filter unit disposed in front of the local suction unit for filtering foreign substances, and a local imaging unit for imaging the local filter unit, and the local determination step is characterized by imaging the local filter unit to determine blockage of the local filter unit when the local exhaust unit is determined to be defective, thereby determining a defect in the local filter unit or the local suction unit. Claim 3 In claim 2, the local prediction step comprises: a prediction path step for receiving cutting speed data according to the cutting path of the cutting section; a prediction thickness step for receiving thickness data of the workpiece; and a prediction execution step for predicting the amount of foreign matter and harmful gas generated per section based on the cutting speed data and the thickness data; and the local response step is characterized by controlling the exhaust volume of the local exhaust section to be amplified in real time according to the amount generated per section predicted in the prediction execution step, thereby providing a control method for an eco-friendly stainless steel laser cutting device that significantly reduces dust and harmful gas dispersion. Claim 4 A control method for an eco-friendly stainless steel laser cutting device that drastically reduces dust and harmful gas dispersion, wherein, in paragraph 3, it further comprises an exhaust control step that prevents foreign substances and harmful gases from scattering to the outside of the local exhaust section and the lower exhaust section, and wherein the exhaust control step is characterized by controlling the pressure difference between the local exhaust section and the lower exhaust section to guide foreign substances and harmful gases to the local exhaust section or the lower exhaust section. Claim 5 In claim 4, the lower exhaust unit comprises a lower dust collection unit disposed at the bottom of the bed unit for sucking in foreign substances and harmful gases, a lower measuring unit for measuring the pressure difference between the lower dust collection unit and the local exhaust unit, and a lower controlling unit for controlling the suction power of the lower dust collection unit according to the pressure difference measured by the lower measuring unit; and the exhaust control step comprises: a pressure measuring step for measuring the pressure difference between the local exhaust unit and the lower dust collection unit through the lower measuring unit; a pressure controlling step for increasing the suction power of the lower dust collection unit through the lower controlling unit when the pressure difference measured in the pressure measuring step is less than a preset reference pressure difference, thereby inducing an airflow to allow foreign substances and harmful gases to flow to the bottom; and a pressure maintaining step for reducing the suction power of the lower dust collection unit through the lower controlling unit when the pressure difference measured in the pressure measuring step is greater than or equal to a preset reference pressure difference, thereby maintaining the pressure difference between the local exhaust unit and the lower dust collection unit at the preset pressure difference.

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