JPS63295092A - Exhauster for laser beam machine - Google Patents

Abstract

PURPOSE:To protect treatment efficiency from degradation due to the fluctuation of concentration of by-product by detecting the concentration of the by-product generated from a work during laser beam machining and controlling the volume of the air in a pumping means according to a detected output. CONSTITUTION:The change of concentration of hydrogen sulfide, by-product developed in a circulating chamber 7 due to the fluctuation of the output is detected successively by a densitometer 13 of hydrogen sulfide and inputted into a control device 15 through a signal line 14. An exhauster 12 is controlled by comparing a detected output with a set value. As a result, the exhauster 12 controls variably a displacement so that the concentration of hydrogen sulfide in the circulating chamber 7 is kept within a certain range. Accordingly, the absorption of laser beam by the atmosphere is kept from changing and the machining accuracy is maintained.

Description

[Detailed Description of the Invention] [Industrial Application Def] The present invention uses laser beam scanning to reduce gas and dust generated in the processing section of a laser processing device that processes fabrics, leather, etc. This invention relates to a smoke evacuation device for removing by-products such as by-products from a processing area by blowing air.

[Conventional technology]

Conventionally, this type of device is shown in Fig. 3 (Japanese Patent Application No. 6
2-10496). In Fig. 3, reference numeral 1
is a support stand, and in this example, a conveyor is shown. A cloth 2, which is a workpiece, is supported on the conveyor 1.

Reference numeral 3 denotes a laser beam emitting swing mirror for performing cutting and other processing on the fabric 2 by irradiating the fabric 2 with a laser beam while scanning the fabric 2 two-dimensionally. 4 is a cover provided in the laser processing apparatus and forms a processing chamber 5 by covering the processing portion of the fabric 2 to which the laser beam is irradiated; 6 is a cover for providing ventilation flow along the conveyor 1 in the processing chamber s; This is a blower/exhaust device installed in the processing chamber 5 to generate air flow. Here, there is an upstream blower device 8 that takes in air B from outside the processing chamber and sends out a ventilation flow A onto the conveyor, and an air flow fan downstream of the It is comprised of a downstream side blower device 9 for sucking in exhaust gas and sending it out to a duct 10 outside the processing room, and an exhaust fan 12 for sucking exhaust air from the duct 10 and exhausting it to the outside from another duct 11.

Next, the operation will be explained. First, a ventilation flow A as shown in FIG. 3 is generated between the upstream side blower device 8 and the downstream side blower device 9 of the air blower/exhaust device 6 on the conveyor 1 . This ventilation stream must be generated as close to the surface of the fabric 2 as possible in order to immediately remove smoke (processing by-products) generated from the processed area. The blower 8゜9 and the exhaust fan 12 are operated at a fixedly set rated output, so that the air B outside the processing chamber 5 - the upstream blower 8 - the ventilation flow A - the downstream blower 9 -> the duct 1
0→Exhaust 8112-Duct 1]-Exhaust C A ventilation air flow having a constant condition as shown by the arrow in FIG. 3 is formed. Under this condition, when the laser processing device is operated and the laser beam is irradiated from the mirror 3 to the fabric 2 on the conveyor 1 while scanning it two-dimensionally, by-products of the processing by the laser beam can be seen from the processed part of the fabric 2. However, this smoke is immediately removed from the processing section by the ventilation flow man, is carried along with the ventilation air flow, and is discharged to the outside of the processing chamber 5 as exhaust gas C.

In the conventional smoke exhaust system for laser processing equipment with such a configuration, the amount of by-products generated from the processing area changes depending on the change of the processing plate in the processing chamber, so the ventilation air flow under certain conditions changes. The former method has the disadvantage that the machining secondary material centering within the machining chamber changes. That is, for example, when the amount of processing increases, the concentration of processing by-products in the processing chamber increases, causing problems such as attenuation due to absorption and scattering of laser light and odor and contamination of the fabric 2, and when the amount of processing decreases. This causes a problem in that the concentration of processing by-products in the processing chamber decreases, resulting in a decrease in energy efficiency and gas treatment efficiency when exhaust gas treatment is performed downstream of the exhaust line, for example.

This invention was made to solve the above-mentioned problems, and can prevent changes in laser light intensity and odor and contamination of fabrics caused by processing by-products such as gas and dust generated during processing, as well as preventing external An exhaust system for laser processing equipment that can keep the concentration of processing by-products in the exhaust gas emitted to the exhaust gas within a predetermined range and constantly maintain the energy efficiency and gas processing efficiency near the design values when treating the exhaust gas. Intended to provide smoke equipment.

[Means for solving problems]

In order to achieve the above-mentioned object, the smoke evacuation device for a laser processing device of the present invention is for use in a laser processing device that processes a workpiece supported by a support stand by irradiating the workpiece with a laser beam. In the smoke evacuation device, a means for supplying and exhausting smoke air to the workpiece being processed, a detection means for detecting the concentration of processing by-products generated from the workpiece during processing, and a detection means for detecting the concentration of processing by-products generated from the workpiece during processing. A control means is provided for controlling the wind direction of the air supply/exhaust means in accordance with the detection output of the means.

In an embodiment of the present invention, the detection means includes, for example, a hydrogen sulfide concentration meter that detects hydrogen sulfide as a processing by-product, a carbon dioxide concentration meter that detects carbon dioxide gas as a processing by-product, and a carbon dioxide concentration meter that detects carbon dioxide as a processing by-product. This includes a hydrocarbon concentration meter that detects hydrocarbons, and a dust amount meter that detects dust as a by-product of processing, and these can be used alone or in an appropriate combination depending on the type of workpiece. It's a bastard.

In another embodiment of the present invention, the support base has a breathable structure that allows airflow to pass from one surface to the other surface, and at least the processed portion of the support base is surrounded by a cover. A processing chamber is formed on one side of the support base in the cover, and a circulation chamber is formed on the other side, and the supply/exhaust means is configured to send atmospheric gas sucked from the circulation chamber into the processing chamber. A blower device that blows air along one surface of the support table and exhausts it back into the circulation chamber; and an opening provided in the cover on the processing chamber side that introduces outside air from the circulation chamber through the breathable support table. The exhaust device includes an exhaust device that exhausts the air to the outside, and the detection means performs detection within the circulation chamber, and the control device controls the exhaust environment of the exhaust device.

[For production]

When the workpiece supported by the processing section of the support table is processed by irradiating the workpiece with a laser beam, the amount of processing by-products generated from the processing section is reduced due to changes in the amount of processing, such as differences in processing patterns. However, in the smoke evacuation device for a laser processing device of the present invention, the concentration of processing by-products generated from the workpiece during processing is sequentially detected by the detection means, and the detection output of the detection means is Accordingly, the control means controls the flow of the supply/exhaust means, and applies a smoke flow to the workpiece being processed in accordance with the amount of processing by-products generated to reduce the concentration of by-products in the exhaust gas. This is to maintain the concentration within the range.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a menyu conveyor 1 serving as a support base for a ventilation structure supports a fabric 2 as a workpiece on it,
The fabric 2 can be conveyed to the right in the figure in accordance with the processing timing. Cover 4 surrounding the processing part of mesh conveyor 1
defines a processing chamber 5 above the mesh conveyor 1 and a circulation chamber 7 below.
A swing tJJE laser 3 is disposed that emits laser light while scanning it two-dimensionally for processing such as cutting. The processing chamber 5 can take in external air B through the opening of the cover 4, and the air supply/exhaust device i! It can be exhausted by I6. That is, in this embodiment, the air supply/exhaust device 6:
Upstream side blower device 8 that takes in air from one end of the circulation chamber 7 at the bottom of the mesh conveyor 1 and sends the air onto the fabric 2 as a parallel flow.
A downstream blower device 9 takes in this parallel flow A downstream and returns it to the circulation chamber 7, and a downstream blower device 9 takes in air from inside the circulation chamber 7 through a duct 10 and discharges it from the duct 11 to the outside as exhaust C. A blower 12 is included, thereby generating, in addition to the parallel flow A, a downward flow that passes the fabric 2 and the mesh conveyor 1 from the processing chamber 5 side to the circulation chamber 7 side through the fir tree. There is. A gas concentration detector [3] is arranged in the circulation chamber 7, and its detection output is given to the exhaust gas control device 15 by a signal i$14. This control device 15 is designed to control the rotation of the exhaust fan 12 so that the output detected by the detector 13 is maintained within a preset range.

Next, the operation will be explained.

For example, when the workpiece is a fabric containing animal protein, such as wool fabric, the odor components in the processing by-product gas produced by laser processing are shown in the gas chromatograph analysis results shown in Figure 2. As shown, hydrogen sulfide accounts for most of it. Therefore, in this case, a hydrogen sulfide concentration meter may be used as the detection PJ 13, and changes in the hydrogen sulfide concentration in the circulation chamber due to changes in the processing section are sequentially detected by this hydrogen sulfide detector 13, and are transmitted via the signal line 14. Control device 15
is input to. As a result, the control device 15 compares the detector output with a set value and controls the rotation of the exhaust fan 12 within a certain dead zone width using a normal method. As a result, the displacement of the Vr fan 12 is variably controlled so that the hydrogen sulfide concentration in the circulation chamber 7 is maintained within a certain range.

As described above, in this embodiment, the concentration of hydrogen sulfide, which is a processing by-product, in the processing atmosphere circulating in the processing chamber 5 and the circulation chamber 7 is measured, and the concentration is maintained within a certain range. Since the rotation of the exhaust fan 15 is controlled, even if the amount of processing per unit time (number of processed pieces, processing length, etc.) of the fabric 2, which is the workpiece, changes, it will not change depending on the atmosphere of the processing laser light in the processing room. In addition to effectively suppressing changes in the absorption capacity or the adhesion of processing by-products to the fabric, it also ensures that the hydrogen sulfide concentration in the exhaust gas is within a certain range when exhaust gas treatment is performed. This prevents a decline in the efficiency of the processing equipment and stabilizes it.

In the above embodiment, a hydrogen sulfide concentration meter was used as the optimal detector 13 for processing wool fabrics, etc., but hydrogen sulfide concentration meters are generally not reliable for long-term continuous use. There is also the problem of poor stability. Therefore, a method may be adopted in which the hydrogen sulfide concentration is estimated by measuring the concentration of carbon dioxide gas or hydrocarbons, which are thought to exist in a certain ratio with hydrogen sulfide in laser processing by-products such as wool fabrics. In such a case, detector 1
As step 3, use a carbon dioxide concentration meter or a hydrocarbon concentration meter.

In addition, if the generation of dust such as soot as a by-product of laser processing becomes a problem, a dust detector such as a photoelectric type is installed as the detection M13 to measure the dust concentration in the circulating air flow in the circulation chamber 7. do. In this case, the exhaust fan 12 is controlled so that the dust concentration in the circulation chamber is within a certain range, but this reduces fluctuations in the amount of attenuation due to absorption and scattering of the laser beam by the dust in the processing chamber 5. It is possible to maintain processing accuracy and prevent fabric contamination.

Incidentally, in the above-mentioned embodiment, the case where the detector 13 is a single measurement detector has been described, but it goes without saying that the various gas concentration meters and dust detectors described above may be installed as the detector 13. do not have. Further, the installation location of the detector is not limited to the inside of the circulation chamber, but may be placed at an appropriate position in the circulation airflow path or the exhaust path including the inside of the duct. Furthermore, although the example of the supply/exhaust device is one in which air is sucked and exhausted from inside the cover using the exhaust fan 12, a method in which air is pressurized and introduced from the outside into the pressurizing chamber 5 and released through the exhaust duct 11 is used instead. You can also get the same effect.

〔Effect of the invention〕

As described above, in the smoke exhaust device for laser processing equipment of the present invention, the concentration of processing by-products generated during processing is measured and the exhaust amount is controlled so that the concentration falls within a certain range. This suppresses changes in the degree of absorption and scattering of the processing laser beam due to fluctuations in the gas concentration or dust concentration of processing by-products, thereby preventing a decrease in processing accuracy and preventing odor from forming on the processed product. Contamination can also be effectively prevented, and since the concentration of the treated gas is stable during exhaust gas treatment, the energy efficiency and removal efficiency during gas treatment are improved.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a smoke evacuation device for a laser processing device according to an embodiment of the present invention, Fig. 2 is a diagram showing an example of analysis results of processing by-product gas components by gas chromatograph, and Fig. 3 1 is a configuration diagram showing a smoke evacuation device for a conventional laser processing device; FIG. In the figure, the same reference numerals indicate corresponding parts, 1 is a mesh conveyor (support stand), 2 is a fabric (workpiece), 3 is
Shake! 1111 mirror, 4 is a cover, 5 is a processing chamber, 6 is a blower/exhaust device, 7 is a circulation room, 8 is an upstream side blower, 9 is a downstream side blower, 10, 11 is a duct, 12 is an exhaust fan, 1
3 is a detector, 14 is a signal line, and 15 is a control device. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (6)

[Claims] (1) In a smoke exhaust device for a laser processing device that processes a workpiece supported by a processing section of a support stand by irradiating the workpiece with laser light, A supply/exhaust means for providing an exhaust gas flow, a detection means for detecting the concentration of processing by-products generated from the workpiece during processing, and an air volume of the supply/exhaust means is controlled in accordance with a detection output of the detection means. A smoke evacuation device for a laser processing device, characterized by comprising a control means. (2) The smoke evacuation device for a laser processing device according to claim 1, wherein the detection means includes a hydrogen sulfide concentration meter that detects hydrogen sulfide as a processing by-product. (3) The smoke evacuation device for a laser processing device according to claim 1, wherein the detection means includes a carbon dioxide concentration meter that detects carbon dioxide gas as a processing by-product. (4) The smoke exhaust device for a laser processing device according to claim 1, wherein the detection means includes a hydrocarbon concentration meter that detects hydrocarbons as processing by-products. (5) A smoke evacuation device for a laser processing device according to claim 1, wherein the detection means includes a dust amount measuring device that detects dust as a processing by-product. (6) The support has a breathable structure that allows airflow to pass from one side to the other, and at least the processed portion of the support is surrounded by a cover, and one side of the support is inside the cover. A processing chamber is formed on one side, and a circulation chamber is formed on the other side, and the supply/exhaust means is configured to send atmospheric gas sucked from the circulation chamber into the processing chamber along one side of the support base. and an exhaust device that introduces outside air from an opening provided in the cover on the side of the processing chamber and exhausts it from the circulation chamber to the outside through the air permeable support base. Claim 1, characterized in that: the detection means performs detection within the circulation chamber; and the control means controls the exhaust air volume of the exhaust device. A smoke evacuation device for the laser processing device described.