JPH0323275B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser processing device for processing a workpiece such as a plate-shaped metal plate by various methods such as cutting and drilling using a laser beam. It is.

As is well known, laser beams are widely used in industry to process various materials, and in the field of metal processing, laser beams are used to process plate-shaped workpieces such as metal plates. It is used for cutting and drilling.

Generally, in laser processing equipment that processes plate-shaped workpieces, a processing head is equipped with a reflecting mirror for irradiating the workpiece with a laser beam from a laser oscillator and a condensing lens for focusing the laser beam. and a processing table that horizontally supports and moves the workpiece. In laser processing, the laser beam is generated by a laser oscillator and sent from the processing head to the workpiece using an assist gas (e.g. oxygen gas) to melt the workpiece.
irradiated with.

This assist gas reacts with the workpiece to help melt the workpiece, and also functions to remove molten metal and slag. It also has the effect of protecting the condenser lens from scattering of molten metal.

In laser cutting, the energy of the laser beam focused on the processing point of the workpiece is absorbed by the workpiece as thermal energy, and the assist gas (O ₂ gas) oxidizes the workpiece. The heat of reaction due to the reaction is also added to this. The workpiece is melted and cut by this thermal energy. Generally, when cutting with a laser beam, the effect of heat generated in the processing area on the surrounding area is reduced by plasma arc cutting,
It is characterized by being extremely small compared to gas cutting. However, when the workpiece is a thick plate or the cut shape is fine and complicated, the range of the heat-affected part becomes wider in order to slow down the processing speed. Therefore, when the shape to be cut is minute and complicated, the required fine shape is melted and completely removed. On the other hand, when using thick plates, there was a problem in that the precision of the cut surface deteriorated.

To deal with this, the conventional method was to cut the workpiece while cooling it with water, but after the cutting process, the cooling water remained in the pores at the tip of the nozzle due to capillary action, causing the cutting to be interrupted. There were also problems such as the assist gas scattering and adhering to the lens when restarted.

A first object of the present invention is to provide a new laser processing apparatus that can process fine shapes while preventing the influence of heat generated in the processing area on the surrounding area.

A second object of the present invention is to provide a laser processing apparatus that can prevent the influence of heat on the peripheral area of the processing even at low processing speeds and perform processing with good precision on the cut surface.

A further object of the present invention is to provide a laser processing apparatus in which the processing head is equipped with a cooling device that efficiently prevents the thermal energy of the laser processing portion from diffusing to the surrounding area.

A further object of the present invention is to provide a laser processing apparatus having a processing head that prevents the cooling water of the cooling device from flowing back into the nozzle.

Other objects and advantages of the invention will become apparent from the description of the accompanying drawings, which illustrate preferred embodiments of the invention and its principles.

As shown in FIGS. 1 and 2, a laser processing device designated by the number 1 is connected to a laser oscillation device 3, such as a CO ₂ (carbon dioxide) laser oscillation device. The laser oscillation device 3 is currently available and produces a laser beam LB,
It is arranged so as to send it to the laser processing device as shown by the arrow in FIG.

The laser processing device 1 includes a base 5, a post 7 fixed to one end of the base 5 and formed vertically, and supported above the base 5 by the post 7 in a horizontal cantilever shape. It consists of an overhead beam 9. A fixed table 11 having a plurality of slide balls 13 is provided at the upper end of the base 5 to horizontally place a workpiece W such as a sheet metal to be processed. At the front end of the overhead beam 9, a processing head assembly 15 having a mirror assembly 17 and a condenser lens 19 is provided. The mirror assembly 17 is provided so as to refract the laser beam LB from the laser oscillation device 3 toward the condenser lens 19 and the workpiece W. In order to feed the mirror assembly 17, in this embodiment two further mirror assemblies 21, 23 are provided.
is provided. Therefore, the laser processing device 1 as described above receives the laser beam LB from the laser oscillation device 3 and directs the laser beam LB to process the workpiece W through the processing head assembly 15 as shown by the arrow. It is now becoming possible to supply

In order to supply and position the workpiece W, the laser processing apparatus includes a first carriage 25 that is horizontally movable, and a first carriage 25 that is movably placed on the first carriage 25 and that is configured to move the workpiece W. A second carriage 27 is provided which holds a plurality of gripping means 29 for gripping W. 1st above
The carriage 25 is slidably mounted on a pair of lasers 31 fixed parallel to each other on the upper end of the fixed table 11, and is driven to move the processing head assembly 15.
It is designed so that it can move freely toward and away from the machining zone located directly below. The second carriage 27 holding the gripping means 29 is placed on the first carriage 25 and can be driven to horizontally move in a direction perpendicular to the rail 31. The gripping means 29 is removably attached to the second carriage 27 and can be adjusted depending on the width of the workpiece W to be processed. Further, in order to support both ends of the workpiece W, a pair of moving tables 33 and 35 having a plurality of slide balls 13 can be attached to the first carriage 25,
These movable tables 33 and 35 are adapted to be moved together with the workpiece W by the first carriage 25. Furthermore, the fixed table 11
Retractable stopper means 37 for initially positioning the workpiece W on the
is provided on an arm member 39 horizontally fixed to a part of the laser processing device 1. Therefore, the workpiece W is held in place by the gripping means 29 such that its end portion first comes into contact with the stopper means 37.
When held by the fixed table 11
positioned above. In the above positioning,
It is assumed that the gripping means 29 are placed in an initial position near the post 7 by the first carriage 25.

With the above configuration, when the workpiece W is positioned directly below the processing head assembly 15 on the fixed table 11 by the first and second carriages 25 and 27, the workpiece W is exposed to the laser beam. Cut or drilled by LB.

Of course, the laser beam LB produced by the laser oscillator 3 is sent to the processing head assembly 15 and directed downward by the mirror assembly 17 as shown by the arrow. . The laser beam LB is then supplied to the workpiece W through the condenser lens 19 together with an assist gas such as oxygen gas.

Further, the first and second carriages 25, 2
Those skilled in the art will readily understand that 7 can be moved automatically and continuously under programmed numerical control.

Next, the processing head assembly 1
The configuration of the nozzle assembly provided in No. 5 will be explained. Referring to FIG. 3, the nozzle assembly 41 includes an inner nozzle equipped with an ejection port 43 for irradiating the workpiece W with a laser beam LB together with assist gas, a coolant passage 45 for ejecting coolant, and its ejection port. 47 and an outer nozzle are integrally configured to form a double nozzle. This inner nozzle consists of an inner nozzle body 49 and a detachable inner nozzle tip 51. The outer nozzle similarly consists of an outer nozzle body and a detachable outer nozzle tip 53. The coolant passage communicates with a coolant inlet 55 . Further, a screw 57 is formed on the outer diameter portion of this inner nozzle body. The inner nozzle main body 49 is held by a sleeve-shaped holding member 59 so as to be vertically slidable. Further, the sleeve-shaped casing 61 is integrally fixed to the annular member 63. In this embodiment, the sleeve-shaped casing member 61 includes a pressure gauge 65 for measuring the pressure of the assist gas ejected to the workpiece W together with the laser beam.
It is equipped with A ring-shaped collar member 67 is fitted into the substantially central portion of the double nozzle so as to be slidable in the vertical direction.

This double nozzle is held in the casing 61 by a spring 73 via a washer 71 so that its horizontal position can be adjusted by a plurality of adjusting screws 69. This double nozzle, which is vertically slidably held in a sleeve-like retaining member 59, is fitted with an annular adjusting nut 7 engaged with a screw 57.
5 so that its vertical position can be adjusted, and is supported by an annular member 79 having an opening 77. Further, the double nozzle and the sleeve-shaped holding member 59 are held by the pins 81 and 83 so as not to rotate, but can be moved in the vertical direction. Furthermore, the nozzle assembly 41 includes a pressing mechanism 85 for counteracting warpage or distortion of the workpiece.
It is equipped with

This pressing mechanism 85 includes a caster roller 89
and an annular caster roller holding member 87 for fixing the caster roller, and is fixed to the lower surface of the annular member 79 with bolts.

An annular discharge nozzle 91 for sucking and discharging the coolant is provided inside the annular caster roller holding member, and the coolant that is ejected from the outer nozzle and accumulated on the upper surface of the workpiece W is provided. is sucked and discharged from an annular suction port 93 surrounding the outer nozzle by a vacuum pump (not shown). Further, a seal ring 95 is attached to this caster roller holding member to prevent the coolant from spreading to the surroundings, and this seal ring 95 is in contact with the upper surface of the workpiece W. A first assist gas guide member 97 having a tapered hole is installed in the large inner diameter portion of the inner nozzle body to throttle the assist gas, and a second assist gas guide member 97 of the same shape is installed in the lower small diameter portion. An assist gas guide member 99 is installed inside. As is clear from FIG. 3, the first assist gas guide member 97 and the second assist gas guide member 97
The tip of the assist gas guide member 99 is spaced apart from the inner circumferential surface of the inner nozzle body, and there is a slight gap between the outer circumferential surface of the tip side of each assist gas guide member 97, 99 and the inner circumferential surface of the inner nozzle. space 10 of
1,103 are provided respectively.

As can be understood from the above explanation, in short, the present invention provides an assist gas guide member with a tapered hole formed in the inner nozzle to perform a throttling action on the assist gas, and the tip of the assist gas guide member is inserted into the inner nozzle. Since the assist gas guide member is provided at a distance from the inner surface of the nozzle and a space is formed between the outer circumferential surface of the tip side of the assist gas guide member and the inner circumferential surface of the inner nozzle, the assist gas flows through the assist gas guide member. When passing through the tapered hole, the speed will be gradually increased. When the assist gas is ejected from the tip of the assist gas guide member, a turbulent flow is generated in a part of the assist gas flow toward the space side.

Therefore, when the assist gas is injected from the inner nozzle onto the workpiece, the cooling water and spatter tend to be blown up and adhere to the condenser lens, and the cooling water and spatter flow against the flow of the assist gas. As a result, the cooling water and spatter may be caught in the turbulent flow at the tip of the assist gas guide and flowed toward the space, or may be blown back by the speed-increasing action of the tapered hole, causing the cooling water and spatter to collect. This can effectively prevent adhesion to optical lenses.

It should be noted that the present invention should not be limited to the above-described embodiments, but can be implemented in other embodiments by making appropriate design changes.

[Brief explanation of the drawing]

FIG. 1 is a side view of a laser processing apparatus according to the present invention. 2 is a plan view of the laser processing apparatus shown in FIG. 1. FIG. FIG. 3 is an enlarged sectional view of the nozzle assembly of the laser processing machine in FIGS. 1 and 2. FIG. (Explanation of symbols representing main parts of drawings), 9
7,99...assist gas guide, 101,10
3...Space part.

Claims (1)

[Claims] 1 an inner nozzle 49 for ejecting assist gas and irradiating a laser beam onto the workpiece W;
51 and is provided with an outer nozzle 53 for spouting a cooling medium to the workpiece W, and this outer nozzle 53
In the laser processing apparatus, a suction port 93 is provided around the inside nozzle for sucking the cooling medium injected to the workpiece W, and a tapered hole is formed in the inner nozzle to perform a throttling action on the assist gas. Guide members 97 and 99 are provided, and the tips of the assist gas guide members are spaced apart from the inner surface of the inner nozzle, and a space 101 is provided between the outer circumferential surface of the tip side of the assist gas guide member and the inner circumferential surface of the inner nozzle. , 103.