JPH03189088A - Laser beam machine - Google Patents

Abstract

PURPOSE:To vary the image forming position of a laser light without changing a lens by controlling a movement of a second optical means placed between a laser oscillator and a first optical means for bringing the laser light to image formation by a control means in accordance with thickness of a material to be worked. CONSTITUTION:By irradiating a laser light emitted from a laser oscillator 7 to a material B to be worked through a second optical means 11 and a first optical means 10 whose movement is controlled in accordance with thickness of the material B to be worked by a control means 9, an image is formed in a prescribed position in the thickness direction of the material B to be worked. That is, between the laser oscillator 7 and a first optical means 10, a second optical means 11 being movable along an optical axis of the laser light is provided. By moving this second optical means 11 along the optical axis to a position corresponding to thickness of the material B to be worked, the diameter of the incident surface of the laser light which is made incident on a first optical means 10 is varied. In such a way, the laser light can be brought to image formation in a prescribed position in the thickness direction of the material B to be worked.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a laser processing device that can control the imaging position of laser light according to the thickness of a workpiece.

<Prior Art> Conventionally, a technique has been used in which a workpiece is irradiated with a laser beam emitted from a laser oscillator to cut or weld the workpiece.

In the above technology, a laser beam emitted from a laser oscillator is focused by a lens to form an image on a workpiece according to an operation such as cutting or welding to form a laser spot. Lenses with different focal lengths are used depending on the material of the workpiece or the thickness of the workpiece. For example, if the workpiece is a nonmetallic material, a lens with a focal length of 2.5 inches is used.

In addition, if the unprocessed material is metal and the plate thickness is 3.2 cm or less, a lens with a focal length of 2.5 inches and a plate thickness of 3.2
In the case of m ~ 9■, a lens with a focal length of 5 inches and a plate thickness of 9
In the case of 111 or more, a lens with a focal length of 7.5 inches is used.

Also, laser processing equipment such as a laser cutting device that cuts a two-dimensional shape by scanning a laser spot along a predetermined processing line on a workpiece placed on a surface plate, or a laser welding device that performs welding. is being developed. Recently, laser oscillators with an output of several kilowatts have been developed.

A laser processing device equipped with a high-output laser oscillator is capable of cutting or welding a wide range of steel plates ranging in thickness from several thicknesses to several tens of thicknesses.

<Problems to be Solved by the Invention> In conventional laser processing equipment, when cutting or welding a workpiece, the laser beam is focused on the surface of the workpiece or at positions spread apart from the surface. It is being processed.

When performing processing such as cutting or welding on a workpiece, effectively utilizing the energy of laser light leads to improved processing efficiency and quality of the processed part. For this reason, lenses with different focal lengths are used to condense the laser beam according to the thickness of the workpiece, and the imaging position of the laser beam is changed. However, a lens with a long focal length is expensive, and it is troublesome to replace the lens each time the work is performed.

An object of the present invention is to provide a laser processing device that can change the imaging position of laser light according to the thickness of a workpiece without changing lenses.

Means for Solving the Problems> In order to solve the above problems, a laser processing device according to the present invention is arranged on the optical axis of the laser beam and forms an image of the laser beam in the thickness direction of the workpiece. a second optical means movably disposed between the first optical means and the laser oscillator along the optical axis of the laser beam;
and a control means for controlling the movement of the second optical means according to the thickness of the workpiece.

Effect> In the above means, by irradiating the workpiece with the laser light emitted from the laser oscillator through the second optical means and the first optical means whose movement is controlled by the control means,
An image can be formed at a predetermined position in the thickness direction of the workpiece.

That is, a second optical means movable along the optical axis of the laser beam is provided between the laser oscillator and the first optical means, and the second optical means is moved along the optical axis to a position corresponding to the thickness of the workpiece. By moving the laser beam along the first optical means, the diameter of the incident surface of the laser beam incident on the first optical means can be changed, thereby making it possible to form an image of the laser beam at a predetermined position in the thickness direction of the workpiece.

<Example> An example of a laser cutting apparatus to which the above means is applied will be described below with reference to the drawings.

Figure 1 is an overall explanatory diagram of the laser cutting device, Figures 2 and 3 are illustrations of the torch block, Figure 4 is a block diagram of the control system, and Figures 5 (A) to (C) are illustrations of the workpiece. FIG. 6 is a flowchart, which is an explanatory diagram for forming an image of the laser beam in the thickness direction of the material.

First, the overall configuration of a laser cutting device A (hereinafter simply referred to as "cutting device 1") will be explained with reference to FIG. 1. The cutting device A can be used to cut steel plates and stainless steel plates.

It is configured as a cutting device for cutting workpieces such as plastic boards and plywood into predetermined shapes. In particular, in this embodiment, a steel plate is used as the material to be cut B, and the cutting device WIA is configured as a so-called numerically controlled cutting device WIA that can cut out a preset shape from the material to be cut B.

In the figure, rails 1 are laid parallel to each other along the X direction.
A traveling frame 2 is arranged above.

This traveling frame 2 is driven by an X motor 2a and is configured to be able to travel in the X direction.

A transverse frame 3 is provided on the traveling frame 2 along the X direction. A transverse rail 3a parallel to the X direction is fixed to the transverse frame 3.

The transverse rail 3a is provided with a transverse carriage 4 that is driven by an X motor 4a and is movable along the X direction.

The transverse carriage 4 includes a lifting bracket 5 that is driven by two motors 5a and is movable in the Z direction, that is, in the up and down direction.
is provided.

A torch block 6 for irradiating laser light onto the material B to be cut is attached to the lifting bracket 5.

The laser oscillator 7 is fixedly provided at a predetermined position on the floor, and the laser oscillator 7 and the torch block 6
are connected by a laser light path 8. The laser beam path 8 includes a bellows 8a provided parallel to the X direction, a bellows 8b provided parallel to the X direction, a bellows 8c provided parallel to the Z direction, and a mirror unit 8d fixed to the traveling frame 2. , a mirror unit 8e fixed to the transverse carriage 4.

The control device 9 controls drive motors such as the X motor 2a, the X motor 4a and the Z motor 5a to control the position of the torch block 6, and also controls the emission timing of the laser beam by the laser oscillator 7 and the movement direction of the movable lens 11, which will be described later. and the amount of movement.

The operation of cutting the material to be cut B by the cutting device A configured as described above will be briefly described.

When cutting information for the length of the material to be cut is input into the control device 9 in advance and cutting work is started, control pulses are given to the X motors 2a and 4a according to the information, and the torch block 6 is moved at a predetermined speed and in a predetermined direction. Move to. Then, in synchronization with the movement of the torch block 6, the laser oscillator 7
When the laser beam is driven to emit a laser beam, the laser beam emitted from the laser oscillator 7 travels along the X direction through the bellows 8a, is refracted in the X direction by the mirror unit 8d, and travels sideways through the bellows 1lI8b. B
It is refracted in two directions at point e and reaches the torch block 6 through the bellows 8c. The torch block 6 then irradiates the workpiece B to cut the workpiece B into a predetermined shape.

Next, the configuration of the torch block 6 will be explained with reference to FIGS. 2 and 3.

The torch block 6 is attached to an elevating bracket 5 provided on the traversing carriage 4 via a torch bracket 5b, and is configured to be movable in the vertical direction together with the elevating bracket 5 driven by two motors 5a.

The torch block 6 also includes a nozzle 6a, a first cylindrical body 6b for fixing the nozzle 6a, and a fixed lens 10 serving as a first optical means. Second cylindrical body 6 for fixing the fixed lens 10
c. A moving lens 11 serving as a second optical means. moving lens 1
1, a moving mechanism for the third cylinder 6d, and a moving mechanism for the third cylinder 6d. Motor 6e for driving the moving mechanism 12
It is made up of.

The nozzle 6a is detachably attached to the first cylindrical body 6b. A tapered hole 6a+ is formed in the center of the nozzle 6a to allow laser light to pass therethrough, as well as assist gas consisting of carbon dioxide gas, nitrogen gas, and helium gas.

Upper end of the first cylindrical body 6b (upper side in Fig. 3, same below)
, a flange 6 that comes into contact with a flange 6c+ formed at the lower end (lower side in FIG. 3, the same applies hereinafter) of the second cylinder 6c.
b, is formed. Further, a chamber 6b formed inside the first cylinder 6b is provided at a predetermined position on the side surface of the first cylinder 6b.
A nipple 13a to which a hose 13 for supplying assist gas is attached is fixed.

The first cylindrical body 6b has a flange 6c formed on the second cylindrical body 6c.
It is attached to the second cylindrical body 6c via a positioning mechanism 14 provided at +.

The positioning mechanism 14 has a hole 14 having an L-shaped cross section and an inner diameter larger than the outer diameter of the first cylindrical body 6b.
a + and a holding member 14a formed in a ring shape with an outer diameter approximately equal to the outer diameter of the flange 6C+, and the holding member 1
4a, and a screw member 14b whose tip abuts the side surface of the flange 6b. The holding member f4a has the first cylindrical body 6b inserted into the hole 14a.
The first cylindrical body 6b is attached to the second cylindrical body 6c by fastening to the flange 6C+ with screws (not shown). Therefore, the first cylindrical body 6b is configured to be movable in a direction perpendicular to the optical axis 15 of the laser beam.

As described above, by attaching the first cylindrical body 6b to the second cylindrical body 6C via the positioning mechanism 14, the center of the hole 6a formed in the nozzle 6a is adjusted to coincide with the optical axis 15 of the laser beam. Is possible.

A fixed lens 10 is attached to the inner lower end of the second cylindrical body 6c via a holding member 10a. The center of this fixed lens 10 is arranged to coincide with the optical axis 15 of the laser beam.

The fixed lens IO is constituted by a convex lens having a focal length corresponding to a preset distance to the material to be cut B, and directs the incident laser beam along the optical axis 15 and to the material to be cut according to the diameter of the incident surface. 0, which is an image formed in the thickness direction of material B
In this example, the fixed lens lO has a focal length of 2.5 inches.
A convex lens is used.

A flange 6cz is formed at the upper end of the second cylindrical body 6c, and a moving mechanism 12, which will be described later, is connected via this flange 6cz.
is configured. Further, an elongated hole 6cs is formed in the vertical direction at a predetermined position on the side surface of the second cylindrical body 6c.

In this embodiment, as shown in the figure, the second cylindrical body 6C is constructed by fixing two cylindrical bodies, but this is a measure to facilitate the work when assembling the torch block 6. The second cylindrical body 6c may be composed of one cylindrical body or a plurality of cylindrical bodies.

A plurality of linear bearings 16 are provided inside the second cylindrical body 6c, and the third cylindrical body 6d is disposed so as to be movable along the optical axis 15 via the linear bearings 16.

A holding member 11 is attached to the movable lens 11 at the lower end of the third cylindrical body 6d.
It is attached via a. The center of this moving lens 11 is arranged to coincide with the optical axis 15 of the laser beam.

A screw member 12a constituting the moving mechanism 12 is fixed to the upper end of the third cylinder 6d. Further, on the side surface of the third cylindrical body 6d, at a position corresponding to the elongated hole 6Cs formed in the second cylindrical body 6c, there is a hole 6Cs formed in the second cylindrical body 6c. A rotation prevention member 6d is fixed.

The movable lens 11 is constituted by a convex lens having a predetermined focal length, and condenses the incident laser light and makes it enter the fixed lens 10.

Furthermore, the movable lens 11 changes the diameter of the incident surface of the laser beam that enters the fixed lens 10 in accordance with the thickness of the material B to be cut. Therefore, the movable lens If is configured to be able to move in the axial direction along the optical axis (5) of the laser beam. That is, the third cylinder 6d to which the movable lens 11 is attached is configured to be movable along the optical axis 15. In this embodiment, the movable lens 11 has a focal length of 5 inches.
A convex lens is used.

Next, the configuration of the moving mechanism 12 will be explained.

A bearing 12b is fixed to the outer periphery of a flange 6cz formed at the upper end of the second cylindrical body 6c. A gear 12c is rotatably supported on this bearing 12b.

The gear 12c includes a cylindrical portion 12c, and a cylindrical portion 12c.
A gear portion 12cz is formed at the upper end of the gear portion 12cz. The cylindrical portion 12c is fitted into the bearing 12b via a fitting portion formed inside the lower end thereof. Further, a hole 12c for fixing a screw member 12d is formed in the center of the gear portion 12c2.

The screw members 12a and 12d are screwed together to convert rotation of the gear 12C into linear movement. Therefore, the screw member 12a is fixed to the upper end of the third cylinder 6d, and the screw member 12d is fixed to the gear 12c.

A boss 12a is formed at the top of the screw member 12a. The end of the bellows 8C is fixed to the boss 12a+, thereby connecting the laser light path 8 from the laser oscillator 7 to the torch block 6 and the torch block 6.

The gear 12c includes a gear 6e attached to a motor 6e.
+ is in mesh with each other, and the gear 12c and screw member 12d can be rotated by driving the motor 6e.

The motor 6e is fixed to the torch bracket 5b. Further, a holder 50 is integrally formed on the torch bracket 5b, and a second cylindrical body 6 is attached to this holder 5C.
c is attached.

Therefore, the flange 6Cz of the second cylinder 6c and the third cylinder 6
The moving mechanism 12 and motor 6e configured on the upper part of d are as follows:
They are configured so that their relative positions can be maintained by the torch bracket 5b.

In FIG. 2, 17 is a hide sensor that detects the distance between the nozzle 6a and the material to be cut B, and a capacitive sensor that detects the capacitance between the sensor and the material to be cut. It is possible to use sensors such as an air-hide sensor that detects back pressure when pressurized air is injected, and a contact sensor that comes into contact with the surface of the material to be cut. In this embodiment, a capacitive sensor is used.

When the motor 6e is driven in the above configuration, this rotation is transmitted to the third cylindrical body 6d via the gears 5e, 12c and the screw members 12d, 12a. The rotation prevention member 6d provided on the third cylinder 6d engages with the elongated hole 6c formed in the second cylinder 6C, thereby preventing the third cylinder 6d from rotating. The body 6d moves vertically along the optical axis 15.

Next, the control system of the cutting device A will be explained with reference to FIG.

In the figure, 9a is a control unit that constitutes the control word W9,
The motor 6e operates according to the input thickness information of the material to be cut B.
and generate a drive signal for each motor 2a, 4.
a, 5a, laser oscillator 7 CP that generates a drive signal for the assist gas supply device 22 (not shown), etc.
U9a1. Material to be cut B manually input by input device 21
R A M 9 at which temporarily stores information etc. related to
An operation program for the cutting device A and a calculation program for setting the distance between the movable lens 11 and the fixed lens 10 according to the thickness of the material to be cut B, or a calculation program for setting the distance between the movable lens 11 and the fixed lens 10 according to the thickness of the material to be cut B. It is configured by a ROM 9 as that stores a chart etc. in which the distance to the fixed lens 10 is set.

The input device 21 is a device for inputting information such as the material, plate thickness, cutting shape, etc. of the material to be cut B, and the information input from this input device 21 is transmitted to the control unit 9a via the interface 23. . The display 24 is the input device 21
The information input by the user and the operating status of the cutting device A are displayed.

The driver 25 is for driving each motor, and the driver 26 is for driving the laser oscillator 7. It drives the assist gas supply device 22.

Next, image formation of laser light by the cutting device A constructed as described above will be explained with reference to FIGS. 5(A) to 5(C).

FIG. 5(A) shows the relationship between the material to be cut B and the focal point 18 of the laser beam when the material to be cut B is very thin.

The distance between the fixed lens 10 and the material to be cut B in the figure is detected by the hide sensor 17, and when this distance changes from a preset value, the distance between the fixed lens 10 and the workpiece B is
The distance is maintained at a constant value by driving the motor 5a to move the torch block 6 up and down.

Further, the imaging point 18 is set at a position separated from the surface of the material to be cut B by a distance it. The distance 11 is a value determined experimentally.

Here, the distance between the laser oscillator 7 and the fixed lens 10 is L
(constant), the distance between the laser oscillator 7 and the moving lens 11 is u (u+-us), the distance between the fixed lens 10 and the moving lens 11 is d (d, ~ d,), the fixed lens IO and the imaging point 18 If the distance from V (v+ to V,) is the focal path Mr of the fixed lens 10, and the focal length f2 of the movable lens 11, then from the formula of the combined lens, V-β U-α F However, ft・d f ,+f! The following relationship holds true: +d r++rz+a.

In the above equation, when the focal length fl+IN of each lens 10.11 is set, and the distance U between the laser oscillator 7 and the movable lens 11 and the distance V between the fixed lens 10 and the imaging point 18 are set, the fixed lens 10 and the movable This means that the distance d to the lens 11 is uniquely determined.

Further, FIG. 3B shows a case where the laser beam focal point 18 is set on the surface of the material to be cut B, which is effective when the thickness of the material to be cut B is 9 am or less.

Figure (C) shows the material to be cut B and the image point 1 of the laser beam when cutting a thick plate with a thickness of 6 m or more.
This shows the relationship with 8.

The distances d1 to d between the fixed lens 10 and the movable lens 11 in FIGS. 5(A) to 5(C) can be determined based on formulas (1) to (2). Therefore, the ROM 9 of the control unit 9a
The arithmetic program of the above formula and the relationship chart of the distances #v, ~V, between the fixed lens 10 and the imaging point 18 according to the plate thickness are stored in a=, and the cutting target input in the control unit 9a is stored. Set the distances V, ~V, from the chart according to the thickness of material B, and also set the distance M dr to obtain the distances v1 ~ V.
~d, and based on this calculation result, the motor 6e
It is possible to set the distances d1 to d3 from the fixed lens 10 by moving the third cylindrical body 6d in a predetermined direction and thereby moving the movable lens 11 by applying a control pulse to the third cylinder 6d.

Next, the operation of the cutting device A configured as described above will be explained in the sixth section.
This will be explained using the flowchart shown in the figure.

First, the traveling frame 2 and the traversing carriage 4 are moved in a predetermined direction to detect the origin of each device (Sl).

Next, cutting information such as the material, plate thickness, and cutting speed of the material to be cut B, and information such as the cutting shape of the material to be cut are input to the control unit 9a using the input device 21 (S2).

When the input of the predetermined cutting information is completed, the control unit 9a sets the position of the laser beam imaging point 18 based on the input thickness information of the material to be cut B, and also directs the laser beam to the set position. The distance d between the fixed lens 10 and the movable lens 11 for forming an image is calculated. Then, a control pulse is given to the motor 6e based on the calculation result, and the movable lens 11 is moved to a predetermined position (S3).

Next, the X motor 2a and the X motor 4a are driven to move the torch block 6 to match the cutting start position for the material to be cut B (S4 to S8).

When the torch block 6 reaches a predetermined cutting start position, the two motors 5a are driven and the torch block 6 is set at a predetermined height relative to the material B to be cut. From now on, the distance between the nozzle 6a of the torch block 6 and the workpiece B is determined by the hide sensor 1.
Controlled by 7.

Next, the laser oscillator 7 is driven to emit laser light according to a predetermined cutting program stored in the ROM 9 C3. At the same time, assist gas is supplied from the assist gas supply device 22 to the first cylindrical body 6b (39, 310
). Furthermore, the cutting shape information stored in the RAM 9 ct is read out, and the X motors 2a and
Motor 4a is driven in a predetermined direction. Through this series of operations, the material to be cut B is continuously cut into a predetermined shape (Sll-S14).Next, it is determined whether or not the cutting for the pre-input cutting shape has been completed (515). Sll,
Returning to step 313, the cutting is continued, and when the cutting is finished, the operation of the laser oscillator 7 is stopped and the operation of the assist gas supply device 22 is also stopped. S16. SL? ) ends and all operations end.

<Effects of the Invention> As described in detail above, according to the laser processing apparatus according to the present invention, the laser beam emitted from the laser oscillator is moved by the second optical means and the first optical means whose movement is controlled by the control means. By irradiating the workpiece through the irradiation, an image can be formed at nine kiln positions in the thickness direction of the workpiece.

Therefore, there is no need to change the lens as in the conventional technology.
Furthermore, by using a relatively inexpensive lens with a short focal length, the energy of the laser beam can be efficiently applied to the workpiece. Therefore, the processing efficiency in laser processing can be improved, and the quality of the processed part can be improved. For example, when cutting workpieces, it is possible to improve the roughness and flatness of the cut surface, and when welding workpieces, it is possible to maintain the penetration depth at a constant value. It has the following characteristics.

[Brief explanation of drawings]

Figure 1 is an overall explanatory diagram of the laser cutting device, Figures 2 and 3 are illustrations of the torch block, Figure 4 is a block diagram of the control system, and Figures 5 (A) to (C) are illustrations of the workpiece. FIG. 6 is a flowchart for explaining the process of forming a laser spot on a material. A is the cutting device, B is the material to be cut, l is the rail, 2 is the traveling frame, 2a is the X motor, 3 is the traversing frame, 4 is the traversing carriage, 4a is the X motor 5 is the lifting bracket,
5a is 2 motors, 6 is a torch bronck, 6a is a nozzle, 6b is a first cylindrical body, 6c is a second cylindrical body, 6d is a third cylindrical body,
6e is a motor, 7 is a laser oscillator, 8 is a laser beam path, 9 is a control device, 9a is a control unit, 10 is a fixed lens,
11 is a moving lens, 12 is a moving mechanism, 15 is an optical axis, 17
18 is a hide sensor, 18 is a laser spot, 21 is an input device, 22 is an assist gas supply device, 23 is an interface, 24 is a display, and 25.26 is a driver.

Claims (1)

[Claims] a first optical means disposed on the optical axis of the laser beam and for forming an image of the laser beam in the thickness direction of the workpiece; and a first optical means disposed on the optical axis of the laser beam between the first optical means and the laser oscillator. 1. A laser processing apparatus comprising: a second optical means disposed so as to be movable along the second optical means; and a control means for controlling the movement of the second optical means according to the thickness of a workpiece.