JP2743734B2 - Processing head of laser processing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a processing head of a laser beam machine.

2. Description of the Related Art Conventionally, a processing head of a laser processing machine has a housing housing a condenser lens for condensing a laser beam, and a nozzle capable of being displaced relative to the housing along the optical axis of the laser beam. A method of adjusting the focal position of a condenser lens housed in a housing according to processing conditions such as a thickness and a material of a workpiece is known (for example, Japanese Patent Publication No. 2-57478, Japanese Unexamined Patent Publication No. Hei 4-57478). No. 52096). In such a conventional apparatus, the nozzle is urged downward by a spring elastically mounted between the nozzle and the housing, and the nozzle is held at a required height position of the housing by a lock / unlock mechanism. When the focal position (height of the housing) of the condenser lens is changed according to the processing conditions of the workpiece, the nozzle is moved up and down by a required amount with respect to the housing, and the nozzle is moved to the housing by the lock mechanism. I keep it. Therefore, even if the focal position of the condenser lens is changed, the distance between the nozzle and the workpiece can be kept constant.

However, in the above-mentioned conventional apparatus, since the lock and unlock mechanisms are provided to hold the nozzle in the housing, there is a disadvantage that the working head becomes large. In addition, when the focal position of the condenser lens is changed, the following adjustment work is performed in order to keep the distance between the nozzle and the workpiece constant. That is, first, the locked state of the nozzle by the lock / unlock mechanism is released, then the housing and the nozzle are lowered, and the lower end of the nozzle is brought into contact with the workpiece serving as the reference plane. The mechanism adjusts the position of the nozzle in the process of locking the nozzle to the housing, and finally raising the housing to separate the lower end of the nozzle from the reference plane. Therefore, such a conventional apparatus has a disadvantage that it takes time to adjust the position of the nozzle.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention provides a housing containing a condenser lens for condensing a laser beam, and a housing slidably fitted to the housing and mounted on the housing. A nozzle that can be relatively displaced along the optical axis of the laser beam, a spring that is elastically mounted over the housing and the nozzle to bias the nozzle in one direction relative to the housing, an outer peripheral portion of the housing, and an inner peripheral surface of the nozzle A compressed air supply source for supplying compressed air to the pressure chamber to urge the nozzle in a direction opposite to the urging direction of the spring; An adjusting means for adjusting a pressure of air to adjust a holding position of a nozzle with respect to a housing is provided.

According to such a configuration, when the focal position of the focus lens is changed in accordance with the processing conditions such as the plate thickness and the material of the workpiece, that is, when the distance between the housing and the workpiece is changed, If compressed air of a required pressure is supplied to the pressure chamber, the nozzle stops at a position where the resilience of the spring and the compressed air supplied to the pressure chamber are balanced, and the nozzle is held at the same position. Can be. Therefore, if the relationship between the focus position of the focus lens and the compressed air supplied to the pressure chamber is determined in advance, even if the focus position of the focus lens is changed in accordance with the processing conditions, the distance between the nozzle and the workpiece is changed. Can be kept constant. Further, a lock, which was conventionally required to hold the nozzle in a predetermined position of the housing,
The unlock mechanism can be omitted. Therefore,
It is possible to provide a processing head whose configuration is simpler than that of the related art and whose nozzle position is easily adjusted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiment. In FIG. 1, reference numeral 1 denotes a processing head of a laser processing machine, and the processing head 1 is attached to a movable frame (not shown) vertically downward. Then, by moving the movable frame in the X direction, the processing head 1 can also move in the X direction. The processing head 1 is provided so as to be able to move up and down with respect to the movable frame by a lifting mechanism (not shown). The control device described later controls this lifting mechanism to move the processing head 1 up and down. Thereby, the focal position of the condenser lens 4 when the workpiece 3 on the processing table 2 is irradiated with the laser beam L can be adjusted. Since the processing table 2 on which the workpiece 3 is mounted is movable in the Y direction orthogonal to the X direction, the processing table 2 and the processing head 1
Are relatively moved in the X and Y directions to obtain the workpiece 3
Required laser processing, such as cutting and drilling, can be performed. The processing head 1 comprises a housing 5 provided on the movable frame so as to be able to move up and down, and a nozzle 6 slidably fitted on the outer periphery of the lower end of the housing 5. The condenser lens 4 is fixedly provided. At a required position of the housing 5, an assist gas supply passage 5a is formed. When the workpiece 3 is irradiated with a laser beam L to perform laser processing, the assist gas is supplied into the housing 5 through the supply passage 5a. Assist gas is supplied. At that time, the assist gas is supplied to the processing position of the workpiece 3 via the internal space of the housing 5 and the internal space of the nozzle 6. The lower portion of the housing 5 below the position where the supply passage 5a is provided is a tapered portion 5b having a reduced diameter at the lower end. doing. That is, the tapered portion 5b
The lowermost portion in the above is a small-diameter outer peripheral portion 5c, and the continuous upper portion is a large-diameter outer peripheral portion 5d having a larger diameter than the small-diameter outer peripheral portion 5c. Further, both outer peripheral portions 5c,
The boundary portion 5d is bulged radially outward to form a large-diameter outer peripheral portion 5d.
The inner peripheral portion of the nozzle 6 is slidably fitted to the outer peripheral portions 5c and 5d and the flange portion 5e. On the other hand, the nozzle 6 is formed in a stepped cylindrical shape, and an inner peripheral surface of a lower small diameter portion thereof is
Tapered hole 6 through which laser beam L and assist gas pass
a. The inner peripheral portion above the tapered hole 6a is a small-diameter inner peripheral portion 6b which is larger in diameter than the tapered hole 6a, and the upper inner peripheral portion continuous from the small-diameter inner peripheral portion 6b is the small-diameter inner peripheral portion. Large-diameter inner peripheral part 6c which is larger in diameter than part 6b
The upper end of the large-diameter inner peripheral portion 6c is formed as a stopper portion 6d bulging radially inward. The small-diameter inner peripheral portion 6b of the nozzle 6 is connected to the small-diameter outer peripheral portion 5c of the housing 5, the large-diameter inner peripheral portion 6c is connected to the flange portion 5e of the housing 5, and the stopper portion 6d is connected to the large-diameter outer peripheral portion 5d of the housing 5. Are slidably fitted to each other. In this embodiment, in order to maintain the airtightness of each sliding portion, the stopper 6d of the nozzle 6 and the housing 5
The seal members 7 are mounted at required positions of the flange portion 5e and the small-diameter outer peripheral portion 5c. By fitting the nozzle 6 at the lower end of the housing 5 in this manner, the large-diameter outer peripheral portion 5d or the flange portion 5
e and the large-diameter inner peripheral portion 6c of the nozzle 6 facing them
A cylindrical space is formed by the stopper portion 6d and the compression spring 8 having a predetermined spring constant over the flange portion 5e and the stopper portion 6d constituting this space.
Is armed. Due to the elasticity of the compression spring 8, the nozzle 6 is always urged upward with respect to the housing 5. Further, a ring-shaped space is formed by the small-diameter outer peripheral portion 5c or the flange portion 5e of the housing 5, the large-diameter inner peripheral portion 6c of the nozzle 6 opposed thereto, and the step end face adjacent thereto. The space is a pressure chamber 9. The pressure chamber 9 is connected to a compressed air supply 13 by a radial through hole 6e drilled in the nozzle 6 and a conduit 10 connected thereto, and
Compressed air can be supplied from the compressed air supply source 13 to the pressure chamber 9. When compressed air is supplied to the pressure chamber 9, the pressure of the compressed air urges the nozzle 6 downward against the elasticity of the compression spring 8. On the other hand, when the compressed air is not supplied into the pressure chamber 9, the nozzle 6 urged upward by the compression spring 8 causes the stopper 6 d shown in FIG. It stops at a position where it contacts the boundary between the portion 5d and the tapered portion 5b. Further, the conduit 1
In the middle of 0, there is provided a pressure adjusting means 14 composed of a regulator that changes the air pressure in proportion to the electric signal,
The pressure of the compressed air supplied to the pressure chamber 9 can be adjusted by the pressure adjusting means 14. In this embodiment, when the focal position of the condenser lens 4 is changed in accordance with the processing conditions of the workpiece 3, the housing 5 is moved in accordance with the changed focal position of the condenser lens 4. The nozzle 6 is moved up and down by a required amount, so that the distance δ between the lower end of the nozzle 6 and the workpiece 3 is kept constant. For this purpose, in the present embodiment, the control device 1
5 stores in advance the optimum height of the condenser lens 4 (the height of the housing 5) according to the processing conditions such as the plate thickness and the material of the workpiece 3. At the same time, the compressed air to be supplied to the pressure chamber 9 corresponding to the height of the condensing lens 4 under each processing condition so that the distance δ between the workpiece 3 and the lower end of the nozzle 6 becomes constant. The pressure is stored in the control device 15. More specifically, the pressure of the compressed air supplied to the pressure chamber 9 causes the compressed air in the pressure chamber 9 to urge the nozzle 6 downward, and the compression spring 8 urges the nozzle 6 upward. Since the stop position is determined by balancing the repelling force, the position of the workpiece 3 and the lower end of the nozzle 6 corresponding to the height of the condenser lens 4 (height of the housing 5) under each of the above processing conditions is determined. The pressure under each processing condition such that the interval δ is constant is stored in the control device 15 in advance. The space accommodating the compression spring 8 is communicated with the internal space of the tapered portion 5b by a communication hole 5f formed in the tapered portion 5b. Therefore, when the assist gas is supplied into the tapered portion 5b, The assist gas is also introduced into the space accommodating the compression spring 8 through the communication hole 5f. In the present embodiment, when the assist gas is supplied, the urging force for urging the nozzle 6 upward by the assist gas introduced into the space and the assist gas act on the tapered hole 6a of the nozzle 6 Since the urging force for urging the workpiece 6 downward is balanced, it is possible to avoid the influence on the nozzle 6 due to the pressure of the assist gas that changes depending on the processing conditions of the workpiece 3. According to the above configuration, when changing the processing conditions such as the thickness and the material of the workpiece 3, the change is performed by the control device 15.
Then, the control device 15 raises and lowers the housing 5 by a required amount by an elevating mechanism (not shown) based on data stored in advance, and positions the condenser lens 4 at a height where an optimum focal position is obtained. At the same time, the control device 15
Transmits the selected compressed air pressure to the pressure adjusting mechanism 14 based on the data on the compressed air pressure and the height of the nozzle 6 stored in advance so as to correspond to the position of the condenser lens 4. Thereby, the pressure adjusting means 14 adjusts the pressure of the compressed air supplied from the compressed air supply source 13 to the predetermined pressure transmitted from the control device 15, so that the compressed air of the predetermined pressure is supplied to the pressure chamber 9. Is done. As a result, the nozzle 6 is moved up and down with respect to the housing to a position where the pressure of the compressed air in the pressure chamber 9 and the urging force of the compression spring 8 are balanced, and then stopped. The nozzle 6 can be held in the housing 5 by supplying the compressed air of the same pressure to the pressure chamber 9, and therefore, the distance δ between the lower end of the nozzle 6 and the workpiece 3 is kept constant. be able to. According to this embodiment, when the focal position of the condenser lens 4 is changed according to the processing conditions such as the thickness of the workpiece 3 and the material, the housing 5 is moved in accordance with the processing conditions. The holding position of the nozzle 6 is automatically adjusted, so that the operation of adjusting the position of the nozzle 6 when the processing conditions are changed can be performed extremely easily. Further, the conventional processing head is provided with a lock and unlock mechanism for fixing the nozzle 6 to the housing 5, so that the processing head becomes larger by that amount. Since such a lock and unlock mechanism is not required, the configuration of the processing head 1 can be simplified as compared with the related art.

As described above, according to the present invention, it is possible to provide a processing head having a simpler structure and a simpler nozzle position adjustment than the conventional one.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Processing head 3 Workpiece 5 Housing 6 Nozzle 8 Compression spring 9 Pressure chamber 13 Compressed air supply source 14 Pressure adjusting means

Claims (1)

(57) [Claims] 1. A housing housing a condenser lens for condensing a laser beam, a nozzle slidably fitted in the housing and capable of being displaced relative to the housing along the optical axis of the laser beam. A spring that is elastically mounted over the housing and the nozzle and urges the nozzle in one direction with respect to the housing; a pressure chamber formed between an outer peripheral portion of the housing and an inner peripheral surface of the nozzle; A compressed air supply source for supplying compressed air to urge the nozzle in a direction opposite to a spring urging direction, and adjusting a pressure of the compressed air supplied to the pressure chamber to hold the nozzle with respect to the housing. And a pressure adjusting means for adjusting the pressure of the laser beam.