JPH07214357A - Laser beam machine - Google Patents

Abstract

PURPOSE:To reduce the piercing time for a work made of thick plate. CONSTITUTION:The melting light L2 generated at a piercing part 5a is received by a detecting means 15 during the piercing operation to a work 5, and inputted into a control device 4. The control device 4 is provided with a focal point correcting part 4A, and this focal point correcting part 4A lowers the position of the focus F of a converging lens 2 to the height matching with the piercing part 5a by driving a motor 8 every time the quantity of light of the melting light L2 to be inputted from the detecting means 15 becomes smaller than the prescribed reference value. This constitution realizes the efficient piercing even with the work 5 of thick plate and reduces the time required for the piercing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam machine, and more particularly to a laser beam machine capable of reducing the time required for piercing.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 4-284993 is known as a laser processing machine capable of shortening the time required for piercing processing. In the laser processing machine of the above publication, the focus position of the condenser lens is lowered by lowering the condenser lens with respect to the workpiece during the piercing process. With such a configuration, the piercing process can be completed in a relatively short time even for a thick workpiece.

[0003]

However, in the above conventional laser beam machine, the relationship between the degree of progress of the piercing process and the descent operation of the focal position of the condenser lens has not been clarified. Japanese Patent Application Laid-Open No. 5-253686 is known as a laser processing machine that monitors the reflected light of a laser beam reflected from a workpiece to determine the focus position of a condenser lens. However, this Japanese Patent Laid-Open No. 5-2
The apparatus of Japanese Patent No. 53686 is only for focusing the condenser lens before the start of processing, and does not monitor the fusion light generated from the workpiece during laser processing. Moreover, since the inert gas is blown to the work piece when focusing the condenser lens, not only a pipe for the inert gas is required, but also the inert gas is assisted after the focusing of the condenser lens. I had to switch to gas.

[0004]

According to the present invention, when the focal point of the condenser lens is coincident with the piercing processing position of the workpiece, the fusion light generated from the processing portion of the workpiece is maximized, and the laser beam is increased. It was made paying attention to the fact that the energy density of the light beam is maximized. That is, the present invention includes a laser oscillator that emits a laser beam, a condensing lens that is housed in the focus head and is movable relative to the focus head along the optical axis of the laser beam, and the condensing lens. In a laser processing machine including a drive mechanism that moves relative to the focus head, and a control device that controls the operation of the drive mechanism, and perform cutting after performing piercing processing on the workpiece,
When performing the piercing process, a detection means for receiving the fusion light generated from the piercing process portion and inputting the fusion light to the control device is provided, and the light amount of the fusion light input from the detection means during the piercing process is stored in advance. The focus position correction unit that adjusts the focus position of the condenser lens via the drive mechanism to a position where the light amount of the fusion light input from the detection means is larger than the reference light amount by comparing with the reference light amount. It was installed in.

[0005]

According to this structure, when the piercing process is performed on the workpiece having a large thickness, the position of the machined portion is gradually changed as the piercing process progresses. At the same time, the focus of the condenser lens can be automatically moved. Therefore, the piercing process can be efficiently performed, and the time required for the piercing process can be shortened as compared with the conventional case.

[0006]

EXAMPLE An example in which the present invention is applied to a pulse oscillation type laser processing machine will be described below.
The laser beam machine includes a laser oscillator 1 that oscillates a laser beam L and a focus head 3 that houses a condenser lens 2 that condenses the laser beam L oscillated from the laser oscillator 1. The oscillator 1 is controlled by the control device 4 in terms of pulse oscillation. The focus head 3 is moved up and down by an elevator mechanism (not shown), and the workpiece 5 is placed on a machining table (not shown). Then, by relatively moving the processing table and the focus head 3 in directions orthogonal to each other in a horizontal plane,
The workpiece 5 can be cut into a desired shape.
The condenser lens 2 held by the lens holder 6 can be moved up and down along the optical axis of the laser beam L with respect to the focus head 3. A rack 7 is integrally connected to the lens holder 6, and a pinion 9 on the side of the motor 8 attached to the housing 3a of the focus head 3 is meshed with the rack 7. The motor 8 is rotated by the control device 4 in the forward and reverse directions by a predetermined amount. Therefore, when the motor 8 is rotated by the control device 4, the condenser lens 2 moves up and down with respect to the housing 3a in a state where the height of the housing 3a is constant, whereby the height position of the focal point F of the condenser lens 2 is increased. Can be adjusted. An optical fiber connector 12 is attached to the housing 3a of the focus head 3, and the optical fiber 1 connected to this through the optical fiber connector 12.
Position one end 13a of 3 inside the focus head 3,
The opening 3b on the lower side is exposed. The other end of the optical fiber 13 is exposed to the photodiode 14, and the photodiode 14 converts light into an electric signal and inputs the electric signal to the control device 4. In this embodiment,
The optical fiber connector 12, the optical fiber 13 and the photodiode 14 constitute a detecting means 15. Therefore, the laser beam L from the laser oscillator 1 whose pulse oscillation is controlled by the control device 4 is condensed by the condenser lens 2 of the focus head 3 and then the workpiece 5 is processed.
Is irradiated. The photodiode 14 constituting the detecting means 15 is adapted to receive light generated by the irradiation of the laser beam L continuously, that is, both when the pulsed laser beam L is irradiated and when it is stopped. At this time, the wavelength of the laser beam L is 10600 nm as an example.
Further, since the wavelength of the fusion light L2 generated from the fusion portion 5a of the processed portion of the workpiece 5 is about 300 to 900 nm, for example, if the photodiode 14 capable of detecting the wavelength of 700 nm is used, the laser beam L is detected. It is possible to detect only the fusion light L2 generated from the fusion portion without performing the above. Thus, in the present embodiment, when the position of the focal point F of the condenser lens 2 coincides with the melted portion of the processed portion of the workpiece 5, the melted light L2 becomes maximum and the laser beam L
The focus F of the condenser lens 2 is moved with the progress of the piercing process, paying attention to the maximum energy density. That is, the control device 4
Condensing lens 2 during the piercing process for workpiece 5
A focus position correction unit 4A that adjusts the position of the focus F, a piercing end determination unit 4B that determines that the piercing process is completed, and a function determination unit 4C that determines whether the function of the detection unit 15 is good or not are provided. A display unit 4D that displays the determination result by each of the determination units 4B and 4C is provided. As shown in FIG. 2, the focus position correction unit 4A includes
A predetermined reference light amount L3 is stored in advance, and the focus position correction unit 4A compares the light amount of the melting light L2 input to the control device 4 from the detection means 15 after the start of the piercing process with the reference light amount L3 to melt the light. The light amount of the light L2 is the reference light amount L3
When it becomes smaller than this, the motor 8 is rotated to automatically lower the focus F of the condenser lens 2 to a height at which the light amount of the fusion light L2 becomes larger than the reference light amount L3. Further, the piercing end determination unit 4B stores in advance a piercing end determination light amount L4 which is a reference for determining the end of the piercing process, and the fusion light L2 input to the control device 4 from the detection unit 15 after the start of the piercing process. And the piercing end determination light amount L4 are compared with each other, and when the light amount of the melting light L2 becomes smaller than the piercing end determination light amount L4, it is determined that the piercing processing has been completed, and that effect is displayed on the display unit 4D. It is supposed to be displayed. With the above configuration, the operation when the piercing process is performed on the thick workpiece 5 will be described with reference to FIGS. 2 to 3. First, as shown in FIG. 3A, at the start of the piercing process, the focal point F of the condenser lens 2 is located slightly above the surface of the workpiece 5, and from that state. The laser beam L is applied to the workpiece 5 to start the piercing process. The piercing processing portion of the workpiece 5 irradiated with the laser beam L is melted by being heated, and the melted portion 5a.
Then, the melting light L2 is generated, and the melting light L2 is input to the control device 4 via the detection means 15. The light amount of the fusion light L2 input to the control device 4 immediately after the start of processing is smaller than the above-described reference light amount L3, as shown at the left end position in FIG. Therefore, the focus position correction unit 4A rotates the motor 8 to automatically lower the focus F of the condenser lens 2 to a height at which the light amount of the fusion light L2 is larger than the reference light amount L3. As a result, the position of the fused portion 5a and the position of the focal point F coincide with each other, so that the energy density of the laser beam L in the fused portion 5a becomes maximum (FIG. 3 (b)). After that, when the piercing process progresses and the piercing hole is gradually deepened, the light amount of the fusion light L2 becomes smaller, and eventually becomes smaller than the reference light amount L3 as indicated by L2 ′ in FIG. This means that the position of the fused portion 5a gradually decreased with respect to the position of the focal point F as the piercing process gradually progressed. 8
Is rotated by the required amount, and the light amount of the melting light L2 becomes the reference light amount L.
The position of the focal point F of the condenser lens 2 is lowered to a position larger than 3 (FIG. 3C). Thereby, the position of the fused portion 5a and the position of the focal point F coincide with each other, and therefore,
The energy density of the laser beam L in the molten portion 5a becomes maximum. In this way, each time the light amount of the fusion light L2 becomes smaller than the reference light amount L3 during the piercing process (L2 ″, L2 ″ ′ in FIG. 2), the focus position correction unit 4A
The focus F of the condenser lens 2 is automatically lowered to a position that coincides with the melting portion 5a. As described above, in the present embodiment, as the piercing process of the workpiece 5 having a large plate thickness progresses,
Since the focal point F of the condenser lens 2 is made to coincide with the fused portion 5a, it is possible to efficiently perform the piercing process while maintaining the energy density of the laser beam L in the fused portion 5a at the maximum. When the piercing process proceeds and the light amount of the melting light L2 becomes smaller than the piercing end determination light amount L3, the piercing end determination unit 4B determines that the piercing process is completed, and the display means 4D indicates that. indicate. Since the present embodiment is configured as described above, it is possible to efficiently perform the piercing process on the workpiece 5 having a large plate thickness, and thus to reduce the time required for the piercing process. Moreover, the situation from the start to the end of the piercing process can be monitored very well. In addition,
After the piercing process is completed and the piercing hole is formed as described above, a required cutting process is performed on the workpiece 5 from the position of the piercing hole. Further, in the present embodiment, as shown in FIG. 1, the reference light generating means 16 for generating the reference light J detectable by the detecting means 15 is provided, and the reference light J generated by the reference light generating means 16 is provided. Is detected by the detecting means 15. Then, the detector function determination unit 4C of the control device 4 determines whether or not the detection means 15 is functioning normally. More specifically, one end 18a of the optical fiber 18 is attached to the focus head 3 by the optical fiber connector 17 so as to face the one end 13a of the optical fiber 13 of the detecting means 15. On the other hand, the other end of the optical fiber 18 faces the light emitting diode 19. Then, as shown in FIG. 4, the control device 4 causes the light emitting diode 19 to generate the reference light J having a predetermined wavelength when required. The reference light J is supplied from one end 18a of the optical fiber 18 to one end 1 of the optical fiber 13 of the detecting means 15.
The light is emitted toward 3a, is detected by the detection means 15, and is input to the control device 4. On the other hand, the detector function determination unit 4C causes the reference light J actually detected by the detection means 15.
The lower limit of the detection function determination light amount K that can be determined to be within the normal range is stored in advance. Then, when the detected light quantity J ′ of the reference light J actually detected by the detection means 15 is smaller than the judgment light quantity K, the function of the detection means 15 is judged to be defective. At that time, the fact is displayed on the display unit 4D. Therefore, in this embodiment, it is possible to easily detect that the one end 13a of the optical fiber 13 constituting the detection means 15 is fogged by dust or the like and the light receiving function of the light is deteriorated.

[0007]

As described above, according to the present invention, it is possible to obtain the effect that the time required for the piercing process can be shortened as compared with the prior art.

[Brief description of drawings]

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

FIG. 2 is a diagram showing fluctuations in the amount of fusion light input from a detection means to a control device during piercing processing.

FIG. 3 is a view showing a progressing process of piercing processing.

FIG. 4 is an explanatory diagram for determining whether the function of the detection unit is good or bad.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser oscillator 2 ... Focusing lens 3 ... Focus head 4 ... Control device 4A ... Focus position correction part 5 ... Workpiece 7 ... Rack (driving mechanism) 8 ... Motor (driving mechanism) 9 ... Pinion (driving mechanism) 15 Detecting means L ... Laser beam L2 ... Melting light L3 ... Reference light amount

Claims (2)

[Claims] 1. A laser oscillator for emitting a laser beam,
A condenser lens housed in the focus head and movable relative to the focus head along the optical axis of the laser beam; a drive mechanism for moving the condenser lens relative to the focus head; and the drive mechanism. In a laser processing machine that is equipped with a control device that controls the operation of, and performs cutting processing after performing piercing processing on a work piece, melt light generated from the piercing processing location during piercing processing is performed. The detection means for receiving the light and inputting it to the control device is provided, and the light quantity of the melting light input from the detection means is compared with the reference light quantity stored in advance during the piercing process, and the melting light input from the detection means is compared. A focus position correction unit that adjusts the focus position of the condenser lens via the drive mechanism to a position where the light amount of light is larger than the reference light amount. Laser processing machine, characterized in that provided in the control device. 2. A reference light generating means for generating a reference light detectable by the detecting means is provided, and the reference light generated by the reference light generating means and inputted to the control device from the detecting means is stored in advance. The laser processing machine according to claim 1, wherein a detector function determination unit that determines whether the function of the detection unit is good or bad by comparing with the function determination light amount is provided in the control device.