JPS5945090A - Laser condenser in laser working machine - Google Patents

Abstract

PURPOSE:To make a titled device light in weight and small in size and to eliminate the need for manual focusing by utilizing the pressure of an assist gas in maintaining automatically the focal position of laser light in a specified position with respect to the work. CONSTITUTION:When the pressure Pc indicated by a pressure gauge 6 between a flow rate control valve 4 and a nozzle 5 in a laser condenser is set at a certain value, the distance l between the tip of a nozzle cylinder 10 and the work is made automatically constant. Therefore if the pressure Pc is controlled by the valve 4, the cylinder 10 slides vertically with respect to an optical waveguide cylinder 10. Since the cylinder 10 is supported on a cylinder 7 by means of a balancing spring 13, the desired distance l can be set by moving upward or downward the cylinder 10 in its axial direction. If the surface of the work is rugged, the cylinder 10 maintains the distance l constant by moving upward or downward by following up to the ruggedness during working and therefore the focal position of a condenser lens 12 is maintained always in the specified position with respect to the top surface of the work.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a laser focusing device for a laser processing machine.

In the laser focusing device in conventional laser processing machines,
Because the focal position of the laser beam is fixed relative to the workpiece,
When machining workpieces with different thicknesses, there is the hassle of having to adjust the focus position of the laser beam each time according to the thickness of the workpiece.In addition, the workpiece may warp. If the surface is uneven, there are defects such as the inability to perform processing at the optimal focal position.

In the present invention, the focus position of the laser beam is adjusted by using gas pressure, which is currently commonly used in laser processing, without using any special detection means or drive source. It is an object of the present invention to provide a laser condensing device which aims to eliminate the above-mentioned drawbacks by automatically maintaining a constant position.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is an overall view showing an embodiment of a laser focusing device according to the present invention.

The compressed gas container 1 is filled with high-pressure gas that is injected onto the workpiece during laser processing, and the high-pressure gas injected from the compressed gas container 1 passes through a pressure control valve 2 to maintain a constant pressure. The current pressure is displayed by the pressure side 3.

The high-pressure gas that has passed through the pressure regulating valve 2 described in "2" then passes through the flow rate regulating valve 4, and finally passes through the gas inlet 8 provided on the outer periphery of the light guide tube 7 of the laser processing machine and the light guide described in "2". The nozzle tube 10 is inserted into the hollow part of the nozzle tube 10 through a guide groove 10a bored in the axial direction of the nozzle tube 10 that fits into the tube 7.
A nozzle 5 formed at the tip of the ink jets the liquid toward the additional material 11. .

In addition, the flow rate control valve 4 and the nozzle 1\'i31. The pressure generated between the O and the nozzle 5 formed at the tip is the pressure n16
displayed by.

Further, inside the nozzle cylinder 10, there is a nozzle 5 formed at the tip.
A condensing lens 12 is disposed coaxially with the laser beam 15 reflected by the total reflection mirror 1G disposed within the light guiding tube 7. After the light is focused by the V-light lens 12, it is irradiated from the center of the nozzle 5 onto the workpiece J1.

Furthermore, the nozzle cylinder]0 is the guide (7ri1) of the nozzle cylinder lO.
Since the slider 9 provided on the light guide tube 7 is slidably inserted into the inside of the light guide tube 7, it is slidable in the axial direction with respect to the light guide tube 7. Since a balance spring 13 is mounted between the nozzle tube] 0 and the light guide tube 7, the weight of the nozzle tube 10 is supported by the light guide tube 7 via the balance spring 13.

Next, the pressure Po between the flow control valve 4 and the nozzle 5 in the laser condensing device configured as described in section 2 and the distance Q between the tip of the nozzle @10 and the workpiece 11 are calculated. Explain the relationship.

Since the gas used in the laser processing machine is generally at high pressure, the gas passing through the flow control valve 4 and the tip nozzle 5 undergoes adiabatic expansion. At this time, it is known that an 11th order relational expression holds true.

However, a4: Flow passage cross-sectional area of the flow rate control valve 4 a: Flow passage cross-sectional area between the tip nozzle 5 and the workpiece 11 P: Atmospheric pressure PA: The scum pressure indicated by the pressure side 3 Pc: According to the pressure gauge 6 Indicated gas pressure γ: adiabatic index 7-84 r PC+PA+If γ is constant, the following relational expression can be derived from the previous person.

a = f (PC) Further, a5 is expressed by the following formula.

a = πa5Q However, π: Pi (J5: Tip nozzle diameter Q: Distance from tip nozzle 5 to workpiece 1.1 Therefore, the following relational expression holds.

Flood=ni-f (PC) However, K = ] / x d 5 = const.

That is, if the pressure I)c is set to a certain value, the distance 1JIt,
Q will also become fixed by itself. Therefore, when the pressure PC is adjusted by the flow rate control valve 4, the nozzle tube lO can freely slide vertically with respect to the light guide tube 7, and is supported by the light guide tube 7 via the balance spring 13. As a result, the nozzle tube 10 moves up and down in the axial direction, making it possible to set the desired distance Q.
ll, the nozzle tube follows the unevenness], O
moves up and down, and the distance Q is always kept constant, so the focal point 1 of the condenser lens J2 is always kept at a constant position as it is placed above the top surface of the object. In addition, the spring force of the balancing spring 13 elastically mounted between the nozzle tube 10 and the light guide tube 7 can be adjusted, and by changing the balance with the gas injection pressure, the distance fi' can be adjusted by adjusting the pressure 1]. It is also possible to widen the setting range of iQ. Furthermore, if the nozzle tube 10 is fixed to the light guide tube 7 using the stopper 14 attached to the light guide tube 7, it can also be used as a conventional focal position fixing method.

The present invention is configured as described above, and has the following advantages: (1) It does not require a special driving source, is low in cost, and is lightweight.

A compact laser focusing device that can automatically adjust the focal position can be realized.

(2) Even if the surface of the workpiece is uneven or the surface of a sheet, plate, etc. is warped, the focal position of the laser beam can always be maintained at an optimal position relative to the workpiece surface.

(3) The current laborious manual focus positioning work is no longer necessary.

(4) Incorporation into laser processing equipment for large kite production 1;
Therefore, automation of the production system becomes easy.

It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing an embodiment of a laser beam illumination device according to the present invention.

Claims (1)

[Claims] 1. Means for injecting gas onto the workpiece, means for adjusting the gas pressure, and adjusting the gas pressure allows the focal position of the laser beam to be set with respect to the workpiece, and during processing, the focus position of the laser beam can be set. 1. A laser focusing device for a laser processing machine, comprising automatic focus setting means that follows the irregularities of a workpiece and keeps the set position constant. 2. A laser focusing device in a laser processing machine according to claim 1, wherein the means for injecting gas to the workpiece comprises a compressed gas container and a pressure regulating valve. 3. A laser focusing device in a laser processing machine according to claim 1, wherein the means for adjusting the gas pressure comprises a flow control valve. 4. The automatic focus setting means comprises a light guide tube for the laser beam and a hollow nozzle tube that is slidably fitted into the light guide tube, and a nozzle formed at the tip of the nozzle tube is inside the nozzle tube. A condensing lens is disposed coaxially with the laser beam and condenses the laser beam onto the workpiece, and the nozzle tube is supported by the light guide tube via a balance spring. Laser condensing device for laser processing machines in scope 1.