JPS6363597A - Laser beam machining method - Google Patents

Abstract

PURPOSE:To form a stabilized roughness pattern with the adjustment of a gas flow with its detection by feeding the colored gas in the same pressure and flow as those of an assist gas in the case of projecting pulsatively a laser light by a mechanical chopper on the rotary face of the body to be worked. CONSTITUTION:The working surface is roughened uniformly and finely by projecting a pulsative laser light 11 through a rotary mechanical chopper 14 on the surface of the rotary rolling roll 1 located on a supporting device M. The laser beam machining is performed in the assist gas atmosphere jetting from a gas nozzle 15 and the atmosphere is sometimes deteriorated with the gas flow being blown away by the rotary mechanical chopper 14. In this case, the irradiation roughness pattern on the rolling roll 1 surface is made in a stabilized uniform state by flowing the colored gas in the same pressure and same flow amount from a gas nozzle 15 with its changing over from a bomb 22, detecting its gas flow and adjusting the gas flow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser processing method having a gas flow detection means for correctly adjusting the direction of spraying assist gas onto a workpiece.

[Conventional technology]

In recent years, a laser beam is projected onto the surface of a rolling roll in a pulsed manner to form countless micro-holes on the roll surface, and rolls with the micro-holes formed therein have been used during the temper rolling process after annealing cold-rolled steel sheets. Therefore, a method has been adopted in which a pattern of micro holes on the surface of a roll is transferred to the surface of a steel sheet.

This processing method using a laser beam differs from the concave-convex pattern formed by the conventional shot blasting method in which micro-steel balls are blown onto the roll. Since the pitch is constant and an accurate pattern is formed as a whole, it has the characteristic that the sharpness of the steel plate surface treated with this method after painting is improved.

This conventional workpiece rotation support device, a laser projection device with a condensing lens, a mechanical chopper that pulses the laser beam, and a gas nozzle for spraying assist gas onto the surface of the workpiece are used. An example of the equipped laser processing device is shown in Fig. 2-3. ' In the figure, 1 is a rolling roll which is a workpiece,
It is rotatably supported by a support stand 2.3. Reference numeral 4 denotes a drive unit which applies rotational force to the support base 3 via a power transmission unit 5 to rotate the rolling roll 1. 6 is the above cities 2
This is the base on which ~5 was installed. The above 2 to 6 constitute a rotation support device M.

Reference numeral 7 denotes a laser oscillator, which is attached to a cart 10 that is movable on rails 9 provided on a base 8. The rail 9 is provided parallel to the axis of the rolling roll 1, and the rail 9 is provided parallel to the axis of the rolling roll 1.
can be moved parallel to the surface of this rolling roll. Reference numeral 11 denotes a light guide tube, which serves as a path for guiding the laser beam emitted from the laser oscillator 7 to a condensing lens 12. Also, a reflecting mirror 13 is provided inside the bent portion of the light guide tube to guide the laser beam emitted from the laser oscillator 7 to the condenser lens 12. Reflect the beam and use the condensing lens I
2 to irradiate the surface of the rolling roll. Reference numeral 16 denotes a torch having a condensing lens 12 provided therein, and a through hole 16a through which the beam passes is bored at the tip.

The above cities 7, 10, 11, 12, 13, 16, etc. constitute a laser projection device.

A laser beam emitted from the laser oscillator 7 and converged by the condensing lens 12 passes through the through hole 16 of the torch 16.
A is focused onto the rolling roll 1 via a mechanical chopper 14. In addition, the disk-shaped mechanical chopper 14 has a large number of slits arranged along the outer circumference of the disk through which the laser beam can pass.The disk-shaped mechanical chopper 14 is rotated at high speed by a motor M to pass the laser beam. By irradiating the rolling roll 1 in the form of chopped pulses, countless microscopic holes are formed on the roll surface with a constant pinch.

Reference numeral 15 denotes a gas nozzle for spraying assist gas, the tip of which is provided so as to open immediately adjacent to the outer peripheral end of the mechanical chopper 14, from which assist gas (for example 02) is directed to the laser beam focus position on the surface of the roll 1. By spraying toward the target, the microholes drilled by the laser are formed in a uniform shape and at the required depth.

[Problem that the invention seeks to solve]

Here, the roughness pattern formed by micro holes on the roll surface is determined by the number of rotations on the support base of the rolling roll, which is the workpiece.
It is determined by various factors such as the rotation speed of the mechanical chopper, laser output, assist gas flow rate and pressure. Also,
During laser processing, if the assist gas is not maintained at a constant position relative to the beam focus on the roll surface, the roughness pattern will change significantly. It is necessary to adjust the mutual positions of the gas nozzles, gas nozzles, etc. so that they are always in an optimal relationship. However, since the gas nozzle 15 is provided with an opening immediately adjacent to the outer peripheral edge of the chopper 14,
The flow of the assist gas ejected from here is influenced by the wind pressure generated as the chopper 14 rotates, and is deviated from the beam center on the roll surface, which deteriorates the roughness pattern of the roll formed. This tendency becomes more pronounced as the rotational speed of the chopper and the workpiece rolls is increased in order to improve productivity.Moreover, since changes in the flow of assist gas cannot be visually observed, gas nozzles and other related There was a problem in that it was difficult to adjust various elements.

The present invention has been made in view of such conventional problems, and an object of the present invention is to solve the above problems by providing a detecting means that allows the flow of assist gas to be visually recognized.

[Means for solving problems]

This invention includes a rotation support device for a workpiece, a laser projection device having a condensing lens, a mechanical chopper that pulses a laser beam, and a gas nozzle for spraying an assist gas onto the surface of the workpiece. In this laser processing method, the gas flow is detected by supplying colored gas to the gas nozzle at the same pressure and flow rate as the assist gas, and the position of the gas nozzle is adjusted.

[Effect]

When the workpiece attached to the rotation support device and the mechanical chopper are rotated at predetermined speeds, and then colored gas is supplied to the gas nozzle at the same pressure and flow rate as the assist gas during machining, the assist gas is emitted from the gas nozzle. Instead, colored gas is ejected and the gas flow is visible, so the gas flow that deviates from the specified position due to the rotational wind pressure of the chopper must be kept in the correct direction by adjusting the gas nozzle, etc., and then the colored gas By switching to the assist gas, the correct flow direction of the assist gas can be obtained.

〔Example〕

The present invention will be explained below based on the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. Note that the same parts as in the conventional example are given the same reference numerals, and redundant explanation will be omitted.

In the figure, 17 is a high-pressure gas cylinder containing assist gas, and 18 is a pipe leading from this cylinder to the gas nozzle 15. 19 is a pressure control valve, 20 is a flow rate control valve, 2
Reference numeral 1 denotes a switching valve, which is provided in each pipe 18. In addition, 22 is a gas cylinder containing a non-flammable colored gas, and 23 is a pipe leading from this cylinder to the gas nozzle 15. 24 is a pressure control valve, 25 is a flow rate control valve, 26
are switching valves, both of which are provided in the piping 23.

Next, the operation will be explained.

The rolling roll 1, which is the workpiece, is mounted on the support stand 2.3,
Roll 1 is rotated at a predetermined speed. Next, move the laser projection bag ffL to the processing start position with respect to the roll 1,
The chopper 14 is rotated at a predetermined speed. And in advance,
The laser beam is irradiated only while the roll 1 rotates once. Next, the switching valve 26 is opened, and the pressure control valve 24 and flow rate control valve 25 are set so that the pressure and flow rate of the colored gas ejected from the gas nozzle via the piping 23 become the pressure and flow rate of the assist gas to be sprayed during processing. control. At this time, the position of the gas nozzle 15 is adjusted so that the colored gas ejected from the gas nozzle 15 flows in the correct direction with respect to the micro holes on the roll 1 formed by laser irradiation. .

When this adjustment is completed, the switching valve 26 is closed to stop the supply of colored gas, the assist gas switching valve 21 is opened, and the pressure control valve 19 and flow rate control valve 20 are controlled so that the pressure and flow rate are at predetermined values. Then, the laser oscillator 7 is set to ○N and normal machining work begins. Through the above steps, a predetermined roughness pattern can be formed on the roll 1. Note that the colored gas is nonflammable and visible, and may be a gas such as water vapor or white smoke.

(Effects of the Invention) As explained above, according to the present invention, the following effects can be obtained.That is, the gas nozzle can be adjusted easily and accurately, and the roughness pattern formed on the surface of the workpiece can be changed. Even if the rotation speed of the chopper is changed, the optimum injection position of the assist gas can be easily detected, so a stable roughness pattern can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the main parts of the embodiment according to the present invention, Fig. 2 is an overall top view of a laser processing device common to the present embodiment and the conventional example, and Fig. 3 is an explanatory diagram of the main parts of the conventional example. . 12...Condensing lens, 14...Mechanical chopper, 15...Gas nozzle, L...
... Laser projection device, M ... Rotating support device; Gas flow detection means 22 ... Colored gas cylinder, 23 ... Piping, 24 ... Pressure control Valve, 25...Flow control valve, 26...Switching valve.

Claims (1)

[Claims] A processing device equipped with a rotating support device for the workpiece, a laser projection device with a condensing lens, a mechanical chopper that pulses the laser beam, and a gas nozzle for spraying assist gas onto the surface of the workpiece. A laser processing method characterized in that, in laser processing, a colored gas is supplied to the gas nozzle at the same pressure and flow rate as an assist gas, thereby detecting the gas flow and adjusting the position of the gas nozzle.