JPH03184686A - Method for machining inner circumferential face with laser beam - Google Patents

Abstract

PURPOSE:To enable high speed machining by making outer circumferential surface of a conical rotary body formed with rotation of recessed arc line to reflecting mirror surface at the time of machining the circumferential face in a pipe with laser beam. CONSTITUTION:The conical rotary body 1 is formed by rotating the recessed curve La around one axial line X and the outer circumferential surface thereof is made to the reflecting mirror face 3 and the rotary body 1 is set along the center axial line X is the pipe W. The laser beam B is projected to the reflecting mirror surface 3 and by the reflecting action thereof, the laser beam condensed as annular-state around the center axial line X, is projected to the inner circumferential surface of pipe W. By this method, the high speed laser beam machining without needing complicate laser beam optical system, can be executed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for processing the inner peripheral surface of a pipe using a laser beam, and in particular, a method for processing the inner peripheral surface of a pipe uniformly over its entire circumference. This relates to a processing method suitable for.

(Prior Art) Mechanical processing such as shearing, welding, etc. or surface treatment using the thermal energy of a laser beam has been conventionally performed in various ways.

Conventionally known laser beam processing is performed by condensing a laser beam from a laser source into a single focal point using a condensing optical system.

(Problems to be Solved by the Invention) Laser beam processing as described above is suitable for processing the outer surface of plate materials and the like, but is not suitable for processing the inner surfaces of pipe materials and the like. In particular, when processing the inner peripheral surface of a pipe uniformly over its entire circumference, it is necessary to rotate and scan a dotted laser beam around the central axis of the pipe. A potentially complex laser beam optical system is required, and if the inner diameter of the tube is small, it may be impossible to guide the laser beam to the inner peripheral surface of the tube.

In view of the above-mentioned problems, the present invention aims to provide a new method for processing the inner circumferential surface of a tube using a laser beam, which can process the inner circumferential surface of a tube at high speed without requiring a complicated laser beam optical system. The purpose is

[Structure of the Invention] (Means for Solving the Problems) According to the present invention, the above object is to use the outer peripheral surface of a conical rotating body formed by rotating a concave arc around one axis as a reflecting mirror surface. , the conical rotating body is placed in a tube along its central axis, a laser beam is irradiated onto the reflecting mirror surface, and the reflecting action of the reflecting mirror surface causes the inner circumferential surface of the tube to form an annular shape around its central axis. This is achieved by a method of machining the inner peripheral surface of a tube using a laser beam, which is characterized by irradiating a focused laser beam.

(Function) According to the pipe interior processing method according to the present invention, a laser beam is focused in an annular shape around the rotation center axis of the conical rotating body, whereby the pipe inner circumferential surface is laser processed over its entire circumference at once. .

(Example) The present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of the method for processing the inside of a tube using a laser beam according to the present invention. In these figures, reference numeral 1 indicates a conical rotating body, and the conical rotating body 1 is a rotating body formed by rotating a concave arc line La around one axis, and its entire outer peripheral surface is It is considered as a reflective mirror surface 3.

The concave arc line La may be one circular arc line, with one end La
It touches the axis A1, that is, the rotation center axis A, at the other end Lab.
Displaced in the radial direction by a predetermined amount from the rotation center axis A at one end L
It forms a vertex on the at side, and forms a circular bottom end on the other end Lab side.

The conical rotating body 1 is connected to a support rod 7 extending along an extension of the rotation center axis A at a bottom surface 5 on the bottom end side of the conical rotating body 1. The tube is arranged along the central axis X of the tube. That is, the conical rotating body 1 is provided movably in the axial direction within the tube W in such a manner that its rotation center axis A and the center axis X of the tube W are aligned with each other.

As mentioned above, when the unfocused laser beam B is irradiated onto the entire reflecting mirror surface 3 of the conical rotating body 1 located in the tube W, the laser beam B is As shown in the figure, the light is focused in an annular shape around the rotation center axis A of the conical rotor 1 with a diameter determined by the curvature of the inner circumferential surface of the conical rotor 1.

Therefore, by determining the curvature of the outer peripheral surface of the conical rotating body 1 according to the inner diameter of the pipe W to be processed, the annular laser beam B is focused in an annular shape at a position that matches the inner peripheral surface of the pipe. It becomes like this. This allows the laser beam B to be irradiated simultaneously and uniformly over the entire circumference of the inner circumferential surface of the tube.
The inner peripheral surface of the pipe is uniformly laser-processed over its entire circumference.

Then, when the conical rotating body 1 is moved in the axial direction along the central axis X of the tube W, the laser beam B is irradiated over the entire inner peripheral surface of the tube W, and the required laser processing is performed. It becomes like this.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Effects of the Invention] As can be understood from the description of the embodiments as described above, in the method of machining the inner peripheral surface of a tube using a laser beam according to the present invention,
Because the laser beam is focused around the central axis of rotation of the conical rotating body by the reflection action of the reflective mirror surface formed by the outer surface of the conical rotating body, by placing the conical rotating body within the tube along its central axis, As described above, the annularly focused laser beam is irradiated uniformly over the entire circumference of the inner peripheral surface of the pipe, and laser processing is performed all at once over the entire circumference. As a result, simply by inserting the conical rotating body into the tube, the inner peripheral surface of the tube can be processed at high speed without requiring a complicated laser beam optical system.

In addition, this method for processing the inner circumferential surface of a tube can be carried out even when the inner diameter of the tube is small within the range where a conical rotating body can be inserted into the tube, so that the inner circumferential surface of small diameter tubes can also be properly laser processed. become possible.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the method of processing the inner circumferential surface of a tube using a laser beam according to the present invention, and FIG. 2 is a cross-sectional view taken along the line 1--H in FIG.

Claims (1)

[Claims] The outer peripheral surface of a conical rotating body formed by rotating a concave arc around one axis is used as a reflecting mirror surface, the conical rotating body is placed in a tube along its central axis, and a laser beam is directed to the reflecting mirror surface. A method for processing an inner circumferential surface of a tube using a laser beam, characterized in that the inner circumferential surface of the tube is irradiated with a laser beam that is focused in an annular shape around the center axis of the inner circumferential surface of the tube by the reflection action of the reflecting mirror surface.