Mitsubishi Jukogyo Kabushiki Kaisha

Yasumi Nakura

Takashi Ishide

Tadashi Nagashima

Isao Shirasu

Shoichi Hamada

Masaru Tomeoka

Takuya Kitera

Osa Matsumoto

Michito Sakamoto

Kunio Terada

Masatoshi Sato

Shoichi Urushibata

Shigeo Hashimoto

Naruo Sakamoto

Masahiko Meka

In a method for monitoring laser beam welding, a sequential signal representing a laser oscillating wave form is received, light of a predetermined wavelength in the light emitted from the weld zone is received, and the two signals thus received are processed to determine the minimum intensity of the light of the predetermined wavelength and thereby accurately deduce welding beam input and penetration of welding. An apparatus used in practicing the monitoring method includes a monitoring optical fiber for receiving and transmitting the light emitted from a weld being made on a workpiece, an interference filter for selectively passing light of a predetermined wavelength, and a processing device for determining an intensity of the light of the predetermined wavelength.

Monitoring method and system for laser beam welding

An improved laser beam welding apparatus for an inner circumferential surface of a tube is disclosed herein, which apparatus comprises an elongated flexible tube containing an optical fiber extended along the length thereof so as to transmit a laser beam, position detecting means disposed in the vicinity of the top end of the flexible tube to determine relative positioning thereof with respect to a work tube in which the flexible tube is inserted, holding means provided with an expander and disposed adjacent to the position detecting means for holding the tip end of the flexible tube in the work tube, rotary drive means disposed closer to the tip end of the flexible tube than the holding means, a rotary cylinder connected to the rotary drive means to be rotated with respect to the flexible tube, guide means mounted on the rotary cylinder in a relatively rotatable manner with respect to the rotary cylinder and held in contact with the inner surface of the work tube for supporting the rotary cylinder in a concentric relation to the work tube, and an optical train arranged with the rotary cylinder for receiving a laser beam emitted from the optical fiber and focusing a reflected laser beam onto the inner surface of the work tube.

Laser beam welding apparatus for an inner circumferential surface of a

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Takasago, Japan

Yasumi Nakura