Abstract: A YAG laser machine for processes such as drilling, cutting, and welding includes a YAG laser generator and a guide beam generator for generating a visible guide beam such as a He--Ne laser. During periodic adjustment of beam path by adjustment of the optical elements a cover member is removed. Detachable element(s) are used for preventing reflected beam portion of the laser beam from leaking outside the machine and a safety system is interlocked with a detaching movement of the detachable element(s) for holding the YAG laser generator in a stopped state. Additionally a safety system is present that interlocks the mounting movement of detachable guide beam visual inspection system to hold the Yag laser generator in a stopped state. The guide beam visual inspection system includes a fiber scope with a polarizing plate.

Abstract: A laser apparatus includes an electric power supply system and a cooling water supply system. Both the electric terminals of the electric power supply system for connection with an external power cable and ports of the cooling water supply system for communicating with external pipes are placed in the forward part of the laser apparatus for facilitating its maintenance. A storage tank stores cooling water to be supplied to a laser oscillator. Both an ion exchanger and a filter are commonly housed in the tank to downsize the apparatus, to minimize the water leakage and to effectively purify the cooling water. Interchangeable flow control valves are provided for different electric power frequencies. According to the available power frequency an appropriate one of the valves is chosen and connected to internal piping to achieve the desired flow rate of the cooling water supplied to the laser oscillator.