PROCESSING METHOD OF QUARTZ GLASS MOLDING

PROBLEM TO BE SOLVED: To prevent the cracking and separation of the quartz glass and to remove a removing layer of a substance layer over a wide range from a quartz glass molding by the high-pressure jet by determining the working pressure to a specific value. SOLUTION: The compressed water jet 5 is flowed from a feed line 1 into a mixing chamber 4 through a water nozzle 3. The fine powder-type abrasive substance 7 such as garnet or the like is fed to the mixing chamber 4 through a lateral inlet 6. The abrasive substance 7 introduced into the mixing chamber 7 is carried by the water jet 5, and fed to a converging tube 10 mounted on a lower end of the mixing chamber 4. The water jet 12 including the abrasive substance 7 is jetted from a converging nozzle of an end part of the converging tube at a high speed to be collided with the surface of a work piece 2. On this occasion, the working pressure is lower than the pressure applied to a conventional method, and the maximum value is determined to be 150 MPa, so that the cracking and the separation of the quartz glass can be prevented and a surface layer can be removed over a wide range.