DETECTOR IN WATER JET MACHINING

PURPOSE: To prevent a product from being badly machined to improve its machining quality by comparing a detected value from an acceleration detector provided in a jet receiving means to a reference value, and providing a control means for controlling the movement of a nozzle or an object to be machined in response to the comparison result. CONSTITUTION: When a water jet 10 is spouted from a nozzle 1 to penetrate a work 3 in a state where the nozzle 1 is stopped, and is projected on the water surface of a catcher 5, vibration is produced in water 8 under the water surface by the projection of the water jet. An acceleration detector 6 arranged in the catcher 5 detects the vibration, a signal from the detector is converted into a numerical value and calculated in comparison with a reference value by means of a calculation device 7, and the calculated result is outputted to a control means 9. By command from the control means 9, a nozzle driving means 2 or a work driving means is driven-controlled to move the nozzle 1 or the work 3 to machine the work 3 into a desired shape by means of the water jet 10, and thus to enhance its machining quality.