METHOD FOR MOUNTING COIL OF NOZZLE ATTACHING SENSOR IN LASER MACHINING APPARATUS

PURPOSE:To execute the subject mounting where assembling is easy and inductance of a coil is made uniform and low temp coefficient is obtd. by coating surface of a sensor for detecting gap with heat resistant and good insulating material and winding a metallized cable into spiral groove arranged on the surface thereof. CONSTITUTION:At the time of supplying high frequency current to a case 29 formed as coil 31-state, eddy current is generated corresponding to distance on the surface of the material W to be machined. As this eddy current increases impedance of the coil 31, by measuring this impedance, the distance between tip part of a nozzle 21 and the material W can be accurately detected. Further, as the cable 31 is wound into the spiral groove 27 on the surface of the heat resistant and good insulating material, expansion with temp. of this member 25 is little and the temp. coefficient of the coil 31 is little, too. Further, as pattern of copper, etc., used to the cable 29 has the constant width and thickness, dispersion of the inductance of individual sensor 23 is little, and adjustment is unnecessary. Then, in the figure, No.1 indicates the laser beam machine, No.15 indicates the machining head and No.21 indicates the nozzle respectively.