| 摘要 |
PURPOSE:To prevent a die life from being shorten and improve the accuracy of metal flow control by irradiating locally the circumferential part of a forming gap of an extrusion die with heating laser beam for controlling metal flow from the front part of an extruder. CONSTITUTION:A trial extrusion is performed by a die 7 having a forming gap 7a corresponding to the cross sectional shape of a die material E so as to prepare data on an oscillating starting point of heating laser beam, an irradiation position and an irradiation area of heating laser beam, etc., in accordance with the shape and size, etc., of the die material E to be worked. The irradiation position of laser beam is decided with a neighboring part of a forming gap slow in metal flow speed as a reference. The regular working is performed according to the data, a heating laser beam oscillator 15 is actuated at a prescribed time point and extrusion is carried out while a prescribed area on the circumference of a forming gap on the rear of the die 7 is locally heated. Consequently, a deformed die material excellent in shape accuracy can be extruded. Further, local heating can be performed concentrically within a very narrow range at need and metal flow control can be improved in accuracy, too. |
