| 摘要 |
PURPOSE:To enable temp. of a nozzle itself to elevate rapidly and to attempt to improve efficiency of an operation, by carrying out heating of a nozzle part of an injection molding machine by charging directly a metal material constituting the nozzle with electricity. CONSTITUTION:To carry out injection molding, a band heater wound on the outer circumference of a heating cylinder 14 is heated, a low electric voltage is applied to terminals 22 and 24 on the outer circumference of a base end part of a nozzle 20 to cause a large electric current to flow, a screw is rotated with a nozzle main body 32A heated and a definite amt. of molten raw material is stored at the apex of the screw, passed through a resin path 30 and injected in a mold cavity. A temp. sensor is provided on the nozzle 20 and the resin temp. in the resin path 30 of the nozzle is indirectly detected and is transferred to an electric voltage by means of an amplifier to adjust the heating temp. of the nozzle main body 32A. Therefore, the temp. can be changed in accordance with the cooling temp. of a thick part and a thin part. Moreover, occurrence of sink marks and voids in a molded item can be thereby prevented. |
