Die casting machine and control method thereof

Abstract

Provided is a die casting machine and die casting machine control method that are able to change the operation of a plunger at an appropriate timing. A die casting machine operates a plunger such that the plunger moves forward, detects that molten metal extruded from a sleeve by the forward movement of the plunger has arrived at a cavity, determines a deceleration starting position and a intensification starting position for changing the operation of the plunger, using, as a reference (reference position Ls), the position of the plunger 15 at the time when it is detected that molten metal has arrived at the cavity, and, when the plunger moves to the deceleration starting position and intensification starting position, changes the operation of the plunger to operations corresponding to the respective positions.

1 . A die casting machine comprising:
 a sleeve into which molten metal to be injected to a cavity of a mold is poured;   a plunger housed in the sleeve;   an arrival detector configured to detect that molten metal extruded from the sleeve by a forward movement of the plunger has arrived at the cavity;   an operation change position determination unit configured to determine an operation change position for changing an operation of the plunger, using, as a reference, a position of the plunger at the time when the arrival detector detects that molten metal has arrived at the cavity; and   an operation controller configured to operate the plunger such that the plunger moves forward and to, when the plunger moves to the operation change position, change the operation of the plunger.   
     
     
         2 . The die casting machine of  claim 1 , further comprising:
 a piston connected to the plunger and configured to move by hydraulic pressure; and   a cylinder housing the piston, wherein   the operation controller operates the plunger by controlling supply of hydraulic oil to a rear oil chamber of the cylinder and discharge of hydraulic oil from a front oil chamber of the cylinder, and   the arrival detector detects that molten metal has arrived at the cavity, on the basis of a change in hydraulic pressure of the front oil chamber.   
     
     
         3 . The die casting machine of  claim 1 , wherein the arrival detector detects that molten metal has arrived at the cavity, on the basis of a change in speed of the plunger. 
     
     
         4 . The die casting machine of  claim 1 , wherein the arrival detector detects that molten metal has arrived at the cavity, within a predetermined monitoring range set with respect to the position of the plunger or the time during which the plunger is operating. 
     
     
         5 . The die casting machine of  claim 1 , wherein
 the operation change position is a deceleration starting position, and   the operation controller decelerates the plunger when the plunger moves to the deceleration starting position.   
     
     
         6 . The die casting machine of  claim 1 , wherein
 the operation change position is an intensification starting position, and   the operation controller changes the operation of the plunger to an intensification operation when the plunger moves to the intensification position.   
     
     
         7 . A method for controlling a die casting machine, the die casting machine including a sleeve into which molten metal to be injected to a cavity of a mold is poured and a plunger housed in the sleeve, the method comprising:
 operating the plunger such that the plunger moves forward;   detecting that molten metal extruded from the sleeve by a forward movement of the plunger has arrived at the cavity;   determining an operation change position for changing an operation of the plunger, using, as a reference, a position of the plunger at the time when it is detected that molten metal has arrived at the cavity; and   when the plunger moves to the operation change position, changing the operation of the plunger.