Injection device and injection control method
Provided is an injection device and an injection control method which are capable of preventing a drooping phenomenon from an injection nozzle even during high cycle molding, and capable of appropriately plasticizing and molding a resin having poor thermal stability. An injection device ( 10 ) of the disclosure includes: an injection cylinder ( 30 ) which accumulates a molding material and has an injection nozzle ( 33 ) at the front; an injection plunger ( 31 ) which is moved backward in the injection cylinder ( 30 ); an injection plunger driving device ( 50, 150 ) which moves the injection plunger ( 31 ) backward; and an injection controller ( 60, 160 ). The injection controller ( 60, 160 ) retreats the injection plunger ( 31 ) by the injection plunger driving device ( 50, 150 ) to perform metering in a plastication metering step of metering the molding material supplied into the injection cylinder ( 30 ).
1. An injection device, comprising:
an injection cylinder which accumulates a molding material and has an injection nozzle at the front;
an injection plunger which is moved backward in the injection cylinder;
an injection plunger driving device which moves the injection plunger backward; an injection controller; a position detection device which detects a position of the injection plunger; and
a pressure detection device for detecting a resin pressure of the molding material in the injection cylinder, wherein
the injection controller is configured to calculate a retreat speed of the injection plunger in a plastication metering step of an n-th injection cycle from a metering time of the injection plunger measured by the position detection device in a plastication metering step of an (n-1)-th injection cycle, and the injection controller is configured to directly control the injection plunger to retreat based on a value of the resin pressure and the retreat speed to perform metering, before a suck-back step can be omitted, wherein the n is an integer of 3 or more.
2. The injection device according to claim 1 , wherein in the plastication metering step of the n-th injection cycle, the injection controller retreats the injection plunger at the retreat speed to a position at which the injection plunger has been moved from a pre-set metering end position toward the injection nozzle side by a certain width.
3. An injection control method of an injection device which is the injection device according to claim 1 , comprising a plastication metering step in which the molding material supplied into the injection cylinder having the injection nozzle at the front is metered while the injection plunger is retreated, wherein
a retreat speed of the injection plunger in a plastication metering step of the n-th injection cycle is calculated from the metering time measured in a plastication metering step of the (n-1)-th injection cycle, and the injection plunger is retreated at the retreat speed to perform metering of the n-th injection cycle, wherein n is an integer of 3 or more.
4. The injection control method of the injection device according to claim 3 , wherein in the plastication metering step of the n-th injection cycle, the injection plunger is retreated at the retreat speed until the injection plunger reaches a position at which the injection plunger has been moved from a pre-set metering end position toward the injection nozzle side by a certain width.