Injection molding device

An injection molding device comprising:

• a barrel;
• an injection screw disposed inside the barrel;
• and
• an injection driving unit that drives the injection screw,
• wherein the injection screw includes:
• a screw body connected to the injection driving unit;
• a screw head coupled to a front end of the screw body;
• and
• a check ring movably coupled to the screw head, the check ring includes:
• an accommodation groove that accommodates at least a portion of the screw head;
• a front member disposed in front of the screw head accommodated in the accommodation groove;
• and
• an accommodation member connected to the front member and surrounding a side surface of the at least a portion of the screw head accommodated in the accommodation groove, and
• when the injection screw moves forward to supply a molding material in the barrel to a clamping device, as the front member is pushed by the molding material accumulated on a front side of the injection screw, the check ring moves rearward from the screw head,
• the injection screw includes a limitation part coupled to the screw head;
• the limitation part supports the check ring to limit a distance by which the check ring moves forward from the screw head;
• the check ring includes an accommodation hole for accommodating the limitation part;
• the screw head includes a coupling hole to be coupled to the limitation part;
• the limitation part is accommodated in the accommodation hole in a state of being inserted into the coupling hole and couples the screw head and the check ring;
• the accommodation hole is formed in the accommodation member as a hole that extends in a front-rear direction so that the check ring moves in the front-rear direction with respect to the screw head;
• the check ring includes a discharge hole connected to the accommodation groove,
• the discharge hole is formed in the accommodation member through the accommodation member at a location spaced apart rearward from the front member so that the discharge hole has a certain spacing from the accommodation hole;
• the molding material transferred forward by the screw body passes through a space between the check ring and the screw head and flows into the accommodation groove, and the molding material flowing into the accommodation groove is discharged forward from the accommodation groove through the discharge hole;
• the check ring includes a stay prevention hole for discharging the molding material remaining inside the accommodation groove;
• and
• the stay prevention hole is formed to pass through the front member and has a smaller size than an outer diameter of a front surface of the screw head.