Method for injection molding

A method for injection molding for introducing and melting molding material in a barrel containing a screw, and thereafter injecting a molten material into a mold, said method comprising the steps of:

• carrying out pilot production to collect data showing a relationship between a screw retreat distance from a forward limit and screw driving torque when introducing and melting the molding material in the barrel, and integrating the screw driving torque with respect to the screw retreat distance from a reference position, which is preset near the forward limit, to a retreat completion position of the screw, thereby obtaining a first integral value;
• storing as a reference value the first integral value obtained when a conforming item is produced in the pilot production;
• carrying out actual production to measure screw driving torque when introducing and melting the molding material, and integrating in real time the screw driving torque with respect to the screw retreat distance from the reference position to a screw position at each time, thereby obtaining a second integral value;
• and
• monitoring the second integral value, when the second integral value coincides with the reference value, determining that the step of introducing the molding material is completed, and stopping a rotation of the screw.

A method for injection molding for introducing and melting molding material in a barrel containing a screw, and thereafter injecting a molten material into a mold, said method comprising the steps of:

• carrying out pilot production to collect data showing a relationship between elapsed time from a beginning of retreat of the screw from a forward limit and screw driving torque when introducing and melting the molding material in the barrel, and integrating the screw driving torque with respect to the elapsed time from the forward limit to a retreat completion position of the screw, thereby obtaining a first integral value;
• storing as a reference value the first integral value obtained when a conforming item is produced in the pilot production;
• carrying out actual production to measure screw driving torque when introducing and melting the molding material, and integrating in real time the screw driving torque with respect to the elapsed time from the forward limit to a screw position at each time, thereby obtaining a second integral value;
• and
• monitoring the second integral value, when the second integral value coincides with the reference value, determining that the step of introducing the molding material is completed, and stopping a rotation of the screw.

A method for injection molding for introducing and melting molding material in a barrel containing a screw, and thereafter injecting a molten material into a mold, said method comprising the steps of:

• carrying out pilot production to collect data showing a relationship between elapsed time from a beginning of retreat of the screw from a forward limit and screw driving torque when introducing and melting the molding material in the barrel, and integrating the screw driving torque with respect to the elapsed time from a reference position, which is preset near the forward limit, to a retreat completion position of the screw, thereby obtaining a first integral value;
• storing as a reference value the first integral value obtained when a conforming item is produced in the pilot production;
• carrying out actual production to measure screw driving torque in the step of introducing and melting the molding material, and integrating in real time the screw driving torque with respect to the elapsed time from the reference position to a screw position at each time, thereby obtaining a second integral value;
• and
• monitoring the second integral value, when the second integral value coincides with the reference value, determining that the step of introducing the molding material is completed, and stopping a rotation of the screw.