Manufacturing apparatus and manufacturing method of molded products

A manufacturing apparatus comprising:

• an injection cylinder to which molten resin is supplied and which is configured to inject molten resin;
• an injection plunger disposed such that the injection plunger fits in the injection cylinder and moves in a first direction and a second direction opposite to the first direction;
• a pressing member configured to be able to be separated from the injection plunger and press the injection plunger for moving the injection plunger toward the first direction;
• a driving source configured to drive the pressing member in the first direction and the second direction;
• a control portion configured to control the driving source;
• and
• a sensor configured to detect contact and/or separation between the injection plunger and the pressing member,
• wherein the injection cylinder includes a base body configured to contain molten resin, and a sleeve configured to be detachably attached to the base body,
• wherein the injection plunger is configured to be inserted into an inner portion of the base body through an opening portion formed in the sleeve and slide on the sleeve,
• wherein the control portion is configured to control the driving source to move the pressing member to a first position when metering molten resin supplied into the injection cylinder in a state where the pressing member is separated from the injection plunger,
• wherein, in a state where the pressing member is separated from the injection plunger, molten resin supplied into the injection cylinder presses the injection plunger to move the injection plunger in the second direction, and
• wherein a contact between the injection plunger and the pressing member that is located at the first position is formed by the moving of the injection plunger in the second direction and is detected by the sensor.