System and apparatus for injection molding

An apparatus for controlling an injection unit that is arranged to transfer a material to a mold cavity, wherein the injection unit includes a barrel, a ram, a material intake portion that is disposed on a first end of the barrel, and a nozzle that is disposed on a second end of the barrel, wherein the ram is rotatably and slidably disposed in a cavity defined by the barrel, and wherein the nozzle is in fluidic communication with the mold cavity, the apparatus comprising:

• an actuation unit including a first actuator, a second actuator, a torque transducer, and a load cell;
• and
• a controller;
• wherein the first actuator is configured to rotate the ram within the barrel;
• wherein the second actuator is configured to exert a linear force on the ram to extend and retract the ram relative to the barrel;
• wherein the load cell is arranged to monitor the linear force exerted on the ram by the second actuator;
• wherein the torque transducer is arranged to monitor a torque that is being exerted by the first actuator to rotate the ram;
• wherein the controller is operatively connected to the first actuator and the second actuator;
• wherein the controller is in communication with the torque transducer and the load cell
• wherein the controller includes an instruction set that is executable to control the injection unit during an injection cycle that includes an advance shot stage, a pack stage, a hold stage, and a material fill stage;
• wherein the instruction set is executable to:
• deactivate the first actuator such that the ram is not rotated within the barrel during the advance shot stage, the pack stage, and the hold stage;
• control the injection unit to inject material into the mold cavity during execution of the pack stage;
• and
• control the first actuator to rotate the ram within the barrel to maintain a constant torque based upon feedback from the torque transducer and simultaneously control the second actuator to exert a compression force on the ram towards the nozzle and to retract the ram during the material fill stage.