A method to predict the remaining useful life of a plasticizing screw for an injection molding machine is provided. The method comprises: creating an energy-pressure ratio distribution estimate for normal operation of the screw for a mold; creating a temporally local energy-pressure ratio distribution estimate from real time data for the screw for the mold; comparing the local distribution with the distribution for normal operation; and generating an alert if the comparison of the two distributions predicts that the remaining useful life is negligible.

A three-dimensional shaping apparatus includes a plasticizing unit, a nozzle, a stage, and a control unit, wherein the plasticizing unit includes a driving motor, a screw, a barrel, and a first heater that heats a material supplied between the screw and the barrel, and the control unit performs a process of decreasing an output of the first heater when at least one of a first condition, a second condition, and a third condition is satisfied, provided that the first condition is that a measurement value of a first temperature sensor that measures a temperature of the screw or the barrel is larger than a first predetermined value, the second condition is that a torque value of the driving motor is smaller than a second predetermined value, and the third condition is that a measurement value of a pressure sensor that measures a pressure in a flow channel between a communication hole and a nozzle opening is smaller than a third predetermined value.

An injection molding machine includes: a screw inserted in an injection cylinder and configured to be movable in the axial direction; a motor configured to move the screw; a torque detection unit configured to detect the torque of the motor; a position detection unit configured to detect the position of the screw; a motor drive control unit configured to drive the motor while imposing torque limitation so that the motor's torque will not exceed a limit torque, to thereby advance the screw to the foremost position in the direction of injection; and a determination unit configured to determine that unmelted resin remains inside the injection cylinder if the moving speed of the screw becomes lower than or equal to a predetermined speed while the screw is advancing to the foremost position.

An injection apparatus includes (a) a barrel; (b) a nozzle at a front end of the barrel; (c) a screw in the barrel; and (d) a drive assembly including: (i) a housing having a front end coupled to the barrel; (ii) a spindle in the housing and fixed to the screw; (iii) a first motor in the housing and having a hollow first rotor through which the spindle passes. The first rotor is coupled to the spindle for driving rotation of the screw about the axis. The drive assembly further includes (iv) a second motor in the housing axially rearward of the first motor. The second motor has a hollow second rotor through which the spindle passes. The second rotor is coupled to the spindle for translating the screw along the axis in response to rotation of the second rotor relative to the spindle.

A plasticizing device includes a plasticizing section that includes a feeding port for receiving a material and plasticizes the material to generate a melted material, a material feeding section that includes a depositing port communicating with the feeding port and feeds the material from the depositing port to the plasticizing section, and a blowing section that blows gas into a feeding path connecting the depositing port and the feeding port.

A method for generating a signal indicative for nozzle maintenance, including feeding modeling material through a feed channel of a printhead to a nozzle of the printhead in a three-dimensional modeling system, determining a parameter indicative of a fluid resistance of modeling material within the nozzle. Determining the parameter includes determining a flowrate of the modeling material within the feed channel, determining a pressure exerted on the modeling material within the feed channel and determining a pressure exerted on the modeling material outside the feed channel, determining a pressure difference between the pressure exerted on the modeling material within the feed channel and the pressure exerted on the modeling material outside the feed channel, and calculating the parameter from the determined flow rate and the determined pressure difference. A method and system for three-dimensionally modeling a three-dimensional object using the method for generating a signal indicative for nozzle maintenance.

A phase adjusting device includes: a torque acquisition unit acquiring a torque; a position acquisition unit acquiring the rotational position of the first motor; a first motor control unit rotating the first motor in a first rotational direction until the torque exceeds a threshold, and then in a second rotational direction until the torque exceeds the threshold again; a storage control unit storing, in a storage unit, a first rotational position when the first motor is rotated in the first rotational direction and the torque exceeds the threshold and a second rotational position when the first motor is rotated in the second rotational direction and the torque exceeds the threshold again; a phase position calculator calculating a third rotational position, based on the first and second rotational positions; and a second motor control unit rotating the first motor to the third rotational position.

A control device for an injection molding machine is equipped with a pressure acquisition unit configured to acquire a resin pressure, a pressure reduction control unit configured to, after the screw has reached a predetermined metering position, reduce the resin pressure to a target pressure by performing at least one of reverse rotation and sucking back of the screw, and a standby pressure control unit configured to, after the resin pressure has reached the target pressure, keep the resin pressure within a predetermined range by causing the screw to be rotated in a state in which a position of the screw in an axial direction of the cylinder is maintained.

In a method for operating an injection moulding machine in the absence of a backflow barrier, plastic melt is injected by a plasticising device into a cavity in a screw antechamber of a plasticising screw adapted to rotate about a longitudinal axis and to move translationally by a drive unit during an injection phase and a holding-pressure phase. A rotational drive of the drive unit is controlled such that a speed of the plasticising screw causes overlay of a backflow of the plastic melt from the screw antechamber back into screw threads of the plasticising screw by an opposing delivery flow as a result of a rotation of the plasticising screw due to a translational injection movement of the plasticising screw. A differential flow is established from the backflow and the opposing delivery flow and influenced at least during the injection phase by influencing the speed of the plasticising screw.

An injection molding machine includes: a first driving device rotating a screw provided inside a heating cylinder; a second driving device moving the screw forward and backward; a metering control section configured to, by controlling the first driving device and the second driving device, to meter resin while melting the resin, and thereafter rotate the screw in reverse to thereby reduce the pressure of the resin; a first sensor unit for detecting the pressure; a second sensor unit for detecting one or more kinds of physical quantities that affect the change of the pressure; and a prediction section predicting decompressing rotation information based on the pressure detected by the first sensor unit and the one or more kinds of physical quantities detected by the second sensor unit. The metering control section controls the first driving device based on the decompressing rotation information predicted by the prediction section.