Abstract: When a metering process is started, a screw rotates at a preset rotating speed, thereby carrying out back pressure control to keep the pressure of a resin at a preset pressure, and retreats. When the screw is located near a preset metering completion position, the control mode is switched to positioning control for the preset metering completion position, and a screw rotation stop command is outputted. The screw overruns for some distance before its rotation stops after it retreats and stops at the preset metering completion position. A resin quantity for the overrun is corrected to obtain a preset metered resin quantity by reversely rotating the screw by a rotational amount corresponding to the overrun.

Abstract: A mold is mounted with a locating ring mated into a hole in a stationary platen. A distance measuring unit is disposed to the side of the injection nozzle. The distance A between the sprue hole and the outer circumference of the locating ring and the distance B between the distance measuring unit and the outer circumference of the locating ring are both known. The distance C between the central axis of the nozzle hole and the side of the injection nozzle is also known. If the distance D to the side of the injection nozzle is measured by means of the distance measuring unit, the displacement between the central axis of the sprue hole and the central axis of the nozzle hole is obtained by calculating {(A+B)?(C+D)}. The injection nozzle is centered by being moved manually or automatically by the amount corresponding to the displacement.

Abstract: When a metering process is started, a screw rotates at a preset rotating speed, thereby carrying out back pressure control to keep the pressure of a resin at a preset pressure, and retreats. When the screw is located near a preset metering completion position, the control mode is switched to positioning control for the preset metering completion position, and a screw rotation stop command is outputted. The screw overruns for some distance before its rotation stops after it retreats and stops at the preset metering completion position. A resin quantity for the overrun is corrected to obtain a preset metered resin quantity by reversely rotating the screw by a rotational amount corresponding to the overrun.

Abstract: A screw is rotated at a set speed and retreated by performing back pressure control for keeping a resin pressure at a set pressure. When the retreat position of the screw reaches a change point set nearby a set metering completion position, the back pressure control for keeping the resin pressure at a set resin pressure is stopped. A command for positioning the screw at a metering completion position is output to position the screw at the metering completion position. At the same time, when a screw position reaches the change point, the screw is reversed by a set value at a set speed.

Abstract: An injection apparatus in an injection molding machine transmits a drive force generated by an injecting servomotor to a screw through a drive force transmitting mechanism to move the screw for performing injection. In addition, the injection apparatus has a dead zone of movement provided by a predetermined distance in the range of the injecting servomotor to the screw.

Abstract: A temperature control device for a proximal portion of a heating cylinder of an injection molding machine capable of performing check and control of a flow rate of a heat medium easily, improving maintainability and also reducing a manufacturing cost. At least one pair of through holes for flowing the heat medium for temperature control are formed in a jacket to be attached to a proximal portion of a heating cylinder of an injection molding machine. In a passage by pipes connecting the through holes and forming the passage with the through holes, a flow-rate control mechanism and a flow-rate detection mechanism for the heat medium flowing in the passage are arranged. The heat medium is supplied to the passage to control temperature of the proximal portion of the heating cylinder.

Abstract: An excessive load detection device for an injection molding machine capable of detecting an excessive load exerted on the injection screw when the screw is driven with resin remaining unmolten in the heating cylinder. An output torque of the servomotor for axially moving the screw is limited to a predetermined value by a torque limiter and the screw is driven to move forward in a direction of injection by a predetermined amount at a predetermined velocity. If reference time elapses before the axial motion of the set amount is completed or a position deviation exceeds a reference value, it is determined that the remaining resin has low fluidity to cause an excessive load on the screw and an alarm is issued. When the axial motion of the screw is completed without an alarm, the screw is moved backward and forward alternately predetermined times. A servomotor for rotating the screw is driven in the same manner to detect an excessive load on the screw.

Abstract: The present invention provides an injection unit having a structure designed for easier machining of a resin guiding hole located in a front plate constituting the injection unit in tile injection molding machine, as well as for reducing tile thermal influence of the heating cylinder and tile plate body on the resin guiding hole. The front plate of the injection unit has a nose member (5), in which a hopper (6) and the heating cylinder (7) are attached, and the plate body (4) linked to a tie bar (10), which are components separated from each other. The injection unit is constructed by joining the heating cylinder (7), the nose member (5) and the plate body (4) to one another through air gaps (23, 24, 28, 29) formed between these components.

Abstract: A screw linkage structure in an injection molding machine comprises a screw (8) having at its base a spline portion (11), a spline bush (9) for receiving the spline portion (11), a screw sleeve (4) having a front surface to which the spline bush (9) is secured, and a retainer (10) serving to prevent the screw (8) from being disengaged from the spline bush (9). The spline portion (11) formed on the screw base is fitted into the spline bush (9) and includes an annular groove (15). The spline bush (9) has a through-hole acting as a retainer attachment hole (16) at the position corresponding to the annular groove (15) of the screw base to be fitted thereinto. The retainer (10) is then inserted into the retainer attachment hole (16) of the spline bush (9) until its leading edge reach the annular groove (15) of the screw base, thereby preventing the screw (8) from being disengaged from the screw sleeve (4).