An injection unit for a shaping machine includes an injection piston arranged displaceably in an injection cylinder and at least two drive units for displacement of the injection piston. Each of the at least two drive units is lubricated by an oil chamber which is oil-tightly sealed off in relation to the surroundings, and each oil chamber holds an oil volume, above which is arranged an air volume. The air volumes of the oil chambers are connected together in air-conducting relationship by a connecting conduit.

An injection piston drives a screw. An injection hydraulic cylinder drives the injection piston and is partitioned into first and second chambers. A first oil discharge port is disposed in the injection hydraulic cylinder to be blocked by a piston part when the piston part of the injection piston advances to a pressure-holding switching position, and discharges hydraulic oil from the second chamber. A second oil discharge port is disposed in the injection hydraulic cylinder to be capable of discharging hydraulic oil from the second chamber regardless of the position of the injection piston. The injection piston has first and second members. The joint of the first and second members is disposed at a position separated from an end of the piston part on a side of the second chamber by a predetermined distance.

A method for increasing the injection speed of a melted plastic injection device for injecting said melted plastic into a molding cavity (51), said injection device comprising a first cylinder (1) provided with a tubular casing (2) defining a first inner diameter d.sub.1, and a first piston (3) slidable inside said tubular casing (2), adapted to be loaded with melted plastic and to inject said melted plastic toward the molding cavity (51); a second cylinder (21) constrained to the first cylinder (1) and provided with a second piston (23) which rod (24) is connected to the first piston (3) and is adapted to actuate said first cylinder (1) during an injection operation; the method comprising the steps of: —releasing second cylinder (21) and first cylinder (1) by extracting the first piston (3) from the tubular casing (2); —coaxially inserting a tubular body (12), defining a second inner diameter d.sub.3 which is smaller than the first inner diameter d.sub.1, into the tubular casing (2); —disconnecting the first piston (3) from the rod (24); —connecting a third piston (13) to the rod (24), said third piston (13) being sized to slide inside said tubular body (12); —constraining second cylinder (21) and first cylinder (1) by inserting the third piston (13) into the tubular casing (2).

An injection unit for a shaping machine includes an injection piston arranged displaceably in an injection cylinder and at least two drive units for displacement of the injection piston. Each of the at least two drive units is lubricated by an oil chamber which is oil-tightly sealed off in relation to the surroundings, and each oil chamber holds an oil volume, above which is arranged an air volume. The air volumes of the oil chambers are connected together in air-conducting relationship by a connecting conduit.

A plasticizing device includes a drive motor, a screw that is rotated by the drive motor and that has a grooved face provided with a groove, a barrel that has an opposed face opposed to the grooved face and that is provided with a communication hole communicating with the groove at the opposed face, a first heating section that heats the material supplied to the groove, a temperature sensor that measures a temperature of the groove, and a control unit that controls the drive motor and the first heating section, wherein the control unit performs a first process for rotating the screw at a first rotation speed by controlling the drive motor, and a second process for rotating the screw at a second rotation speed higher than the first rotation speed by controlling the drive motor, and the control unit controls the first heating section so that a temperature measured by the temperature sensor falls within a predetermined range when performing the first process and the second process.

An injection unit for a shaping machine includes an injection element suitable for introducing a plasticized material into a mold tool by a linear movement of the injection element. The injection element is coupled in linear motion-transmitting relationship to a bearing element, and at least two linear drives are adapted to exert a force on the injection element by the bearing element. The force can be transmitted by a transmission element from the at least two linear drives to the bearing element and thus to the injection element, and at least one clearance is arranged between the bearing element and the transmission element such that deformations of the bearing element are not transmitted to the transmission element or are transmitted to a reduced degree.

An injection molding machine with an injection system and a clamping system. The injection system may include a removable injection module defining a portion of the material flow path. The injection module may include all of parts that come in contact with the material between the material source and the mold. The injection module may include a valve arrangement movable between a fill position to load the injection module with material and an inject position to eject material from the injection module into the mold. The actuators for the injection module may be supported on the machine rather than the injection module. The clamping system may include a platen linear actuator to open and close the mold, and a hydraulic clamping system to apply clamping force to the closed mold. The hydraulic clamping system may include a free-float valve manifold assembly that selectively places the hydraulic cylinders in free-float mode.

An injection unit for a shaping machine includes an injection element suitable for introducing a plasticized material into a mould tool by a linear movement of the injection element. The injection element is coupled in linear motion-transmitting relationship to a bearing element, and at least two linear drives are adapted to exert a force on the injection element by the bearing element. The force can be transmitted by a transmission element from the at least two linear drives to the bearing element and thus to the injection element, and at least one clearance is arranged between the bearing element and the transmission element so that deformations of the bearing element are not transmitted to the transmission element or are transmitted to a reduced degree.

The present disclosure provides an injection machine for a recycled plastic injection molding system. The injection machine comprises a supplying system configured to drive plastics from an entry end to downstream of receiving route, a heating system disposed to downstream of the supplying system and configured to melt plastics and drive plastics to the downstream of receiving route, and a buffer system disposed to downstream of the heating system and configured to be a receiving state and a supplying state. When the buffer system is in the receiving state, the buffer system is configured to receiving plastics from the heating system. When the buffer system is in the supplying state, the buffer system is configured to drive plastics to downstream of the receiving route.

A screw can be driven along an axial direction of a heating barrel and rotatable. An injection piston drives the screw along the axial direction. An injection hydraulic cylinder is partitioned into a first chamber in which pressured hydraulic oil for driving the injection piston is supplied and a second chamber from which hydraulic oil is discharged, and drives the injection piston in the axial direction by hydraulic pressure. A first oil discharge port is blocked by the injection piston when the injection piston advances to a holding pressure switching position. A second oil discharge port can discharge the hydraulic oil from the front chamber regardless of the position of the injection piston. The first oil discharge port is disposed at a position opposed to the first oil discharge port across a center axis of the injection hydraulic cylinder, and is connected to the first oil discharge port.