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 (3) into the tubular casing (2).

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.

A micro moulding machine and process for forming small plastic parts for the medical device industry. The machine adds heat in two steps to a precision sized plastic pellet and then displaces the entire pellet volume into the mould cavity. A substantial amount of heat is added to the pellet by forcing it through an orifice very near the gate of the mould. The pneumatic pressure to drive the pellet through the orifice is controlled to regulate the amount of heat introduced into the pellet.

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.

Resin supply system in which resin material is stored in a pouch (120) in a degassed state ready for use. The pouch comprises a body portion (122) forming a reservoir for resin material and a connector portion (125) in fluid communication therewith. The connector portion includes an outlet (127) which is configured to be connected to an injector head (180) of an injector assembly (100), the injector head being connectable to a mould by means of connecting tubing to provide a resin supply (130) thereto. The pouch is configured to be mountable in a housing (110) of the injector assembly and is compressed by hydrostatic pressure of water surrounding the pouch in a chamber (115) of the housing. The application of pressure by a piston (150) moving in a direction (155) transfers pressure to the water and then to the pouch in a controlled manner to provide the resin supply to the mould. After use, the pouch is removed and discarded thereby substantially eliminating the need for cleaning of the housing after use.

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.

Agitating pins employed in a kneading apparatus extend in the horizontal direction and rotate around a rotation axis of an agitator extending in the horizontal direction, so that the kneading apparatus can repeat a process in which a material is kneaded and beaten against an inner wall surface of a kneading vessel and the material adhering to the inner wall surface of the kneading vessel, especially on the upper side from the rotation axis of the agitator, falls under its own weight through the clearance between the agitating pins. As a result, the material hardly adheres to the inner wall surface of the kneading vessel, so that the kneading efficiency can be enhanced.

The present invention provides an injection device which is capable of injecting a certain amount of a resin material in each injection process, while suppressing entry of air into a barrel and cost increase due to increase in the number of components. An injection device 1 according to the present invention is provided with: a resin material inlet 13; a drive unit 20 which generates a driving force for injecting a resin material from an injection port 12; a plunger 17 which is provided so as to be movable forward and backward in the axial direction of a barrel 11, and moves backward when the resin material flows into the barrel 11 and injects the resin material filled in the barrel 11 through the injection port 12 by moving forward within the barrel 11; a pusher member 18 which pushes the plunger 17 toward the injection port 12 of the barrel 11; a driving force transmission unit 21 which transmits the driving force generated in the drive unit 20 to the pusher member 18; and a control unit 25 which controls these constituent units so that the inflow of the resin material into the barrel 11 is started and measurement of the resin material is completed when the load received by the drive unit 20 from the pusher member 18 located at a specified position reaches a predetermined value.

An injection molding apparatus has an injection cylinder in fluid communication with the mold, wherein movement of a piston within the cylinder injects a selected quantity of resin into the mold. A plasticizing unit includes a flighted screw rotating in a heated containment barrel for plasticizing resin the plasticizing unit in selective fluid communication with the injection cylinder for supplying the injection cylinder with plasticized resin. A conduit connects the plasticizing unit to the injection cylinder to communicate resin from the plasticizing unit to the injection cylinder.

A control device of an injection apparatus outputs a control command to a hydraulic pressure device to perform injection by supplying hydraulic fluid to the back of an injection piston 15 from an accumulator 25 and, at this time, to execute speed control for controlling the speed of the plunger by an opening degree of an injection control valve. Further, the control device outputs a control command to the hydraulic pressure device to perform boosting by opening a booster valve to supply hydraulic fluid to the back of the booster piston and pressurizing the hydraulic fluid behind the injection piston by the booster piston and, at this time, to execute pressure control for controlling the pressure of the molding material by an opening degree of the injection control valve. Further, the control device can start outputting a control command for pressure control after start of outputting a control command for opening the booster valve in transition from injection to boosting.