An injection molding machine includes: a cylinder that holds a molding material to be injected into a mold; a plasticizing member provided in the cylinder so as to be movable and rotatable; a temperature measurer that measures a temperature of the cylinder or of the mold; and a period setting unit configured to set a cold start prevention period, which is a period for restricting the injection of the molding material into the mold, based on the temperature measured by the temperature measurer until a temperature of the molding material or the temperature of the mold rises. The period setting unit stores temperature-time data in which the temperature measured by the temperature measurer is associated with time, and adjusts the cold start prevention period based on an actual temperature of the stored temperature-time data.

A process for the preparation of an article by powder injection molding, the process including the steps of providing a feedstock containing a powder of a ceramic, a metal or a metal alloy dispersed in a binder, heating the feedstock, and injecting the heated feedstock into a mold cavity of a mold, where it cools and hardens to the configuration of the mold cavity. The process is characterized in that step c) is carried out under the application of vibrational energy onto the feedstock.

A shooting pot assembly for a two-stage injection unit includes: (a) a housing; (b) a plunger chamber in the housing; (c) an injection plunger in the plunger chamber; and (d) a conduit network including (i) a feed conduit, (ii) an outlet conduit, and (iii) a transfer conduit. The shooting pot assembly further includes (e) a purge valve assembly having a purge conduit open to the plunger chamber and in fluid communication with the transfer conduit via the plunger chamber when the plunger is in the advanced position. The purge valve assembly further includes a purge valve closure member movable between a closed position, in which the purge conduit is blocked, and an open position, in which the purge conduit is open for flushing stale melt from the transfer conduit through the purge conduit via supply of fresh melt into the transfer conduit from the feed conduit.

Provided is an injection device and an injection control method which are capable of preventing a drooping phenomenon from an injection nozzle even during high cycle molding, and capable of appropriately plasticizing and molding a resin having poor thermal stability. An injection device (10) of the disclosure includes: an injection cylinder (30) which accumulates a molding material and has an injection nozzle (33) at the front; an injection plunger (31) which is moved backward in the injection cylinder (30); an injection plunger driving device (50, 150) which moves the injection plunger (31) backward; and an injection controller (60, 160). The injection controller (60, 160) retreats the injection plunger (31) by the injection plunger driving device (50, 150) to perform metering in a plastication metering step of metering the molding material supplied into the injection cylinder (30).

A mixing extruder for an injection molding machine includes a barrel unit and an extruder screw. The barrel unit includes an extruder tube. The extruder screw includes a screw rod, a helical mixing channel, and a helical gas flow channel communicating with the helical mixing channel. The helical mixing channel and helical gas flow channel both extend around the screw rod. The helical mixing channel extrudes a paste outwardly from a material discharge opening formed at an end of the extruder tube, whereas the helical gas flow channel connects a suction pump through a gas discharge channel formed in the extruder tube oppositely of the material discharge opening.

An injection apparatus of the invention injects a molding material supplied from a material supply port, and includes a die, a material supply apparatus that extrudes the molding material that is thread-like or strip-like via the die, and a material guide apparatus that guides the molding material supplied via the die to the material supply port. The material discharge port of the material supply apparatus and the die protrude downward in the material supply apparatus, and a pressure inside the material guide apparatus is reduced by a pressure reducing apparatus from a pressure reducing port provided above the material discharge port of the material supply apparatus and the die.

After the injection shaft moves backward and the gas is supplied into the injection chamber, it is desired to accurately control the gas supply amount in the injection device in which the injection shaft is moved forward to compress and dissolve the gas in the molding material in the injection chamber. An injection device of the disclosure supplies a gas into an injection chamber via a gas supply hole which passes through an injection shaft and is opened at a tip surface of the injection shaft. The injection device and a gas dissolution method thereof according to the disclosure perform backward and forward movement of the injection shaft for a plurality of cycles. The injection device of the disclosure has at least one seal ring and at least one piston ring aligned in an axial direction on an outer circumferential surface of the injection shaft.

A molding apparatus includes a machine base, a feeding unit, a material reflow preventing device and a pair of molds. The material reflow preventing device includes a material conduit and a heating unit. The material conduit includes inlet and outlet ports at two opposite ends, inner and outer peripheral surfaces radially opposite to each other, and a low-temperature conduit section, first, second and third heating conduit sections interposed between the inlet and outlet ports. The inner peripheral surface has a spiral groove which extends from inlet port to the outlet port. The heating unit is disposed to heat the material conduit and control the different temperatures in the sections. The reflow of a fluid-state material along the spiral groove is gradually reduced and suspended and is solidified in the low-temperature conduit section.

An optical precision mold machining device is mountable on a chuck of an ultraprecision machining apparatus to perform an aspherical molding process by a cutting tool, and includes a fixture gripped by jaws of the chuck and having positioning holes in a matrix arrangement, a plurality of fasteners extending through the corresponding positioning holes, and a mold including a retained surface with locking holes for insertion of the fasteners, and a mold surface portion having a sprue, a runner and multiple mold bases. Each mold base has sub-runners in communication with the runner. An injection direction of the sprue is parallel to an initial running direction of the runner. The mold is moved with the fixture relative to the cutting tool to a predetermined machining position where each mold base is machined to form therein a cavity with an aspherical cross-section.

The device for feeding molten plastic material into a molding cavity (30) includes a melting chamber (20) in which metered solid plastic material is introduced, a sonotrode (10) provided for tightly inserting a portion thereof into said melting chamber (20), causing the plastic material to melt by means of vibration, and relative movement of the sonotrode (10) and melting chamber (20) allows driving the molten plastic material inside a molding cavity (30) communicated with said melting chamber (20), the device including resistance sensors (40) allowing an electronic control device (50) to know the resistance that the plastic material has against the movement of the sonotrode (10).