A production method and device for a curved resin pipe via resin injection molding that uses an assist material. An inner curve part and/or an outer curve part of a pre-selected curved section of a cavity which is formed in a mold is configured from a temperature-adjustable piece section. After molten resin is injected into the cavity from an injection molding device, the temperature of the piece section is controlled by a control unit such that the inner curve part has a lower temperature than the outer curve part, and an assist material is injected into the cavity from an assist material injection unit and is passed through the cavity so as to form a pipe path. The resin remaining in the cavity is cured to produce a curved resin pipe.

The invention relates to a system for manufacturing polymer parts, comprising: a material-injection portion, a mould movable between at least one open position and a closed position, the mould comprising an outer mould portion, wherein the injection portion is suitable for injecting material into the closed mould so as to form at least one part when the injection portion is connected to the closed mould, and wherein the system is suitable for moving the injection portion relative to the mould after injection, the outer portion being kept in contact with the part formed by injection in order to cool the part during the movement of the injection portion.

The purpose of the present invention is to improve the mechanical strength of a boss in correspondence with the direction in which the principal stress is generated in an impeller formed of fiber-reinforced resin. A hub 11 is provided with a first region arranged on the back surface 11b side, and a second region arranged on the front surface 11a side. In the first region the frequency with which the reinforcement fibers F dispersed at the periphery of a boss hole 12 are oriented inclined with respect to the radial direction of the hub 11 is high, and in the second region the frequency with which the reinforcement fibers dispersed at the periphery of the boss hole are oriented along the rotational axis line is high.

A molded article 1 is made of a resin material 3 containing cellulose fibers 2. The molded article 1 has a surface portion 4 that is in a range satisfying T.sub.F0.1T where T is the thickness of the molded article 1 and T.sub.F is a distance from the surface of the molded article 1, and the molded article 1 satisfies D.sub.F1.1D where D is an average cellulose concentration of the overall molded article 1 and D.sub.F is an average cellulose concentration of the surface portion 4. Thus, the molded article suppresses an increase in bending modulus while considerably improving a tensile modulus.

Methods of molding a barrel, such as a syringe barrel having very low draft, are disclosed. Thermoplastic syringes having very low interior draft angels are also disclosed.

A mold for molding an object having a section of increased thickness includes a mold cavity comprising a first zone and a second zone and a means for providing a different thermal conductivity at the first and second zone of the mold cavity.

A molding structure comprising a first mold body, a second mold body suited for combining with the first mold body, a molding core, a first heating element, and a second heating element is provided. A mold cavity is formed between the first mold body and the second mold body when the first mold body and the second mold body are joined together. The molding core is disposed in the mold cavity, wherein the molding core comprises a body, an inner surface, and an outer surface. The first heating member is disposed through the body to heat the molding core. The second heating element is movably disposed on the outer surface of the molding core to preheat the molding core.

A core mold component defining a lower surface of the injection mold set corresponding to the lower surface of the annular component is heated to a base temperature. A cavity mold component defining the upper surface of the injection mold set corresponding to the Class A surface of the annular component is heated to a higher temperature than the base temperature. Faces of two streams of metallic resin, including the metallic resin flakes, injected into the mold set are caused to come together at the knit line. Metallic resin flakes are caused to flow into inboard and outboard overflow cavity through respective inboard and outboard gates positioned adjacent the knit line.

The present invention prevents internal cracks occurring when an impeller molded using a fiber reinforced resin is manufactured by injection molding. This method for manufacturing an impeller is provided with: an injection step of filling a cavity with a molten resin containing reinforced fibers, from a gate side into which the molten resin flows, toward an opposite-gate side opposite to the gate side; and a dwell step of applying required pressure to the filled molten resin. In the injection step and the dwell step, directional cooling is performed with a temperature gradient such that the temperature becomes lower from the gate side toward the opposite-gate side. According to this method for manufacturing the impeller, the opposite-gate side shrinks with a decrease in the temperature of the molten resin since the temperature of the opposite-gate side is lower. Meanwhile, because the temperature on the gate side is increased, the molten resin can be replenished from the gate side so as to correspond to the amount of shrinkage on the opposite-gate side, and therefore the occurrence of internal tensile residual stress and cracks due to the shrinkage can be prevented.

A machine including a mold which delimits an overmolding cavity, for receiving a hollow portion of a bi-material part, cooling means along the overmolding cavity, a core positionable inside the hollow portion and containing heating means for bringing the core to a heating temperature higher than 150 C., and an injector injecting an overmolding material, formed by the core and the hollow portion, for forming an inner portion of the bi-material part. In order to obtain the overmolded inner portion even if the hollow portion has poor heat resistance, the cooling means maintain the overmolding cavity at a cooling temperature lower than 110 C. while the core is brought to the heating temperature, while the overmolding material has been injected by the injector into the overmolding cavity.