Abstract:
Process and apparatus for injection molding of molded parts made from plastic material having at least one cavity, which includes: a) injection of plastic melt from an injection unit along a melt flow path into the cavity of an injection-molding die; b) injection of a fluid into the still molten plastic material, so that the latter is pressed against the walls of the cavity; c) allowing the plastic material to solidify until the latter forms the molded part in self-supporting manner; and d) releasing the molded part from the cavity of the injection-molding die.
Abstract:
A liquid and gas assisted injection molding apparatus comprising a source of liquid coolant, a source of compressed gas, a source of heated viscous plastic, a mold cavity means for controllably injecting said plastic into said cavity, means for controllably injecting said compressed gas into said cavity, means for controllably injecting said liquid coolant into said cavity, and means for selectively controlling the injection of said plastic, gas and liquid coolant.
Abstract:
A process for injection molding of thermoplastic materials which includes a nozzle body having a bore to provide a flow path for molten thermoplastic. One end of the nozzle body is adapted for connection with a sprue of an associated mold body, and the other is adapted for connection with an end of an associated injection molding machine. The nozzle body has a shut-off valve fluid pin housing adapted for reciprocating movement in the nozzle bore to control the flow of plastic through the nozzle body. The shut-off valve fluid pin housing also includes a body having an adjustable fluid pin with a tip portion and a fluid passage formed in the body and open at the tip portion and the other end of the fluid passage communicating with a source of two pressurized fluids, one in vapor and liquid phase and another in gas. The shut-off valve is actuated to allow thermoplastic material to flow and subsequently a first pressurized fluid vapor is allowed to flow to form a hollow cavity in the thermoplastic material and then terminated and a second fluid which is a gas is allowed to flow into the cavity followed by the liquid of the first fluid. The fluid flow is controlled by the fluid pin shape and stroke adjustments. After the thermoplastic material has set, the pressurized fluid is vented through the fluid pin housing passage into a fluid condenser for recovery of the vapor and liquid and then into atmosphere.
Abstract:
A process for producing moldings comprises the steps of injecting a plastified synthetic resin into a mold cavity, thereafter or simultaneously injecting heated fluid having a viscosity of 0.01 - 100 poise into the same mold cavity to fill it with said fluid in such a manner that said heated fluid is surrounded by said synthetic resin within said mold cavity and releasing said fluid from said mold cavity after at least a portion of said synthetic resin has set. If the injected synthetic resin contains any foaming agent, a foamed article having its outer smooth skin can be obtained according to the present invention. If the injected synthetic resin contains no foaming agent, a hollow, smooth-surfaced article can be obtained.
Abstract:
A center-portion molding member having a center-portion transfer shape surface and a side wall surface is inserted and fitted in a frame-portion molding member having a frame-portion transfer shape surface to form a part of a cavity. The center-portion molding member has a groove portion in the side wall surface. The groove portion protrudes from the frame-portion transfer shape surface. Before injected resin transfers a shape of the center-portion transfer shape surface, the side wall surface of the center-portion molding member is sealed with the resin to form, between the center-portion transfer shape surface and the resin, a space in which gas is confined.
Abstract:
A method for controlling an injection process in an open-loop or closed-loop manner in the production of a molded part injects melt mass by at least one injection unit into at least one cavity enclosed by a tool by means of at least one nozzle. The at least one cavity has at least one measuring location, which is coupled to a binary detector, which can change from a first defined state to a second defined state. The binary detector changes the state thereof at the time at which the melt mass arrives at the measuring location. On the basis of the state change of the binary detector, an open-loop or closed-loop control unit controls the injection velocity V of the at least one injection unit in an open-loop or closed-loop manner, the temperature T of the melt mass before the injection, the termination of the injection at the at least one nozzle, and/or the starting of a subsequent process.
Abstract:
The present invention provides an injection molding method capable of impregnating a supercritical fluid stably and partially in molten resin in a plasticizing cylinder of an injection molding apparatus. The above object is achieved by providing the method of injection molding which includes measuring a filling amount of the molten resin in the plasticizing cylinder, introducing a supercritical fluid into the molten resin in the plasticizing cylinder while moving back the screw by a predetermined distance without rotating the screw from a position of the screw at the time of completing the measuring, detecting a pressure of the molten resin, and determining based on the pressure an injection start position for the screw.
Abstract:
The invention relates to a method, which includes molding a metal insert from a casting by injection assisted by a fluid under pressure in concave space, forming the insert. The method including the step of restricting the space if necessary, in order to obtain a transverse cavity reducing the mass of the unit.
Abstract:
There is disclosed a process for producing a resin molded article by using a resin into which fine metal particles are so introduced as to be hardly dissolved at the melting temperature of the resin and as to obtain high solubility in a high-pressure carbon dioxide. This process comprises the steps of forming a high-pressure fluid by dissolving, in a high-pressure carbon dioxide, a fluorine-containing metal complex and a fluorine-based solution capable of dissolving the same metal complex; introducing the high-pressure fluid into a heated and molten resin; and molding the resin having the high-pressure fluid introduced thereinto, to shape the molded article.
Abstract:
For producing a plastic component (2) with an internal hollow space (3), at first plastic is injection molded into an injection mold (4) and its cavity (6) and then for displacing the plastic melt from the internal hollow space (3) to be formed, gas under pressure is injected into the still liquid plastic melt, after which for cooling the plastic, a cooling liquid is also introduced into this internal hollow space (3). So that this cooling can be performed as quickly as possibly, the gas is compressed with the help of the cooling liquid and inserted or injected into the plastic melt, so that the cooling liquid directly follows the gas, wherein it can already extend into the internal hollow space (3) before this space is completely formed by the gas, i.e., gas and cooling liquid can be present simultaneously in the internal hollow space (3) to be formed.