Abstract: The invention relates to a method and an apparatus for injection molding parts, which comprises a mixture of at least one plastic material and at least one additive in the form of fibrous or powdered fillers or reinforcement materials.

Abstract: A method for injection molding plastic molded parts from thermoplastic, comprises the following steps: the production of a thermoplastic melt (1) through the rotation of a plasticizing and injection screw (2) in a preplasticizing cylinder (3); the addition to the thermoplastic melt (1) of a fluid (4) by introducing the fluid (4) into the preplasticizing cylinder (3); the mixing up the thermoplastic melt (1) to which the fluid (4) has been added, through the rotational motion of the plasticizing and injection screw (2); the injection of the mixture of thermoplastic melt (1) and fluid (4) into the cavity (8) of an injection molding tool (5).

Abstract: The invention relates to a method for injection molding a plastic molded part in an injection mold, comprising a) injecting a specified amount of plastic melt into the injection mold; b) introducing a compressed fluid between a part of the wall of the injection mold and the injected plastic melt; c) allowing the plastic melt to cool until the plastic molded part is self-supporting; and d) removing the plastic molded part from the mold. The invention specifies that, during or after step a) and during or before step b), the cavity of the injection mold is sealed against the environment, preferably by activating at least one seal.

Abstract: A method and an apparatus are disclosed for producing plastic objects with solid regions and hollow regions. The method has the following steps: a) blocking off a part of the cavity (2) of a molding tool (1), so that little or no plastic melt can reach the blocked-off region (8); b) injecting plastic melt into the unblocked region (9) of the cavity (2) of the molding tool (1); c) releasing the blockage, so that plastic melt can reach the previously blocked-off region (8) of the cavity (2); d) injecting a pressurized gas into the melt by means of at least one fluid injection nozzle (7), so that the melt injected into the molding tool is distributed into the desired regions of the cavity (2) while forming a hollow space and is pressed against the cavity walls of the molding tool (1); e) allowing the molded part (6) to cool; f) relieving the cavity (2) of the pressure of the pressurized fluid; and g) demolding the molded part.

Abstract: An apparatus and method provides that before, during, and/or after the plastic objects have been injection molded, a portion of the first plastic component, the second material, and/or a mixture of the two components is conveyed to at least one storage element with a variable volume. This element adjoins the flow path of the material melt. After completion of the injection molding process of the plastic objects and/or before the material is injected for the next plastic object to be produced, the plastic or the material stored in a storage element with a variable volume is conveyed to the flow path of the melt of the plastic or material. This frees the melt flow path of a mixture of the two plastic components and/or obtains a desired material mixture for producing the next plastic object.

Abstract: A method and an apparatus are disclosed for producing plastic objects with solid regions and hollow regions. The method has the following steps: a) blocking off a part of the cavity (2) of a molding tool (1), so that little or no plastic melt can reach the blocked-off region (8); b) injecting plastic melt into the unblocked region (9) of the cavity (2) of the molding tool (1); c) releasing the blockage, so that plastic melt can reach the previously blocked-off region (8) of the cavity (2); d) injecting a pressurized gas into the melt by means of at least one fluid injection nozzle (7), so that the melt injected into the molding tool is distributed into the desired regions of the cavity (2) while forming a hollow space and is pressed against the cavity walls of the molding tool (1); e) allowing the molded part (6) to cool; f) relieving the cavity (2) of the pressure of the pressurized fluid; and g) demolding the molded part.

Abstract: Proposed is a process for injection molding of products (1) made of thermoplastic material, whose walls (2) enclose a hollow space (3), wherein the molten plastic is injected in a predetermined amount into the cavity or molding nest (6) of a mold (5), during and/or upon which a fluid pressure medium (gas) is applied so that with the formation of the hollow space the molten plastic is distributed along and set against the walls of the cavity or molding nest. The pressure medium (gas) is fed into the cavity or molding nest (6) and into the molten plastic at first essentially only in the direction of flow of the molten plastic and in a quantity and/or at a pressure that causes a void (8) to form within the molten plastic, terminating at a distance from the end of the flow path.

Abstract: A device for injection molding articles of plastics material having hollow spaces. The device includes a molding tool with a mold cavity. Plastics material melt is fed to the mold cavity through a nozzle. Another pressurized medium is supplied to the mold cavity through a hollow needle at a location different from the location of the nozzle. A needle core is mounted in the hollow needle. The needle core is axially displaceable within certain limits. The opening of the hollow needle to the mold cavity can be opened and closed or its cross-sectional area can be varied by moving the needle core.

Abstract: A method and an apparatus are disclosed for producing plastic objects with solid regions and hollow regions. The method has the following steps: a) blocking off a part of the cavity (2) of a molding tool (1), so that little or no plastic melt can reach the blocked-off region (8); b) injecting plastic melt into the unblocked region (9) of the cavity (2) of the molding tool (1); c) releasing the blockage, so that plastic melt can reach the previously blocked-off region (8) of the cavity (2); d) injecting a pressurized gas into the melt by means of at least one fluid injection nozzle (7), so that the melt injected into the molding tool is distributed into the desired regions of the cavity (2) while forming a hollow space and is pressed against the cavity walls of the molding tool (1); e) allowing the molded part (6) to cool; f) relieving the cavity (2) of the pressure of the pressurized fluid; and g) demolding the molded part.

Abstract: A method and an apparatus for producing plastic objects with hollow spaces is disclosed. The method comprises the following steps: injecting a sufficient amount of plastic melt into the cavity (2) of the molding tool (1); simultaneously and/or subsequently injecting a pressurized fluid into the melt by means of a fluid injection nozzle (7); allowing the molded part (6) to cool; relieving the cavity (2) of the pressure of the compressed fluid, and demolding the molded part, while plastic melt is driven out into at least one overflow cavity (8), which is connected to the cavity (2). According to the invention, the volume of the overflow cavity (8) is changed, and in particular enlarged. This volume increase advantageously is controlled or regulated. The advantage achieved thereby is that the injection molding cycle, especially the overflow of melt into the overflow cavity (8), remains controllable by simple means.

Abstract: The proposal is for a device for injection molding plastic items enclosing hollow spaces with which a further pressurised medium like air, gas or a fluid can be introduced through a hollow needle (5) at a point differing from the nozzle into a mould (1), the mould hollow or cavity (4) of which can be filled with molten pastic through a nozzle. There is a needle core (9) which can be moved axially to a limited extent in the hollow needle (5) and it is possible via this needle core (9) to vary the cross-section of or open and close the aperture (16) of the hollow needle (6) opening into the mould hollow or cavity (4). The needle core (9) bears a thickened head or plate (10) in front of the end of the aperture in the hollow needle, the outside diameter of which corresponds at least approximately to the outside diameter of the hollow needle, so that it forms, with the aperture end (6) of the hollow needle (5), a radially directed splitting valve.

Abstract: It is proposed that a pressure control device and/or pressure regulating device (8) be used for a fluid medium, in particular air or gas, preferably nitrogen, which is to be supplied to an injection mold in addition to the molten plastic, this pressure control device and/or pressure regulating device (8) being provided as a stationary, but preferably as a mobile unit between a pressure generator/pressure accumulator (7) and an injection system associated with the injection mold (3), e.g., in a nozzle head or add-on building block.

Abstract: A device for injection molding articles of plastics material having hollow spaces. The device includes a molding tool with a mold cavity. Plastics material melt is fed to the mold cavity through a nozzle. Another pressurized medium is supplied to the mold cavity through a hollow needle at a location different from the location of the nozzle. A needle core is mounted in the hollow needle. The needle core is axially displaceable within certain limits. The opening of the hollow needle to the mold cavity can be opened and closed or its cross-sectional area can be varied by moving the needle core.

Abstract: A method and an apparatus of injection molding articles of thermoplastic material. The method includes initially forcing molten plastics material into an injection mold in an amount sufficient for forming the article. Subsequently, a flowable medium is forced into the injection mold with a pressure which distributes the plastics material uniformly over the surface of the mold cavity of the injection mold so as to form a hollow body. The hollow body is then cooled while the pressure of the medium is maintained. Finally, the pressure of the medium is released and the molded article is removed from the injection mold. The pressure of the medium in the mold cavity is controlled and/or varied at least temporarily until the plastics material has cooled. The apparatus for carrying out the method includes a pressure reservoir for the medium which is connectible to the injection mold through lines. The lines include control and/or regulating elements.

Abstract: A method of manufacturing multiple-layer molded articles with an outer skin of compact thermoplastic material and a core of foamed thermoplastic material includes initially introducing the material for the skin into a mold cavity in a quantity sufficient for the desired thickness of the skin and subsequently feeding into the mold cavity the material for the core to which the expanding agent has been added. During and/or after being introduced into the mold cavity, the core material containing expanding agent is temporarily subjected by means of an additional gas and/or a pressurized, low-boiling liquid to an active pressure which exceeds the gas pressure of the expanding agent. Subsequently, the additional gas or the low-boiling liquid is removed from the hollow space which is still free of skin material and core material.

Abstract: A method and an apparatus of injection molding articles of thermoplastic material. The method includes initially forcing molten plastics material into an injection mold in an amount sufficient for forming the article. Subsequently, a flowable medium is forced into the injection mold with a pressure which distributes the plastics material uniformly over the surface of the mold cavity of the injection mold so as to form a hollow body. The hollow body is then cooled while the pressure of the medium is maintained. Finaly, the pressure of the medium is released and the molded article is removed from the injection mold. The pressure of the medium in the mold cavity is controlled and/or varied at least temporarily until the plastics material has cooled. The apparatus for carrying out the method includes a pressure reservoir for the medium which is connectible to the injection mold through lines. The lines include control and/or regulating elements.

Abstract: A method for manufacturing multilayer molded articles of at least two plastics material components having substantially different properties with respect to behavior, processing and/or temperature changes. The plastics material components are injected from different extruder unit through a common sprue brushing into a mold cavity of a molding tool. The plastics material components are introduced in a predetermined time sequence initially into different cross-sectional areas of a common sprue cone and are subsequently forced into the sprue cone in a converging manner toward a sprue duct of the sprue bushing.

Abstract: A device for manufacturing molded articles of plastics material which have an outer skin of a plastics material free of expanding agents and a porous core of a plastics material containing an expanding agent includes an extruder head with a main duct in communication with a discharge opening. Two feed ducts for the two plastics materials lead angularly offset into the main duct at locations axially spaced from the discharge opening and from each other. A closing needle is axially movably placed in the main duct. The two feed ducts can be separated from the main duct by means of the closing needle. The closing needle defines a connecting duct extending essentially in axial direction. The connecting duct ends at the end face of the closing needle and at the circumference of the closing needle radially toward the more remote feed duct.

Abstract: An extruder system has an extruder provided internally with a worm. A source of an additive fluid under pressure is connected to a conduit opening into the barrel. An upstream valve and a downstream valve are provided in this conduit and a pressurizable fluid reservoir is provided in the conduit between the valves. The extruder is continuously rotated in the barrel to plastify a resin therein. The valves are alternatively opened and closed, that is one is open when the other is closed and vice versa, so that a fluid first flows from the source through the upstream valve into the reservoir and then from the reservoir through the downstream valve into the barrel to be mixed by the worm with the plastic resin therein. The reservoir can be a cylinder having a piston advanced when the downstream valve is opened to force the charge of additive fluid in the reservoir into the barrel.

Abstract: A method for injection molding a product having a non-cellular skin layer and a cellular core portion. The method involves successive or simultaneous injection of a non-foamable resin material and a foamable resin material through a sprue bushing having an injection channel connected to the mold cavity and a pair of fixed feed channels intersecting with the injection channel. The injection mold has a bore with a sprue bushing therein. The sprue bushing having an injection channel therein and intersecting with a pair of fixed feed channels. Injection units deliver the materials to the pair of fixed feed channels.