Ex-cell-o Gmbh

Kmmco Structural Foam, Inc.

Lang Fastener Corporation

James W Hendry

Je-Chin Han

Donald L Reuschel

A method and apparatus for making a twin-wall internally corrugated plastic structural part provided with a smooth, dense, solid, thin walled, non-cellular skin comprising injecting a thermoplastic or resin material into a pair of closed mold members which define a sealed cavity. A small amount of plastic material is initially injected into the cavity with the material impinging upon and being dispersed over the mold members thereby forming a generally continuous thin skin substantially the mold surfaces. Thereafter, successively and intermittently injecting an inert gas under pressure through one mold member during continued injection of the plastic material into the cavity thereby pressurizing the skin against the walls of the mold cavity and progressively commingling the inert gas under pressure and the inwardly flowing plastic material as both enter the cavity until the cavity is filled with an internal corrugated body integral with and bonded to the skin. Further steps include cooling the twin-wall internally corrugated structural part to permit the same to solidify as an integral unit and venting the mold cavity to atmosphere to relieve pressure from the corrugated plastic structural part. The intermittent injection of the inert gas introduces minute amounts of pressurized gas into the continuously injected plastic material.

Apparatus for making a twin-wall, internally corrugated plastic

Method of making a twin-wall internally corrugated plastic structural

The apparatus molds during each cycle homogeneous plastic material and foam plastic material. It includes a barrel member, a main passageway therein in which is located the screw member. A pair of injecting means for filling molds are provided, one having a homogeneous plastic injection chamber and the other having a foam plastic injection chamber. The first injection means is connected to the screw and barrel member upstream of the place where the inert fluid is introduced into the main passageway whereby homogeneous plastic material is discharged from the main passageway into the first injection means. The apparatus includes means for introducing an inert fluid into the main passageway whereby the rotating screw member mixes the gas with the molten plastic as it moves towards the discharge port which is connected to the second injection means whereby foam plastic material is injected into the foam plastic injection chamber. Each injection means has one or more nozzles connected to a mold located in a press. The molds for both the homogeneous and foam plastics material may be located in different presses or in the same press so that upon each cycle of the screw and barrel assembly and after both injection means have injected the plastic materials into the respective molds, the press or presses close and form the homogeneous plastic parts and the foam plastic parts. The several injection means or devices may be operated simultaneously or sequentially. Thus, it is possible to mold and form homogeneous and foam plastic parts during the same cycle using only one screw member.

Apparatus for injection molding of parts from foam plastics material

This apparatus is used to improve the heat distribution on the cavity surface in foam molding dies where a smooth finish on the resin filled foam molded plastic product manufactured by an injection molding process is desired. This invention improves the method for heating the mold cavity using a condensing vapor in a molding die by a channel and slit type orifice means in the mold around a portion of the periphery of the part to be molded. Another channel and slit type orifice means around the remaining periphery is included in the die for removing the condensing vapor or condensate from the mold cavity. During the heating process when condensing vapor is introduced into the mold the sprue opening to the extruder is sealed by a valve means to prevent condensate from collecting therein.

Method and apparatus for heating a mold cavity uniformly

A method and apparatus is provided for making a composite structural homogeneous resinous article having (a) a smooth, shiny non-cellular or homogeneous relatively thin injection compression molded liner on the outer surface and (b) a cellular relatively thicker injection molded core integral with the molded liner. One extruder is connected by valve controlled passages to a pair of injection devices, each device having an injection chamber. One chamber stores the homogeneous plastic resin and the other chamber stores the foam plastic resin. A first mold assembly having a movable upper mold part and a stationary lower mold part form a cavity, with a gap opening, at a first molding station. The cavity is in communication with the first injection chamber. A second mold assembly having a second cavity, which is closed, is provided at the second molding station and is formed by the aforementioned movable upper mold part of the first mold assembly, which is transferred thereto, and with another stationary lower mold part. The second cavity is in communication with the second injection chamber. Controls are provided for insuring the correct amount of each resin to be extruded and stored in the injection chambers. Fluid operated means are provided for energizing the first injection device to inject the homogeneous plastics material therein into the first mold cavity. This is followed automatically by rapidly applying a compressive force to the first mold assembly to compression mold the relatively thin injection compression molded liner. Thereafter the upper mold part of the first mold assembly, with the molded liner retained therein, is transferred to the second molding station and immediately the stored foam resinous material is injected into the second mold cavity to form with the solid liner the composite homogeneous-foam plastic article having an integral relatively thin, smooth, shiny and homogeneous molded outer surface.

Method and apparatus for making an integral structural cellular and

This invention is an improved injection molding nozzle whereby the shut-off plunger is operated by a fluid and the opening of the nozzle is accomplished by the flow of plasticized material through the nozzle. A control rod internal to the nozzle controls the movement of the plunger shut-off member and is adjustable so that the amount of plasticized resin flowing through the nozzle can be accurately controlled.

Injection molding nozzle

This invention substantially improves the surface finish on resin filled foamed molded plastic products manufactured by injection molding by pre-heating the skin surface of that part of the mold in contact with the part prior to the injection cycle of the machine and then subsequently chilling the mold via internal tube connections to shorten the time needed in the manufacturing cycle for solidifying the part sufficiently for release from the mold.

Method and apparatus for injection molding foamed resin products having

A method for the manufacture by foam molding of plastic products by first injecting into a mold non-cellular plastic resin and then injecting a foamed plastic resin of the same basic composition as the non-cellular plastic resin. The process and apparatus consisting of a single extruder and single injection chamber wherein the non-cellular and foamed plastic resin are extruded from the same extruder and stored in an accumulator until shot into the mold by a hydraulic cylinder. Controls are provided for the correct amount of each type of resin to be extruded and stored and the process can be adapted so that the sprue portion of the final product will be solid resin. By a simple addition, coloring of the resin may be accomplished so that the basic resin, method or apparatus will not require changes.

Method for injection foam molding

An apparatus for the manufacture by foam molding of plastic products by first injecting into a mold solid plastic resin and then injecting a foamed plastic resin of the same basic composition as the solid plastic resin. The process and apparatus consisting of a single extruder and single injection chamber wherein the solid and foamed plastic resin are extruded and stored until shot into the mold by hydraulic pressure. Controls are provided for the correct amount of each type of resin to be extruded and stored and the process can be adapted so that the sprue portion of the product will be solid resin and by a simple addition, coloring may be added so that the basic resin, method or apparatus will not require changes.

Apparatus for injection foam molding

Apparatus for making a foamed plastics product. A foamed plastics product is formed by introducing into an at least substantially fully plasticated material a series of discontinuous gaseous bubbles while said plasticating material is under a substantial and often variable pressure, accumulating said material and intermixed bubbles in an injection zone while maintaining said pressure thereon and thereafter injecting said material into a mold whereupon said pressure is sufficiently released to permit expansion of said gas bubbles and the formation of a foam thereby. Said gas is introduced, as aforesaid, by a series of separate injections wherein the pressure on the gas being injected rises from substantially zero to a level potentially in excess of the highest pressure expected to be developed within the plasticating means. Thus, regardless of the pressure existing in the plasticated material at any given moment, gas will be injected into said plastic material when the pressure on the gas attains a suitable differential over the pressure in the plasticated material at any given moment and such injecting will be in substantially uniform quantities regardless of the pressure existing within said plastics material at the time of any given injection thereinto. The apparatus aspects of the invention contemplate injecting the gaseous material into the plasticated plastics material by a high-speed positive displacement pump, as a piston pump or a diaphragm pump, wherein each stroke of the pump injects one bubble of gas into the plastics material.

Pumped injection of gas for making foamed plastic

This invention embodies an intensifier cylinder assembly within the main hydraulic ram of a plastic molding machine whereby the clamping force holding the mold halves together can be increased during the shot cycle of the machine by at least three times the normal clamp force of the machine. Additionally, the location of the intensifier reduces the number of high pressure hydraulic fittings in the machine improving the safety factor while reducing the overall cost of the intensifier itself since the ram piston now becomes the housing for the intensifier piston.

Intensified cylinder assembly

The nozzle manifold assembly of an injection molding machine is infinitely adjustable horizontally perpendicular to the nozzle axis. The nozzles themselves project through slots in the front clamp plate of the machine which give flexibility to the mold designer in his placement of sprues and runners for filling the mold. Additionally this manifold assembly and its associated injection hardware, such as the shot accumulator, hydraulic pressure accumulator and valving, are mounted on a carriage assembly which is capable of moving horizontally in a direction parallel to the axis of the nozzles thereby allowing the nozzles and associated heater bands to be accessed and maintained without the need for removing the mold from the machine.

Adjustable manifold and nozzle assembly for foam molding machines

Plastic molding machine, primarily adapted for generating and molding a closed-cell foam thermoplastic material. The foam is generated by introducing a gas inert to the thermoplastic material into a granular mixture of same so that the gas is thoroughly intermixed among the granular particles. The gas is then held under pressure while the granular particles are reduced to a flowable material, said pressure being sufficient to assure that the gas will not be expelled therefrom during such process. In one preferred embodiment, gas is mixed into the granular thermoplastic in a hopper and held therein under pressure as said granular material is fed into a screw and plasticated thereby. The plastic material is then conducted at a relatively low pressure, such as that generated by the extrusion machine used for plasticating the material, through a branched system past a check valve in each branch of said system, to an injection assembly. As each injection assembly receives a predetermined amount of plastic material, means are energized preventing more plastic material from entering thereinto but continued operation of the pressure generating device will continue filling other injection assemblies for as long as any thereof are capable of receiving such material. When all injection assemblies are filled, same are actuated simultaneously to drive the plastic material therefrom into the mold cavity. Injection assemblies may supply mold cavities in any pattern, and a single mold cavity may be associated with a given injection assembly or two or more injection assemblies may supply any one given mold cavity. Local zones, preferably subjected to rapid cooling, are provided with undercut notches connected to the sprue, runners or cavity and filled thereby with plastic. Same is cooled ahead of the cooling of the molded part and provides means for holding the mold closed. This permits removal of the mold from the machine prior to cooling of the molded part and opening of the mold which in turn permits more effective use of multiple molds with a given machine.

Growing community of inventors

Englewood, TN, United States of America

James W Hendry