Lear Corporation

International Automotive Components Group North America, Inc.

Gregory A Homann

James Hendry

David Turczynski

Michael W Gaudiello

A method and system for forming an injection molded plastic part. After the injection of plastic material has started, a volume of gas from a fixed volume reservoir is introduced into the plastic material at a low pressure forming a hollow cavity. The gas is introduced into the mold by a gas pin having a temperature sensing device, such as a thermocouple, positioned on it. The introduction of this volume of gas is initiated when the temperature of the plastic material in the mold has reached a predetermined value. After the mold is filled and packed with plastic, pressurized gas is introduced into the hollow cavity forming the completed plastic part.

Gas pin for thermocouple for gas assisted injection molding

A method and system for controlling a fluid-assisted injection molding process for producing a molded plastic article. The fluid can be gas, water or another fluid. One or more pressure transducers are positioned in the mold cavity and generate signals to control the initiation of the pressurized fluid, the packing of the material in the mold and/or the switchover from the packing phase to the holding phase. The transducers can be positioned at or near the gate or pre-gate, at or near the fluid channel area, and/or at or near the end of the fill area.

Process control for gas-assisted injection molding applications

A mechanical shut-off valve member for use with gas-assisted injection molding systems. A piston member is slidingly positioned in a body member or housing and spring-biased to a closed position. The valve member is opened by the injection of plastic material through the valve member and into a mold cavity. The spring biasing force closes the valve member and shuts off the flow of plastic once the mold cavity is filled with the requisite amount of plastic material. The shut-off valve member prevents any backflow of plastic material into the nozzle or injection molding machine during further steps in the injection molding process, including injection of gas or fluid into the plastic in the mold cavity.

Mechanical shut-off valve for gas-assist injection molding

A method and system for producing hollow rib structures for trim components and panels using gas assisted injection molding. Movable insert members are provided in the mold cavity, particularly at the ends of the structural rib members. After the plastic material is injected into the mold cavity, the plastic is packed in the mold, and the insert members are locked in position. Selectively activatable locking mechanisms are used to lock up the insert members. Thereafter, gas or another fluid is introduced into the rib members in order to provide hollow channels therein. Movement of the insert members provides a recess or groove for placement of the displaced resin from the rib members. The displaced resin material completes the formation of the molded plastic article.

Plastic injection molding with moveable insert members

A method and system for producing hollow rib structures for trim components and panels using gas-assisted plastic injection molding. Movable and floating core members are provided in the mold cavity, particularly adjacent structural rib members. After the plastic material is injected into the mold cavity, the plastic is packed in the mold. The moveable core members are then moved creating a void or opening in the mold cavity. Thereafter, gas or another fluid is introduced into the rib members to provide hollow channels in them. The fluent plastic material in the rib member is displaced into the voids forming integral portions of the completed plastic article.

Plastic injection molding with moveable mold members forming speaker grill

A method and system for producing thin walled plastic products with hollow rib members using gas-assisted plastic injection molding. The mold is allowed to open a predetermined distance as the gas is injected into the plastic material in the mold cavity. A plurality of post members, such as ejector pins, are located on a biased ejector frame and maintain their positions relative to the mold cavity in order to form solid portions or areas in the molded part.

Open mold molding

A method and system for producing hollow rib structures for trim components and panels using gas assisted injection molding. Spring biased movable insert members are provided in the mold cavity, particularly at the ends of the structural rib members. After the plastic material is injected into the mold cavity, gas is introduced into the rib members in order to provide hollow channels therein. The displaced resin material forces the insert members to the full cavity positions and completes the formation of the molded plastic article.

Plastic injection molded articles with hollow rib members

A method and system for multiple-cavity gas-assisted plastic injection molding. Each of the mold cavities are oriented in the vertical direction with the valve gates for the plastic material being positioned at the lower vertical ends of the mold cavities. With four mold cavities, an &ldquo;X&rdquo;-shaped runner pattern is utilized, although an &ldquo;H&rdquo;-shaped pattern could also be utilized. The centerline of the manifold is offset from the centerline of the mold. Gas is injected through in-article gas pins positioned in the mold cavities. The direction of the melt front advance is vertical from the bottom of the mold cavities to the top of the cavities. The gas pin location is also at the gate end of the part, either at or forward of the gate or resin entry point.

Multiple cavity gas assisted plastic injection molding

A method and system for producing hollow rib structures for trim components and panels using gas assisted injection molding. Rotatable insert members with recesses therein are provided in the mold cavity, particularly at the ends of the structural rib members. Once the plastic material has been injected into the mold cavity, the insert members are rotated, exposing said recesses to the mold cavity. Then, gas is introduced into the rib members displacing a portion of the molten plastic material into the recesses forming hollow channels or openings in the plastic material. The displaced resin material completes the formation of the molded plastic article.

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Canton, MI, United States of America

Gregory A Homann