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US 9,283,706 B2Granted
Method and apparatus for compression molding fiber reinforced thermoplastic parts
AssigneeThe Boeing Company
InventorEdward M. Fisher, Jr.
Life of this patent
Estimating the term…
Abstract
A fiber reinforced thermoplastic part with integral fittings is compression molded. A slug of pre-consolidated, fiber reinforced thermoplastic is heated until flowable and then injected into a mold tool to form both the part and the fitting.
Claims25
A method of compression molding an elongated fiber reinforced thermoplastic part, comprising:
- pre-consolidating a quantity of fiber reinforced thermoplastic resin flakes into a mold charge, wherein the step of pre-consolidating the quantity of fiber reinforced thermoplastic resin flakes further comprises:
- placing the quantity of fiber reinforced thermoplastic resin flakes into a chamber, wherein the fiber reinforced thermoplastic resin flakes have a generally oval shape such that fibers of the fiber reinforced thermoplastic resin flakes have varying lengths of between approximately 0.5 inches and approximately 1.0 inches;
- heating a number of electrical resistance coils integrated into ceramic band heaters sleeved over the chamber to a melting temperature of a resin in the fiber reinforced thermoplastic resin flakes, and compacting the fiber reinforced thermoplastic resin flakes in the chamber into the mold charge;
- loading the mold charge into a charge cylinder;
- heating the charge cylinder until the mold charge is flowable;
- heating a mold, wherein the mold comprises a part cavity and at least one fitting cavity;
- injecting the flowable mold charge into the heated mold to mold the mold charge into the part, wherein the step of injecting the flowable mold charge into the heated mold further comprises:
- injecting the flowable mold charge into the heated mold to mold the mold charge into the part to achieving a uniform distribution of the fibers of varying lengths in the part, wherein the uniform distribution promotes isotropic mechanical properties and strengthens the part;
- and
- cooling the mold until the part is capable of retaining its shape.
7 more elements
An apparatus for compression molding a fiber reinforced plastic resin part, the apparatus comprising:
- a tool for pre-consolidating a pre-consolidated charge from a quantity of fiber reinforced thermoplastic resin flakes, wherein the tool includes:
- a tube into which a quantity of fiber reinforced thermoplastic resin flakes can be introduced, and at least one band heater sleeved over the tube for heating the tube;
- the quantity of fiber reinforced thermoplastic resin flakes, wherein the fiber reinforced thermoplastic resin flakes have a generally oval shape such that fibers of the fiber reinforced thermoplastic resin flakes have varying lengths of between approximately 0.5 inches and approximately 1.0 inches, wherein the fiber reinforced thermoplastic resin flakes consist essentially of:
- a fiber content of about 30% to about 65%, by volume and a resin content of about 35% to about 70%, by volume;
- a mold having a longitudinal axis, a part cavity, and at least one detachable fitting cavity;
- a charge cylinder having a longitudinal axis generally axially aligned with the longitudinal axis of the mold to reduce a possibility of fiber degradation, wherein charge cylinder is coupled with the part cavity and adapted to contain the pre-consolidated charge of the fiber reinforced thermoplastic resin flakes;
- a heater for heating the charge cylinder to form a flowable mixture of resin and reinforcing fibers from the pre-consolidated charge;
- a piston in the charge cylinder;
- and
- an actuator coupled with the piston for forcing the piston through the charge cylinder along the longitudinal axis of the charge cylinder to compress the flowable mixture into the part cavity.
7 more elements
Dependencies are inferred from the claim text.