Fiber choppers for molding processes

Details Fiber choppers for molding processes Fiber choppers for molding processes

1999-09-17

2001-04-17

Theisen, Mary Lynn (Department: 1732)

Plastic and nonmetallic article shaping or treating: processes

Forming articles by uniting randomly associated particles

With liberating or forming of particles

C264S517000, C425S080100, C425S082100

Reexamination Certificate

active

06217805

ABSTRACT:

TECHNICAL FIELD
This invention relates to a process and apparatus for producing fiber-reinforced molded composites. More specifically, this invention relates to the use of fiber choppers therein.
BACKGROUND ART
Fiber choppers are employed in conjunction with liquid resin spray dispensers to form a stream of resin-impregnated chopped fibers that are laid down on a substrate to form a glass fiber reinforced structure. As an elongated glass fiber strand passes between rollers, it is chopped into relatively short fiber segments and propelled by the action of the rollers out through a nozzle opening in the body of the chopper. The body and thus the nozzle are oriented so as to direct the stream of fibers into intersecting relationship with a stream of catalyzed resin, thus forming a stream of resin-impregnated chopped fibers. The stream of resin impregnated fibers is directed toward a substrate, and is allowed to impinge the substrate and form a layer of resin-impregnated fibers on the substrate. Typical products include auto body parts, underground storage tanks and boats.
One industrial application for a chopper is compression molding of interior trim panels for automobile doors. Vinyl panels first are vacuumed formed and transferred to the open mold of a compression mold. A chopper than sprays chopped glass fiber strands onto the vinyl preform. The glass is shaped onto the vinyl preform and followed with a polyol, isocyanate (—NCO) urethane resin mixture. The glass loading and glass spray pattern often cause problems. For example, ribs molded into the panel require high glass loadings of short fibers in the rib area. Edges of the panel require additional glass for added strength. Frequently, a single chopper cannot provide the proper glass loading, glass pattern, glass distribution and the like.
DISCLOSURE OF INVENTION
The process and apparatus of this invention is used with at least one chopper unit. The fiber chopper may be a laser beam chopper or an existing standard chopper unit. In one preferred embodiment, the process for producing a fiber-reinforced molded composite comprises the steps of providing a mold, sequentially spraying a moldable composition into the mold and subsequently providing chopped fibers to the moldable composition from a single fiber chopper. The process first deposits moldable composition into the mold and then deposits the moldable composition and chopped fibers in mold. Finally, the process molds the moldable composition and fibers in the mold under heat and compression to form the molded composite.
The apparatus for producing this fiber-reinforced molded composite comprises a mold including a means for heating and compressing the mold, a means for providing a moldable composition to the mold including a nozzle for spraying the moldable composition into the mold, a single fiber chopper for providing chopped fibers to the mold and a programmable multi-axis robot including a cantilevered overhead arm with a mounting plate attached to a distal end of the arm.
The nozzle and fiber chopper are attached to the mounting plate and aligned sequentially so that the nozzle first sprays moldable composition into the mold and the chopper subsequently sprays chopped fibers to the moldable composition so that a blend of fibers and moldable composition follow the first spray of composition into the mold.
In another preferred embodiment, our process and apparatus for producing a fiber-reinforced molded composite comprises providing a moldable composition to a molding apparatus, a first fiber chopper providing chopped fibers to the apparatus from a first direction, a second fiber chopper providing chopped fibers to the apparatus from a second direction, wherein the first direction is different from the second direction and molding the moldable composition and fibers in the apparatus under heat and pressure to form the molded composite.
Preferably, the first fiber chopper is on one side of the nozzle spraying resin mixture and the second chopper is on the opposite side of the nozzle, i.e. 180° apart. In another embodiment, a circular chopper surrounding the resin nozzle provides a veil of chopped fibers to the mold.


REFERENCES:
patent: 3871556 (1975-03-01), Breer et al.
patent: 4405681 (1983-09-01), McEvoy
patent: 4568003 (1986-02-01), Sperry et al.
patent: 5164197 (1992-11-01), Thary
patent: 5192387 (1993-03-01), Buckley
patent: 5208269 (1993-05-01), Brown
patent: 5240969 (1993-08-01), Brown
patent: 5295583 (1994-03-01), Bischofberger et al.
patent: 5336455 (1994-08-01), Kelman
patent: 5484653 (1996-01-01), Kennedy et al.
patent: 5496509 (1996-03-01), Yamamoto et al.
patent: 5503782 (1996-04-01), Dyrud et al.
patent: 5512715 (1996-04-01), Takewa et al.
patent: 5538786 (1996-07-01), Hurley et al.
patent: 5643507 (1997-07-01), Berrigan et al.
patent: 5681867 (1997-10-01), Brown
patent: 5716092 (1998-02-01), Dellinger et al.
patent: 5727357 (1998-03-01), Arumugasaamy et al.
patent: 5767177 (1998-06-01), Omente et al.
patent: 5772941 (1998-06-01), Nakano
patent: 5843365 (1998-12-01), Pinson et al.
patent: 6087624 (2000-07-01), Brown
patent: 6983676 (1999-11-01), Brown

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