US 4,946,526 AGranted

Method for compression molding of laminated panels

AssigneeLTV Aerospace and Defense Company

InventorsJamie L. Petty-Galis, James C. Foster

Life of this patent

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Abstract

A process for producing reinforced laminate plastic panel structures by thermoplastic compression employing internal mold mandrels which are significantly embrittled during or subsequent to the compression step. Hat stiffened panels formed from two thermoplastic resin sheets may be produced by using elongated mandrels formed of ceramic particulate material adhered together by a binder such as an alkali metal silicate. The mandrels are arranged between a skin sheet and hat stiffener sheets with the respective sheets disposed between the platens of a hydraulic press or other suitable compression molding mechanism. Sandwich laminate structures can be formed employing free thermoplastic resin sheets with a first set of ceramic particulate mandrels interposed between one adjacent pair of sheets and a second set of such mandrels interposed between the other adjacent pair of sheets.

Claims25

Dependent claims

In a method for the formation of a reinforced laminate panel structure, the steps comprising:

(a) disposing a first sheet formed of a thermoplastic resin on a first molding member having a female mold receptacle;
(b) disposing a mold mandrel conformable to said mold receptacle and formed of particulate ceramic material and a binder functioning as an adhesive between the said ceramic material at a location opposite said mold receptacle whereby said thermoplastic resin sheet is interposed between said mold receptacle and said mandrel;
(c) disposing a second thermoplastic resin sheet over said mandrel whereby said mandrel is interposed between said first and second sheets;
(d) subsequent to step (b) heating at least said first thermoplastic resin sheet to the melt point of said sheet to render said sheet deformable and compressing said mandrel into said mold receptacle to shape said first sheet to the conforming profiles of said mandrel and said receptacle;
(e) subsequent to or concomitant with step (d), heating said second thermoplastic resin sheet to the melt point thereof;
(f) subsequent to step (c) and subsequent to or concomitant with step (e) compressing said first and second sheets together while said first and second sheets are heated to the melt points thereof and thereafter allowing said sheets to cool so that such sheets are laminated together and the portion of said first sheet in said receptacle is shaped conformably to the profiles of said mandrel and said receptacle;
and
(g) concomitant with or subsequent to the heating of step (f) disrupting the binder integrity in said mold to cause said ceramic particulate material to be in a frangible condition and withdrawing said particulate material from between said first and second sheets.

5 more elements

In a method for the formation of a reinforced laminate panel structure, the steps comprising:

(a) disposing a first sheet formed of a thermoplastic resin on a first molding member having a plurality of longitudinally extending female mold receptacles;
(b) disposing a plurality of longitudinally extending mold mandrels conformable to said mold receptacles and formed of particulate ceramic material and a binder functioning as an adhesive between said ceramic material at locations opposite to said mold receptacles whereby said thermoplastic resin sheet is interposed between said mold receptacles and said mandrels;
(c) disposing a second thermoplastic resin sheet over said mandrels whereby said mandrels are interposed between said first and second sheets;
(d) placing a second molding member over said second sheet whereby said sheets and said mandrels are interposed between said first and second molding members, heating said first and second thermoplastic resin sheets to the melt points thereof to render said sheets deformable and forcing said mold members together to compress said mandrels into said mold receptacles to shape said first sheet to the conforming profiles of said mandrels and said receptacles and to compress said first and second sheets into contact with each other while said sheets are heated to the melt points thereof and thereafter allowing said sheets to cool so that such sheets are laminated together and the portion of said first sheet in said receptacle is shaped conformably to the profiles of said mandrel and said receptacle;
and
(e) concomitant with or subsequent to the heating of step (d) disrupting the binder integrity in said mold mandrels to cause said ceramic particulate material to be in a frangible condition and withdrawing said particulate material from between said first and second sheets.

3 more elements

In a method for the formation of a reinforced laminate panel structure, the steps comprising:

(a) disposing a first outer sheet formed of a thermoplastic resin on a first molding member;
(b) disposing a first plurality of spaced-apart longitudinally extending mold mandrels formed of particulate ceramic material and a binder functioning for said ceramic material on said thermoplastic resin sheet whereby said thermoplastic resin sheet is interposed between said first molding member and said mandrels;
(c) disposing an intermediate second thermoplastic resin sheet over said first plurality of mandrels whereby said mandrels are interposed between said first outer and intermediate sheets;
(d) placing a second plurality of longitudinally extending mold mandrels formed of particulate ceramic material and a binder for said ceramic material on said intermediate thermoplastic resin sheet at locations opposite spaced intervals between said first plurality of longitudinally extending mold mandrels whereby said intermediate sheet is interposed between said first and second plurality of mandrels;
(e) placing a second outer thermoplastic resin sheet over said second plurality of said longitudinally extending mandrels;
(f) placing a second molding member over said second outer sheet whereby said sheets and said mandrels are interposed between said first and second molding members, heating said thermoplastic resin sheets to the melt points thereof to render said sheets deformable and forcing said mold members together to compress said second plurality of mandrels to shape said intermediate sheet to the conforming profiles of said mandrels and to compress shaped portions of said intermediate sheet into contact with said first and second sheets while said sheets are heated to the melt points thereof and thereafter allowing said sheets to cool so that such sheets are laminated together and said intermediate sheet in said receptacle is shaped conformably to the profiles of said mandrels;
and
(g) concomitant with or subsequent to the heating of step (f) disrupting the binder integrity in said mold mandrels to cause said ceramic particulate material to be in a frangible condition and thereafter withdrawing said particulate material from between said first and second sheets.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/114,621Filed 29 Oct 1987
Granted: 7 Aug 1990
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

B29D 99/0014
Producing wall or panel-like structures, e.g. for hulls, fuselages, or buildings: provided with ridges or ribs, e.g. joined ribs
B29C 33/448
With means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles: destructible
B29C 51/006
Shaping by thermoforming , i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing;…:…
B29C 51/30
Component parts, details or accessories; Auxiliary operations: moulds