Apparatus and method for making preforms in mold

Abstract

Apparatus and a method of preparing fiber preforms disperses fibers and binder on a forming support surface such that the materials are conditioned and then applied to the surface where the composite material solidifies. Reinforcing material, such as fiber, is mixed with binder, such as thermoplastic or thermoset materials, so that the materials adhere. Then, the adhesive mixture is dispersed in a controlled pre-determined weight ratio on the support surface where the mixture sticks to the support surface, cools and solidifies. The deposited mixture can be an open mat having interstices between fibers. The deposited mixture can also be shaped further into a final desired shape before complete solidification. This method eliminates the need for solvents and their associated problems. The process does not require a vacuum or plenum system to hold the reinforcing material in place. The preform can be made in any shape, including sections or asymmetric configurations and remain in mold while being processed to a composite molded article.

1 . A method of making a preform in a mold, said mold being adapted so that said preform remains in-mold during subsequent processing to a composite molded article, said method comprising: 
 providing reinforcing material;    providing binder blend material;    mixing the reinforcing material and the binder blend material in a venturi mixer so that the binder material adheres to the reinforcing material;    applying a stream of the mixture from the venturi mixer through a heating zone to a prepared surface of a mold tool, said applying being conducted without use of a plenum system;    applying a stream or curtain of gaseous cooling media to the material on said prepared surface; and    sufficiently solidifying the mixture to form said preform in said mold, wherein said preform remains in said mold during subsequent processing to a composite article.    
   
   
       2 . The method of  claim 1 , wherein the step of applying a stream of the mixture includes spraying the mixture against the prepared surface.  
   
   
       3 . The method of  claim 1 , wherein the step of providing the reinforcing material includes providing chopped fibers.  
   
   
       4 . The method of  claim 3 , wherein the step of providing the chopped fibers includes providing chopped fiberglass.  
   
   
       5 . The method of  claim 1 , wherein the step of providing the reinforcing material includes emitting a stream of chopped fibers into said venturi mixer.  
   
   
       6 . The method of  claim 1 , wherein the step of providing binder includes emitting a stream of binder particulate into said venturi mixer.  
   
   
       7 . The method of  claim 1 , wherein the step of providing binder includes conditioning the binder before mixing the binder with the reinforcing material.  
   
   
       8 . The method of  claim 7 , wherein conditioning the binder includes heating the binder.  
   
   
       9 . The method of  claim 1 , wherein the step of mixing the reinforcing material and the binder includes a stream of reinforcing material and a stream of binder and mixing the streams in a venturi mixer.  
   
   
       10 . The method of  claim 9 , wherein the mixed streams of reinforcing material and binder are emitted from said venturi mixer and wherein said mixture is applied so as to form a plurality of layers on said prepared surface.  
   
   
       11 . The method of  claim 1 , wherein said heating zone comprises applying heat by forming a controlled heating zone and propelling the mixture of reinforcing material and binder through the heating zone.  
   
   
       12 . The method according to  claim 12 , wherein applying heat includes creating a flame.  
   
   
       13 . The method of  claim 1 , wherein an end effector apparatus is provided in operative, moveable relationship with respect to said mold, said end effector apparatus heating elements to apply heat to form a heating zone, having the venturi from which the mixture of reinforcing material and hybrid binder are propelled through said heating zone to said prepared surface, and elements to form and apply at least one curtain of gaseous cooling media to said prepared surface.  
   
   
       14 . The method of  claim 1 , wherein the step of applying the mixture to a prepared surface includes applying the mixture to an at least vertically oriented prepared surface.  
   
   
       15 . The method of  claim 1 , wherein the step of applying the mixture to a prepared surface includes applying the mixture to a solid prepared surface.  
   
   
       16 . The method of  claim 1 , wherein the step of applying the mixture to a prepared surface includes applying the mixture to a surface at ambient air conditions.  
   
   
       17 . The method of  claim 1 , wherein the step of applying the mixture to a prepared surface includes applying the mixture to a surface having apertures therein.  
   
   
       18 . The method of  claim 1 , further comprising shaping the mixture after application to the prepared surface and prior to solidifying.  
   
   
       19 . The method of  claim 1 , wherein the step of solidifying the mixture includes cooling the mixture so that it conforms to the shape of the support surface.  
   
   
       20 . The method of  claim 1 , further comprising applying a moldable material to the preform to form a composite and curing the composite to form a part.  
   
   
       21 . The method of  claim 20 , further comprising applying a vacuum to the composite before the part is cured.  
   
   
       22 . The method of  claim 1 , further comprising applying at least one of heat and pressure to the preform to form a molded part.  
   
   
       23 . The method of  claim 1  further comprising adding resin to the preform prior to applying at least one of heat and pressure to the preform.  
   
   
       24 . A preform formed in accordance with the method of  claim 1 .  
   
   
       25 . A method of making a preform for use in forming a structural part, comprising: 
 providing a stream of fibrous reinforcing material;    adhering particulate binder material to the reinforcing material by combining a stream of binder material to the stream of fibrous reinforcing material in a venturi device to form an adhesive mixture; and    applying the adhesive mixture of the reinforcing material and the binder material from said venturi through a heating zone and against a support surface, optionally applying a stream of gaseous cooling media to the material sprayed on said surface, such that the mixture adheres to the support surface; and solidifies into the preform.    
   
   
       26 . The method of  claim 25 , wherein said applying said adhesive mixture comprises spraying and said method includes applying said stream of gaseous cooling media by passing a cooling air curtain over the adhesive mixture sprayed on the support surface.  
   
   
       27 . The method of  claim 26 , wherein said spraying and said cooling occur in the absence of a plenum system applied about or to the support surface.  
   
   
       28 . The method of  claim 25 , wherein adhering binder material to the reinforcing material includes conditioning the binder material with heat and forcing the conditioned binder material into the stream of reinforcing material.  
   
   
       29 . The method of  claim 26 , wherein said spraying includes creating a heating zone and feeding the adhesive mixture through the heat zone.  
   
   
       30 . The method of  claim 28 , wherein providing a stream of fibrous material includes blowing chopped fiberglass.  
   
   
       31 . The method of  claim 26 , wherein spraying the adhesive mixture includes spraying the mixture onto a vertical support surface.  
   
   
       32 . The method of  claim 26 , wherein spraying the adhesive mixture includes spraying the mixture onto a solid surface.  
   
   
       33 . The method of  claim 26 , wherein spraying the adhesive mixture includes spraying the mixture onto a perforated surface.  
   
   
       34 . The method of  claim 26 , wherein spraying the adhesive mixture includes spraying the mixture onto the support surface under ambient air conditions.  
   
   
       35 . A preform formed in accordance with the method of  claim 25 .  
   
   
       36 . A composite structure molded obtained from the preform formed in accordance with the method of  claim 25 .  
   
   
       37 . An end effector adapted for connection to a robot arm for applying a heated adhesive mixture of a binder and a reinforcing fiber to a surface, said effector comprising: 
 a frame support;    at least two spaced burners mounted on the frame to produce respective flames, with the two flames being oriented to heat a region disposed there between;    a nozzle arrangement for dispensing a mixed stream of binder and reinforcing fiber into the heated region to cause heating of the mixture.    a respective manifold associated with each of the burners and having an inlet for a cooling medium connected thereto; and,    a respective shield member disposed between each manifold and an associated burner to minimize interaction between the stream of cooling medium and the heated region.    
   
   
       38 . The end effector according to  claim 37  connected to a robot arm.  
   
   
       39 . The end effector according to  claim 37  wherein the at least two burners are elongated, are symmetrically disposed on the frame, extend parallel to one another and are inclined inwardly.  
   
   
       40 . The end effector according to  claim 39  wherein the manifolds are elongated, are symmetrically disposed on the frame, extend parallel to one another, and extend along the length of the associated burners to produce a curtain of cooling medium.  
   
   
       41 . The end effector according to  claim 40  wherein the shields are elongated, are symmetrically disposed on the frame, and extend parallel to one another.  
   
   
       42 . The end effector according to  claim 41  wherein the nozzle arrangement includes a venture tube mounted on the frame between the two burners, and having an inlet opening for receiving the reinforcing material at one end and a spray pattern outlet nozzle for the mixed stream at its other end, an inlet port extending into the interior of the venture tube for the introduction of a liquid binder, and an air inlet to the interior of the venture for the introduction of a carrier gas.  
   
   
       43 . The end effector according to  claim 42  wherein the outlet nozzle has an elongated shape extending parallel to the extension direction of the burners.  
   
   
       44 . The end effector according to  claim 43  wherein a pair of said venture tubes are provided with their output nozzles being axially aligned in the extension direction of the burners.  
   
   
       45 . The end effector according to  claim 37  wherein the nozzle arrangement includes at least one venture tube mounted on the frame between the two burners, and having an inlet opening for receiving the reinforcing material at one end and a spray pattern outlet nozzle for the mixed stream at its other end, an inlet port extending into the interior of the venture tube for the introduction of a liquid binder, and an air inlet to the interior of the venture tube for the introduction of a carrier gas.  
   
   
       46 . The end effector according to  claim 45  wherein the at least two burners are elongated, are symmetrically disposed on the frame, extend parallel to one another and are inclined inwardly; and the outlet nozzle has an elongated shape extending parallel to the extension direction of the burners.  
   
   
       47 . The end effector according to  claim 46  wherein a pair of said venture tubes are provided with their output nozzles being axially aligned in the extension direction of the burners.