Abstract:
The invention relates to a process for the manufacture of a part penetrated by fluid channels or ducts for the manufacture of a mold that includes channels or ducts for the circulation and/or transfer of a fluid from the molding portion to the non-molding portion and vice versa. The part is formed and manufactured by a Stratoconception (TM) method based on the principle of decomposing the part, via a set of inter-stratum planes, into a succession of strata. After assembly, the part is formed, and channels are provided in the various inter-stratum planes for allowing a fluid to pass through the part. The invention also relates to the parts obtained by the process.

Description:
CROSS-REFERENCE TO RELATED U.S. APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a process for manufacturing a part having a fluid circuit, and to a part obtained by the process. 
     2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98. 
     More particularly, the invention aims to solve the problems encountered when producing a channel for transferring fluids (liquid or gas) through the wall of a part, that is to say for transferring fluid from the inner cavity of the part to its outer surface (and vice versa). This invention is preferentially applicable in molds intended for the field of plastics processing (polystyrene injection molding, thermoforming), the foundry-work field (sandcasting), the mechanical field (tooling manufacture), the hydraulics field (manufacture of filters), and the glass-making field, this list not being exhaustive. 
     BRIEF SUMMARY OF THE INVENTION 
     In particular, the object of the invention is to replace and/or improve, in tooling, the use of holed filters or of drilled microholes on the surface of the tooling, these microholes serving usually:
         vents for facilitating assisted or unassisted extraction of fluids;   fluid diffusers necessary for the manufacturing process in question.       

     The problems of the prior art are solved thanks to the invention, which consists in using the Stratoconception™ method in order to apply it to the manufacture of a part and of its integrated fluid circuit. 
     The Stratoconception™ method is described in the following patents and patent applications: FR 2 673 302, WO 00/31599 and WO 00/31600. 
     The subject of the present application is a novel application that solves abovementioned problems of the processes of the prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention will be more clearly understood with the aid of the description below, given with reference to the following appended figures. 
         FIG. 1  is a top perspective view of a portion of tooling, seen from the impression side for molding a part to be produced, according to a first non-limiting exemplary embodiment of the invention. 
         FIG. 2  is another perspective view of the tooling portion of  FIG. 1 , seen from the rear side. 
         FIG. 3  is a perspective view of a part of the tooling portion of  FIG. 1 , which is bounded, for explanation purposes, by two planes (P 1 , P 2 ) perpendicular to the opening plane of the mold and to the stratification direction. 
         FIGS. 4   a  and  4   b  are part perspective and sectional views for defining the composition of the fluid transfer channels and view of G in detail. 
         FIG. 5  is across-sectional view of the tooling of  FIGS. 4   a ,  4   b , produced in an inter-stratum plane (Pi) and showing a stratum ( 6 i), seen along the arrows AA. 
         FIGS. 6   a  and  6   b  are perspective and isolated perspective views of the tooling according to the invention, produced with inter-stratum flat-surface planes, and of H in detail. 
         FIGS. 7   a  and  7   b  are perspective and isolated perspective views of the tooling according to the invention produced with warped-surface inter-stratum planes, and of I in detail. 
         FIG. 8  is an isolated and exploded perspective view of an inter-stratum plane (Pi) showing the construction of the channels by joining the strata ( 6   i ) and ( 6   i+1 ) together at an inter-stratum plane (P i ). 
         FIG. 9  is a sectional view of one of the fluid transfer channels produced in an inter-stratum plane (P i ) according to a first variant. 
         FIG. 10  is another sectional view of one of the fluid transfer channels produced in an inter-stratum plane (Pi) according to a second variant. 
         FIG. 11  a perspective view of the channels obtained in an inter-stratum plane P i  according to a second embodiment. 
         FIG. 12  is a sectional view showing a third variant of fluid channels provided in inter-stratum planes P i . 
         FIG. 13  is a detailed schematic view of tooling produced according to the invention and provided with a feed duct or diffusion duct of rectangular cross section. 
         FIG. 14  is a detailed schematic view of tooling produced according to the invention and provided with a feed duct or diffusion duct of circular cross section. 
         FIG. 15  is another detailed schematic view of tooling produced according to the invention and provided with a feed duct or diffusion duct of any cross section. 
         FIG. 16   a ,  16   b ,  16   c  are schematic views showing the position of the angle of inclination (α) relative to the angle (β). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The producing of fluid discharge or diffusion channels in a portion of tooling intended for a motor vehicle will be described, byway of a non-limiting example of the application of the invention, in conjunction with  FIGS. 1 to 16 . 
     Of course, the invention may applied to any part, other than tooling, which includes a fluid circulation channel. 
     The invention consists in using the Stratoconception™ method to produce, in the various inter-stratum planes (these may be flat or warped), channels ( 2 ) for allowing a fluid to pass through the tooling ( 1 ) and around an object when molding the latter ( FIG. 1  and  FIG. 2 ). 
     Said cooling is formed from a rear face ( 7 ) and from a front face constituting the plane of opening of the tooling and including a molding cavity ( 9 ) for molding an object (not shown). According to this process, the tooling ( 1 ) is, by its design, subdivided into strata ( . . .  6   i ,  6   i+1  . . . ) which, after being joined together, form a tooling ( 1 ) ( FIG. 3 ). At the time of designing the tooling, each inter-stratum is provided with a set of channels ( 2 ) (hatched zone in  FIG. 4 ) around the molding cavity ( 9 ) (and emerging into the latter) passing through the tooling. 
     These channels are thus closed and emerge at one end in the molding cavity ( 9 ) and at the other end on the rear face ( 7 ) so as to allow a fluid to pass from one side of the tooling or part to the other. 
     This set of channels ( 2 ) is formed from a feed portion ( 3 ) and a diffusion portion ( 4 ) connecting, on one side, the molding cavity ( 9 ) and, on the other side, the rear face ( 7 ) of the tooling ( FIG. 4 ). To manage the fluid flow, the feed portion ( 3 ) may have a depth (P′r) greater than or equal to the depth (Pr) of the diffusion portion ( 4 ) ( FIG. 5 ). 
     The use of “warped-surface” stratification makes it possible to eliminate in-fill problems ( FIG. 6 ) and/or to maintain a fluid flow that is always normal to the molding surface ( FIG. 7 ). 
     The channels ( 2 ) of one and the same inter-stratum plane (whether flat or warped) (P i ), which are produced, entirely or partly, in one face of a stratum ( 6   i ), are open towards said inter-stratum plane (P i ) whereas the face facing the next stratum ( 6   i+1 ) (whether flat or warped) may include the complementary shape of the channels ( 2 ) ( FIG. 8 ). 
     In one and the same inter-stratum plane, the separation of the feed portion ( 3 ) from the diffusion portion ( 4 ) is calculated, by an offset of a value (d), from the profile ( 10 ) of the part ( FIG. 9 ). Said profile is determined by calculating the intersection of the surface of the molding cavity ( 9 ) with the inter-stratum plane (P i ). This value (d) may follow a law of variation according to the fluid circulation requirements and allows the channel ( 2 ) to be varied according to the profile ( 10 ) of the part in each inter-stratum plane (P i ). 
     The inter-stratum plane is formed from channels ( 2 ) (hatched zone in  FIG. 4 ) for fluid circulation and from bearing zones ( 5 ) between the strata ( 6   i ) and ( 6   i+1 ), it not mattering whether these are located in the diffusion portion ( FIG. 9 ) or in the feed portion ( FIG. 10 ). In this case, secondary bearing zones ( 11 ) may be provided in the feed portion. These secondary bearing zones make it possible to ensure precision and rigidity of the stack of strata if the area of the feed portion is much larger than that of the diffusion portion ( FIG. 10 ). In certain cases, the rigidity of the tool may even need to be improved by producing nested strata as defined in the Applicant&#39;s patent FR 2 834 803. 
     When the bearing zones ( 5 ) are located in the feed portion, the latter is then formed from feed ducts ( 12 ). This configuration defines a first variant ( FIG. 9 ). The feed ducts ( 12 ) are mutually parallel and characterized by a width (w) and a pitch (p) between two successive feed ducts. The diffusion portion thus ensures the flow of the fluid over the entire profile ( 10 ) of the molding cavity ( FIG. 9 ). 
     Likewise, in a second design variant, the diffusion portion is provided with bearing zones and is formed from “diffusion” ducts ( 13 ) ( FIG. 10 ). The diffusion ducts ( 13 ) can therefore be wither mutually parallel, or normal to the surface of the cavity, or else inclined at an angle (β) to the flow direction of the fluid in the feed channel ( FIG. 10 ) and characterized by a width (w) and pitch (p) between two successive diffusion ducts ( 13 ). The result obtained on the tooling after assembling the strata is a network of diffusers in the form of slots ( 8 ) distributed over the entire molding surface ( 11 ). Seen from the rear, the tooling has a wide slot in each inter-stratum plane formed by the recess of the feed portion. 
     A third design variant has also been proposed ( FIG. 12 ). This relates to the production of channels in parts or portions of parts that are slender, their slenderness being such that the diffusion portion of thickness (d) is predominant. Thus, the feed portion takes the form of a simple duct in which no bearing zone ( 5 ) is integrated. These bearing zones are therefore necessarily integrated in the diffusion portion, which is then formed from diffusion ducts ( 13 ) which may be mutually parallel, normal to the molding surface, or else inclined at an angle (β) to the flow direction of the fluid in the feed channel. The use of an angle (β) is preferred as it allows the diffusion of the fluid to be optimized and homogenized. 
     The geometry of the channels ( 2 ) width (w) and pitch (p) between two successive ducts ( 12 ) or ( 13 ) and the constant or variable thickness (es) of the strata can be parameterized according to the flowrate of fluid which has to pass from one face of the tooling to the other. The pitch “p” is defined by as the center-to-center distance between two ducts ( 12 ) in the case of a system of parallel ducts ( FIG. 9 ) and as the length of the segment of the profile ( 10 ) separating two normal ducts ( 13 ) or two ducts inclined at an angle (β) ( FIG. 10 ,  FIG. 12 ). 
     The geometry of the ducts (( 12 ) or ( 13 ) or ( 14 )) is defined by its depth (Pr) and its cross section ( 14 ) in a plane perpendicular to the inter-stratum plane, which may be straight ( FIG. 13 ), of circular section ( FIG. 14 ) or of any section ( FIG. 15 ). 
     The angle (β) is parameterizable and calculated numerically, and this may vary over the entire length of the part so as to enable the pressure drops to be minimized (mainly for the third variant). 
     This angle (β) is defined in the plane of the stratum, but it may also be supplemented with a second angle (α) defined in the thickness of said stratum ( FIG. 16 ). 
     All these parameters make it possible, when designing the tooling, to optimize and homogenize the flow of fluid over the entire molding surface so as to ensure the best performance for the tooling so that it can produce parts of optimized quality and/or with a minimal cycle time. Software packages dedicated to the Stratoconception ™ method carry out, mathematically and numerically, the decomposition into strata, the creation of said fluid transfer channels and the optimization of their parameters by implementing a specific algorithm.