The present invention relates to infusion moulding and more particularly to a resin infusion distribution system or mould for use in moulding large cored panels. The invention also relates to a method of manufacturing large cored panels.

Infusion moulding is a process whereby resin is drawn through dry material such as fibreglass mat using a vacuum. The mat is placed in a mould and enclosed within an impervious cover which is sealed against the mould. Vacuum is applied via hoses connected at strategically placed air-outlets in the cover. Likewise resin is supplied via hoses connected at strategically placed resin inlets in the cover which are generally on an opposite side of the mould to the vacuum connections so that resin is drawn fully through the mat to completely fill all voids therein.

The operation of setting up the mould with the impervious cover and the various connections as described above is a relatively tedious operation and relies very much on the skills of the workman to place the various connections in the most appropriate locations to ensure complete resin infusion throughout the mat. Furthermore, virtually all the materials used in setting up the process for the existing infusion moulding process are discarded after each moulding operation and this is inefficient from both a time and cost aspect.

The present invention is concerned with manufacturing large cored panels and the existing process or system would result in equal or greater inefficiencies.

Accordingly, it is an object of the present invention to provide an improved system for use in moulding large cored panels by an infusion moulding process, which overcomes or avoids the inefficiencies of existing systems or at least provides a useful alternative. One form of the invention provides a mould for infusion moulding cored panels, comprising a base, re-useable side rails for mounting on said base, and an impervious cover for extending over said base and said side rails to form an airtight enclosure between said base, said cover and said side rails, said side rails having an array of interconnected surface grooves spaced along the length of the rail and adapted, in the case of one side rail, to disperse resin into said enclosure, and in the case of the other side rail, to apply a vacuum to said enclosure.

Another form of the invention provides a resin infusion distribution system for infusion moulding cored panels, said system comprising a mould base having spaced parallel bottom side rails, said rails having a groove in the upper surface thereof extending over the length of the rail, a removable upper rail on each side rail, respectively, one said upper rail being a vacuum rail and having spaced interconnected grooves along the length thereof for applying a vacuum to the mould, the other said upper rail being a resin supply rail and having a groove extending longitudinally along the underside thereof and mating with the groove in the upper surface of the corresponding bottom rail, said resin supply rail having spaced grooves on an inwardly directed face thereof in fluid communication with said longitudinal groove whereby resin supplied to said longitudinal groove may be drawn into the grooves on the inwardly directed face of the resin supply rail and dispersed therefrom.

A still further form of the invention provides a method of manufacturing large cored panels comprising the steps of:

i) wrapping fibreglass matting around a substantially flat core of insulating material; ii) placing the wrapped core on a mould base; iii) placing side rails on said base to extend entirely along opposite sides of said wrapped core, said side rails having a height substantially equal to the thickness of said wrapped core; iv) placing an impervious flexible cover over said core and side rails to form a seal with said base and thereby provide a mould fully enclosing said core and side rails; v) applying a vacuum at strategic points along the length of one said side rail in a manner whereby said vacuum is applied to said core substantially evenly along the entire length of said side rail; and vi) supplying catalysed resin at strategic points along the length of the other said side rail whereby said resin is applied to said core substantially evenly along the entire length of said side rail and, by virtue of said vacuum, is caused to permeate entirely through said matting until all voids in said matting are filled with resin.

In order that the invention may be more readily understood one particular embodiment will now be described with reference to the accompanying drawings wherein;

Fig. 1 - is a perspective schematic part section view, of a resin infusion mould according to the invention, Fig. 2a - is a perspective view of a vacuum block of the mould in Fig. 1, Fig. 2b - is a part section taken on the line 2b - 2b of Fig. 2a, Fig. 3 a - is similar to Fig. 2a but shows a resin block of the mould of Fig. 1, Fig. 3b - is a part section taken on the line 3b - 3b of Fig. 3 a, Fig. 3 c - is a section taken on the line 3c - 3c of Fig. 3a, Fig. 4 - is a part transverse sectional view through the mould prior to use, Fig. 5 - is similar to Fig. 4 but shows the mould in use and part way through a moulding operation, Fig. 5 a - is an enlargement of the portion shown within the broken lines of Fig. 5, more accurately depicting the resin infusion process which is only shown schematically in Fig. 5, and Fig. 6 - is similar to Fig. 5 but shows completion of the moulding process.

Referring initially to Fig. 1 the resin distribution system or mould is shown to consist essentially of a mould base 10 supported by legs 11, spaced opposed side rails 12 and 13 which sit on top of the base 10, a front end retainer member 14 which is formed integral with the base 10 and a rear end retainer member 15 which is not secured to the base 10, but merely sits in position on the base. The components described thus far provide the base and side walls of the mould and a cover 16, shown only by broken lines in Fig. 1, extends over the mould beyond the side rails 12 and 13 and end retainer members 14 and 15. The cover 16 is an impervious transparent or translucent blanket usually in the form of a plastics sheets.

A vacuum pump 17 is connected via flexible hoses 18 (shown schematically in Fig. 1) to various points along the length of the side rails 13 as will be described in more detail hereinbelow. Likewise, resin containers 19 are provided with flexible hoses 20 which connect to side rails 12 at spaced locations therealong as will be described in more detail hereinbelow.

Figs. 2a and 2b show in more detail one of the side rails 13 which hereinafter will be referred to as a vacuum block. Each vacuum block 13 is essentially wedge-shaped and has a inwardly directed vertical face 21 and an outwardly directed inclined face 22. The inclined face 22 is provided with spaced vertically extending grooves 23 which are preferably tapered slightly from a narrow inward end to a wider opening in order to facilitate cleaning thereof. The vacuum blocks 13 are made from material that releases from resin with minimum maintenance, such as for example, a plastics material such as polypropylene. Figs. 3 a, 3b and 3 c show in detail one of the side rails 12 which hereinafter is referred to as a resin block. Each resin block 12 is also wedge- shaped and comprises an inwardly directed vertical face 24 and an outwardly directed inclined face 25. The inwardly directed face 24 is provided with spaced vertical grooves 26, and the vertical grooves 26 are joined together adjacent the top edge of the resin block by a horizontal groove 27. Furthermore, the vertical grooves 26 are further joined together by a semi- cylindrical horizontal groove 28 which extends along the underside of the resin block over the entire length thereof. The vertical face 24 stops short of the plane of the base face 29 of the resin block (more evident in Fig. 4) to provide a gap 29a for purposes which will become apparent hereinbelow.

The mould base 10 may be formed from various materials such as steel, aluminium or fibreglass and in an alternative arrangement the base 10 is formed from a flat aluminium tabletop with separate fixed blocks (not shown) in the form of side rails that support the vacuum blocks 13 and resin blocks 12.

Referring now to Fig. 4 there is shown a sectional view of the resin distribution system or mould ready for commencement of a moulding operation. As shown the flexible hoses 18 and 20 are connected to respective sides of the mould base 10 by threaded fittings 30 which are retained in the base 10 by nuts 31 and allow the hose pass therethrough in sealed relationship. A silicon sealing compound 41 is installed around the inner end of the conduit within a cavity provided in the base 10 for the purpose of ensuring a proper seal whilst facilitating removal of the conduit at the completion of a moulding operation as will be described below. The base 10 is provided with semi- cylindrical grooves 32 and 33 on respective sides of the base and the groove 32 cooperates with the groove 28 of the resin block to form a cylindrical channel along the length of the resin blocks with the inwardly directed opening 29a. The cylindrical channel provides resin access to the vertical grooves 26 and to the inside of the mould via the opening 29a. The vacuum blocks 13 are wrapped in a breather cloth 37 such as for example Peelply™, which is impervious to the passage of resin but will allow air to pass therethrough. The flexible hoses 18 are connected to the base 10 in a similar manner to the hoses 20 on the resin side of the mould.

In order to produce a large cored panel using the infusion distribution system described in Figs. 1 to 4 reference should now be made to Fig. 5. Once the mould is assembled in the manner shown in Fig. 4, a core 34 is installed within the mould between the side rails 12 and 13. The core is formed of an insulating material such as polyurethane and is provided with transverse grooves 35 across the top and bottom surfaces to assist in dispersion of resin as well as providing a keying in effect for the resin. Prior to installation of the core 34 it is wrapped in a fibreglass mat 36 and once in place the impervious cover 16 is provided over the entire mould as shown in Fig. 5. The cover is retained in place by an adhesive seal 42 around the perimeter of the cover to seal the cover onto the mould base 10.

When the assembly is completed vacuum is applied via the vacuum pump 17 and flexible hoses 18 to the vacuum blocks 13. A series of vacuum blocks 13 form the contiguous side rail and by virtue of the grooves 23 and the cloth 37 around the vacuum blocks 13, vacuum is applied to the inside of the mould at the vertical face 21 of the vacuum blocks. The horizontal groove 33 and the vertically extending grooves 23 ensure that the vacuum is applied relatively evenly over the entire outwardly directed face 22 and, by virtue of the breather cloth 37, over the entire inwardly directed face 22.

Once the vacuum is applied catalysed resin in the resin containers 19 is caused to flow via flexible hoses 20 to the vertical face 24 of the resin blocks 12. The groove 28 in combination with the semi-cylindrical groove 32 ensures that resin flows longitudinally of the mould between the various resin inlet points and the grooves on the vertical face 24 of the resin blocks 12 in combination with the horizontal groove 27 ensures that resin is dispersed relatively evenly over the entire inwardly directed face of the series of resin blocks. As is evident in Fig. 5 the resin 38 moves across the mould towards the opposite side and permeates through the fibreglass mat 36. Whilst the resin is shown in Fig. 5 on the outside of the fibreglass mat for illustrative purposes the enlarged Fig. 5a shows the actual permeation of the resin through the fibreglass mat 36. The maximum vacuum is applied until all voids within the fibreglass mat and the grooves 35 in the core 34 are filled with resin. This becomes evident by inspecting the progress at the visual inspection point 39 adjacent the vacuum blocks 13. The transparent impervious cover allows this inspection to be made. Once resin has fully permeated and filled all the voids in the fibreglass mat a clamp 40 is applied to each of the resin inlet hoses 20 close to the connections with the mould base 10. Since the resin is unable to penetrate the cloth 37 there is no evidence of the resin at the vacuum outlet connections or in the hoses 18. The resin is then allowed to cure.

The removal process involves firstly removing the impervious cover 16 and then removing the side rails 12 and 13. Once the side rails are removed the completed panel may be lifted from the mould. Since the mould base 10 and the side rails 12 and 13 were applied with a waxed coating prior to the moulding process the completed panel is easily removed.

The components of the mould are able to be readily cleaned after a moulding operation ready for further use. The resin inlet hose 20 remaining in the connection to the mould base 10 may be readily pulled from the threaded fitting 30 and discarded and the grooves in the resin blocks 12 may be readily cleaned to remove any residual resin remaining therein. The base 10 is cleaned and re- waxed and the blocks 12 and 13 are re- waxed ready for a further moulding operation. The impervious cover 16 may be re-used or after several moulding operations may require replacement. It should be apparent from the description hereinabove that the present invention provides an improved infusion distribution system or mould which is readily re-usable and is far more efficient in assembly and use than existing infusion moulding systems. Whilst one particular embodiment has been described in detail it will be readily apparent to persons skilled in the art that modifications may be made without departing from the spirit and scope of the invention. For example the resin and vacuum inlets through the base 10 could be altered whereby the connections are made through the impervious cover 16. Furthermore, the groove arrangement on the resin and vacuum blocks could be modified provided they facilitate a relatively even distribution of resin and vacuum, respectively, over the length of the mould.