Abstract:
A building panel includes a central core and a pair of opposed coating surfaces formed integrally with the core. The method of forming the building panel includes the application of a flowable, settable coating material to respective surfaces of at least two baffles ( 100 ), placing the baffles in a substantially parallel, spaced interrelationship, at least substantially filling the space between the two baffles ( 100 ) with a settable core material prior to setting of the core material, and allowing the core material and coating material to set.

Description:
FIELD OF THE INVENTION 
     The following invention relates to a method and apparatus for forming a building panel. The invention also relates to a building panel. 
     Lightweight concrete building panels are known. Such panels are produced in a raw, unfinished condition for installation. After being installed into a building under construction, the panels are rendered or otherwise coated to provide an acceptable surface finish. This process requires the labour of a skilled renderer in applying the rendered finish with a trowel. Furthermore, the strength of such known lightweight concrete panels is not high. 
     OBJECT OF THE INVENTION 
     It is an object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages and/or more generally to provide an improved building panel and a method and apparatus for forming a building panel. 
     DISCLOSURE OF THE INVENTION 
     There is disclosed herein a method of forming a building panel or panels, the method including: 
     applying a flowable, settable coating material to respective surfaces of at least two baffles, 
     placing the baffles in a substantially parallel, spaced interrelationship, 
     at least substantially filling the space between the two baffles with a settable core material prior to setting of the coating material, and 
     allowing the core material and coating material to set. 
     Preferably, the baffles are located with respect to one another prior to filling the space with core material. 
     Alternatively, the baffles can be moved together after filling the space with core material but prior to setting of the core material and coating material. 
     Preferably, the baffles are moved apart and/or separately removed after setting of the core material and coating material so as to release the formed panel(s). 
     Preferably, the method further provides n+1 baffles in a parallel spaced interrelationship, between which n panels are formed where n equals any integer greater than or equal to 1. 
     Preferably, after the baffles are moved apart, the panels are removed in a direction substantially parallel to the plane of the baffles by application of force thereto. 
     Preferably, the baffles are located within a mould box or supporting frame. 
     Preferably, the baffles are moved toward one another by means of hydraulic clamping cylinders. 
     There is further disclosed herein an apparatus for use in forming a building panel in accordance with the above disclosed method, the apparatus including: 
     a mould box or supporting frame into which said coated baffles are receivable, 
     means to locate said coated baffles in association with one another so as to define a minimum space therebetween, and 
     means to apply a settable core material between each of said baffles. 
     Preferably, the apparatus further includes a means to apply a coating material to both sides of at least some of said baffles prior to applying said settable core material between each of said baffles. 
     Preferably, each baffle is substantially hollow, having a pair of spaced apart side sheets. 
     Preferably, each baffle has air inlet means by which air can be injected to the space between the sheets so as to outwardly expand the same under pressure to assist in releasing the set panels from the baffles. 
     Alternatively, each baffle is solid. Plywood is a suitable material for a solid baffle. The plywood can be plastics coated. As a further alternative, the baffles can be a composite of plywood, nylon, PVC and steel. 
     Preferably, the baffles have extraction engagement holes to which an extraction device can be anchored for the purpose of applying force to the set panels for removal. 
     Preferably, said mould box or supporting frame is formed upon a mobile structure. 
     Preferably, the mobile structure has one or more posts to which clamping cylinders are affixed, said clamping cylinders being associated with side walls of the mould box or supporting frame. 
     Preferably, the side walls of the mould box or supporting frame act as end baffles. 
     There is further disclosed herein a plant for forming building panels, the plant including: 
     means for applying a flowable, settable coating material to respective surfaces of at least two baffles, 
     means for placing the baffles in a substantially planar, spaced interrelationship, 
     means for substantially filling the space between the two baffles with a settable core material prior to setting of the coating material, and 
     means for conveying the individual panel throughout the plant for the purpose of cleaning and coating the same with said settable coating material and for arranging the coated baffles in said substantially parallel, spaced interrelationship. 
     Preferably, the plant also includes means for conveying a mould box or supporting frame into which and from which the baffles are inserted and removed and means for transferring the mould box from a first, baffle removal position to a second baffle insertion position, between which positions the mould box or supporting frame is rotated. 
     Preferably, the means for substantially filling the space between the two baffles with a settable core material includes a hopper from which there extends one or more filling tubes, the hopper being mounted upon a frame and being pivotable about a horizontal axis, the hopper being adapted to be raised and lowered such that the filling tubes enter and are withdrawn from a space between adjacent baffles while core material is being delivered thereto by said filling tubes. 
     Preferably, means are provided to oscillate the hopper horizontally, during vertical withdrawal of the tubes and delivery of the core material. 
     There is further disclosed herein a building panel formed by the above disclosed method or by use of the above disclosed apparatus or as produced by the above disclosed plant. 
     There is further disclosed herein a building panel including a core having been set from a settable core material and a coating on either side thereof, the coating on either side having been set from a settable coating material concurrently with setting of said core material. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred methods of the present invention will now be described by way of example with reference to the accompanying drawings which depict a preferred apparatus for use in the method, wherein: 
     FIG. 1 is a schematic side elevational view of a mould box or supporting frame having a baffle lifted therefrom by means of a lifting frame, the mould box or supporting frame shown with its end doors open, 
     FIG. 2 is a schematic elevational view of the lifting frame of FIG. 1, 
     FIG. 3 is a schematic elevational view of the mould box or supporting frame of FIG. 1 with the end doors closed, 
     FIG. 4 is a schematic end elevational view of the mould box or supporting frame of FIG. 1 with baffles in place therein, 
     FIG. 5 is a schematic plan view of the mould box or supporting frame of FIGS. 1,  3  and  4  with the baffles in place, 
     FIG. 5A is a schematic exploded illustration of a portion of the structure depicted in FIG. 5, 
     FIG. 6 is a schematic end elevational view of the mould box or supporting frame, 
     FIG. 6A is a schematic exploded partial view of a pair of baffles having a panel formed therebetween, 
     FIG. 7 is a schematic general plant layout, 
     FIG. 7A is a schematic general plant layout of a modified plant, 
     FIG. 8 is a schematic cross-sectional elevational view of the plant layout of FIG. 7 taken at A—A in FIG. 7, 
     FIG. 9 is a schematic plan view of a conveyor layout, 
     FIG. 10 is a schematic elevational view of the conveyor layout of FIG. 9, 
     FIG. 10A is a schematic elevational view of a baffle, 
     FIG. 11 is a schematic elevational view of a spray assembly and associated pumping apparatus, 
     FIG. 11A is a schematic elevational view of another spray assembly and its associated pumping apparatus, 
     FIG. 12 is a schematic elevational view of concrete core filling apparatus, 
     FIG. 12A is a schematic end elevational view of another concrete core filling apparatus, 
     FIG. 12B is a schematic front elevational view of the apparatus of FIG. 12A, 
     FIG. 13 is a schematic end elevational view of a mould release system, 
     FIG. 13A is a schematic end elevational view of another mould release system, 
     FIG. 13B is a schematic end elevational detail of part of the mould release system of FIG. 13A, and 
     FIGS. 14 and 14A are schematic partial elevational views of finished panels. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIGS. 1 to  6 A of the accompanying drawings there is schematically depicted a mould box or supporting frame  10 . Mould box  10  has a pair of side walls  11 , a bottom  12  and a pair of solid end doors  13 . Walls  11 , bottom  12  and end doors  13  define a cavity into which a number of baffles  14  can be inserted. 
     The sides  11 , bottom  12  and end doors  13  are preferably fabricated from solid steel or other metal or strong material. The end doors  13  are hinged at the bottom edge thereof to the bottom  12 . The doors open outwardly and downwardly as shown in FIG.  1 . The baffles  14  fit neatly into the mould box or supporting frame  10  and divide the mould cavity into sections, i.e., individual cavities between respective baffles into which building panels are cast. 
     The internal length of the mould box or supporting frame determines the panel length which is typically 2.6 m. The internal height of the mould box or supporting frame determines the panel width which is typically 0.6 m. The spacing between the inserted baffles is set by means of spacers  22  which are typically 75 mm wide. That is, the space between the baffles is typically 75 mm. It should be appreciated however that these dimensions can vary depending on the required panel dimensions. 
     As illustrated, the mould box or supporting frame is situated upon a mobile base  20  has wheels  23 . A pair of posts  19  extends upwardly from the mobile base  20 . To each post  20  there is affixed an hydraulic clamping cylinder  18 . Clamping cylinder  18  cooperates with one of the side walls  11  as shown in FIG.  5 . The opposing side wall  11  is affixed to the base  20 . 
     A lifting frame  15  as shown in FIG. 2 has a pair of hooks  21  at its lower extremities. These hooks  21  are adapted to cooperate with individual baffles  14  for the purpose of lifting the same out of the mould box or supporting frame. The lifting frame  15  can be raised and lowered by means of an overhead pulley system or crane for example. 
     With reference to FIG. 6A, each baffle  14  has a pair of spaced apart sheets  24  defining a space  25  therebetween. Sheets  24  are preferably steel or other metal such as aluminium. The sheets are intended to be substantially planar, though capable of flexing under the application of internal air pressure to the cavity  25 . Each baffle  14  has an extraction engagement hole  16 , the purpose of which shall be described below. 
     In use of the apparatus as described above, building panels can be fabricated as follows. 
     By use of an appropriate pulley or crane system, the lifting frame  15  can be raised so as to raise an individual baffle  14  from the mould box or supporting frame  10 . The baffle  14  can then have applied thereto a coating. The coating as applied to the surfaces of the baffles  14  is typically 3 mm thick. However, this dimension can vary depending on particular applications. Typically, the coating is applied by a spraying technique, typically using apparatus of a type, though smaller than, spray guns used for concrete pool finishing and in the mining industry and sold under the trade mark “Shotcrete”. 
     The coating material typically has a blend of sand, cement, water and a cross-linking polymer emulsion. The coating material can also include supplementary cementitious materials. Typically, the cross-linking polymer emulsion is sourced from National Starch and Chemicals Pty Ltd. However, there are many other polymers available and suitable for use in the present process. The emulsion is typically used as a concrete additive for repair and patching of concrete. The emulsion is used as a partial replacement for water to give flexibility and added tensile strength to the coating applied to the opposed planar surfaces of the baffles  14 . The cross linking polymer emulsion is used as a partial replacement for water to give flexibility and added tensile strength to the spray mortar skin. Optional additives to the coating material include fibres, typically polypropylene fibres as used in concrete crack control, coloured oxides, silica fume and flyash. The coating material can be modified to suit any local materials or finished panel requirements. 
     Irrespective of the emulsion used, the coating materials in general should display good adhesion to the core material, good tensile strength, flexibility, water resistance and provide a durable surface to the finished panel. 
     With the end doors  13  in the closed position, the baffle  14  is inserted into the mould box or supporting frame  10 . Alternatively, the baffles can be placed first, then the doors closed to assist in aligning the baffles into precise position. At this stage, lifting rods are also inserted into the end doors for the purpose of assisting with removal of the panels after hardening. The spacers  22  are then positioned alongside the baffle. The coating and inserting steps are repeated for the desired number of baffles. 
     The clamping cylinders  18  are then activated to force one of the side walls  11  toward the other until such time as the spaces between the respective baffles is limited by their engagement with the respective spacers  22 . 
     Whilst the sprayed coating is still fresh, the core mix is added to the cavities between the baffles. The mixture used for the core material typically has sand, cement, water, an air entraining agent and a lightweight aggregate, typically coated polystyrene beads, possibly of the type known as BST. The core material can also contain supplementary cementitious materials and/or chemical admixtures. The air entraining agent can be a commercially available admixture. The BST material has expanded polystyrene, chemically coated beads. 
     Whilst maintained in position, the wall panels are allowed to cure, typically over an 18 hour period. The coating material thus fuses with the core material to provide a strong integral wall panel. 
     After curing, the clamping cylinders  18  are released so as to remove lateral pressure from the walls  11  and baffles  14 . To assist in detaching the set panels from the baffles, air can be applied under pressure to the space  26  between the respective opposed sheets  24  of the baffles  14 . As a result the sheets  24  will flex outwardly, detaching the panels  17  therefrom. 
     Upon opening of the end doors  13 , access is gained to the ends of the baffles  14  and formed panels  17 . A hand held pneumatic cylinder has a pair of hooks is then used to push the individual panels  14  out of the mould box or supporting frame. To this end, the hooks on the pneumatic cylinder can be engaged with the extraction engagement holes  16  at the ends of each baffle  14 . A pushing element or foot of the cylinder is then engaged with the end surface of the panel  17  to push the same out through the opposed opened door region of the mould box or supporting frame. That is, the reaction force associated with this pushing action is transferred to the baffles  14  by interengagement of the hand held tool with the baffles  14 . The extraction cylinder is held like a riffle by an operator. With both doors  13  open, and upon activation of a trigger, the pushing foot pushes the concrete panel out through one of the open doors  13  to be received by a pallet for dispatch. 
     It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, the baffles  14  might have an internal frame structure to prevent the opposed sheets  24  from closing towards one another during the application of force by clamping cylinders  18 . Also, the extraction engagement hole  16  might also serve as a means of applying the required internal pressure to the baffle cavity  25  to release the formed panels  17 . 
     Furthermore, the extraction cylinder might have two triggers or a two-pull trigger action, one activation of the trigger, or one of the triggers, serving to activate engagement hooks, and the other acting to activate the pushing foot to extract the formed panel. 
     Typically, the pushing foot pushes the formed panels through a distance of about 300 mm for the purpose of allowing access for manual lifting to the pallet. 
     As an additional feature, steel or other reinforcing mesh or other reinforcing means can be positioned between the baffles to be surrounded by the core material. A further feature can be the fitting of a profiler which can trim the edge of the panel as cast and provide a detail such as a tongue and groove to the edge. 
     In FIGS. 7 to  13  of the accompanying drawings there is schematically depicted the plant layout and other detail associated with a modified method and apparatus for forming building panels. FIGS. 11A,  12 B,  13 A and  13 B show further modified apparatus. This plant layout is designed for higher production throughput than is the case as discussed above with reference to FIGS. 1 to  6 A. The overall method is similar to that described above with reference to FIGS. 1 to  6 A. 
     In the plant of FIGS. 8 to  13 , the baffles no longer include a pair of spaced metal sheets, but instead are formed as a single sheet of material or laminated solid layers of material. Typically, a single sheet of plastics coated plywood forms each baffle  14 . The plant layout of FIGS. 7 and 8 can be described as follows. The individual baffles are placed in a mould box or supporting frame  70  and carried by a fork lift to a chain drive conveyor  71 . The individual baffles are then picked up by a baffle unloading hoist  72  and conveyed in the direction indicated by arrow A along a suspended pipe conveyor  73 . The pipe conveyor conveys individual baffles to a cleaning and oiling station  74  where the baffles are cleaned and coated with oil which acts as a mould release agent. The individual baffles are then conveyed to spraying station  75  where the individual baffles are coating material on both sides with a coating material. The panels are then conveyed by the pipe conveyor to the core filling station  76 . During the time that the baffles are conveyed by the pipe conveyor  73 . The empty mould box or supporting frame  70  is conveyed by a chain drive or other conveyor apparatus to a rotation station  77  where the mould box or supporting frame  71  is rotated through 180° and then further conveyed by the conveyor belt or chain drive conveyor the core filling station  76 . At the core station  76 , the mould box or supporting frame receives the cleaned, oiled and coated baffles for core filling. 
     A core filling apparatus receives the filler material from a mixer  79 . 
     In FIG. 7A, there is schematically depicted in plan view a modified plant layout. FIG. 7A shows the baffle preparation station  400 , the spray station  75 , the mould assembly station  410 , the mould filling station  78 , a demoulding and mould disassembly station  420  and an edge detailing and palletising station  430 . The baffles  14  are suspended from a monorail  73  that is used to transport the individual baffles through the process stations  400 ,  75  and  410 . Individual baffles are cleaned, oiled and generally prepared such that they can receive the settable coating material and can be separated from the moulded panel after it has cured. 
     Demoulding and mould disassembly which occurs at station  420  takes place as follows. Once the panels are sufficiently cured and hardened, the still full moulds are disassembled to remove the panels. The baffles and panels are progressively stripped from the mould frame. The device and operators first take off the outermost baffle and replace it on the monorail as at the beginning of the process. The device and operators then separate the outermost panel from the mould frame and deliver it to the edge detailing and palletising station (FIG.  14  and FIG.  14 A). The process is repeated until all of the full mould has been disassembled and the formed panels removed and delivered to the detailing station. 
     Features of the edge detailing and palletising station are shown in FIGS. 14 and 14A. The formed panels are delivered to the edge detailing and palletising station to be completed. The edge detailing station uses a grinding wheel to create a groove  500  in one long edge of the panel to match the tongue  510  that is formed in the opposite long edge of the panel during the casting process. Once the panels have edge details complete, they are palletised for final curing and ultimate delivery to the customer. In some cases, the panels are cut to different sizes prior to palletising. The panels are indicated by reference  520  in FIG.  14  and FIG.  14 A. The finished panels have a surface finish thereon to determine by the surface texture of the baffles. The settable core material melds to some degree with the skin material and provides a hard wearing and durable surface in the finished panel which does not require subsequent rendering or in situ cosmetic treatment. 
     In FIG. 10A, there is schematically depicted an individual baffle  100  which includes a plywood panel  105  surrounded by a steel frame  101 . At the upper part of the steel frame  101 , there extends a pair of projections  102  which are engaged by hooks suspended from the pipe conveyor. At the bottom of each baffle  100  there projects a pair of mould box or supporting frame alignment lugs  104  which serve to engage with a locating track  135  in the bottom of the mould box or supporting frame, which locating track includes recesses  136  which are spaced by a set distance defining the thickness of a panel to be moulded between the baffles. 
     In FIG. 11 there is shown the detail of a method of simultaneously spraying both sides of a solid baffle  14 . The spray assembly includes a plurality of spray guns  110  positioned at both sides of the baffle  14 . The baffle  14  is drawn by the pipe conveyor  73  inbetween the spray guns  110  during spraying so as to achieve a uniform coating on each side. A carriage  112  is associated with the pipe conveyor  73  in somewhat the same manner as a curtain ring is associated with a curtain rod. The carriage is pulled along the pipe conveyor by a cable or chain. A cable  113  suspended from the carriage  112  includes hooks  103  (FIG. 10A) which engage with the projections  102  of each baffle to suspend and convey the baffle  14 . 
     Also shown in FIG. 11 is a coating material pump  114  which provides a head of a coating material to a coating material metering and delivering apparatus  115 . The metering and delivering apparatus  115  operates like a vein pump and includes a number of wheels or rollers which pass along fixed lengths of tube through which a coating material passes. The rate at which a coating material is delivered to the spray nozzles  110  can be adjusted by altering the distance of travel of the rollers along the lengths of tube, by altering the length of tube, or by altering the diameter of the tubes. 
     In FIG. 11A, a baffle spraying apparatus is shown associated with a different type of pumping apparatus. The individual baffles  14  are sprayed on both sides with the coating material mixture. The mixture is predominantly a water, sand, cement, flyash, fibre, polymer, and other concrete additive blend. It is prepared in a mixer  200 . The mixer  200  delivers the coating material mixture to a pump  115 . The pump  115  delivers the mixture via hoses  111  to the spray guns  110 . The mixture which is under pressure is sprayed by the guns  110  onto the baffles  14 . The mixture then coats the vertical surfaces of the baffles  114 . 
     In FIG. 12 there is depicted a baffle supporting frame  120  and associated core filling apparatus  78 . The core filling apparatus  78  includes a hopper  121  which is filled with sufficient core material to fill the space between all baffles in the baffle supporting frame  120 . The hopper  121  is pivotally mounted at  122  to a frame  123 . Extending from the hopper  121  is a pair of filling tubes  124  through which core material from the hopper can pass. The hopper  121  and filling tubes  124  are adapted to be drawn vertically upwardly along a track  125  by means of a hoist. Once raised into a position wherein the filling tubes  124  are vertically clear of the baffles in the cavity box, the hopper can be pivoted vertically about pivot axis  121  into the vertical position depicted at the right in FIG.  12 . Alternatively, the hopper can be pivoted prior to lifting. By means of the hoist, the hopper  121  can be lowered such that the tips of the fill tubes (which are now extended downwardly from the hopper) are nearby the bottom of the mould box or supporting frame between a pair of baffles. Means are provided for oscillating the hopper  121  from side-to-side in the direction indicated by arrow B whilst raising the hopper  121  and nozzles  124  in the direction indicated by arrow C. The means for providing the oscillation in the direction of arrow B can be camshafts, solenoids, pneumatic rams, hydraulic rams or other oscillation mechanisms. The aim is to fill the space between the baffles with core material at a controlled rate. That is, the rate of delivery of the core material is adjusted such that the core is filled at the same rate as the rate at which the nozzles are vertically withdrawn from the mould box or supporting frame. This controlled rate of filling prevents the core material from shearing a coating material from the baffle surfaces during the filling process. Once space between a pair of baffles is filled, the mould box or supporting frame is shifted along so as to align the next, empty cavity with the filling tubes whereupon the filling tubes are lowered with hopper  121  and the process continued. It should be noted that the hopper  121  and the fill tubes  124  oscillate backwards and forwards in the direction indicated by arrow B during vertical withdrawal such that the tips of each fill tube  124  follow a sinusoidal path. This method of filling also prevents the encapsulation of air pockets in the core. 
     In FIGS. 12A and 12B an alternative core filling station is depicted. Once the moulds are assembled with the settable coating material on each face of the baffles, they are moved into the filling station depicted. The filling station places the core mixture in the moulds, filling the space between each baffle. The core mixture is predominantly a water, cement, flyash, modified and coated EPS, polymer, and other concrete additive blend. The core mixture is prepared and mixed in a core mixer  210  mounted upon a frame above hopper  122 . The core mixture is then delivered to the hopper  122 . The core mixture is delivered from the hopper  122  via the nozzles  124  into the moulds. The hopper  122  and nozzles  124  move in such a manner that the core mixture is placed into each individual space between mould leaves until the entire mould is filled. The moulds are then stored for an adequate period of time to allow partial curing and hardening of the panels. The mixer  210  includes a horizontally oriented substantially cylindrical mixing tub  211  having an opening  212  through which ingredients pass for mixing in the tub  211 . A helical blade or blades  213  are located upon a rotating shaft  214  which is driven by an external motor  215 . The tub  211  is pivotally mounted upon a shaft which is common or coaxial with the shaft of the mixing blades. The tub  211  can pivot so as to allow delivery under flow of the mixed material to the hopper  122 . 
     The nozzles  124  receive the core material from the hopper  122  by a device such as an auger  215  or other pumping device. 
     In FIG. 13 there are shown first and second baffles  14  alongside the side wall of the baffle supporting frame  120 . The upper edge of the sidewall includes a vertically projecting pin  130  which cooperates with a baffle locking pin  132 . The baffle locking pins  132  each include a pair of legs  131 , each defining recesses  133  into which lugs  134  projecting from the ends of each baffle are received. The distance between the recesses  131  defines the spacing between the baffles  14  and thus the thickness of the panels produced. The locking pin  132  at the right hand side shown in FIG. 13 cooperates with the vertically projecting pin  130  to define the position of the first baffle  14 . The locking pins as well as the interaction of the lugs  104  with the bottom of the baffle supporting frame  120  rigidly secure each baffle in place. Also shown in FIG. 13 is a locating track  135  at the bottom of the mould box or supporting frame and defining recesses  136  into which the lugs  104  are received. The locking pins  132  are positioned so as to extend into the space between each baffle and are twisted by a mechanical means through 90° to engage the recesses  133  over the respective pins  134 . 
     In FIG. 13B, there is shown in more detail one of baffles  14 . The baffles are a composite involving plywood, nylon, PVC, and steel. The manufacturing process involves the automation-assisted assembly, filling and de-assembly of the moulds. 
     After setting of the core material, the locking pins  132  are rotated through 90° in the opposite direction to enable release of each panel for conveying out of the mould box or supporting frame. 
     In FIG. 13A there is shown apparatus alternative to that shown in FIG.  13 . Instead of the apparatus indicated by reference numerals  130 ,  131 ,  132 ,  133  and  134 , a plurality of locking clamps  300 ,  302  and  303  are provided. Each locking clamp has a plurality of downwardly depending lugs  304  which, in cooperation with the upper edge of each baffle defines the baffle spacing. Features at the lower end of each baffle are substantially identical with those as described above with reference to FIG. 13. A locking handle  301  is pivotally connected to the locking clamp  300  and includes a tab  305  to engage with features provided at the upper edge of each baffle. A similar tab  305  is provided at the remotely located depending lug of each locking clamp. By use of the apparatus of FIG. 13A, after being sprayed, each individual baffle is moved along the monorail to the mould assembly station. At the mould assembly station, the baffles are assembled into the mould frames and locked into position with the locking clamps otherwise known as “mould combs”. 
     An important distinction between the baffles of the process of FIGS. 7 to  13  to that of FIGS. 1 to  6 A is that it is no longer necessary to apply air to release panels from the baffles. This is due to the fact that the baffles are solid. Also, there is no need to apply lateral force to each baffle to position the same as described with reference to FIGS. 1 to  6 . 
     Also, a hand-held pneumatic cylinder is not used in the plant of FIGS. 7 to  13  to remove the panels from the mould box or supporting frame. Rather, each baffle is sequentially moved sideways and lifted from the mould box or supporting frame using a lifting system as described earlier.