Production Processes: Sandwich panels with rigid facings are produced using two variants in production techniques, viz: 1. Contin Continuous uous product production ion proces processs and and 2. Semi Semi Discon Discontin tinuous uous prod product uction ion proces process. s. Production aspects in either process are aimed at producing products with similar enduse features. !lthough equipment ma" loo# drasticall" different, the $asic foaming techniques and process steps featured in foam production are ver" similar. similar. 1. Continuous Panel Production: Continuous panel ma#ing process involves all ope rations starting from forming sheet metal profiles required for $oth faces, creation of Pol"urethane foam %or &amella 'oc#wool(, creation creation of the panel to panel )oining profile detail, curing of the composite and final cutting of product to length all along a continuous conve"orised line. *wo *wo separate 'oll formers for the two metal facings start from coils of sheet metal and issue out the two facings, which move to the moulding area. ! pair of moving side $elts of a fle+i$le material on either side creates the side closures for retaining the liquid chemicals and for the rigid foam to fill. *hese side $elt also acts as moulds to generate the edge profile. *he top and $ottom sheets are supported continuousl" $" a slat and side chair conve"or precision with plattens #eeping the sheets pressed against the side $elts. *hic#ness *hic#ness of the panel is determined $" the gap $etween the two platten forces and the vertical height of the side $elt featured in each case. *he two sheets and the two side $elts enclose and create the moving hollow space, which is the mould. -rethane chemicals which are carefull" selected are in)ected as precisel" metered individual streams, $lended into one streams and distri$uted evenl". here needed, the inner surface of profiled metal is given a C/'/0! treatment to improve improve $onding strengths. *he chemical s"stem is delivered in to the mould $" an oscillating manifold on which deliver" nozzles are mounted at equal spacing. *hese lines of the liquid chemical mi+ture slowl" find their level over the $ottom sheet evenl". *he" start reacting after the cream time is reached. *he foam then starts to rise, till the rise time is completed. *he top surface of the foam starts to adhere to the $ottom surface of the top sheet after the tac#free time is attained. !ll these these reactions proceed even as the whole mould is moving along. *he Pressure platten conve"ors over the two sheets along with the side $elts are long eno ugh to #eep the Sandwich in closed state for a sufficientl" long duration so that the finished pane ls is full" curved in all respects $efore it leaves this crucial section of the line.
t is to $e noted that the densit" of foam selected for all sandwich panel ma#ing processes are sufficientl" higher than the freerise densit" of the foams. *his is required to ensure that the foam fills all the noo#s and corners of the mould. *he finished panel is cut to length $ " microprocessor controlled cross cut saws cutting the sandwich assem$l" two sheet facings and the foam together. *he a$ove is the $rief process used, which is specificall" tailor made for production of $uilding and cold store panels of e+tra ordinar" uniformit" at ver" production speeds. 2. Discontinuous Panel ma#ing process: n this production process, the principle of panel p roduction is e+actl" similar to the a$ove continuous process. 3owever, all the activities are conducted in a stationar" single station, as against a moving arrangement descri$ed a$ove. *he equipment used is #nown as the Panel Press, which features a vertical h "draulic ram of the length and width of the largest panel desired to $e produced. Profiling of the two faces of metallic facing %or an" other facing li#e 4'P, P5C etc( is done as an off line processes and $rought to and stac#ed on either end of the press. *he mould is created as follows: *he $ase on which the $ottom facing is placed is a precisel" machined flat Platten equipped with a $uilt in heating s"stem. Sides of the mould are made of machined !luminum e+trusions %)igs(, profiled to the male and female )oint features desired. *hese )igs are specific to each thic#ness of panel $eing produced. 6igs also feature accuratel" positioned fi+tures to mount C!7&/C89 components, which get em$edded in to the foam later. hen the preprofiled top and $ottom facing sheets are placed in this mould with special spacers, we create a hollow space which is read" for chemical in)ection complete. *his complete preassem$l" is moved laterall" into the da"lights of the press $ " a positioning actuator. ! heav" ram, which is a precision machined guided $loc#, closes the mould tightl" and holds the mould firml". *he temperature controlled heated plattens #eep the mould at the optimum reaction temperature. *hrough man" nozzles provided on the sides of the mould, P- chemicals mi+ is in)ected to precise volume as per settings in the microprocessor controlled deliver" head. *he liquid mi+ finds its level well $efore the cream time of the chemicals is reached. *he foaming reaction starts and the foam rise graduall" to fill the noo#s an d corners of the mould. *he rising of the foam is complete well $efore the tac#free time, when the adhesion to the sheets starts i.e., well after the foam has filled the mould. *he assem$l" is held in position, in the preheated mould till after the mould release time has elapsed. 7aintenance of each of the time elements of the process is achieved using the microprocessor assisted control s"stem.
*he a$ove descri$es a single panel manufacturing process. 3owever, our modern panel presses feature multiple da"light, dou$le acting machines involving creation of two, four, si+ or more panels in one operation. !s e+plained earlier, each of the a$ove processes are engineered to result in optimum finished product features. 3owever, there are differences in respect of some features and limitations in each. *hese are discussed as follows: 1. !s the name implies, Continuous panel plants produce panels continuousl", with highest uniformit" of properties and dimensions which can $e cut to longer lengths. 3owever, transportation limitation ma" restrict the length to 12 mtr. %Discontinuous panel plants are also a$le to deliver such lengths.( 2. *he main aspect of a continuous plant is the speed of production $eing continuous the manufacture of panels can $e theoreticall" speeded up using faster conve"ors. *he longer process lines emplo"ed in our plants ensure that the panel moulds retains the panels together till the various process times are ensured comforta$l" $efore reaching the cooling curing section of the plant, even at the fastest speed. ;. Panels made in continuous plants show higher uniformit" in foam qualities and $etter architectural flatness. <. /lder Panel presses, which had limited lengths of =mtr %ma+(, have now $een replaced $" machines with a mould length of 12.> m. 3ence, these machines manufacture panels to the longest transporta$le lengths toda", there$" removing this limitation. >. 7ultiple da"light and dou$le acting panel presses have greatl" increased the overall production speeds and capacities. 7ultiple da"lights permit more than one panel pre assem$l" to $e closed at a time. Dou$le acting arrangement features a central ram, which can move up to close and hold the top arra" of moulds, and in its movement downwards, to close and hold the $ottom arra"s. Precision machined platterns have improved the aesthetics of these panels as well. *his process is descri$ed as semi discontinuous, and, in terms of speed of production, ver" closel" match with that of some of the continuous lines, within a more compact production shop. =. Semi discontinuous panels press concept facilitates production of panels featuring Cam &oc#s9 to interloc# panels together for additional integrit". *his is also gives the advantage of producing panels of widths which ma" $e non standard in a mi+ of sizes as ma" $e required. Panel manufacturing capa$ilit" availa$le to us in the &&/?DP!0@& s"stem meets and e+ceeds the dut" requirements of all $uilding designs and those of an" scientificall" designed and constructed cold storage. *he most versatile discontinuous plants at Pithampur and Aaddi along with argua$l" the most modern continuous panel plant in the world at che""ar, *amil 0adu give the compan" a ver" large and geographicall" distri$ution $ase. !ll the facilities also incorporate
inhouse state of art la$orator" facilities for testing all significant properties, including *hermal conductivit", Compressive B Shear B 4le+ural strengths, *hermal sta$ilit" and all relevant Pfoam tests. /ur plants are S/ accreditated and produce products to meet all nternational Standards. e have had the privilege of meeting and e+ceeding the standards prescri$ed $" -0&@5@', A@C3*@&, 7C3@&0, A'/0 E '//*, 4@''!'/ '/C3@', 0DDA, and man" such international users. 0eedless to state, we have the largest e+perience in 4ield erection and finishing of &lo"d panel S"stem countr"wide through dedicated crews to ta#e full responsi$ilit" for correct implementation, finishing and commissioning, speedil" and to prescri$ed standards. /ur technical and contracting capa$ilities are well #nown to important customers and we normall" spare no efforts to place them totall" at their disposal of pro)ect implementing teams. n the latest manufacturing unit of &&/?DS, these pane ls are produced in e+tended lengths featuring continuous production processes which are pro$a$l" the most advanced in the world. *he rigid urethane foams featured in this plant are 1F free from C4C or 3C4C, which are #nown /zone depleting su$stances.
