Insulated Sandwich Panel Line

Overview

An insulated sandwich panel line turns two coils of pre-coated steel and a pair of liquid foam components into finished wall and roof panels in one continuous run. The line pays out top and bottom strip from the Decoiler Section, rolls each strip to its profile in the Roll-Forming Section, lays expanding foam onto the lower skin at the Foaming Section, then carries both skins and the rising foam through the Double Belt Laminator laminator, which holds them to the set panel thickness while the foam bonds. The bonded panel passes through the Curing Oven to finish the reaction, the Cooling Section to bring it back near room temperature, the Flying Cutoff Saw to cut it to length, and the Stacker to lift and stack it for packing. The Control System system keeps line speed, foam ratio, oven zones, and cut length in step so every panel comes out to spec.

Because the line never stops, a panel is in effect extruded endlessly and then cut where it suits the order. A typical line runs 3 to 15 m/min and makes panels 1000 to 1200 mm wide and 30 to 200 mm thick, which covers most wall and cold-store roof work from one machine.

Feeding the strip

The Decoiler Section holds two coils, one for each skin. Each sits on a hydraulic Hydraulic Uncoiler whose Expanding Mandrel expands into the coil bore and centres it, while a Tension Brake holds back-tension so the strip stays flat. A Coil Car brings the next coil from the bay and lifts it onto the reel. When a coil runs out, the Strip Joiner cuts the tail and joins the head of the fresh coil, and the Strip Accumulator pays out its stored loop over an Accumulator Carriage so the line keeps running through the change. An Edge Guide keeps the strip on centre and a Film Applicator lays peelable film over the finished face so it reaches the building site unmarked.

Forming the skins

The Roll-Forming Section shapes each flat strip into the panel face. The Top Skin Former and Bottom Skin Former banks each carry a row of Forming Stand housings, and each stand holds a pair of contoured Profile Roll tools on driven Roll Shaft shafts geared through a Helical Gear Pair. Every stand bends a little more of the rib or micro-profile into the strip, so by the end of the bank the flat coil has become the finished skin shape. The Joint Former rolls the tongue and groove side lap that lets finished panels lock and seal to each other on the wall. Before the strip reaches the foam, a Surface Treater raises the surface energy of the inner face so the foam grips the steel.

Foaming and lamination

Core quality is set at the Foaming Section. Two Day Tank tanks hold polyol and isocyanate at temperature, each warmed by a Component Heater built around a Heating Element. A Metering Pump on each line delivers its component at high pressure and the exact ratio the recipe needs, and the two streams meet in the Mixing Head. There the Injector Nozzle jets collide in the Mixing Chamber, and a Cleanout Piston sweeps the chamber after each pour so the mix stays clean. A Pour Carriage sweeps the head across the strip so the foam covers the full panel width.

The foam-coated lower skin and the top skin then enter the Double Belt Laminator. Its Upper Belt and Lower Belt are conveyors of Belt Platen plates pulled on Belt Chain chains over Belt Roller drums and driven by a Belt Drive Motor. The foam rises and pushes hard against both belts, so a set of Thickness Jack jacks holds the upper belt at the panel thickness, while a travelling Side Dam Belt dam closes the edges so the foam forms a clean side. The Laminator Frame reacts the rise pressure across the whole width.

Curing and cooling

The laminator zone sits inside the Curing Oven. An insulated Oven Enclosure holds the heat, several Zone Heater units warm each length of tunnel, and Circulation Fan fans driven over a Fan Impeller move the air so the cure is even across the panel. Each Oven Thermocouple reports its zone back to the controller. Holding 40 to 70 C through the belt zone lets the foam reach full strength and bond to both skins before the panel is free to leave the press.

The cured panel passes into the Cooling Section. The Cooling Conveyor carries it on Cooling Roller rollers driven by a Drive Belt, while Cooling Fan blowers draw out residual heat. Cooling before the cut keeps the foam from moving after the panel is sized.

Cutting, stacking, and use

The Flying Cutoff Saw cuts the endless panel to length. A Saw Carriage runs along at line speed on a Linear Guide Rail pair while a carbide Saw Blade spun by the Blade Motor crosscuts both skins and the core in one pass. A Length Encoder measures panel travel so the cut lands at the ordered length, and a Dust Extractor pulls away foam dust and chips. Downstream, the Stacker lifts each panel with a Vacuum Lift Beam of Vacuum Cup cups fed by a Vacuum Pump, moving on Stacker Servo axes and Ball Screw lifts, and sets it on a growing stack for banding and shipping.

The whole line is held together by the Control System cabinet, where a Line PLC runs the sequence, a Operator Panel panel selects the recipe, a set of Line Drive drives hold each motor on speed, and a Temperature Controller holds the oven and component setpoints. These panels go to industrial roofs, cold stores, and clad warehouse walls, where a light steel-skinned panel with a foam core gives insulation and a finished surface in one fixing step.