Metal Deck Rollformer

Overview

A metal deck rollformer turns a flat coil of galvanised steel into long corrugated panels that become the structural deck of floors and roofs. The strip never stops moving: it pays off a coil at one end, passes through a row of shaped rollers that bend it a little more at each pass, and comes out the far end as a finished profile that is sheared to length and stacked. Because the shape is made by rolling rather than pressing, one machine can run thousands of metres of identical deck in a shift, and the only limit on panel length is how the panels are handled after the cut.

The line is built around nine subsystems. The Hydraulic Decoiler holds the coil and feeds strip under tension. The Entry Guide and Leveller squares the strip and flattens it. The Roll-Forming Station Bank does the shaping. The Drive System turns every roll at the same speed. The Hydraulic Shear Press cuts each panel to length. The Run-Out Table and Stacker catches and stacks the panels. The PLC Control Panel runs the sequence, the Centralized Lubrication Unit keeps the bearings fed, and the Baseplate and Frame holds everything to a common pass line.

How it works

Forming happens in small steps. A flat strip cannot be folded into a deep corrugation in one move without splitting or buckling, so the profile is built up across many passes, each adding a few degrees of bend. The strip enters flat, picks up its first shallow ribs, and leaves the last stand as the full deck section. This gradual approach is why a deck line has 14 to 20 stations rather than one heavy press. The strip is pushed through by the rolls themselves, which all turn at one matched speed so the metal is neither stretched nor bunched between stands.

The decoiler runs the line from the back. Its Expanding Mandrel expands inside the coil bore through four Mandrel Jaw Segment shoes driven by the Mandrel Expansion Cylinder, so the coil is gripped from the inside and spins on the Decoiler Bearing Stand. A Friction Tension Brake drags on the hub to keep back-tension, and a Coil Hold-Down Arm stops the wrap springing loose. The strip then runs into the Seven-Roll Leveller, where seven staggered Leveller Work Roll rolls flex it past yield in alternating directions to take out the curve set by the coil. Without this step the finished panel would bow.

The forming stations

Each Forming Roll Stand is one pass of the profile. A Upper Roll Shaft and a Lower Roll Shaft carry a matched pair of Profiled Forming Roll rolls, positioned along the shaft by Shaft Spacer Ring rings to set the rib pitch. The shafts run in Ball Bearing bearings inside two Stand Side Housing side plates, and a Top Shaft Screw-Down sets the gap between the rolls. The forming rolls are tool steel hardened to about HRC 60 because they carry the full forming load on every metre of strip, and the whole roll set changes when the line switches to a different deck shape. Toward the end of the line a few Edge Side-Roll Stand stands carry vertical Vertical Side Roll rolls that turn up the panel edges to form the side lap by which one panel hooks to the next on site.

Drive, cutting, and control

Every lower shaft is driven, not idle. The Drive System takes a Servo Motor through a Helical Gearbox and a single Roller Drive Chain running over a Shaft Drive Sprocket on each shaft, with Chain Tensioner idlers keeping it tight. Driving all shafts together is what keeps the line speed matched across the profile.

Cutting is done after forming, not before, because a flat strip is easy to cut but a formed panel needs a shaped tool. The Length-Measuring Encoder counts panel length and tells the PLC when to fire. The Cutting Cylinder cylinders then drive the Hardened Cutting Blade down through the panel against the Profiled Shear Die, which is profiled to support the full section so the cut stays square. Oil comes from the Hydraulic Power Unit, where a Gear Pump feeds the Directional Control Valve under guard of a Pressure Relief Valve. The PLC Control Panel holds the PLC, the Line Drive VFD that ramps line speed, and the Touchscreen Operator Panel where the operator sets length, quantity, and profile.

Materials and roll sets

Deck is rolled from structural galvanised steel in grades from G350 up to G550, in thicknesses of 0.7 to 1.5 mm. The zinc coat means the line must not scuff the surface, so the Run-Out Roller rollers are free-turning and the rolls are kept clean. Higher grades spring back more after each bend, so a line set for G550 uses slightly tighter roll gaps to land on the same final shape. The profile itself is fixed by the forming rolls, so changing from a 38 mm floor deck to a deeper roof deck means swapping the full roll set and resetting the Vertical Side Roll positions.

Use

Deck rollformers sit in steel-building plants and at large precast yards. They run long, repetitive orders where panel length is set by the building bay, often 6 to 12 m, and where every panel must match so the deck lays flat and the side laps engage. Floor deck carries wet concrete until it cures and then acts as permanent formwork and tension reinforcement; roof deck spans purlins and carries insulation and membrane above. The Run-Out Table and Stacker drops finished panels into neat bundles for banding and shipping, and the line is ready for the next length without changing tools as long as the profile stays the same.