Typical Process Flow of a PU Sandwich Panel Continuous Line

1. Definition

A continuous PU sandwich flow forms metal skins, injects reacting polyurethane between them, and cures under a heated double-belt press before tracking cut-to-length. This page is the process map for that family. Detailed m/min and kW tiers live on the PU equipment and speed-tier pages — do not paste PU-edge rockwool or EPS glue numbers into this sequence.

2. Station sequence

1. Upper / lower decoil
2. Feed / shear / protective film as configured
3. Rib / roll form skins (upper and lower)
4. Steel preheat / coat as specified
5. High-pressure PU pour / foam at laminator entry
6. Cure under double belt (~24 m class on the recommended sheet)
7. Tracking / band saw cut (length tolerance about ±2 mm class)
8. Fast roller table → cool / stack (project options)

Industry continuous-line descriptions use the same spine — uncoil, form, preheat, foam, double-belt cure, cut — as market context. The contract equipment list decides which optional modules ship.

3. Double-belt role

The double belt constrains foam expansion, sets panel thickness, and provides heat/time for cure. Side belts control width and guide the panel. Line speed and belt length trade off with chemistry and core thickness — usable speed is not a free upgrade from a longer catalog belt alone.

4. Optional units

Some quotations also list rockwool spray, edge treatment, or rectangular-wool handling. Include them in the process story only when present on the confirmed BOM. Presence of those units does not convert this page into the PU-edge rockwool continuous flow, and absence does not authorize inventing a “pure foam only” claim against a BOM that lists them.

5. Layout and ratings checkpoints

Belt hard-foam variant (~2–6 m/min; ≥35 kW; rubber-belt curing) is a separate tier — see the speed-tier page. Do not merge into one “PU flow speed.”

6. Boundaries

• Not EPS / rockwool glue composite — glue spray + hand-fed boards is a different process page.
• Not PU-edge rockwool continuous — edge foam around mineral wool is a different BOM and power sheet (~90 kW whole-line class).
• Not carved facade / decorative wall equipment — different machine family.
• Do not use this flow’s 4 m/min / 40(+90) figures as the answer for a rockwool-edge inquiry.

7. Buyer FAQ

Is belt hard-foam the same station list?

Same chemical idea (foam between skins), but curing conveyor hardware and speed tier differ. Label “belt hard-foam variant” when that quotation applies; do not force-merge with the 24 m double-belt recommended sheet.

Does every PU continuous quote include rockwool handling?

No. Rockwool spray / edge / rectangular handling appear only when listed. Confirm the BOM before describing the plant as foam-only or hybrid.

Where does the tracking saw sit?

After double-belt cure, synchronized with strip speed for cut-to-length. Recommended wording cites about ±2 mm length class and ~7.5 kW saw power — still subject to the named proposal.

Can I use this flow for PU-edged rockwool panels?

No. Open the PU-edge rockwool process page. Sharing the word “PU” does not make the station lists interchangeable.