Typical Process Flow of a C/Z Purlin Roll Forming Line

1. Process purpose

Continuously convert coil into punched C or Z structural purlins cut to programmed length for steel building frames. This page describes the shared process route — not a single machine’s speed or power table.

2. Route steps

1. Uncoiling — hydraulic or mechanical decoiler holds and feeds the strip
2. Leveling / feeding — removes coil set so punch and form stay stable
3. Punching — bolt and service holes per the buyer drawing (pre-punch is common; layout is not optional guesswork)
4. Roll forming — progressive stands create C or Z geometry; C/Z interchangeable lines add changeover at this stage
5. Shearing — stop-cut, flying shear/saw, or twist-break by ordered configuration; some packages also use front (pre) shear
6. Exit / stacking — run-out table or automatic stacker on higher-automation lines

Public line diagrams commonly show: decoiler → leveler → pre-punch (± pre-cut) → mill → post-cut → stacker. Exact station count follows the proposal.

3. Where this flow applies

• Structural C purlin lines for PEB / warehouse secondary framing
• Structural Z purlin lines with lapping-friendly geometry
• C/Z interchangeable hosts that share the same process spine with a changeover module

4. Station notes (not a rating table)

Do not invent a universal m/min or kW on this process page — those belong on the named C / Z / C/Z machine proposal.

5. Quality and quoting checkpoints

• Compare production speed only when punch map and shear type match
• On C/Z interchangeable lines, confirm changeover time before comparing throughput to a single-section mill
• Do not treat pre-cut vs post-cut as the same cut package — end flare, blade sharing, and scrap behavior differ

6. Boundaries

• Not a light-gauge stud/track process map
• Not a place to publish averaged “industry” speed numbers
• Shear-variant details → dedicated shear encyclopedia entry

7. Buyer FAQ

Is punching always before forming?

Pre-punch is the common structural-purlin pattern. If a proposal places punch differently, follow that drawing.

Where do speed numbers belong?

On the named C, Z, or C/Z machine page / proposal — not as invented averages on this process page.

What is the usual end-to-end station order?

Public diagrams typically show decoil → level → pre-punch (± pre-cut) → form → post-cut → stacker. Station count is proposal-specific.

Does C/Z changeover sit inside this flow?

Yes — changeover is part of the forming stage on interchangeable lines. It does not create a separate process family.