Purlin Production Line: Every Piece of Equipment You Need (With Layout)

Short answer: A complete purlin production line needs seven equipment groups in one sequence: hydraulic decoiler → leveler → hydraulic pre-punch → roll forming main unit → cut system → PLC control cabinet + HMI → run-out table. A mid-size CZ line typically processes 1–3.2 mm galvanized coil into C/Z purlins with webs of 80–300 mm, at 12–32 m/min depending on configuration, with ±1–2 mm length accuracy under PLC control. Budget in four parts: forming main unit, coil handling, punching/cutting hydraulics, and controls/auxiliaries — and always check what each quote includes before comparing.

This guide lists every module, explains capacity planning, gives a factory layout sketch, and compares starter vs automated budget tiers.

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The 7 equipment groups, in line order

1. Hydraulic decoiler — holds the coil and feeds strip under control. Sizes range from a single 3–5 t unit (coil ID φ508/φ610 mm) up to dual-head 6 t/head (12 t) units that allow the next coil to be loaded while the line runs. Coil width capacity (e.g. ≤600 mm) must match your strip.
2. Leveler (guiding/leveling unit) — flattens the strip and removes coil set ahead of punching and forming. Multi-roll plated shafts (e.g. 3-up/4-down) are typical.
3. Hydraulic pre-punch station — punches web holes (and slots) before forming, while the web is flat, so hole positions stay accurate. Common builds use 2–3 stations; patterns follow the profile drawing (e.g. 14.3 × 25.4 mm ellipses).
4. Roll forming main unit — the heart of the line: 16–22 forming stations (auto-change lines often 20 stands) progressively bend flat strip into the C, Z or U profile. Key materials: rollers Cr12/GCr15 (HRC 58–60), shafts 40Cr (Φ75–100 mm) or 45# steel heat-treated, chain or gearbox drive.
5. Cut system — hydraulic stop-cut (line pauses) or servo tracking cut (cut-on-the-fly, line keeps running). Post-cut with punch assist is common; length accuracy roughly ±1–2 mm under PLC.
6. PLC control cabinet + touchscreen HMI — sets length, batch quantity, speed and (on auto-change lines) the C↔Z recipe. Remote assistance / network control optional.
7. Run-out table — receives finished purlins for bundling; lengths commonly 6 m and up, sometimes with inkjet marking before the table.

Optional but valuable: inkjet marking (prints size/batch per piece) and automatic stackers/strappers at the high-volume end.

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What real CZ purlin line specs look like

Published process data (ZTRFM) for a CZ auto-changeover line:

Module	Example specification
Decoiler	Dual-head hydraulic, 6 t/head (12 t), width ≤600 mm, ID 450–550 mm, OD 1730 mm, brake, electric rotation
Forming	20 stands; rollers Cr12 HRC 58–60; shafts 40Cr Φ90/75; chain drive; optional emboss rolls
Punch/cut	Hydraulic pre-punch, 3 stations; cut + punch power 15 kW; oil tank 300 L
Drive	Servo host 42 kW; high ~32 m/min, normal 12–18 m/min; 380 V / 50 Hz / 3-phase
Gauge	1–3.2 mm Q235/Q355 (HR or GI); inkjet marking; 6 m run-out table; Xinje PLC; ZH/EN UI
Changeover	Auto C↔Z recipe in HMI, ~90–120 s

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Capacity planning: from 500 m to 5,000 m per shift

Estimate output with this sequence:

1. Effective speed — use the normal forming speed for mixed work (e.g. 12–18 m/min) rather than the high-speed figure; punching cadence and cut system lower real throughput.
2. Line utilization — assume 70–80% of shift time for coil changes, set-up and QC on real production.
3. Meters per shift — a line doing 15 m/min average for 6 productive hours ≈ 5,400 m/shift theoretical, realistically ~3,800–4,300 m.
4. Tonnage — multiply meters by kg/m for your section (gauge × developed width × steel density) to check whether coil handling and decoiler capacity match.

Choose decoiler class (3–5 t vs 6 t/head dual) by your largest coil and how often you tolerate changeover stops.

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Factory layout essentials

Minimum line footprint and surroundings to plan:

• Line length: forming + cut + run-out typically needs ~20–30 m in one straight bay (e.g. a 15–20 m machine plus a 6 m run-out table and decoiler space).
• Coil storage: a bay beside the decoiler for current + next coils (forklift or coil car access).
• Finished-goods area: run-out table exit with space for bundling, strapping and forklift pickup.
• Power: check voltage (e.g. 380 V / 50 Hz / 3-phase or 220 V / 60 Hz per order), total connected load (motor + hydraulic, e.g. ~20–55 kW class) and air/oil cooling.
• Safety: full chain guards, machine guards closed during forming, and clear walkways.

Ask the supplier for the exact floor plan (footprint × power × weight) before civil work.

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Budget tiers: starter line vs automated line

Tier	What you get	Typical position
Starter single-profile	C-only or fixed-size line, manual change, stop-cut, basic decoiler	Lowest capital; fixed product
CZ convertible	Manual C/Z changeover, pre-punch, hydraulic cut, standard PLC	Balanced for mixed markets
Auto-changeover CZ	Recipe C↔Z (~90–120 s), servo host, dual-head decoiler, marking	High-mix shops; higher capital
CUZ / fully automated	C+U+Z auto width, stacker/strapper, remote support	Maximum flexibility and throughput

Price moves most with: changeover type (manual → auto), cut system (stop-cut → servo tracking), punching stations, decoiler capacity, and control/automation level. Always request a spec-sheet quote — the same "purlin machine" name can mean very different line scopes.

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Where to see real purlin line specifications

• Fully Automatic CZ Purlin Roll Forming Machine (ZTRFM product page) — complete line description and spec table
• C/Z Purlin Auto-Changeover Forming (ZTRFM Process Library) — module-by-module line spec
• C/U/Z Purlin Auto-Change Forming (ZTRFM Process Library) — CUZ line configuration
• Purlin / Channel / Beam process library
• Production equipment category (ZTRFM)

ZTRFM (zt-rfm.com) is a roll forming sourcing center operated by Zhongtuo Roll Forming (Hebei) Co., Ltd. Purlin standards commonly referenced include AISI S240 / ASTM A1003 (US) and GB/T 6723 (China) for cold-formed open sections.

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FAQ

What equipment is needed for a purlin production line? Seven groups in sequence: hydraulic decoiler, leveler, hydraulic pre-punch station, roll forming main unit, cut system, PLC control cabinet + HMI, and a run-out table. Optional: inkjet marking, stackers and strappers.

How much space does a purlin line need? Typically a straight bay of roughly 20–30 m including decoiler and a 6 m run-out table, plus coil storage and finished-goods areas; confirm the exact footprint with the supplier.

How fast is a purlin production line? Typical normal forming speeds 12–18 m/min for CZ lines with high-speed modes around 32 m/min; single-profile lighter lines can run faster, thicker gauge slower.

What is a pre-punch station for? It punches web holes before forming while the web is flat, keeping hole positions accurate — standard on purlin lines (commonly 2–3 hydraulic stations).

What is the difference between stop-cut and servo tracking cut? Stop-cut pauses the line to cut; servo tracking cut cuts on the move for higher throughput. Length accuracy is typically ±1–2 mm under PLC control.

How much does a purlin production line cost? Prices vary widely with changeover type, cut system, decoiler and automation. Compare spec-sheet quotes (gauge, width, stations, power, decoiler, included line scope) rather than machine name or price alone.

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Article by ZTRFM — Roll Forming Sourcing Center. Specs cited from published ZTRFM product and process documentation; verify final configuration with your supplier before purchase.