Z & C Purlins

Raw Material Receiving (Coil Yard)

Galvanized (Z120/Z150/Z275) or HR (Black) steel coils of 1.5–3.0 mm thickness and 150–450 mm width are received from approved Indian manufacturers such as JSW, TATA, AMNS, and Apollo. Each coil is visually inspected for transit damage, rust, or edge waviness before unloading. Coils are tagged with supplier, heat number, thickness, and weight details for traceability.

Coil Certificate Verification (Mill TC Check)

The QA department verifies each coil’s Mill Test Certificate (MTC) to confirm material grade, thickness, yield strength, zinc coating (Z120/Z150/Z275), and dimensional tolerances. The coating weight is cross-checked by random sample testing using coating thickness gauge. Any non-conforming coil is quarantined and returned to the supplier as per NCR (Non-Conformance Report) procedure.

Coil Storage on Timber Saddles

Accepted coils are placed on wooden saddles to prevent contact with the floor and avoid edge damage. Coils are stored in a dry, covered yard, segregated by size and coating type. Storage layout ensures FIFO (First In First Out) sequence to maintain material freshness and coating integrity.

Coil Loading on De-coiler

Before loading, coil ID is verified against the production plan. Using a crane, the coil is mounted on the de-coiler mandrel. The coil lead end is straightened and fed into the leveller for flatness correction. De-coiler tension and brake are adjusted to prevent telescoping or slack during unwinding.

De-Coiling → Levelling

The coil passes through a levelling machine equipped with multiple rollers to eliminate coil set and ensure uniform flatness across the strip width. Continuous tension between de-coiler and leveler ensures smooth feeding without scratches. The levelled strip is ready for precise forming in the roll forming mill.

Roll Forming (C/Z Section)

The strip is progressively shaped into C or Z section through a series of roll forming stations. Each station performs gradual bending to achieve the desired cross-section while maintaining dimensional accuracy. Forming speed, roll gap, and roller alignment are monitored continuously to prevent edge waviness or twist.

Punching (Hydraulic / CNC)

After forming, hole punching is carried out as per customer drawings using hydraulic or CNC punching units. Punching patterns include bolting holes for purlin connection, service openings, and identification slots. CNC punching ensures accuracy within ±3 mm and repeatability across batches.

Cutting to Length

The formed and punched purlins are cut to order lengths using a hydraulic shear with tolerance ±5 mm. Cutting operation is synchronized with line speed to avoid deformation at ends. Cut pieces are checked for square-ness and burr-free finish before stacking.

Inspection

Each purlin undergoes dimensional inspection for length, width, flange, and lip angles. Surface finish, coating uniformity, and punching accuracy are checked. QA records are maintained in inspection log sheets. Any deviation is rectified before dispatch approval.

Stacking & Dispatch

Finished purlins are stacked on timber spacers to prevent surface scratches and distortion. Each bundle is aligned properly to maintain straightness and ease of handling. Bundles are securely strapped with steel bands and tagged with order details, section type, and Quantity. For additional surface protection, bundles are covered with Tarpaulin packing to prevent moisture, dust, and rust formation. Final dispatch is Made as per the dispatch plan, ensuring safe loading and proper lashing on trucks to avoid transit damage