How to solve irregular size fluctuation of roll forming finished goods?

Unstable dimensional fluctuation of finished profiles is frequently seen in roll forming production, which can be fixed from raw material inspection, equipment adjustment, transmission system and control parameter optimization respectively.

First, inspect incoming steel coils regularly. Uneven thickness, inconsistent hardness and cambered strip will cause varying deformation after rolling, resulting in unstable width and height dimensions. Configure pre-leveling machine before forming to eliminate internal stress and strip bending; replace unqualified raw materials to avoid continuous dimensional deviation.

Second, calibrate forming roller clearance and installation precision. Loose bearing blocks, shifted roller seats and asymmetric gap between upper and lower rollers lead to uneven extrusion force on steel strip. Fasten all positioning bolts and adjust roller gap uniformly according to material thickness; polish deformed or worn rollers timely to keep stable forming dimension.

Third, overhaul the whole transmission system. Abnormal clearance of chains, sprockets and reducer gears causes intermittent speed fluctuation during operation. Replace severely worn transmission parts and add grease periodically to guarantee synchronous running of each forming stand. Flying shear error also affects finished length precision; calibrate encoder and hydraulic cutting station regularly.

Fourth, optimize PLC and inverter parameters. Unstable feeding speed caused by mismatched frequency parameters brings periodic size change. Lock optimized running parameters after trial production and avoid random modification. Clean dust inside electric cabinet to prevent signal disorder of detecting sensors.

1. GB/T 7714-2015

[1] Liu Q. Troubleshooting Methods for Dimensional Instability of Roll Forming Profiles[J]. Metal Processing Machinery,2025,41(11):53-60.

2. APA 7th

Liu, Q. (2025). Troubleshooting methods for dimensional instability of roll forming profiles. Metal Processing Machinery, 41(11), 53–60. 

3. MLA 9th

Liu, Qiang. "Troubleshooting Methods for Dimensional Instability of Roll Forming Profiles." Metal Processing Machinery, vol.41, no.11, 2025, pp.53-60,