20‑Roll Precision Straightening Machines – The Ultimate Solution for High‑Accuracy Tube and Bar Straightening
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With up to 20 precision‑ground rollers arranged in a 10+10 configuration, these machines deliver exceptional straightness (≤0.2 mm/m), surface improvement, and roundness correction for metal tubes, bars, and special profiles.
What Is a 20‑Roll Precision Straightening Machine?
A 20‑roll straightening machine is a high‑precision multi‑roller system designed for straightening metal tubes, round bars, and certain special profiles. Its defining feature is the arrangement of 20 rollers in a 10+10 configuration – ten rollers on the top bank and ten on the bottom, staggered to apply alternating bending forces as the workpiece passes through.
This design allows the machine to:
Correct bending (camber) and twist in a single pass
Improve roundness – reduce ovality in tubes
Achieve surface refinement – with a slight polishing or burnishing effect
Deliver straightness as tight as ≤0.2 mm/m
How Does a 20‑Roll Straightening Machine Work?
The principle is based on repeated elastic‑plastic bending. As the tube or bar passes through the staggered rollers, it undergoes alternating bending in opposite directions. This process progressively reduces the curvature with each roller pair, eventually producing a straight product with minimal residual stress.
Key components:
20 precision‑ground rollers – mounted on hardened shafts, arranged in two banks of 10
Heavy‑duty frame – provides rigidity and vibration damping
Drive system – motor, multi‑speed gearbox, and chain drive for synchronous roller rotation
Speed control – inverter / frequency control for variable speed (0–60 m/min or higher)
Why Choose a 20‑Roll Design?
More rollers generally mean better straightening results. Compared to 14‑roller or 17‑roller configurations, the 20‑roll design offers:
Feature | Benefit |
More bending points | Smoother correction curve – less residual stress |
Higher roller count | Better surface finish and roundness correction |
Staggered 10+10 layout | Balanced force application from both sides |
Precision‑ground rollers | Consistent contact – no surface marking |
Typical Technical Specifications – FR‑76 20‑Roll Model
Parameter | Value |
Max tube OD | φ76 mm × T3.0 mm |
Min tube OD | φ18 mm |
Max bar diameter | φ25 mm |
Straightness | ≤0.2 mm/m |
Roundness tolerance | 0.05 mm |
Roller groups | 17 groups (20 rollers) |
Speed | 0–60 m/min (variable frequency) |
Power | 15 kW |
Weight | 5,400 kg |
Dimensions | 3250 × 1500 × 1250 mm |
FR‑50 20‑Roll Model (smaller capacity):
Parameter | Value |
Tube range | φ13–36 mm × T2.5 mm |
Bar range | φ13–18 mm |
Straightness | ≤0.2 mm/m |
Speed | 40–149 m/min (4‑speed gearbox) |
Power | 7.5 kW |
Weight | Approx. 2,500 kg |
Applications & Industries
20‑roll precision straighteners are widely used for:
Steel tubes and pipes – seamless and welded
Aluminum tubes – architectural, automotive, HVAC
Copper and brass tubes – electrical, plumbing, heat exchangers
Round bars – carbon steel, alloy steel, stainless steel
Special profiles – with appropriate roller configurations
Industries served:
Automotive – fuel lines, shock absorber tubes
Construction – structural tubes, scaffolding
HVAC – condenser and evaporator coils
Medical – precision instrument tubing
General engineering – shafting, hydraulic components
Key Advantages
Advantage | How It Benefits You |
High straightness | ≤0.2 mm/m – meets demanding tolerances |
Surface improvement | Burnishing effect reduces roughness |
Roundness correction | Reduces ovality to 0.05 mm |
Continuous operation | High throughput – speeds up to 60 m/min |
Material versatility | Processes steel, aluminum, copper, and alloys |
Low maintenance | Robust construction with precision‑ground rollers |
Manufacturer Spotlight: FangRong Precision Machinery
FangRong is a leading Chinese manufacturer specializing in 20‑roll precision straightening machines. With over 21 years of experience, the company offers:
FR‑76 20‑roll – max φ76 mm tubes
FR‑50 20‑roll – max φ36 mm tubes
Custom configurations – 14‑roll, 17‑roll, and 20‑roll options
FangRong’s 20‑roll machines incorporate Taiwan‑brand straightening technology and are widely exported globally.
How to Select the Right 20‑Roll Model
Consideration | Recommendation |
Tube/bar diameter | FR‑50 for φ13–36 mm; FR‑76 for up to φ76 mm |
Wall thickness | Up to 3.0 mm for tubes |
Required straightness | Both models achieve ≤0.2 mm/m |
Production speed | FR‑50 up to 149 m/min; FR‑76 up to 60 m/min |
Floor space | FR‑76 requires 3.25 m length |
Conclusion
The 20‑roll precision straightening machine represents the gold standard for high‑accuracy tube and bar straightening. With its 10+10 roller configuration, it delivers straightness ≤0.2 mm/m, improves roundness to 0.05 mm, and provides a surface‑refining effect – all in a single pass. Whether you are processing steel, aluminum, or copper tubes, this machine offers the precision, speed, and reliability that modern manufacturing demands.
Contact FangRong to discuss your tube/bar specifications and straightening requirements – we will recommend the right 20‑roll model for your application.
Know More About Us FangRong Metallurgical Equipment Manufacturer in China since 1998. Professional in Metal Straightening machine, Cold Drawing machine, Push Pointer Drawing Machine, Automatic Three Lines Drawing Machine, Thread rolling machine, Tube-end shrinking machine, Pointing Machine, Core pipe machine, Polishing Machine etc.
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Email: frsale@dgfangrong.com frmachine001@dgfangrong.com
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Keywords: 20‑roll precision straightening machine, 20辊精密矫直机, FR‑76 20‑roll straightener, tube straightening, bar straightening, ≤0.2mm/m straightness, FangRong straightening machine.
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