APPLICATIONS

High Length-to-Diameter Bars in Daily Production

Steel service centers, oil & gas, and heavy machinery plants run bars like these every shift. A 6 m bar with 40 mm diameter has an L/D ratio of 150:1 — supported only at the ends it will sag under its own weight. Our straightening line integrates rolling supports, anti-whip guides, and servo-driven measurement to keep the workpiece stable throughout the correction cycle.

8 m long large-section round bar before straightening inspection
8 m round bar, 140 mm diameter, measured before correction
160 mm section round bar in straightening process
160 mm bar mid-straightening — anti-whip supports engaged
Batch bar straightening operation
Batch straightening — one operator monitors multiple cells
Bar straightening process close-up
Straightening pass on a long round bar
Round bar straightening operation
Round bar being straightened without surface damage

Test Your Long Bars on This Line

Send us 3 sample bars with your current straightness data. We'll run them through the automatic cycle and return a report: before/after straightness, cycle time per correction point, and surface condition. No pressure marks, no whipping.

Request a Sample Test Speak to an Engineer

AUTOMATIC BAR STRAIGHTENING MACHINE

Stop Whipping. Stop Secondary Deflection. Straighten Long Bars Right.

L/D > 150:1 workpieces handled without whipping

Shangda's automatic hydraulic bar straightening line corrects bars from 20 mm to 160 mm diameter and 2 m to 8 m length. It's not just a press — it's a complete production cell with automatic loading, multi-point laser measurement, servo-controlled point pressure, and anti-whip support that holds the bar rigid during correction. Target straightness: 0.1 mm/m across the full length. Unmanned 24/7 operation with one operator monitoring multiple machines.

Discuss Your Workpiece
Automatic bar straightening machine

WORKPIECE-DRIVEN CONFIGURATION

Every Parameter Is Set Around Your Bar, Not the Other Way Around

Before we quote a line, our engineers ask for your material grade, current straightness measurements, bar weight, and batch size. That determines whether you need 3-point or 5-point measurement, how many intermediate supports, and the press force. A 40Cr steel bar at 8 m behaves differently from a 6061 aluminum bar at the same length — the machine must know that.

MaterialCarbon steel, alloy steel, stainless, aluminum
Diameter range20–160 mm
Length range2,000–8,000 mm
Max workpiece weight1,500 kg
Initial deflectionup to 15 mm/m
Target straightness≤ 0.1 mm/m
Loading/unloadingAutomatic roller conveyor + pick-and-place
MeasurementLaser displacement sensors, 3–5 points along length
Cycle time30–90 s per correction point
AutomationCNC closed-loop, MES interface, 24/7 unmanned
Automatic loading and unloading device removes straight round bar

Automatic unloading after straightening — no manual handling of long bars.

WHY IT WORKS ON HIGH L/D BARS

Four Systems That Kill Whipping and Secondary Deflection

Anti-Whip Support System

Intermediate roller supports engage automatically at positions calculated from workpiece length and diameter. The bar never vibrates during press stroke.

Multi-Point Laser Measurement

Three to five laser displacement sensors map the actual deflection curve before and after each correction. You see the bar's real shape, not a single-point guess.

Servo-Hydraulic Point Pressure

Precision force control applies correction at the exact peak of each deflection lobe. No scratches, no indentations, no over-bending that creates new secondary deflection.

Closed-Loop Self-Learning

The CNC logs every correction result. On the next bar of the same batch, pressure and dwell time adjust automatically. Repeatability holds within 0.02 mm across a 12-hour shift.

Round bar point-pressure straightening

Point-pressure correction on a round bar — no contact marks on the surface.

Operators need two days of on-site training. Calibration of laser sensors is quarterly. Hydraulic oil check every 500 hours. No special foundation — level concrete floor is enough.

TECHNICAL DATA

Long Bar Straightening Cell Configuration

Parameter Value
Max straightening length 8,000 mm
Max workpiece diameter 160 mm
Min workpiece diameter 20 mm
Max workpiece weight 1,500 kg
Max initial deflection 15 mm/m
Straightness after correction ≤ 0.1 mm/m
Press force 200–500 kN (servo-hydraulic)
Cycle time per correction point 30–90 s
Measurement system Laser displacement, 3–5 points
Control system CNC closed-loop with AI self-learning
Loading/unloading Automatic roller conveyor, pick-and-place
Motor power 22–45 kW
Floor space (L×W) 10,000 mm × 3,500 mm
Certification ISO 9001, CE available

We have seen this line reduce scrap from 2.1% to 0.3% in a steel service center processing 42CrMo bars 6 m long.

Request a Quote

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