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Call Us: (419) 678-4877

Precision Straightening

Automated Straightening Systems Tube, Bar, Shafts and Profiles

Many forged or turned workpieces and profile-type parts produced for precision applications are not totally straight, despite advanced manufacturing processes. This can create vibration during machining and grinding operations required to finish the workpiece, potentially damaging tooling and creating quality issues. Lincoln Electric Automation’s Coldwater, Ohio operation has developed a straightening system to address this situation.

The Solution

Our fully automated, servo-controlled solution can effectively straighten larger diameter tube or bar stock, shafts, and profiles. These systems incorporate artificial intelligence that automatically adapts to variances in the stock material or component without requiring operator intervention.

In tube and bar applications, these straightening systems have helped to reduce cycle time by up to 60 – 80% as compared to other methodologies while achieving straightness over the entire bar/tube within 0.02″ tolerance.

System Benefits

  • Decreases cycle times by up to 60-80% as compared to other methodologies
  • Achieves straightness over the entire workpiece to the required tolerance
  • All-servo controlled for easy maintenance
  • Can handle large OD product and lengths over 300”
  • Can be adapted to different part/material length and O.D. requirements
  • Fully automatic operation to reduce direct labor
  • Replaces traditional processes that rely on manually loaded and controlled straightening presses
  • Cycle times optimized through machine self-teaching requirements when new material is introduced


  • Raw seamless tube stock
  • Threaded pipe
  • Bar stock in different geometries - (round, square, rectangular)
  • Shafts – axles, cams, drives, gearbox
  • Industrial profiles – guides, racks, I-beams, drilling rods and tools

How It Works

Bundles of bars/tubes/profiles or shafts are loaded onto an accumulation deck and then automatically fed to the straightening equipment. In the straightening process, the stock or component is rotated to measure the runout with sensors at multiple data points along its length. This data is sent to the PLC where it is compared to the straightness specification to determine where it needs to be corrected.

The PLC determines the initial point needing correction and the servo press is indexed along the workpiece by a servo rail to the indicated location where it then bends the stock/part to specification. The piece is then rotated again to collect the data points and determine if there are other points that need attention. This process continues until all the data points are found to be within specification. From there, the workpiece may be moved out of the machine, automatically or by an operator, to the next process.

System Highlights

Automatic X-axis

The C-frame press traverses via servo motion across multiple data points to determine the pre- and post-bent state of the stock.

Measuring Supports

Cam roller guides support the bar/tube during rotation and measurements.

LVDT Measurements

The Linear Variable Differential Transformer (LVDT) measures the straightness of the bar/tube as it rotates.

Servo Press

A servo press riding on a servo-driven axis applies up to 40 US Ton (356 kN) or 50 US Ton (445 kN) bending force to the bar/tube.

Stock Support/Feed Table

Stock support and feed table queue parts ahead of straightening. This can be configured for manual or automatic loading.

Control System (not shown)

Comes standard with a 24VDC Allen-Bradley® control, Rockwell® servo motors and a 15-inch HMI screen with manual and automatic modes.