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Call Us: (419) 678-4877

Precision Straightening

Tube and Bar Straightening Systems

Many bars and tubes 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 tubes and bars, potentially damaging tooling and creating quality issues. Coldwater Machine has developed a tube and bar straightening system to address this situation.

The Solution

This fully-automated, servo-controlled solution has been designed to effectively straighten larger diameter tube and bar stock. These systems incorporate artificial intelligence that automatically adapts to variances in the tubes without requiring operator intervention.  As compared to other methodologies, these tube and bar straightening systems have helped to reduce cycle time by up to 60 – 80% 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 bar to the required tolerance
  • All-servo controlled for easy maintenance
  • Can handle large OD product and lengths over 300”
  • Can be adapted to different tube 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

How It Works

Bundles of bars/tubes are loaded onto an accumulation deck and then automatically fed to the straightening equipment. In the straightening process, the tube or bar 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 bar by a servo rail to the indicated location where it then bends the bar/tube 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 bars 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.