June 2, 2020 - Coldwater Machine, Coldwater, Ohio, a Lincoln Electric Company, has announced the availability of its automated, all-servo-controlled Tube and Bar Straightening System for carbon steel, stainless, aluminum, copper, brass and other materials. These solutions incorporate artificial intelligence that automatically adapt by learning different part types without requiring operator intervention. As compared to traditional approaches, these systems have helped to reduce cycle times up to 80 percent.

Many tubes and pipes produced for precision applications today lack sufficient straightness for finishing operations like machining or centerless grinding. This poses a problem for manufacturers who rely on manually intensive operations using traditional straightening presses to achieve straightness. Compounding this challenge is the shortage of skilled labor for these operations as well as a lack of process repeatability. This can lead to quality problems downstream where vibrations during grinding can lead to inconsistent results as well as potentially damaging centerless grinding wheels, further adding to costs.

How the system works

Bundles of tubes/bars are loaded onto a staging deck and then automatically fed to the straightening equipment. In the straightening process the bar stock is rotated 360 degrees while sensors measure the bar at multiple data points along its length to create a profile. This data is sent to the PLC where it is compared to the straightness specification in order to determine where it needs to be corrected.

A servo press, mounted to a servo-controlled rail, is positioned to the indicated location determined by the sensors and then bends the bar/tube repeatedly over its length to bring it within tolerance. This process continues until the straightness requirements are achieved. As a final check, the tube is then rotated again to collect the data points to confirm that the bar is within specification. Depending on the customer’s process, bars or tubes may then be automatically or manually transferred to other operations.

Benefits of the system include:

• Repeatable process for improved quality
• Reduced requirements for skilled operators
• Decreased cycle times by 60-80 percent as compared to other methods
• Ability to handle different diameters and lengths over 300 in.
• Easy maintenance with all-servo control
• Adaptability to varying tube lengths and O.D. requirements and part batches.