Laser vision improves quality of spiral welded pipe

Citation

(2001), "Laser vision improves quality of spiral welded pipe", Assembly Automation, Vol. 21 No. 2. https://doi.org/10.1108/aa.2001.03321baf.008

Laser vision improves quality of spiral welded pipe

Laser vision improves quality of spiral welded pipe

Keywords Vision, Lasers, Welding

An improved, laser-based system for seam tracking has been introduced by Meta Vision Systems specifically to ensure the weld integrity of spiral pipe as it emerges from the mill (see Plate 5). One of the biggest problems in the manufacture of spiral pipe is inferior weld seam quality, which can render the product inadequate for carrying fluids such as oil, water, chemicals and gases.

Plate 5 Meta has introduced an improved version of SpiralMaster, a laser-based, seam tracking system that ensures the integrity of spiral pipe welds

To ensure that high quality, full penetration welds are laid all the time, Meta developed several years ago the SpiralMaster to track the seam and control the welding heads automatically. The system has now been upgraded to include more powerful control capabilities and additional functionality.

Over 100 users worldwide including such well-known companies as Ameron in the USA, Europipe in France, Salzgitter in Germany, Noksel in Turkey and Capelo Tubi in Italy attest to the system's effectiveness. They also affirm Meta's ability to understand the requirements of spiral pipe mill operators and implement the seam tracking retrofit to improve weld quality. It also enhances productivity and profitability by increasing welding speed, virtually eliminating scrap and rework, and reducing the number of operators needed.

SpiralMaster uses two non-contact, laser vision sensors to measure joint geometry. The first, mounted in front of the inside diameter (ID) weld position, is used for seam tracking, while the second, mounted in front of the outside diameter (OD) weld position, is used to position the external weld head. Both sets of equipment are installed on independent cross-slides which are controlled automatically by feedback signals from the vision sensors.

Using a triangulation system employing a laser stripe and video camera, joint measurement data are gathered in real time including ID and OD gap, mismatch, and the height and lateral position of both torches. Results are displayed on a process screen and two profile video monitors.

The software allows the mill operator to select from pre-programmed procedures using a push-button console conveniently housed in a remote, hand-held pendant from where weld start and stop for both torches are controlled. Arcs shut off automatically if pipe rotation stops and an alarm is triggered if the joint measurements exceed preprogrammed limits. The beneficial results are stable joint fit-up, assured penetration of the ID weld and improved bead quality on the OD, which in turn minimises weld dressing.

In addition to retrofit applications, SpiralMaster may be installed by OEMs on new spiral mills. It works with all types of mill and any grade of steel, and will tolerate wide variations in the quality of edge preparation. Standard field of view is 30mm (H) x 40mm (V), although higher accuracy sensors with smaller fields of view are available for joints with tight fit-ups.

A variety of analogue and digital output signals are provided for customer use. Two 0 - 10V analogue signals are available, which vary proportionally in real time to gap and/or mismatch measurements. Furthermore, to assist in setting up semi-automatic gap control capability, a digital output signal may be configured to open or close in proportion to the measured gap's deviation from a programmed value.

In support of the product, Meta Vision Systems provides mill operators with complete system installation, start-up assistance, training and after-sales service.

Contact: Dr Andrew Pryce, Sales and Marketing Director, Meta Vision Systems Ltd, Oakfield House, Oakfield Industrial Estate, Eynsham, Oxfordshire OX8 1TH, UK. Tel: +44 (0)1865 887900; Fax: +44 (0)1865 887901; e-mail: sales@meta-mvs.com