New system for quality control in welding and joining

Assembly Automation

ISSN: 0144-5154

Article publication date: 1 September 2003




(2003), "New system for quality control in welding and joining", Assembly Automation, Vol. 23 No. 3.



Emerald Group Publishing Limited

Copyright © 2003, MCB UP Limited

New system for quality control in welding and joining

New system for quality control in welding and joining

Keywords: Inspection, Welding, Machine vision

Meta Vision Systems has launched a new, laser-based inspection and measurement tool that examines and reports on critical trends in process quality. Called Meta Inspection, it can significantly reduce defects and scrap, minimize rework and improve component quality by identifying imperfections as they occur (Plate 1).

A development of Meta's computer controlled, 3D seam tracking systems for automated welding, the inspection product is aimed at applications where weld quality is especially important. Post-process results include bead presence, geometry and position as well as trend data such as weld undercut or overcut. Quality checks may be made not just on welds, but equally effectively on sealant and glue beads.

Plate 1 Meta Inspection is a new, non-contact measurement and inspection system for quality control in welding and joining applications

Meta Inspection can provide 100 per cent inspection in real time, which cannot be achieved by other means. Different criteria may be measured and the subjectivity of visual inspection is removed. The quality control system is PC-based and features laser sensors with fields of view ranging from 5 to 60 mm to suit the size of feature to be inspected and the required resolution.

Important feature characteristics are derived rapidly and precisely through principles of triangulation. The Meta Sensor projects a precision-focused line of laser light onto the surface, ensuring that measurements are not affected by changes in ambient lighting conditions. Where the laser line strikes a surface, it forms a contour line of the feature. The sensor's integrated CCD imager views the contour line's shape and position within its high-resolution pixel array, from which accurate Y (cross-profile) and Z (height) co-ordinates are derived.

Dedicated processing and inspection algorithms create electronic profiles from the sensor data and measurements are taken from the electronic profiles. Depending on the intended application, limits or thresholds can be set and compared against the profile data. When thresholds are exceeded, alarm conditions are triggered allowing prompt corrective action to be taken.

Meta Inspection may be installed in-line for continuous quality monitoring or as part of an off-line inspection facility. Sensors are easily mounted in a fixed position close to the process, as part of an auxiliary inspection fixture, when access is difficult, or on the end of a robot. The system is easy to set-up and operate, as system parameters and programmable functions are established using convenient set-up screens and the computer keyboard, while operation is controlled via a push button console.

To ensure reliable, long-term operation, Meta sensors are specifically designed for arduous environments. These robust sensors have no moving parts and have proven themselves across a wide range of challenging applications since 1985.

Application notes are available free of charge from Meta, covering the following specific applications: "Concavity and convexity defects of a tailor welded blank", "Missing weld and open seam", "Fillet weld inspection", "Inspection of tube and pipe longitudinal butt welds", and "Go/No- Go of laser welded transmission components".

For further information, contact: Mike Wilson, Managing Director, Meta Vision System Ltd, Oakfield House, Oakfield Industrial Estate, Eynsham, Oxfordshire OX29 4TH. Tel: 01865 887900; Fax: 01865 887901; E-mail:

Related articles