Laser seam finder improves welds, cuts search time

Next to good brakes, considerate motorists, and meatloaf, a properly welded rear axle is probably one of the things truckers appreciate most. To make sure they have it, Scania AB (Lulea, Sweden) recently installed two arc welding Laser SeamFinder systems from Selcom AB (Partille, Sweden).The two SeamFinders significantly reduced Scania's trimming and fixturing requirements, increased weld...

10/01/1998


Next to good brakes, considerate motorists, and meatloaf, a properly welded rear axle is probably one of the things truckers appreciate most. To make sure they have it, Scania AB (Lulea, Sweden) recently installed two arc welding Laser SeamFinder systems from Selcom AB (Partille, Sweden).

The two SeamFinders significantly reduced Scania's trimming and fixturing requirements, increased welded seam quality, reduced scrap and rework, and even enhanced workplace safety. The company's former welding system had sensors that located seams using the arc only as a guide. As a result, acceptable tolerances were often not achieved, and the robotic welder wasn't capable of repeatedly locating the correct welding position.

"The previous system didn't give us the consistency and quality we needed in welding thin sheets for rear axle housings," says Bertil Gustavsson, Scania's project manager. "Correct alignment is critical to high-quality welds, so we needed to find an alternative that would give us the accuracy required."

Sensor data empowers robots

At the suggestion of Sweden-based system integrator Lofquist Engineering, Scania eventually equiped its robots with Selcom's Laser SeamFinder. The system includes a noncontact laser sensor and software that evaluates and transmits the sensor's data to the robotic controller. The sensor's measurements aren't affected by surface characteristics including the presence of oil or paint.

Martin Sanden, Selcom AB's business area manager for robotic guidance systems, says SeamFinder usually needs just 1 sec to locate fillet, butt, and edge/overlap joints and define them in two dimensions. It can also perform three-dimensional measurements. After locating a welding seam, SeamFinder measures the gap, precisely positions the robot's welding torch, and adjusts the welding parameters, adapting to various gaps and weld width measurements.

SeamFinder's sensor uses laser triangulation to project a fixed beam onto the weld at 32,000/sec. The beam hits the surface, scatters, and is collected by the sensor, which focuses a light spot image on the position-sensitive detector in the sensor's head. Consequently, as the distance between sensor and welding surface changes, the image's position on the detector also changes, which makes it possible to control the robot's adaptive movements and weld accurately and repeatedly.

Seam position and gap data are indicated by SeamFinder's output signals. Results are interpreted as deviations from nominal values, which allows on-line modifications and variations in the robot's path and welding parameters. These programmed parameters include plate thickness and joint type. During the search process, one or more points along the joint are defined in two or three dimensions. All searches are, of course, performed without the arc being actuated.

Mr. Sanden adds that SeamFinder can be integrated with almost any arc welding system with a standard digital I/O interface. The sensors can also be mounted on most welding guns.

For more information, visit www.controleng.com/info .





No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
The System Integrator Giants program lists the top 100 system integrators among companies listed in CFE Media's Global System Integrator Database.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
This eGuide illustrates solutions, applications and benefits of machine vision systems.
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Sensor-to-cloud interoperability; PID and digital control efficiency; Alarm management system design; Automotive industry advances
Make Big Data and Industrial Internet of Things work for you, 2017 Engineers' Choice Finalists, Avoid control design pitfalls, Managing IIoT processes
Engineering Leaders Under 40; System integration improving packaging operation; Process sensing; PID velocity; Cybersecurity and functional safety
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Flexible offshore fire protection; Big Data's impact on operations; Bridging the skills gap; Identifying security risks
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
click me