Weld seam guidance

In a weld seam guide, the welding torch is brought into the optimum position along the welding gap between two components. The gap is continuously scanned with a laser profile scanner running ahead and the optimum position for the torch is calculated.

When the torch reaches the measured position, it is moved to the optimum position at this point by means of the motor axes or a robot. This allows web and component tolerances and heat distortion to be compensated for during welding.

Definition weld seam guide

Welding seam guidance is a technique in which the welding torch and the welding wire are precisely positioned along the welding gap. When aligning the weld metal to the gap, various tolerances play a role that can influence the dimensions, geometry and position of the weld gap in space.

Even if the gap is laid out straight in the design, in practice it can be uneven and show variations in the width and height of the opposite edges. These variations can be caused by various factors such as the type of fixture or the dead weight of the components.

During the welding process, another effect occurs that can hardly be compensated for by design measures: Namely, thermal distortion. To compensate for these effects, the technique of laser weld seam tracking was developed.

Weld seam guidance of a V-seam with Quelltech QS-Track software

Methods of welding seam guidance

There are various methods of weld seam guidance, although classical approaches are used less frequently today.

A traditional method is to guide the welding torch through a gap using a mechanical pin. However, this method is rarely used nowadays due to its susceptibility to interference (e.g. pin clamping) and its limited applicability to simple geometries. In addition, it does not provide any information about the height of the seam.

The state of the art today consists of optical sensors that detect the geometry and position of the seam without contact before the welding process. Point laser rangefinders with moving beam guidance have been used in some cases, but laser line triangulation sensors are becoming more common. These sensors capture 3D profiles of the gap in front of the welding torch.

In combination with special seam tracking software, the data is evaluated and the optimum position (in the x- and z-plane) is transmitted to the axis control of the welding system or welding robot. As a result, the optimum position of the weld seam can be achieved at any time, even if heat distortion occurs.

Weld seam guide with Quelltech

Quelltech offers weld guidance with 2D/3D laser line triangulation sensors (laser scanners) specifically designed for weld guidance. These laser scanners have a small form factor and are very robust against the process light of the welding process. Furthermore, coolers can be mounted modularly to them.

There are easily replaceable protective screens against welding spatter. Depending on the welding process, laser wavelengths complementary to the welding process light can be selected. Special algorithms and laser scanner arrangements allow reliable seam tracking even with deep V gaps and highly polished edges. An easily parameterizable seam tracking software allows seam tracking of almost all geometries.

Spot cloud of a weld seam with penetration notches

What are the advantages of the QuellTech system for weld seam guidance?

In the QuellTech system for weld seam guidance, a key advantage is the modularity of the laser scanners, which are available in measuring ranges from 5 mm to 1000 mm and can be optionally equipped with protective screens and coolers.

Multiple scanner solutions are also possible, where the laser scanners do not influence each other due to special circuitry.

Furthermore, the QuellTech laser scanners are characterized by their high robustness against extraneous light, which is particularly advantageous in the welding process. Laser powers of up to 500 mW are possible.

The QuellTech laser scanners are also mechanically robust and shock-resistant and offer EMC safety even at high field strengths.

They can be used in welding systems with axis guides as well as in robot-guided welding processes.

Communication of the welding system with the QuellTech seam tracking software

The QuellTech seam tracking software offers the user easy setting of geometries and tolerances without programming and enables communication with the welding system. In addition, tack welds can be toleranced, and a selectable automatic feature ensures optimal sensor light intensity. We are happy to offer support for the integration of the seam tracking software into customer-specific software systems.

The QuellTech system for weld seam guidance can guide different geometries among others:

Butt joint
Lap joint
Oblique joint
Parallel joint
T-joint
Flared joint,
Crosscut
Multiple shock
Double T-joint
Corner kick
Multi-layer V-seams

The QuellTech seam tracking system, is suitable for various welding processes such as MIG, MAG, TIG, submerged arc welding, laser welding, laser brazing and plasma cutting.

Areas of application of the weld seam guide

Some areas of application for weld guidance are:

Power engineering: Welding of wind turbine towers
Aerospace: Titanium buildup welding
Welding of body and axle parts, fuel injectors.
Plastics technology: welding of housings
Marine technology: shipbuilding
Steel construction: T-beam welding, crane production
Apparatus engineering: tank welding
Rail vehicle construction: Chassis welding
Offshore: pipeline welding, pipeline cladding
Mechanical Engineering: Housing Welding
Mining: Conveyor welding

The use of QuellTech weld tracking systems offers many benefits, including improved weld quality and reduced scrap. Productivity can also be increased through the use of these systems, because time-consuming learning processes of seam topographies can be shortened.

In addition, the combination with QuellTech’s software for weld seam guidance, enables near-time and near-location monitoring and documentation of seam quality.

Examples / References / Best Cases for Weld Seam Guidance with QuellTech

In the past, we have used Quelltech solutions for weld seam guidance in a wide variety of projects. Here you can find a small excerpt of these projects:

Spot cloud of a multilayer weld seam

QuellTech products for weld seam guidance

QuellTech’s weld guidance products, especially the Q4 laser scanner series, are characterized by their small form factor, compact housings and robustness against extraneous light.

These product features are particularly in demand for upgrading and integration into welding systems.

With accessories such as coolers and protective screens, the Q4 laser scanners are especially suited for use in harsh demanding industrial welding process environments.

QuellTech Laser Scanner Q4-80s with small form factor (86 x 44 x 25 mm) for robotic welding

QuellTech Laser Scanner Q4-60 with optional cooler and protective window system

Do you have questions about weld seam guidance or would you like Quelltech to advise you on this topic?

If you have any questions about weld seam guidance or would like a consultation from QuellTech on this subject, we will be happy to help.

We would like to help you to precisely evaluate your specific measurement task. Through an initial free test measurement of your application, we can give you an early assessment of the feasibility.

There is always potential for improvement, we will help you with that. Contact us for more information or to make an appointment for a consultation.

Your personal contact:

Stefan Ringwald
Tel: +49 89 124 723 75

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