Weld seam inspection

In weld seam inspection, the weld seam is subjected to a visual inspection after the welding process. This inspection can be performed spatially and temporally, directly behind the welding process (inline). A 3D laser scanner scans the surface of the weld seam and the edges. Software continuously compares whether the weld seam is within a tolerance range and automatically checks for welding defects.

Definition and meaning of weld seam inspection

The purpose of a weld inspection is to ensure that the quality of the weld is such that it achieves the required strength of the joint. The weld inspection is an important test to assess, secure and document the strength of the connection between two components. A weak spot in a weld seam can lead to breakage and serious consequences in the use of the parts.

Weld seam inspection: Spot cloud of a pipe weld with pores

What are the test methods in weld inspection?

An inspection after the welding process, verifies the conformity of the performed welding work. There are various test procedures for this:

➜ Visual inspection

Visual inspection by an inspector and automated optical inspection of the weld surface and dimension usually by 3D laser scanner can find weld defects visible on the surface.

➜ Ultrasonic testing, X-ray and eddy current testing

Ultrasonic testing, X-ray testing, and eddy current testing can be used to find defects that may occur inside the weld, such as voids. These tests are quite complex and are typically used for larger material thicknesses where gas tightness is important, such as pipelines. However, weld defects often show up on the weld surface, such as pores, burn-in notches, spatter, weld overheight, or weld penetration.

➜ Optical 3D inspection with laser scanners

Optical 3D inspection with laser scanners checks the 3D geometry and dimensions of the weld seam. The shape, size and position of the weld seam are analyzed. Through this examination of the weld seam structure, various weak points can be identified, which can then be avoided in further welding processes.

Optical 3D inspection with QuellTech laser scanner

Optical 3D inspection with laser scanners from QuellTech enables inline weld seam inspection. This means that immediately after the welding process, a laser scanner is carried along on the same axis or the robot, which continuously inspects the weld seam. The QuellTech laser scanner generates a 3D point cloud. This point cloud is assigned to a tolerance tube and deviations are reported as defects.

The error messages can be set from alarm to plant stop. The 3D point cloud can be saved as useful documentation for quality assurance.

Spot cloud of a weld seam with penetration notches

What are the advantages of QuellTech’s weld seam inspection?

Welding defects can be detected directly inline during the welding process, so these defects can be corrected at an early stage, which in turn increases productivity and reduces scrap.

➜ Immediate measures in case of welding defects

The immediate inspection of the weld seam with QuellTech laser scanners allows immediate action to be taken in the event of a defect. If, for example, a large container is welded, immediate action can be taken in the event of a defect alarm because cost-intensive rejects or time-consuming reworking are no longer necessary. In the case of cladding in pipelines, the time-consuming separate inspection process is no longer necessary, as immediate corrective action can be taken inline (in the process) in the event of a defect.

➜ Compact housing shape: use of QuellTech laser scanners close to the welding process

The QuellTech laser scanners are very robust against extraneous light in welding processes compared to cameras and can therefore be carried inline spatially close to the process.

The housing shapes of the QuellTech Q4 laser scanner series,(set link to products Q4) have basically a small form factor and customer-specific adaptations, such as certain angles, or other plug assemblies, can be taken into account at any time for this housing shape. This facilitates the integration into new and already existing welding systems.

➜ Efficient weld seam control and guidance in one welding cycle

The QuellTech weld seam control complements itself optimally together with the QuellTech weld seam guide. With this combination a precise position of the weld seam can be achieved and at the same time the quality of the weld seam can be controlled inline. A QuellTech laser scanner is guided in front of the welding process and a laser scanner behind the welding process. Thus, two quality requirements during welding can be carried out efficiently and in one welding cycle.

Application areas of weld seam inspection

The use of the Quelltech weld seam inspection inline enables a fast reaction in case of welding defects even before e.g. the weld seams of a pipeline are finished.

Weld seam inspection and weld seam tracking from QuellTech avoid scrap and cost-intensive rework, because compared to other inspection methods, QuellTech solutions can be used in the welding process in a timely and localized manner in the following applications:

Power engineering: Welding of wind turbine towers
Aerospace: Titanium buildup welding
Welding of body and axle parts, fuel injectors.
Marine technology. Shipbuilding
Steel construction. T-beam welding, crane manufacturing
Offshore: pipeline welding, pipeline cladding
Mechanical Engineering: Housing Welding
Mining: Conveyor welding

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

Here the already existing customer cases are linked e.g. the application Pipeline Manufacturing is not anonymized – and is linked to our customer in England

Spot cloud of a multilayer weld seam

QuellTech products for weld seam inspection

The QuellTech Q4 laser scanner series is particularly suitable for weld seam inspection. The Q4 laser scanners are characterized by their small form factor, compact housing and high robustness against ambient 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 inspection or would you like Quelltech to advise you on this topic?

If you have any questions about weld seam inspection 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.

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Stefan Ringwald
Tel: +49 89 124 723 75

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