WeldPrint™ – real time quality monitoring in automated welding applications

Ref: 10808
Technology which analyses and identifies robotic welding faults in real time, measures the stability of welding, and enables processes to be optimised.

Key advantages
  • Real time quality monitoring
  • Reduced product reworking and recall
  • In use in harsh industrial environments


Welding is used in more than 50 per cent of manufactured products in developed countries, yet it is generally recognised as an unreliable process. There has therefore been a need for robust, reliable, real-time welding fault detection, especially for safety-critical applications such as automotive manufacture.

Conventional systems log data for later study or use X-rays or ultrasound to check samples after welding. The time delay from welding to fault detection can result in a significant number of faulty welds.

The invention

The WeldPrint™ system incorporates three key innovations:

  • deriving phase-space portraits from sampled data with subsequent image processing;
  • applying statistical methods, such as Principal Component Analysis, with algorithms appropriate for real-time implementation in welding;
  • multi-dimensional optimisation of processing parameters, using experimental welding data.

WeldPrint interface

WeldPrint™ monitors every weld and detects faults when they occur. Blocks of 4,000 points of electrical data are collected twice a second and converted to signature images. After image processing, statistical analyses of the signatures provide quantitative assessment of the welding, revealing its stability and reproducibility, and providing fault detection and process diagnostics.

WeldPrint™ consists of a front-end interface (pictured) and software based on the Signature Image Processing (SIP) technology engine. A key advantage for users is that the system relies on electrical signals only. It is non-intrusive, simple to set up and sufficiently robust to withstand harsh industrial welding environments. Industry feedback and improvements in the algorithms, including parameter optimisation with a server network, have led to an order-of-magnitude improvement in performance over the past five years. At the same time, the simplicity of the software’s user interface belies the complexity of the underlying mathematics of the SIP technology.


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Principal inventors