3D snapshot sensors enable fast inline geometrical inspection of spot welds

In car body production, the quality of the spot welds is a decisive factor for vehicle stability and safety. Conventional 2D vision systems quickly reach their limits here, as they only provide contrast information and do not provide reliable statements about the geometric characteristics of the weld spots.

The surfaceCONTROL 3D snapshot sensors from Micro-Epsilon, on the other hand, record the complete geometry of the spot weld in a single measurement process and generate a high resolution point cloud. Parameters such as height, diameter, shape and position can be precisely determined and automatically compared with the target values. Deviations or faulty points are detected immediately, which means that rework and scrap can be minimised.

Fast inline geometrical inspection

With the ability to measure several spot welds simultaneously, the inspection process is significantly accelerated. Due to the rapid measurement, the surfaceCONTROL 3D 3500 sensors can be integrated directly into the manufacturing process – without slowing down the production flow. The 3D sensors therefore make a significant contribution to process reliability and enable consistently high quality in spot weld inspection.

The surfaceCONTROL 3D 3500 has a slim, compact design and offers extremely high resolution in the Z-axis (from 1.0 µm). With a repeatability up to 0.25 µm, the sensor sets a new benchmark in high precision 3D measurement technology. Due to its high performance, the sensor is able to reliably detect even the slightest of deviations in planarity, for example, or height differences of very small components (e.g. IC pins) on printed circuit boards. A high data processing speed of up to 2.2 million 3D points per second enables the sensor to increase productivity in the respective application.

Fringe projection

The surfaceCONTROL 3D 3500 sensor operates on the principle of optical triangulation  based on fringe projection, which allows direct 3D measurement of components. Using a matrix projector, a sequence of patterns is projected onto the surface of the target object. The light from the patterns is viewed and recorded by two cameras either side of the projector. The three-dimensional surface of the target object is then generated from the recorded image sequence.

Ease of integration

All surfaceCONTROL 3D systems support the very latest GigE Vision and GenICam standards for easy integration into third-party image processing software. A comprehensive software development kit (SDK) is also provided that allows customers to develop their own analysis software. Also included in the scope of supply is Micro-Epsilon’s 3D Inspect software, which offers a convenient user interface for surfaceCONTROL sensors. The software allows fast commissioning, evaluation of the sensor, set up and optimisation of parameters, and ensures the correct positioning of the measuring object. In addition to fast data output via Gigabit Ethernet, the sensor offers an additional digital I/O interface. The 2D/3D Gateway II supports EtherNet/IP, PROFINET and EtherCAT connections.

Numerous applications

The sensor is suitable for a wide range of applications, including: 3D measurement of high precision mechanical parts; width, tilt angle and position measurement of rivets; surface defect detection; flatness inspection of circuit boards; planarity inspection of unpopulated PCB substrates; detection and evaluation of breaks on clutch discs; completeness check of electronic components on fitted PCBs; 3D text recognition of embossments that cannot be solved using 2D image processing due to lack of contrast; inspection of height and thickness of adhesive beading on smartphone shells; and determination of shape deviation defects on injection moulded parts.