2D/3D laser scanners guarantee production quality using red and blue laser diodes
As well as determining one-dimensional sizes (material thick-ness, vibrations and distance), processed multi-dimensional quality controls (profile and contour measurement) may also be required during the production process, where optical non-contact metrology is ideal due to its high precision, measurement speed and flexibility with respect to the surface of the measurement object. Laser scanners carry out complex 2D/3D measurement tasks. Two new models using a blue laser diode additionally extend the field of application.
The laser line triangulation principle is based on the light intersection method. The point-shaped laser beam is extended to a line via special lenses. Together with the distance information (z-axis), the integrated controller calculates the position of the measurement point along the laser line (x-axis) and outputs both values as 2D coordinates. If the measurement object or the sensor is moved, a 3D image of the object is provided. The scanCONTROL 2600/2900 series of laser scanners from Micro-Epsilon detect up to 2.56 million points per second.
The laser scanners owe their compact design to an integrated controller. The sensor is the size of a cigarette packet and stands out due to its comprehensive range of features. Up to 4,000 profiles per second can be transmitted to a PC for further processing. At the same time, digital inputs can be used for synchronisation, triggering or as encoder in-puts. Laser scanners are equipped with an integrated, highly sensitive receiving matrix that enables measurements on almost all industrial materials, largely independent of the surface reflexion.
The scan-CONTROL laser scanner is used for profile and contour measurements during running production processes of high volume, continuously produced goods (extrusion, milling, drawing, etc.) or single pieces. An extremely powerful integrated controller unit and Ethernet inter-face make the laser scanner suitable for use with robots and for dynamic production technologies e.g. in the automotive production when mounting the windscreens. A laser profile scanner serves to measure the height and position of the adhesive beading on the screen edges.
The laser scanners that use a red laser diode are universally applicable. This proven technology is widespread, and the components used are therefore produced in large volumes and at relatively low cost. For extremely difficult surfaces, Micro-Epsilon offers its scanCONTROL 2600/2900 BL series of laser profile scanners that use a blue laser diode. These laser profile scanners are used, for example, in steel forging plants in order to measure red-hot glowing rail tracks and bogies.
The red glow normally “dazzles” red profile scanners, but blue scanners remain unaffected. Of course, such an application requires special protection measures (cooling, protection housing) that can with-stand the high ambient temperatures in a forging plant. In the case of (semi-) transparent materials, the blue laser line penetrates significantly less into the surface than the red laser. Particularly with white plastics, the red laser point penetrates into the measurement surface. When penetrating the material, the measurement line expands, resulting in a blurred laser line. Also with organic materials, the slight penetration behaviour of the blue laser results in higher measurement ac-curacy.
As Dipl.-Ing. Christian Kämmerer,MBA, Product Manager scan CONTROL comments:
There is an increasing demand for high precision measurements in automated processes, and optical measurement methods are becoming increasingly popular. They can perform dimensional measurements, capture measuring points much faster, and measurement data is typically available in real time in digital format. This enables the automatic correction and control of live processes, of which the aim is to produce “good parts” only.
Dipl.-Ing. Christian Kämmerer, MBA
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