Electricity + Control June 2018

PLANT MAINTENANCE + TEST + MEASUREMENT

phone housing is another typical application. Pre- senting a particular challenge are the very fine contours within smartphones and extremely thin, partially semi-transparent adhesive beading. Here, absolute reliability and 100 % control of the com- pleteness of beading, as well as the height and

the highest precision. Therefore, reliable quality control involving the monitoring of individual pro- duction steps is necessary. The combination of a compact scanner, integral controller and different interfaces makes this laser profile scanner highly suitable for inline applications and for dynamic pro- duction control. Triangulation sensors are also used in measure- ment systems, for examples, for thickness meas- urement of metals. The principle of dimension- al geometric thickness measurement includes one optical distance sensor on each side of the material. Thickness measurement using laser point sensors is based on one point respectively, whereas in thickness measurements using laser profile sensors, the entire laser line is processed. For thickness measurement during production, the difference between the sum of the distance signals and the value of the operating range is determined. Both laser lines must be projected congruently onto the top and the rear side of the material in order to achieve an accurate thickness measurement. The right choice With its high precision, measurement speed, com- pact size and fast data processing, non-contact measurement technology offers many benefits. Users can choose from different measurement systems. Each principle comes with its own par- ticular advantages and limitations that all need to be carefully considered. As demanding applica- tions require, amongst other things, resolution, ro-bustness, temperature stability, linearity or spe- cial mounting and installation conditions. Measurement and inspection systems using laser triangulation

width of the applied adhesive are re- quired. This also applies to the logos on tablets and laptops: Grooves are milled into the aluminium housing, into which the logo elements are glued. The latter must be flush with the housing. Hap- tics (i.e. touch sensation) is a critical factor, as customers would immedi- ately feel any protrusion or depression. Using laser line scanners, these de- pressions are measured to determine the planarity as well as the depth. The parts being glued are also measured to ensure a perfect fit. Laser profile scanners operate with a red or, more recently, a blue laser line. From the very early days, these optical standard sensors used red laser lights for the receiving element as these had the highest sensitivity. With many ap- plications, the laser profile scanner using a red laser line provides precise results. However, when detecting red- hot glowing, transparent or organic objects, the red laser has limitations. This technology has been revolution- ised with Blue Laser Technology in the form of laser point sensors. Unlike the red laser, the blue laser light does not penetrate the measurement object and projects a sharp line. Therefore, red-hot glowing and organic objects can be measured reliably and with the highest precision. The scanCONTROL 29xx-10/BL pro- vides an effective measuring range of just 10 mm with a profile resolution of 1 280 points. This results in a point dis- tance of 7.8 µm, which enables the la- ser profile scanner to provide twice the resolution of previous laser scanners with a 25 mm measuring range. These characteristics enable laser scanners to detect even the smallest parts with

The scanCONTROL 29xx-10/BL stands for precise laser line triangulation measurements of tiny objects.

In the C-frame, the sensors are mounted fixed on an upper and a lower arm for differential thickness measurement. The frame is moved as a unit to reach the measurement position.

Dipl.-Ing. Manfred Pfadt is a Product Manager at Micro-Epsilon Messtechnik GmbH & Co.KG Enquiries email manfred.Pfadt@micro-epsilon. de

28 Electricity + Control

JUNE 2018