Application technology-wise, SPEETEC prevailed over three possible alternatives. One was measurement via encoder systems in the head rollers that drive the conveyor system. This option was discarded because the encoder values alone did not provide sufficiently accurate position information due to the stretching of the plastic belt used to transport the corrugated board blanks. The second possibility – movement and position measurement by means of tactile measuring wheels – was ruled out because they come into contact with the prepared and, at the second print unit, already partially printed surface and also drop down to the conveyor belt in the gaps between the blanks and then rise up again at the next corrugated sheet. “This falsifies the measurement result to such an extent that precise positioning of the individual color layers on top of each cannot be reproducibly ensured,” Thomas Schneider explains. The SPEETEC with its precise position measurement, on the other hand, ensures no color shifts occur during four color printing and, as a result, the individual colors of the multi-color print are precisely registered on top of each other."
Non-contact and yet cost-effective
SPEETEC was also found to be superior to a third alternative: laser velocimeters. While these also perform non-contact measurement, they generally turn out to be a significantly poorer choice in terms of total cost of ownership due to their comparatively high price and the safety-related high integration and operating expenses. The latter is due to the fact that common velocimeters use class 3 laser light. This necessitates a range of technical and organizational protective measures, and the effort and additional costs that go with these. Not so with the SPEETEC: the speed sensor uses a class 1 laser. In this lowest hazard class, the output of the transmitter is so low that it poses no risk to the eyes. No additional safety-related expenses are incurred, so the SPEETEC is also easy to integrate.
