Erhardt + Leimer presents web guider for printed circuits at LOPEC
Typically accuracies of +/- 0.1mm are achieved with web guiders, in special cases the control accuracy is twices as high at +/- 0.05mm. However, absolute position tolerances of maximum 10µm are allowed during the production of printed circuits – a real challenge for the engineers. Erhardt + Leimer, a provider of web guiding and tension measurement equipment based in Stadtbergen, Germany, will present a sophisticated solution for this issue at the upcoming LOPEC trade fair in Munich, Germany.
The task is as follows: a web already printed is printed again with components to give the material the required characteristics. During this second printing process an absolute position accuracy of 10µm is required. The contrast edge (white-grey contrast) that is to act as the guiding criterion is not continuous, but is often interrupted; there is interference in the background.
First, the web is unwound with the web tension being controlled by using a dancer roller. The next process step, a traction unit with web tension control and web guiding must ensure that the web is fed to the subsequent printing process with the required accuracy of +/- 5µm.
The pivoting frame used by E+L in this case is the ELGUIDER DRS 24. This system is said to provide an actuating speed of up to 70mm/s and a control accuracy of <+/- 0.1mm as standard. For the two web edges, two CCD line scan cameras of the type OL 82 with 5150 pixels and 8-times subpixeling are used.
Due to this and other optimisations the pivoting frame system guides the web with an accuracy of at least +/- 5µm and is suitable for usage in the production of printed circuits. The solution by E+L will be one of the highlights at the exhibition booth of the German company.