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Determination of the Placing Accuracy

In order to determine the placing accuracy, special glass components with applied, highly accurate patterns are placed on corresponding substrates. This placing step is examined with a vision system. These experiments are the basis for the inspection of the positional accuracy in two spatial dimensions, as well as for a statement about the angular accuracy. Since examinations investigations are necessary for each accuracy study, this process is repeated several times. For this repetition the machine’s boundary conditions are varied, e.g. the maximum portal speed.

The verification process has the following form:

As Fig. 1 shows, test processes are very simple an are divided in several measuring processes. The measuring processes should be mapped by the machine’s own measuring system. As a component, various glass components or glass chips are used. These glass chips have several markings, which must be recognisable by the vision system of the machine. This is shown in Fig. 2. As a result, Fig. 3 shows how , vacuum tools‘ placement accuracy can be examined.

Fig. 1 Process diagram of a typical machine capability study

Die ermittelten Werte werden mit einem weiteren Messverfahren verglichen. Dieses Messverfahren nutzt zusätzlich zur Markierung auf dem Glas-Chip ein Referenzmuster auf dem Substrat. Bei diesem Verfahren kann eine manuelle optische Prüfung als auch eine automatische Prüfung durch das Vision-System der Maschine erfolgen. Durch eine statistischen Analyse werden die Datenreihen ausgewertet um Kennzahlen wie die Prozessfähigkeit CpK bzw. Cp zu berechnen oder absolute Messwerte anzugeben.

Fig. 2 Measurement on the glass chip with vision system

Fig. 3 Vacuum Tool

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