The contact free measurement system imess S4 measures length, width and rectangularity of sheets during running production. Four cameras record the four edge points of the material and transfer the data to the software at a line speed of up to 350 meters per minute.
The deviations from nominal values may lead to reactions by using the customer PLC via any interface. The system also fulfils the high demands for inline measurement systems and process security by its robust and stable built.
The cameras are positioned like a portal at axes over the belt to move fast and flexible. The camera position has to be known to deliver reliable measurement results. Therefore, linear scales are used to determine the positions in relation to one another. A light barrier triggers the simultaneous recording of pictures of all cameras. In addition, lights flash briefly to reduce motion blur and increase the contrast between material and belt. Therefore, a reliable inspection can be conducted for bright or smooth surfaces. However, depending on the ambient temperature, variation can occur in the sheet length. Complex algorithms tackle the issue including the temperature measured at the system itself at two positions and adjusting the geometry measures accordingly.
The use of high-quality camera hardware and telecentric objective leads to highly accurate measurements. The telecentric technique avoids errors caused by different sheet thicknesses, belt height deviations or upright tilting of the sheets.
The cameras move according to the nominal values prior to measurement to the edge positions of the sheets. Measures and tolerances are either stored in the software manually or by custom control systems. The results are shown numerically in a table or depicted graphically for each job. The automatic creation and storage of measurement protocols belong the software functions like the statistic module.