In all typical process plants these days, knowledge about precise weld seam position is very important in order to optimally control the production processes and to enable logging of the steel strip with meter precision.

The widest variety of machines, such as paint shops, skin pass rolling mills or trimming shears in the exit section of process lines are guided as a function of the weld position. Weld seam detection these days is thus often realized by means of an optical sensor to detect an additional punch hole.

In the future this punched hole can be eliminated with the new WD1 optical sensor from EMG Automation, so as to eliminate air turbulence on the air knives or even mechanical damages on deflector rolls by defective punch holes. Even for processing lines without a punching press the sensor is ideally suited to precisely record the weld seam position.

The innovative optical sensor is based on an area scan camera with an infrared filter, with which the images of the weld seams are filtered and analyzed with FPGA technology (field-programmable gate array).

A subsequent rapid signal output to the plant control system provides an accurate update of the weld seam position, or even general weld seam tracking in existing process equipment, where applicable. In today’s plants in which weld seam detection is already carried out with inductive or optical sensors for detecting notches, even the notching of similar strip widths can often be omitted at the weld seam.

The WD1 sensor can be used with plant speeds up to 600 m/min, with laser welded seams there is currently a strip speed limitation of 200 m/min.