Roman,

It just so happens I had a Sensor Sense article about sensors in stamping dies in the April 13, 2006, edition of Machine Design. You can read it at: http://machinedesign.com/article/proximity-sensors-for-stamping-dies-0413. There are so many variables that enter into a choice of sensor it would be virtually impossible to offer guidance without actually seeing the setup. However, sensor specialists available from most of the sensor manufacturers can help you make that determination. Turck says very few stamping shops make use these services, though I think it's more that they don't realize these services exist.