A machine is process monitored and controlled for continuous bending of long products to a predetermined radius by using three parallel contact-free distance meters (laser transmitters) and by measuring the distances to the bent surface on the product, by calculating the actual bending radius based on the fixed distances between the meters and the measured distances, and controlling the adjustment of the machine in response to the relation between the calculated actual radius and the desired radius. The machine comprises a processor for performing said calculation and controlling the bending device.
