a laser welding system for sealing or cutting polymeric sheets is described . the system comprises a laser source capable of delivering a laser beam . the laser beam is projected onto a region of the polymeric sheets where the sealing or cutting is to be performed . an optical device is provided to image the sealing or cutting as it is performed . an image analyser asserts the sealing or cutting quality . an integrated control means is provided to control the laser source , the projection of the laser beam , the optical device and the image analyser .