SPOTNSEAM - Closed-loop control system for continuous laser spot on seam

CHALLENGE

There is a growing demand from customers requiring tubing or profile products from different materials, diameters and/or wall thicknesses. European tube/pipe manufacturers need to improve overall efficiency of their production and introduce new manufacturing techniques to reduce production costs and to enhance reliability of their products for mission critical or safety related tubing. Critical criteria for this product quality is a continuously precise guidance of both sides of the tubing or profile material to ensure constant process boundary conditions. Simple laser triangulation methods do not suit the requirements as in some processes the material is fed with zero distance between the joint pairs.

BENEFIT

The implementation of a multi sensor monitoring system for seam tracking will increase robustness in seam detection that also covers zero distance between the joint partners. Based on high speed image processing, the ICT solution will embed processing power to enable the generation of control signals in real-time. The interfacing with the environment will be so transparent and independent of machine type that not even the assessment partners’ diverse manufacturing machines benefit from an easy installation approach but also others. The transfer of the system to other setups is supported by modal interfaces that enable the control of any actuator for re-adjustment of laser and seam at affordable investment.

ACHIEVEMENT

A novel seam tracking system for monitoring and control has been developed. An integrated welding head was designed in several engineering steps. The design considered crucial factors like adaption to production line with optical elements for higher power, field of view, focal length, spacing to forming rolls and access of media. For the control of the peripheral system components a real time PLC is used. The tracing of the integrated welding head is carried out by a servomotor installed crosswise to feeding direction. A high-speed camera with embedded FPGA and GigE Vision serves as image acquisition device. Furthermore, the software development and the implementation of algorithms were carried out. The complete set of functions is implemented as hardware operators and guarantees image processing in real-time. The system is able to detect the position and orientation of the seam and tool center point simultaneously. This is a significant advantage since the system can accommodate shift in laser spot position.