In today’s demanding and competitive ship building and repair industry, new technology is very much needed and automation plays a key role to improving the productivity and quality of shipyards. Welding is fundamental task in shipyards and marine/offshore companies. It is used in building and repairing structures for the Ship Hull.

Robotic welding is very attractive because of its robustness and manipulability and this has been recognized as the next step in technological advancement of worldwide Shipyards . There are many commercially available robotic welding systems and they have been applied to shipyards around the world notably in Korea and Germany. One of the key domains which is evolving right now is the simulation of this Robotic welding system in a offline environment, wherein the robotic welding system is integrated into a CAD system and robots are programmed offline. Offline programming systems require the availability of CAD data describing the workpieces to be welded. A model of the robot and the welding process is then simulated in the computer together with a CAD model of the workpieces and environment. With a simulation environment, the robot program can be developed offline and tested before it is downloaded or implemented in the actual robot. Offline robot programming systems therefore require an accurate description of the workpieces and layout of the resource environment.

Fig 1 above shows a typical panel consisting of a steel plate (base) and a number of vertically mounted stiffeners and webs. The webs are welded perpendicularly across the stiffeners, after the stiffeners are welded onto the panel. Welding of the stiffeners vertically onto the plates is a straightforward process using current automated welding systems. The stiffeners are long and straight, which makes automated welding easy.  However, welding webs require much complicated welding motions to overcome access restrictions, as shown in Fig. 2.  Each workpiece has a unique shape and dimension with some repeated patterns. There are variations in the size of the webs, stiffeners and plates.

The biggest advantage of  Robotic welding system is the easier and faster operation compared to a conventional manual welding With the implementation of the offline Teach methods, robots can now be in production even if we want to fine tune a existing Robot program for accomodating a new structure . 

Since the offline system is so easy to operate, the training time required to use the system is much shorter than for a conventional Teach pendant based robotic system. An operator with certain knowledge of welding process can be trained to use the system within a week.

 Apart from the improvement of welding cycle time, the welding quality of the robotics system is better than manual arc welding due to the implementation of optimised welding parameters on the system and non-stop welding lines. Besides, the precise motion of the robot in addition to the arc sensing for search and tracking the seams have also contributed for a better welds. As the actual welding is handled by the robot, the operator can now stay away from the fumes and heat generated by the welding. A less hazardous and better working condition for human is another advantage of using the robotic system.

with DELMIA we can simulate the complete Arc welding process as described above and see youself for the detailed videos below to get a good illustration of the solution.