Towards Automated Welding in Big Shipbuilding Assisted by Programed Robotic Arm Using a Measuring Arm
This paper presents an automated robotic welding system adapted for shipbuilding in large shipyards. This solution has been devised in the shipyard of Navantia located in the south of Spain, in the context of ROBOT FASE II R&D project. It also presents the human teams that have developed this welding system. The article explains the 3 parts that make up the welding system. The location of the robotic welding arm of the Fanuc brand is detailed in the first part. In addition, the gantry and spatial coordinate axes are described and indicated where the robotic arm is housed. The second part contains the system capture of the coordinates in the space for the reading of the singular points to be soldered. These points are measured by a portable measuring arm. The last part is composed of the system of communication between the different parts throughout the computer. The computer is responsible for synchronizing the measuring arm and the robotic welding arm by translating the points to be soldered.
Automatic welding robot system for the horizontal position in the shipyard
In the horizontal position welding, a series of trials for automatic welding technique have been carried out. However, their results have been used under some limited scopes. In this study, a welding robot system was developed to automate the horizontal welding in ship building construction. The small mechanical robot incorporates CAN-communication based motor drivers to minimize wiring of the welding robot. In order to weld on various gaps between workpieces, an automatic gap measurement and an algorithm for weld pass design were developed. A database of optimum welding conditions for FCAW(flux cored arc welding) and GMAW(gas metal arc welding) process was also established. The developed welding robot system showed a good performance in the shop test, and it is being optimized in HHI shipyard.
No Root Gap Horizontal Butt-welding with MAG Process
It has been used many kinds of horizontal butt-welding methods at block-to-block erection stage in shipbuilding companies. For examples, some companies use conventional FCAW process with one side or both sides groove joint welding, others use carriage with torch holder type mechanized welding method. Although lots of efforts were done until now, some problems in quality and productivity still remain in ship's hull welding. In this study, we have attempted to raise productivity and quality on horizontal position of welding with following 3 
 items. 
 I) Prepare groove condition with no root gap for making easy fit-up work. 
 2) Develop improved MAG (100% CO2 gas shielding) welding process with solid wire for making sound root bead 
 from one side. 
 3) Develop and apply quite new automatic welding carriage. 
 The stability of new welding process was confirmed by conducting mechanical tests of weldments to verify the 
soundness ofweldments.