Is it possible to let welding robots work from drawing programs and recording specific welding knowledge in software? This was a major challenge for Construction company De Waal, a leader in propulsion technology for shipbuilding. In 2015 De Waal therefore started the program ‘Applied Innovations for Maritime Automation’ (TIMA in Dutch) to achieve the robotised welding of tillers for rudders systems. In the first test phase, it has been possible to weld tillers with a robot without having to spend a lot of time programming. In the meantime both welding procedure and welder have been certified to 'weld under' and the project is now in the final phase.
Within the four-year program 'Applied Innovations for Maritime Automation' Scheepswerf Slob and Valk Welding participate in the project alongside De Waal. Before the four-year project TIMA, which finishes at the end of this year, the final welding automation for the welding of complete rudder parts has to be finished. Mark van Keulen, technical engineer at De Waal is working on this with Valk Welding.
‘’Also in the field of shipbuilding, we are dealing with aging of know-how, causing us to lose an enormously valuable part of the knowledge and experience if we don’t take care in time. We see that it is difficult to get new professional welders or to train welders to be. That is why we outsource part of the work. In the meantime, the pressure to keep up with the high-times of production loadis difficult, knowing craft trades will disappear in due time, and a large part of the work will be moved abroad. That is why we see the use of welding robots as a possible solution,’’ founding director Johan Verlaan explains. ‘’That is why we started this innovative battle.’’
In the current situation, the tillers for the rudder systems are welded semi-automatically. The circle-shaped welds have to be altered in several layers and they have to be welded to both sides to prevent deformation. The operator is present during the whole production cycle, to turn the workpiece with a crane. ‘’The cycle time is 40 minutes, of which 16 minutes are handling time.’’
In the test setup, for which Valk Welding delivered a Panasonic TM-2000 welding robot and a 2 ton positioner with counter bearing, the tillers are prepared and positioned. De Waal developed the hydraulic clamping system, suitable for the whole product family. ‘’’The welding robot first welds on one side up to welding height A8, after that, the other side and thereafter, from A8 to welding height A15 on the second side. The workpiece is rotated 5 times this way in the manipulator to prevent deformation and is completely welded in 24.5 minutes, of which 14.3 minutes are effective welding time and the rest is searching and touch sensing sequences. Because the operator only has to be present the first five minutes to clamp the workpiece and start the welding robot, the saving in man-hours is 85% compared to the semi-automatic production,’’ Mark van Keulen says.
Because the rudder systems are built in different sizes by De Waal, the position of the steering cylinder settings and the shape of the tillers also differ within the product family. Van Keulen: ‘’The challenge is to transfer that into a clamping system and a reference point to program the robot. A configurator is developed for this purpose, which generates the program for the welding robot on the basis of the shape information from the Inventor CAD programmes. Within DTPS, the offline programming software for Panasonic welding robots, the basic program for a tiller was generated only once. With the help of the DTPS Plugin QPT (Quick Programming Tools), the configurator adjusts the welding program to the dimensions of the specific product within half a minute. In this way, you can weld single piece production with the robot, without the programming taking a lot of time.’’
For large welding heights, the Thick plate module from Panasonic is used. Thick plate ensures that every weld is copied automatically, so it is not needed to program every single weld. Furthermore, the welding heights and the welding order is recorded in the software, so both the welding quality and the production knowledge is guaranteed. That procedure is now certified by Lloyds, as well as the welding operator. ‘’That is how you guarantee the know-how to be preserved for the future, and a high-quality product is delivered with a constant welding quality,’’ Van Keulen emphasizes.
To make the use of the welding robot profitable, a larger installation is necessary, in which the welding robot operates in multiple workstations. For that, several concepts are being made at this moment, based on a welding robot on an XYZ gallows concept and a welding robot on a portal construction. One of these concepts will be built before the finishing of the ‘TIMA’ project at the end of this year. Mark van Keulen: ‘’Valk Welding is the only partner that is competitive enough to realize such projects, and which is unique with its software development and welding robot automation.’’
With the automation project, De Waal can implement a capacity increase, so it will not be needed to outsource part of the production anymore. ‘’This large innovation goes further than just a financial consideration, but it is mainly investment in new technology with which we can make big steps for the future. This year, we do exist for 80 years and we are headed towards the hundredth anniversary as an innovative company,’’ Johan Verlaan looks ahead.
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