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Automating non-repetitive production

Innovation in shipbuilding: March 2018Panel welding

Think of the automotive industry, and the first image that will come to mind is likely that of swivelling robotic arms, welding car body after car body as they move down the production line. Such automated production on a mass scale is nothing new, and has facilitated the dominance of the car in the last half-century as a mode of transport that can be made quickly, cheaply, and endlessly.


However, think of shipbuilding, and a more probable image is that of hundreds of human workers teeming around a towering steel vessel, each of them undertaking complex individual tasks to bring about the completion of the ship as a whole. It seems impossible to be believe that this gargantuan task can be finished with human hands alone.


Of course, there is a substantial disparity in scale between cars and ships, particularly vessels of the large, commercial type. Nevertheless, both shipbuilding and the automotive industry share a great deal of similarities: they are both engaged in manufacturing, operate a continuous production line and, most importantly, are both driven by the pursuit of the highest possible level of efficiency.


As such, it may seem surprising that shipbuilding has not greatly incorporated automated production, especially given that it generally embraces technological advances. When one considers the day-to-day operation of a shipyard, however, it is more understandable: in general, shipyards undertake a string of non-repetitive production tasks which are tailored to each individual vessel. While robots can accommodate for this in theory as they can be reprogrammed, the requirement to manually adjust their parameters for every job cancels out any efficiency gain, and thus lessens the case for their widespread use. Therefore, for most shipyards, humans, or at least human operators, are still the greatest enabler of shipbuilding projects.


Dutch robotics
Manual work may, however, cease to be such a necessity in light of recent innovations in production automation in shipbuilding. While some very specific tasks can only be performed by a worker, there are universal engineering tasks – such as welding, profile cutting, and edge preparation – that can now be fully automated, saving shipyards a great deal of time and cost, not to mention workers from demanding and sometimes dangerous tasks. This is particularly true in the case of panel and block welding, a massively time-consuming but essential task on most shipbuilding projects.


Kranendonk, based in Tiel in the Netherlands and with sales/service offices in Singapore, China, Japan and the US, is a major designer and manufacturer of automated production solutions, focusing their efforts on automating non-repetitive production. Originally working with steel manufacturers, they branched out into working with shipyards in 1986 after solving the issue of programming taking longer than the job itself and cancelling out any efficiency gains.


Their solution was to import the data from the 3D CAD models that act as the foundation of vessel construction, automatically generating programs and jobs for welding/cutting robots and thus fully automating the production process. In its most up-to-date form, this technology is based on Kranendonk’s unique RinasWeld software, compatible with, amongst others, Aveva, ShipConstructor, Catia and Intergraph, and file extensions including .step, .iges, .atx and .ifc, which automatically generates robotic welding pathways based on weld strategies, sequencing and welding rules, and highlights unreachable welds. Features of the latest version include digital visual simulation of the robot paths, error reporting from the shopfloor, overnight program generation, workload distribution over up to eight robots working on the same piece, control by tablet and smarter integration with the design software.


With RinasWeld as the foundation, Kranendonk have been able to automate a number of different processes for shipyards. According to Kranendonk’s Justin Geraerds, “all the products we have are the result of unique customer demands. Most of them grew over the years to a typical product range from cutting solutions, CNC-edge milling machines, up to the biggest welding gantries in the world. Customers ask us to help them find a solution for their challenges in the production process.” The manifold demands of shipyards have led to six main offerings from the company: a profile cutting line, which utilises a robotic plasma cutter; an edge preparation system, to help shipyards satisfy IMO PSPC demands; a web welding gantry, which welds sub-assemblies such as micro panels and bulkheads; a panel welding gantry, designed for inaccessible spaces; a double hull / block welding gantry, which can weld extreme products sizes such as double bottom hull sections; and finally a robotic pipe shop, in which, notably, flanges are automatically aligned, fitted in the correct postion and welded before bending to massively reduce production time.


With the ever-increasing size of many vessel types, exemplified by 2017’s 400m, 192,700dwt containership MOL Triumph, Kranendonk have worked to ensure their products can facilitate the assembly of extremely large sections and panels. As ships get bigger, it becomes clearer to see how automated production allows for substantial efficiency gains. The company’s double hull / block welding gantry, for instance, can weld double hull sections up to 24 x 16 x 7 metres in size, but can also reach spaces of only 700 x 700mm with small robots, which tend to present problems for human welders.


Adaptability and feasibility
As every shipyard is different, Kranendonk are well aware of the need for their products to be scalable, able to be fitted into spaces of varying height, width, and length. Depending on production needs, the company are able to install more or less robots, build larger or smaller gantries, and integrate products into existing production lines. Whilst Kranendonk can physically adapt their products, shipyards must themselves adapt their workflows. As Geraerds states: “The whole logistics flow around automation solutions is crucial. We can predict the cycle time for the robot by the minute, so planning could be perfect and very efficient, but if the rest of the yard can’t keep up with the pace, we can’t use the full potential of automation. Therefore we go into a feasibility study together with our customer in an early a stage as possible. This can be years before ordering. It’s not only implementing equipment, it’s implementing a complete new mindset affecting the complete flow, not only production, but also design and design for production.”


Market demand
Although shipyards tend to be wary of drastic changes to tried-and-tested workflows, a number of high-profile customers have taken the leap towards automated robotic production by partnering with Kranendonk. These include Imabari Shipbuilding Group, known for building bulkers and large container ships, who installed three panel welding gantries varying in size from 13 to 15.5 meters, each using four robots, between 2014 and 2017. Similar equipment is also reportedly in production at one of the European Fincantieri yards. Over this three year period, three double hull welding solutions were also installed at an undisclosed yard in Japan. Two use eight robots, divided evenly over four double beamed gantries. The other uses four robots, divided evenly over two double beamed gantries. Philly Shipyard (formerly known as Aker Philadelphia Shipyard), too, has also dealt with Kranendonk, upgrading their existing double hull welding gantry will the latest version of RinasWeld, plus two new robots.


More recently, Kranendonk have installed two Edge preparation systems and two panel welding gantries at a large shipbuilding company in Singapore. Currently in production at their facilities in Tiel is the biggest shipbuilding robot ever created, capable of welding sections up to 24 metres wide and 7 metres high, and almost any length, due to the use of a rail with four gantries and a total of 12 robots, bound for the same megayard. Singapore is also home to one of Kranendonk’s robotic pipe shops, installed at Keppel Singmarine.


As for the future, Geraerds suggests that the “next step is to combine our robot assembly technology with intelligent cameras to eliminate the need for labour intensive manual fitting and tack welding. This however needs a new approach of shipbuilding and will be a long-term development.” With access to 60 engineers in Tiel, Kranendonk are hoping to drive the development of non-repetitive automated production lines in shipping, with the ultimate goal of automating production end-to-end. Despite the industry having some way to go technologically, logistically and mentally, it is evident that the advanced fusion of digital design tools with robotic production lines gives shipbuilders the option of a new way of working that can be quicker, cost-effective, and safer.