Wärstilä: hour less unmanned production without any welding interruptionsPrint this page
About 5 years ago Wärtsilä The Netherlands bought their first arc welding robot with the aim to start unmanned production. By carefully chosen products and components it is possible to weld hours in unmanned production circumstances.
By: Christophe Delacourt
The aim was clear: as much as deposition to be realised but with good quality. A selective choice of shielding gas, welding wire and robot system is needed.
Worldwide active
Wärstilä is one the world’s largest suppliers of medium and low speed diesel and gas engines. Wärtsilä’s customers are builders, owners and operators of sea going vessels, off shore installations and power plants. Worldwide the company has more than 14.000 employees divided over 13 locations in almost 70 countries. About 1/3 of the turn over (approx. 3,2 billion euro in 2006) comes from supply to power plants, 1/3 from engines for sea going vessels and similar installations and the rest from services. In The Netherlands the company has operations in Zwolle, Drunen, Schiedam and Kruiningen with a total of 1.100 employees.
Dutch location Kruiningen
At the location Kruiningen reconditioning of mainly large two stroke sea vessel engines is done. Reconditioning is a process in which the worn down heart has to be rebuilt to its original dimension. From the worn down parts the damaged services have to be removed, refurbished by using the welding (cladding) process. Finally machining and service treatment will take place.
The location in Kruiningen is one of the 5 so called “reconditioning centres” which Wärtsilä has in their worldwide operations. Apart from this location in The Netherlands the y have locations in Canada (Vancouver), Singapore, China (Shanghai) and Italy (Genoa).
The Dutch location is servicing worldwide customers whose ships will arrive in ports in North-Western Europe. The company today uses 3 welding robots which are continuously being used and work all 3 as unmanned operation.
Expertise ‘reco’
The in the company available knowledge and experience for reconditioning is impressive. Jaap Weber, chief welding engineer at Wärtsilä Kruiningen; “We have a fixed group of employees from which most of them are working several years and some even more than 20 years at our company. Our expertise is also acknowledged within the whole group. Other locations within the Wärtsilä group look at us a frontrunner and the by us developed technology is being used in other companies.”
Maintaining market share by using robots
The company is constantly working with maintaining its expertise as well as looking for the possible improvements for quality as well as testing of new technologies. About 5 years ago the company started using an arc welding robot with the specific aim to weld in unmanned continuous operation. In order to get the quality of this process up to its present optimal level, a period of experimenting with programming, machine lay-out as well as consumable choice has taken place. In the mean time, the welding process with robots is optimal. This means the robot can hours long, in some cases a whole weekend, work unmanned without any interruption (other than normal activities from the operator) creating a perfect result.’
The company has lots of success with the robot application. The 3 robots will weld approximately 600 to 700 kgs of welding wire in one weekend in unmanned production runs. This fact results in a speed of supply Wärtsilä can deliver their products to their customers.
In order to maintain the high market share in a market which can never count on regular and standard products, the order planning does not have more than one week between order placement and supply of finished components. In such a process issues as quality and speed of supply are crucial.
The welding robot can using a selected choice of welding gasses and welding supply work hours without interruption and in unmanned production circumstances.
Activities suppliers in welding process
The company is asking their suppliers the necessary involvement in process optimalisation. From the beginning of the robotic project Air Products together with Valk Welding have been involved by using the proper gasses, welding wires and programming functions in order to have an optimal quality. Especially by unmanned production runs, the quality of gasses, welding wire and its programming are extremely important to reach the optimal quality.
After the start it was quite soon clear that use of standard gasses is not possible to reach the robots quality and speed of working. An intensive period of testing and experimenting followed. The aim was clear; to deposit as much as possible welding material in the shortest available time but with good quality. The combination of proper welding wire, proper welding gasses and correct programming, made it possible to create this unmanned production unit handling especially silicates from the welding process in a proper way.
Wärtsilä The Netherlands in figures
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Legal for
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BV (Besloten Vennootschap
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Year of founding
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1966 (at that time Traas Metaal)
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Location
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Kruiningen
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Activity
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Reconditioning of components from large two stroke ships engines
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Employees
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85 employees of which 12 welders
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Number of robots
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3
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Turn over
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€ 14.000 .000
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Company surface
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8.500 m2
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Forming of silicates under control
Finally the company is a very satisfied user of Air Products Maxx-gasses. Weber: “After intensive testing with several gasses, out of which tests with gasses from several suppliers, we are convinced that we reach the perfect result as we have now using these welding gasses. The advantages for us are mainly reduction of silicates and welding with a large stick out (30-40 mm) which brings us a high deposition rate. The tests we have done with other gasses gave a reasonable result for a lower price but it was not enough to have an unmanned robot welding under perfect conditions. Finally it turns out to be a little bit more expensive but much more performing.
For the cladding of steel Wärtsilä choose for the Ferromax registered Plus gas. The recepy that the supplier developed together with Wärtsilä guarantees because of the amount of helium which is added to the gas mixture.
During the multiple pass welding of this steel, the creation of silicates maintains under control which results in a low pollution which makes unmanned production possible. In the mean time the deposition rate is extremely high. For ss Wärtsilä is using the Inomaxx air shielding gas (98% Argon and 2% C02) and for special materials such as Inconel 625 Alumaxx shielding gas (70% Argon and 30% helium) is being used. In using helium the welding pulp gets more liquid because Inconel is a difficult welding material and using helium more heat is being put in the welding puddle.
Quality gas mixture determined by mixture
The quality of the gas mixture is determined by its mixture. This is created due to several parameters. Weber: “The parameters are being determined on our deposition rate. For us the most important thing is to weld as much as possible/deposit as much as filler material in a short period of time. Because we started with a new gas mixture, we could increase our stick out length and we realised a higher deposition rate. It was not easy to develop the optimal welding process but we now have advantages from our continuous effort to create the absolute and optimum quality. In the beginning when I came back to work on Monday morning, some times the robot had welded continuously however quality was sometimes not the expected quality so we could restart the whole process from zero. Now a day’s standard quality is every time perfect and we are reaching a production which cannot be reached with any manual of semi automatic welding process.”
Open and honest communication
The contact with suppliers in general has changed strongly according to Jaap Weber. “In the old days we regularly went to a trade show where I renewed my contacts and saw new welding technologies. At this time I have no time for that. To stay informed I read my welding magazines and journals and receive suppliers at Wärtsilä to discuss about new technologies. I am always open for improvements but seeing is believing. That is why I regularly try new products or production methods because only when using new products or technologies under production circumstances you will find out if this new technology is acceptable or improving your present welding process. If it does not bring the expected improvements, we will return to the old situation. Open and honest communication that is what it is all about. This has brought our company to the position where we are right now.
Olaf Filius
Future
For the future the company will see a further growth and improvement with extra welding robots. Weber: “I think that coming years another one or two robots will be purchased in order to increase our production. Although it is difficult in our market to forecast the demand, we will have to improve our knowledge and know how in order to reply to this market demand. Further improvements will be in the possibility to increase the deposition rate. The quality of the welding process only has to be maintained because it is already optimal.