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Mechanisation or rather immediate robotization?

Mechanisation or rather immediate robotization?

07/02/2018 | Allemagne

Jos Lotgerink, Managing Director of Dumeta, has a clear opinion on how companies can best manage the transition from manual welding, throughmechanisation and automation to robotized welding.

In medium-sized enterprises welding by hand is still very common, but it is continuously harder to find good welders. Although welding robot manufacturers are making robots more suitable for smaller quantities as well, the high investment costs are an obstacle for the transition to robotized welding, especially when it comes to very large and heavy components. Jos Lotgerink, welding-positioner- expert, believes it is important to proceed in a simple manner and on a gradual basis in order to keep the cost price low and to continuously improve production capacity.

Mechanisation, automation, robotization

 “At the fairs where we participate as exhibitors, people increasingly ask us whether the integration of robots with our welding positioners is possible. This question comes mainly from companies in countries that are in development and whose sales increase very rapidly. Some companies would like to use robots as quickly as possible, but they act very impulsively. To visualise it: Today you ride on a horse with carriage and tomorrow you want a Ferrari, says Mr. Lotgerink”. Due to his experience he can say that these companies do not always understand that robots call for another way of thinking and working with regard to the welding process. This sometimes takes additional time and leads to additional costs.
As an example, he mentions a client who produces ship rudders. The company processes large sheet metal plates that must be rolled and shaped. In the rowing there is a frame structure for its stability. For 70 years these ship rudders have been welded by hand. At first on the basis of BMBE process, followed by other welding processes, but still by hand. This customer wanted to buy a welding robot, which would require an investment of about 100,000 EUR. For him, the acquisition would have had the result that pre-machining would had to be carried out more accurately, thereby the costs would have been ultimately higher than with manual welding. In other words: Companies can definitely save time with a robot, but if they lose this elsewhere, they do not really improve”. 

Handling of products

Without doubt Mr. Lotgerink recognises the benefits of welding robotics, but notes that sometimes businesses make their purchasing decisions too impulsively. In his opinion there are very good alternatives that help reduce costs with a relatively low investment. He mainly focusses on the handling of large and heavy workpieces. “Start simple and take a closer look at the handling of your workpiece. If so far everything is done with a crane, a good welding positioner can already bring much profit. Thanks to the appropriate working height, the welder can work faster and more efficiently. In addition, absence due to illness and physical stress can be reduced. The experience, which a company makes with a welding positioner, handling and clamping of workpieces, also benefits the robotized welding in the future.
For robot welding the cooperation between welding positioner and robot is very important. A standard welding positioner consists of two axes, turning and tilting. The axes are driven by servo motors, which can be controlled by a robot. “The model and brand have influence on the functioning of the controller. For example, a Kuka robot does not communicate with Fanuc servo motors. Here the welding robot is the crucial factor: It does not only control the welding positioner, but also the welding device. Robot manufacturers have in many cases their own positioner range, but not always. At Dumeta, we do not build complete robot welding systems, but work closely with robot suppliers”.

Important intermediate step

Especially in the processing of larger and heavier workpieces, of about 3 or 4 tons, there are, according to Mr Lotgerink, opportunities to save even more. “The best solution depends definitely on the nature of the workpiece. Nevertheless, I am convinced that the intermediate step “mechanisation” between manual welding and robot welding is significant, also with regard to the future. The increasing ageing of the population continues. This means that employees must physically have the ability to work longer. Handling is therefore also connected to working ergonomically. You cannot ask 68-year-old employees to be as agile and strong as a twenty year old. There is no doubt that the interest in mechanisation will continue to increase “. 

Source: Wennekes, M. (2016). Mechanisation? Robotization? LASTECHNIEK, 36 - 37.