Laser welding as a means to permanently join components has gained considerably in importance over the last few years. In many cases laser welded joints are the solution to a more compact design. It also leads to a reduction in the cost and weight of components and – in the automotive industry in particular – to a lowering of petrol consumption. For many years EMAG has followed its objective to offer its customers – from a single source – all the machining technologies and processes that can be applied to round and “not so round” workpieces, right up to the ready-to-install component assembly. Many workpieces first undergo a number of cutting processes and are then assembled and laser welded. Since 2003 EMAG has been able – with EMAG LASER TEC – to offer complete manufacturing solutions from first cut to laser welded, ready-to-install component assembly.
EMAG LASER TEC - ELC 250 DUO: Complete solutions – from metal cutting to laser machining
06/02/2008 - Oliver Hagenlocher
The ELC 250 DUO
The ELC 250 DUO is a very compact laser machining tool. Machining stations, laser, laser cooling unit, electrical cabinet and peripherals are all mounted on a common, self-supporting base frame. The outstanding advantages of this design are the high degree of precision and long-term constancy, much shorter commissioning periods and the possibility to move the whole system with very little effort, allowing the user to adjust quickly to changing production requirements. The DUO variant of the ELC features two spindles. This twin-station operation allows for cycle time-concurrent loading and unloading of the work spindles. An integrated beam diverter allows for the laser to be switched between focusing optics, thus optimising its degree of utilisation and increasing productivity.
The ELC is equipped with a diffusion-cooled CO2 slab laser (DC Diffusion-Cooled series) made by ROFIN SINAR. The distinguishing features of the DC series are their excellent beam-focusing capability, their compact design and their low operating costs, especially where energy and laser gas consumption – and maintenance work – are concerned. Its excellent beam-focusing capability (K-number > 0.9, i.e. close to the physical maximum of K = 1) ensures that the welding seam geometry can be fine-tuned to suit particular workpiece requirements. The beam can produce narrow, deep welding seams by using little heat, but also wider seams.
Diffusion-cooled lasers are known to attract low operating costs. This includes extremely low laser gas consumption. The laser uses Premix gas from a laser gas bottle.
The laser system’s “entrails” are located above generously dimensioned maintenance doors that provide easy access for the setter. Setup and maintenance times are thus drastically reduced. To achieve the ambitious twin objectives of increased productivity on the one hand and reduced setup times on the other, new ground has also been broken on the question of integrated workhandling. The EMAG ELC 250 DUO features 12 NC axes, a precondition for great flexibility in workhandling and for the realisation of the short setup times demanded also for smaller batch sizes. The machine is equipped with SINUMERIK 840D control and a large number of practice-orientated software aids from EMAG LASER TEC.
The advantages of laser welding
- High power density
- High processing speeds
- A low heat load minimises component distortion
- Exceptional process integrity
Twin-spindle design offers a high degree of productivity
In reality, laser welding machines are often used to clear bottlenecks and as such face high demands on productivity levels, availability and component quality. It is the reason why the ELC 250 DUO’s welding station features two spindles. Whilst one spindle accommodates the component assembly during the welding process, the second one is used to unload the previously welded assembly and to load and clamp the constituent parts for the next assembly. The laser beam switches between the two stations. This guarantees optimal use of the system and a high productivity rating.
ELC 250 DUO – optimal for transmission components
An increasingly important area of application for laser welding is the manufacture of transmission systems. Many components, such as differential housings, drive rings and output shafts for passenger car transmissions, are frequently machined individually, then assembled and welded together. It makes transmission systems more compact and ensures they also meet the highest demands for noise level reduction and power density. Laser welding has, to a large extent, achieved ascendancy over other methods of permanently joining components, such as the screw fitting of differential housing and ring gear.