Spot welding – A challenging task

There's no accounting for taste when it comes to the looks of a car body – but when it comes to the importance it's greatest task, protecting the passengers from harm as good as possible, everyone will agree upon it. In order to ensure the safety of the passengers, the car body must be torsionally rigid and the other components must be firmly attached to it. In case of alternative drive and mobility concepts, the need to combine a mixture of different materials, such as steel, aluminum, plastic, and composite materials must also be taken into consideration.+

This secure connection is created by thousands of welding spots on the car body, the doors, the hood, etc. Each component contributes to the rigidity of the vehicle and thus to protecting the passengers. In car body manufacturing, the welding spot connections are performed fully automatic with consistent precision and quality.

For exactly this purpose, electric cylinders are used to evenly generate the force of the welding tongs. In order for a welding spot to meet all quality requirements, the welding electrodes must be constantly pressed together and held with the correct amount of force during the welding procedure.

Repeat accuracy, process reliability and durability are just as important quality criteria for the used welding tongs drive, as accurately positioning the welding spots so that the surrounding surfaces aren't damaged. This includes that welding spatter does not occur when a welding tong application functions optimally.

The technical solution

The mechanical design of our electric cylinders is variable, so that it exactly fits to the used welding tong construction, whether you use X-tongs or C-tongs.

The design of the electric cylinder is selected depending on:

• Available installation space
• Required stroke
• Required welding power
• Required speed
• Used control system

More properties of the electric cylinders:

• Maintenance-free for the entire service life due to the patented bath lubrication
• No regreasing required throughout the entire service life
• Very high efficiency
• Easy to install
• Excellent power density / enhanced heat distribution via bath lubrication
• Twice the service life as compared to the market standard
• Low costs throughout the service life and higher OEE as compressed air preparation of the electric cylinder is not needed
• Easily integrated into control systems using flexible encoder systems and connector options
• Exact positioning thanks to ball screws using servo drive technology with high-precision encoders
• Perfect force and repeat accuracy throughout the entire service life, with no need of additional sensors
• Very low noise as compared to pneumatically operated welding tongs