A good indicator of the welding quality in resistance welding is the force level during the current flow. The more evenly the force is applied during welding, the better the parts will join. Dalex has developed the EPS electro-pneumatic welding drive for resistance welding systems to ensure this in a simple and energy-efficient manner. It ensures an almost constant and effective welding force over the entire welding process.

Short cycle times and convenient operation

The EPS consists of a servomotor-driven linear unit, which is designed as a spindle drive, and a tracking unit attached to it, in which a pre-tensioned spring filled with compressed air transfers the welding force to the welding spot. The servomotor drive stroke allows the welding electrodes to be adjusted precisely, quickly and steplessly in relation to each other according to the required welding task and component geometry. A speed of up to 200 mm/s can be set.

When the welding electrode is placed on the welding point with the linear unit, the "pneumatic spring" is only subjected to a fraction of the welding pressure that is defined and set beforehand. This ensures that the electrode is placed on the workpiece gently and without impact. Once the electrode is in contact, a sensor in the tracking unit gives the signal to adjust the spring travel to the defined spring compression. Thanks to the pre-control of the pressure, the welding force is already at the required level and the welding process can begin without delay.

Low energy consumption and wear

In addition to the quality of the weld, the system also offers advantages in terms of operating costs. The pneumatic drive only requires compressed air when adjusting the electrode force, and then only in very small quantities to adjust the pressure of the pneumatic spring. In addition, the welding force and current can be kept as low as possible by adjusting the parameters.

As the drive concept does not require sliding seals, but works with roller bearing guides, the influence of friction is very low. This supports the high dynamics of the drive and reduces wear.