Electrode force measurement on welding guns (spot welding, resistance welding)
During the manufacture of vehicle bodies, welding robots are mainly used. The various body parts are connected to welding points. Differently designed welding tongs set the connection points in the desired locations. Electrode forces, welding current and welding time are controlled in order to achieve a consistent quality of the welding points.
In order to check the adjusted electrode forces, mobile and stationary force sensors are used. Primosensor manufactures measuring systems for this purpose. The stationary sensors are mounted in the range of motion of robots. In a fixed rhythm, they move to the force sensor with the welding electrodes, in order to compare the applied closing force with the preset setpoint and to adjust accordingly. Mobile force sensors are designed for setup, service and control measurements. A connected handheld indicator directly displays the current force value of the welding gun.
These measuring systems (test kits) are very flexible due to battery operation. A Li-Ion battery allows a working time of several hours. The mobile force sensors are equipped with a handle, which effectively decouples the occurring moments from the hand when the pair of tongs is closed. The display unit is housed in a robust housing equipped with an impact protection seal. It detects the load range of the force sensor and automatically sets the corresponding measuring range. Via a Bluetooth interface, force data can be transferred to a smartphone or a tablet PC and visualized with the Primoscope-APP. The collected data can be written as csv-file for further processing.
Mobile and stationary force sensors are available in two sizes for load ranges 10 kN and 20 kN. The concave force introduction areas allow repeatable measurements with all common electrode caps. The devices can be used as calibrated test equipment according to ISO 9001.