The railway industry relies more and more on automation for arc welding. Weldments can be complex and very diversified in terms of material type, thickness and shape.

Servo-Robot laser vision systems have been installed on robots mounted on large gantries to weld aluminium passenger cars, agricultural product cars and bogies.

Aluminium passenger cars

Aluminum passenger cars are now becoming common around the world because of the demand for light weight cars. During production, the panels are bent to form the required shapes. Due to the inaccuracy of this last process and the inability of the robot to compensate, 3D laser vision systems have proven very useful in the detection of the joint position and in tracking the joint.

Laser vision systems are the best alternative to through-the-arc seam tracking which is unreliable on aluminum material.

Agricultural product cars

Robotics systems have been installed on agricultural products which carry liquids. Two robots are mounted on a gantry.

The purpose of the arc welding robots is to weld the roof and also the hatch on the top which form a saddle shape. This fillet weld made on the hatch would be impossible to weld with a blind robot due to the difficulty of building these large components accurately as well as positioning them under the 20m x 6m gantry.

Bogies

Bogies are other components which are quite difficult to weld with arc welding robots due to their complex shape and stringent quality requirements. Positioning of the electrode is very critical in order to get the required penetration.

Robotic cells equipped with our laser vision systems were installed to weld these parts with adaptive control of the welding parameters. The robotic cell includes a 6-axis articulated robot mounted on a 2-axis gantry. The part is fixed on a 2-axis positioner that allows optimum positioning of the part at all times. A total of 10 axes are controlled in synchronous motion while tracking with the laser vision system.