Abstract: This invention belong to a mounting technology for aligning parts, a self-aligned elastic positioning. A problem this invention solves is alignment of parts without using mechanical fine pre-alignment. Wherein one part has elastic bumps, another part has V-grooves and the parts fit into each other. The invention is using elastic material for the bumps to fit the V-grooves. Whereas the bumps are made of elastic material and shaped partly to the V-bumps by moulding. The two parts can slide along in the direction perpendicular to the plane of the surface of the part. The movement in the perpendicular direction can be controlled by an external force. This means that the bumps and V-grooves have good alignment in xy-orientation and are also partial aligned in z-orientation. The elasticity of the bumps allows for thermal expansion differences without stresses to the parts while maintaining high precision alignment at a point.