A method for improving the properties of a joint between two cable ends having obtaining two cable ends, having uncovered conductors being joined in a connection zone, each cable end also including an uncovered insulation zone including uncovered insulation formed as a cone adjacent the uncovered conductor, covering the conductors with an additional insulation layer, measuring the additional insulation layer and the cones, determining the geometry of the cones and the additional insulation layer based on the measurements, determining a deviation of the geometry from a desired geometry of the cones and the additional insulation layer, where the desired geometry includes a smooth transition between two zones, determining, based on the deviation determination, material to be removed from the cones and the additional insulation layer achieving the desired geometry, and removing the material from the cones and the additional insulation layer.