The invention includes methods of forming openings extending through electrically insulative layers to electrically conductive materials. The X-ray system comprises a radiation detector, a movable X-ray tube assembly and a control unit, wherein in a working state of the system the radiation detector is detachably positioned in a spatially fixed manner and the X-ray tube assembly can be moved into relative positions relative to the radiation detector. The second layer made of a second polymer material having a second maximum blow-up-ratio greater than the first maximum blow-up-ratio, and the second layer is an inner layer relative to the first layer.