and the cutting tool 24 are removed from the hollow profile the cutting out or separating out of the wall sections 19 20 27 can be carried out with a variety of devices with different cutting tools in the device shown in fig4 a cutting tool 24 is used which includes two cutting tool parts 25 26 which extend over the length of the hollow profile 2 so that lateral ends 28 29 of the cutting tool parts 25 26 protrude relative to the hollow profile 2 the upper first cutting tool 25 acts as punch die and has a blade 30 the lower second cutting tool part 26 has a female die 31 which is complementary to the blade 30 and severs at the same time as counter holder laterally to the blade 30 and the female die 31 support zones 32 33 are respective provided which during the separation process come into contact with the inner wall 7 8 9 and support the inner wall 7 8 9 in the here shown exemplary embodiment the inner wall 8 during the separation process the cutting tool 24 is actuated by drive means 34 which are located outside the hollow profile 2 and act on the cutting tool parts 25 26 the drive.