change rotter

Ozark Biomedical may be able to assist. 

the problem is I can't take a rotor out I try to do my best and remove all escrow but it doesn't go out, looks like stuck with something, this not my first time I face this problem i solved with some force to get a rotor out but this time its very hard.

If you have already backed off the nut, and still can't remove it, you may need to use a gear puller.
Be sure to clean and grease the mating surfaces, before reinstalling the rotor, to that hopefully it doesn't happen again.

is your bolt/screw stuck or have you already removed that from the Rotor? you can try applying some lubricant(wd40) or some heat(heat gun, not a torch)

I assume you are aware, but just in case - the rotor nut/screw has left hand threads, so you need to turn it clockwise to loosen it. I think that is the case for all Hermle centrifuges.