It is very important to sterilize cutting tools when working with orchids
I have seen however a person use an Axe on the root ball of cymbidiums
Sterilized tools can stop the spread of Diseases from one orchid to another.
please see link below also
New Hampshire Orchid Society - Viruses
The answer to your question do you need to take care when you do separate your orchids is yes for you may damage the roots also any new young growth may be broken off also
I hope this helps you