hi,
i have problem in design db of my small system , so i describe all relation
to get the whole picture
here what i have:

i have customers with many branches &
each branch has many machines &
each machine exists in many branches

Also : each machine has many components
each component exists in many machines

The problem exist in :
each branch has many machines with it's components , and each component in
this branch machine has it's serial Number (this the most confusion part)

now how i draw this as ERD and Physical tables as i am confused ,

thx ,waiting for your appreciated reply