The time depends on the type of machine, on the dimension of the bag and on the volume of the content.
The chamber vacuum packaging machines usually need between 20 and 40 seconds, but this time changes according to the pump power and dimension: bigger the pump is, faster the vacuum will be.
For the external machines the vacuum cycle usually doesn’t overtake 60 seconds; even in this case the time depends on the vacuum pump power used in the machine.