[kaiz]

We are looking to purchase a 5-axis VMC with either a Siemens 840D or a Fanuc 31i-A5 machine control. I understand there will be customization performed by the machine tool builder, but I would like to know the price difference between basic models of these two machine controls. Please reply if you have some information regarding this.

Thank you.

[802DSpecialist]

The 804D is of course cheaper .....and better

[ShawJohn]

Ask which PCU is in the 840D, there are a few variants, some much more powerful than others.
avoid PCU20 machines as discontinued now and USB doesn't function. And limited to HMI Embedded, instead of HMI Advanced.
There are PCU20, PCU50, PCU50.3, PCU70 each having a few revisions all under the 810D/840D name. Power ranges from low end 16mb RAM Pentium 2's with no HD, to 2gb Ram 2.0Ghz Celeron with HD.

I hope this helps.

Don't know a jot about Fanuc as never used one
My experience is with 3 / 4axis machines but I pressume the same applies.