Mori seiki lathe programming

[Chrisd9300]

Ok so I’m new to the world of lathes and I have a Mori Seiki Mt1500sz. I’m programming with mastercam and trying to avoid a crash on my new to me machine. The main spindle programming is pretty self explanatory as far as setting the work offsets and all but I’m curious about work in the sub spindle after the part is transferred.

I’ve seen where G54 is used on the main and G55 is used on the sub so with that in mind, do I run the first part of the program, let it part off and return home and then stop and set G55 on the face of the part in the sub spindle or is G55 calculated from the machine position. 

I can do about anything on the VMC but the lathe has me a little confused and like I said I don’t wanna crash. 

Thanks for any help it’s appreciated