Changing frame size of injection machine

Hello, Greetings!
I am trying to make injection machine in my country and I could not get square bar of right specification (30*30*3mm) for the frame of injection machine.
Rather, (25*25*3mm) and (35*35*3mm) are available.
Does any design modifications require if I changed the square for frame?
Please suggest me asap!
Thanks in advance!