[jcommin]

I have done a fair amount of plant layouts.

I use AutoCAD. I create my own blocks from the equipment I have. I verify dimensions on all major pieces of equipment. I would map you existing layout and review to see what works/what doesn't.

Manufacturing flow should start from one side and move to the other. This works well if you have docks on both sides of you building (receiving flow to shipping) Non manufacturing activities (office, finance, engineering, maintenance, etc.) should be on the perimeter as to not disrupt the flow of manufacturing/warehousing. Aisles should be wide enough for truck traffic and material flow and they need to be continuous (no dog leg or dead end aisles).

Just a start - then you look at lighting, ventilation, HVAC. Have fun - sounds like a nice project.