A Rubber O ring Die with OD,ID and thickness known...How can we calculate the number of cavities for that Die if we know a fixed length of the machine we are gonna mount on it. FOr eg. A O ring with 10.5 ID and 2 thickness ie OD=10.5+2+2=14.5 I want to design a mould for it on a 300 mm by 300 mm machine...wats the best calculations and design procedure in very simple procedure ??