Through an analysis of the solidification and rheologic behavior

some design rules and their mathematic expression were presented about some key parameters

such as compacting pressure

holding pressure time

pouring volume and pressing force

in the squeeze casting process

or molten metal die forging process（MMDF for short）.The compacting pressure in the process must be more than the sum of the resistant flowing stress of the alloy and the resistant stress along the feeding channels

or the feeding range should be larger than the distant from the pressing palace to the hot spot of the workpiece;or the available pressure at the final solidification position is more than zero in the whole pressing period

if not

shrinkage defects could be observed.The holding pressure time should be larger than the solidification time in the final solidification position

if not

shrinkage cavity or crack easily occurs.The pouring volume should be larger than the sum volume of the workpiece and the technique remainder

and smaller than the valid volume of the pressing chamber

if not

misrun can be observed.The pressing force has to be large enough to make the solidificated alloy flow to feed the shrinkage

to make the workpiece compact and overcome the resistant force from the friction between the punch and the die

if not

misrun or shrinkage cavity could occur.The validity of these rules has been proved by many facts of aluminum alloy and iron and steel.