Conduction time (die mold)

= 0.4

Figure: Schematic of heat transfer processes in the die

The governing equation the heat transfer for die reads

(3.13)

To obtain the characteristic time we dimensionlessed the governing equation and present it with a group of constants that determine value of of the characteristic time by set it to unity. Lets define

(3.14)

  the characteristic path of the heat transfer from the die inner  surface 


to the cooling channels 


subscript		


B 		 boiling temperature of cooling liquid  


M 		 liquid metal melting temperature 

With these definitions equation () is transformed to

(3.15)

which leads into estimate of the characteristic time as

(3.16)

Note the characteristic time is not effected by the definition of the . discussion about the typical estimates and how to calculate it