With the definition of the parting plane and all necessary shut-offs,the core insert and cavity insert have been completely separated.To create the cavity and core inserts,the length,width,and height of the inserts must be defined.
The length and width of the cavity and core inserts must be large enough to:
1. enclose the cavity where the part is formed
2. Withstand the forces resulting from the melt pressure exerted upon the area of cavity
3. Contain the cooling lines for removing heat from the hot polymer melt,and
4. Contain other components such as retaining screws,ejector pins,and others.
All of these requirements suggest making the core and cavity inserts as large as possible.For smaller injection molded parts,increasing the sizing the core and cavity inserts may have little added cost.However,the cost of larger core and cavity inserts can become excessive with increase in the number of cavities or injection molded part size.