The design of cooling system is very important in injection moulding. This is because only when the plastic parts are cooled and solidified to a certain hardness, can the plastic parts be avoided from deformation due to external force after demoulding. 
Because the cooling time accounts for about 70% - 80% of the whole cycling time in moulding, a well-designed cooling system can greatly shorten the moulding time, improve the injection productivity and reduce the cost. The improper design of cooling system will prolong the moulding time and increase the cost. And the uneven cooling will further cause warpage deformation of plastic parts.