Properly increase section dimension of gate and runner; the position of gate is set at thick walls of the plastic parts and should be as symmetric as possible; improve mold exhausting condition; set cold-slug well with sufficient capacity to avoid cold material’s entering into the cavity and influencing filling and shrinkage compensation; properly dispose cooling water channeland intensify cooling at depressed parts with thick walls to achieve effective shrinkage compensation,on the basis that uniform cooling for all parts of the cavity can be ensured; carefully analyze whether a

“bottleneck” exists at the runner of melt within the cavity, otherwise, replace gate position or increase number of gate and when necessary, enlarge section of runner where the bottleneck is located; for products with thick walls, fan gate or flush joint gate can be adopted to shift the possible depression and shrinkage porosity to the gate