1.The runner type
2.Series diameter(mm)：2 2.5 3 3.5 4 4.5 5 6 7 8 （10 12 for reference）
3.How to design the runner diameter for different material
For PE,PA .etc. we can choose smaller diameter,but for PC,PMMA,we choose bigger diameter.
4. Helpful Tips:
(1). For a U-shaped runner, the size of the runner can be changed by adjusting the H value;
(2). Try to select and use a circular runner;
(3). The sectional area of the runner has to be larger than that of its sub runners. See the following diagram which shows a runner divided into two sub runners. If the no. of sub runners is increased, D1 can be reduced appropriately.