1. Material tube temperature is too low, melting plastic temperature is also low, material flow is reduced, so it is easy to form a flow mark in the flow direction.
2. The material circulation time is not reasonable, the material circulation time is too short will cause the melt temperature is low, the filling material liquidity becomes poor, easy to appear the flow mark.
3. The residence time of material in the material tube is insufficient, the material temperature will be low too, then it is not easy fo fill the material, and will also form the flow mark.
