(1) The extrusion coefficient of aluminium profile is too large, the extrusion temperature is too high (bar, cylinder, die three temperatures), and the extrusion speed is too fast.

(2) The extrusion force is unstable, high and low, and the speed difference between multi-speed regulation is obvious, and the speed conversion is rapid when shifting.

(3) Aluminum alloy profiles are extruded with excessive top pressing (stamping), tail running speed or no deceleration, and a large amount of infiltration of dead zone aluminium.

(4) The quality of the rod is poor, the rod is overheated, the grain is large and loose. The residual (V3 aluminium) is too thin.

(5) The design and manufacture of the velocity ratio of extrusion die is unreasonable.