When the aluminum extrusion machine is pressurized, there will be residual air in the
aluminum profile, resulting in bubbles inside and on the surface of the aluminum profile, resulting in unsolvable defects, making the aluminum profile into a waste. To avoid air entering the aluminum profile, find out why the air is being brought in. Here are the four main causes of residual air in extruded aluminum profiles.
1. The hot shear of the long stick leads to the residual air. The shear plane formed during hot shear of the rod is not perfect and vertical. Simple long bar hot shearing of industrial aluminum profiles will cause the rod to bend very seriously, resulting in the aluminum profile with an elliptical cross section and a very large fillet at the shear end. Even with the latest hot rod shears, the angle of the edge of the shear rod will always create a circle, and these circles are the best place for air to remain.
2. Upsetting leads to residual air. Only if the diameter of the cylinder containing the aluminum ingots is larger than the diameter of the rod can the rod be put into the cylinder containing the aluminum ingots. After pressure is applied to the rod inside the aluminum ingot cylinder to cause the rod to expand to the diameter of the ingot cylinder, the gas is discharged. The gas doesn't escape, it stays in the ingots and eventually bubbles.
3. The air residue is caused by the connection of two aluminum rods. Because the surface of the two short rods is basically flat, the probability of carrying air in is very small. The quality of the cut directly interferes with the amount of air carried between the two short rods. At present, there is a high technology that can prevent the connection of two short column rods, and the possibility of air entry.
4. Aluminum extrusion to avoid the entry of air, so as not to appear air residual situation, resulting in a variety of defects in the post-processing.