Kemet Share | Causes and Solutions of Bubbles on Aluminum Profile Surface

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When the aluminum profile extrusion machine is pressurized, air will remain in the aluminum profile, resulting in bubbles in the interior and surface of the aluminum profile, resulting in defects that cannot be completely solved, making the aluminum profile become waste.

The following introduces the main factors of residual air in the four extruded aluminum profiles:

1. long rod hot shear causes residual air

The shear surface formed during hot shear of column rods is absolutely not perfect and vertical. The simple long bar thermal shearing of industrial aluminum profiles will make the bending of the column bar very serious, resulting in an oval cross section of the aluminum profile and a very large rounded corner.

Even if it is the latest long rod hot shear, the edge angle of the sheared column rod will always produce rounding, and these rounding is the best place for air residue.

Solution: Carry out standard inspection on aluminum rods and resolutely eliminate unqualified aluminum rods.

2. upsetting caused residual air

upsetting caused residual air. Only when the diameter of the cylinder containing the aluminum ingot is larger than the diameter of the column rod, the column rod can be put into the cylinder containing the aluminum ingot. After applying pressure to the column rod inside the aluminum ingot barrel to cause the column rod to expand to the diameter of the ingot barrel, the gas carried by

must be discharged. If the gas is not emitted, it will remain in the aluminum ingot and eventually become bubbles.

Solution: Configure the extrusion gasket according to the minimum value of the inner lining size of the extrusion cylinder, replace the extrusion cylinder regularly, check the erosion of the extrusion cylinder and the extrusion pad, measure the inner and outer diameters of the extrusion cylinder and the extrusion pad to configure appropriate extrusion gaskets; Clean the extrusion cylinder once per shift, and regularly etch and wash the extrusion cylinder.

3. the two aluminum rods are connected to cause air to remain

The two aluminum rods are connected to cause air to remain. Because the surface of the two short rods is basically flat, the probability of carrying air into it is very small. The quality of the sawing directly interferes with the amount of air carried between the two stub bars. At present, there is a high-tech technology that can prevent

from connecting two short column rods to eliminate the possibility of air entering.

Solution: Determine a reasonable rod length aluminum rod according to the process parameters such as profile single weight and discharge count.

4. extruded aluminum profile causes air residue

When extruding aluminum profile, air must be avoided to avoid air residue and various defects in post-treatment.

1. Improper oiling causes bubbles in the product.

Solution: Use the correct oiling method and reduce the amount of oiling; Strengthen the training of pre-job operation technology for employees;

2. The pressure surplus is too thin, which causes the metal of the shunt hole to be pulled out during shearing, leaving a gap in the shunt hole of the feeling tool.

Solution: According to the tonnage of the extruder, set aside a reasonable residual thickness, and determine a reasonable aluminum rod with a reasonable rod length according to the process parameters such as the single weight of the profile and the number of discharge counts;

3. The extrusion die is designed with a flat die welding chamber, and the shunt hole of the shunt die is too large to cause bubbles to flow into the cavity.

Solution: Reduce the size of the flat die welding chamber, reduce the die hole of the split die, and the distance from the single side of the extrusion cylinder is more than 5MM.