Reasons and solutions for bubbles appearing on the surface of aluminum extrusion profiles

When the aluminum profile extruder is pressurized, air will remain inside the aluminum profile, causing bubbles to appear inside and on the surface of the aluminum profile, resulting in defects that cannot be completely solved and turning the aluminum profile into waste. In order to prevent air from entering the aluminum profile, it is necessary to identify the reason for the introduction of air. The following are the main factors causing residual air inside four extruded aluminum profiles:

1.Long rod with hot cutting leads to residual air

The shear surface formed during hot cutting of the column is never perfect or vertical. The simple long bar hot cutting of industrial aluminum profiles can cause severe bending of the column bars, resulting in elliptical cross-sections and a very large rounded corner at the cut end of the aluminum profile. Even with the latest long rod hot shear, the edge angle of the sheared column always produces rounding, which is the best place for air residue.

Solution: Conduct standard inspection on aluminum bars and resolutely eliminate unqualified aluminum bars.

2.The upsetting caused residual air

The upsetting caused residual air. Only when the diameter of the cylinder containing aluminum ingots is larger than that of the column rod, can the column rod be placed into the cylinder containing aluminum ingots. After applying pressure to the columns inside the aluminum ingot cylinder, causing them to expand to the diameter of the ingot cylinder, it is necessary to discharge the gas carried by them. If the gas is not emitted, it will eventually turn into bubbles inside the aluminum ingot.

Solution: Configure extrusion gaskets based on the minimum size of the inner lining of the extrusion cylinder, regularly replace the extrusion cylinder, inspect the corrosion of the extrusion cylinder and extrusion gasket, measure the inner and outer diameters of the extrusion cylinder and extrusion gasket to configure suitable extrusion gaskets; Clean the squeezing cylinder with cleaning gaskets once per shift, and regularly etch and wash the squeezing cylinder.

3.Two aluminum rods connected together result in residual air

Due to the connection of two aluminum rods, there was residual air. Because the surface of the two short rods is basically flat, the probability of carrying air in is very small. The quality of sawing directly interferes with the amount of air carried between two short column rods. At present, there is a high-tech that can prevent two short column rods from connecting and eliminate the possibility of air entering.

Solution: Determine a reasonable length of aluminum rod based on process parameters such as profile weight and discharge count.

4.Squeezing aluminum profiles leads to residual air

When extruding aluminum profiles, it is important to avoid the entry of air to prevent residual air from causing various defects during post-processing.

1.Improper oiling can cause bubbles in the product.

Solution: Use the correct oiling method and reduce the amount of oiling used; Strengthen the training of employees' pre job operational skills;

2.The excess pressure is too thin, causing the metal in the diversion hole to be pulled out during shearing, leaving a gap in the diversion hole of the mold.

Solution: Based on the tonnage of the extruder, leave a reasonable residual thickness, and determine the appropriate length of the aluminum rod according to process parameters such as profile weight and discharge count;

3.The design of the extrusion die includes a flat die welding chamber, and the diversion hole of the diversion die is too large, causing bubbles to flow into the mold cavity.

Solution: Reduce the size of the flat mold welding chamber, decrease the hole size of the splitter mold, and keep a distance of at least 5MM from one side of the extrusion cylinder.

Conclusion

When the aluminum profile extruder is pressurized, residual air causes bubbles to appear inside and on the surface of the aluminum profile, resulting in defects that cannot be completely solved and turning the aluminum profile into waste. Through the analysis and comparison of traditional and improved aluminum rod casting, extrusion, and mold design and manufacturing processes, it can be concluded that improving the production efficiency of extruded profiles, controlling the extrusion surface requirements, and solving the bubbles that appear in the production of extruded aluminum profiles are crucial and important.