Analysis of Several Causes of Aluminum Profile Defects During Extrusion Production
In extrusion production, aluminum defects are an important factor in the waste, and a small defect in the aluminum profile will destroy the entire length-cut aluminum profile. Due to the high added value of aluminum profiles, extrusion manufacturers should do their utmost to reduce defects in aluminum profiles.
1, the maintenance of aluminum extrusion presses
The maintenance status of the aluminum extrusion press has a significant impact on whether aluminum profile defects will occur. The quality of the aluminum profiles can be affected by the alignment of the aluminum extrusion press, the condition of the ingot and the extrusion pad.
2, residual air during extrusion
If air is blown into the holding spindle when it is squeezed and then pressed against it, the air is compressed to a small volume and the temperature rises. The air heated by compression will melt the surrounding aluminum alloy and generate air bubbles in the aluminum profile, or the air bubbles will open after being out of the working belt of the mold, thereby forming pores on the surface of the aluminum profile. The occurrence of either of the two conditions will cause defects in the aluminum profile and lead to waste.
Factors that may cause air to be carried in:
1. Gas residue caused by upsetting
Only when the diameter of the ingot is greater than the diameter of the rod, the rod can be loaded into the ingot. After the column rods in the ingots are pressed and the rods are extended to the diameter of the ingots, the carried air must be discharged. This air is released through the â€œexhaust cycleâ€ and the normal operation of the squeeze pad is very important for successful exhaust.
2. Gas residue caused by long rod heat shear
The shear plane produced by the hot shear of the rod is not perfect and vertical. The simple long rod heat shear can cause severe distortion of the rod, resulting in oval cross-sections and large rounded edges of the sheared ends. Even the most advanced long bar heat shear, the corners of the sheared bar will always appear rounded. This rounding can easily cause air to remain when the rod is upset in the ingot.
Long bar hot saws can replace long bar hot shears. With a long hot saw, the surface of the vertical rod can be sawed without deformation and no air can enter. However, some aluminum manufacturers do not want to use hot rod saws because sawing produces aluminum chips. From the point of view of the economics of aluminum extrusion, it is very important that the aluminum chips generated by sawing do not take any time to squeeze and can not reduce the production efficiency of aluminum profiles. These aluminum scraps are low-value scraps and will not increase the cost of any value-added processes. The only need to deal with these scraps is the cost of remelting.
If the long hot saw can increase the aluminum utilization by 0.5%, then the cost of sawdust will be lower than the value of aluminum scrap.
3. Gas residue caused by two-segment splicing rods
Because the surface of the two stub rods is almost flat, the possibility of air entrainment is small. The quality of the sawing directly affects how much air is drawn between the two short rods. There is now a new technology to avoid the emergence of two splicing rods, that is, the column rod rotary welding machine! Prior to cutting out the required length of the bar, the bar-spinning welder can weld the remaining less than set length of bar to the next whole long bar, eliminating the need to bring air through the two sections of the bar. The possibility.
3, solid pollutants
Like the air that is introduced into the extrusion, the defects caused by the contamination will also destroy the entire length of the aluminum profile.
Main sources of solid pollutants:
It is important to keep the factory clean. Long rod storage locations, long rod heating equipment, rod transport equipment for sending aluminum rods, aluminum extrusion press loaders, and aluminum extrusion presses must be kept clean to avoid aluminum. Pollution. Excessive lubrication is an important cause of contamination, and excessive lubrication can easily contaminate aluminum profiles.
2, long rod hot shear pollution
Many contaminants (such as oxides or dirt) on the surface of the long rod will enter the short rod when the long rod is cut. One of the characteristics of the hot shear is that it will not remove any material, but the long rod hot sawing You can eliminate this source of pollution.
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