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How to quickly find defects in aluminum profiles

Due to the particularity of the hot extrusion process, the surface is also prone to some special defects. Some defects can be seen at a glance, such as welding lines, color separation, bright lines, scratches, etc. Some defects need to be revealed by some means, such as inconspicuous concave bone, convex bone, surface finish, etc. Some defects, such as weld lines, are not revealed until the surface is treated.

The profile drawn from the extruder, without surface treatment, is called the base material or blank.

When a profile extrudes two or three bars from the extrusion machine, the first inspection should be started. The first inspection will initially judge whether the quality of the aluminum profile is qualified, and the follow-up inspection can be carried out only after the qualification is confirmed. So what if the defects of the profiles are quickly found during the first inspection?

1. Touch by hand: touch the surface of the profile by hand, some concave or convex bones on the surface can be felt by hand, or if you can feel the concave-convex line with your fingernails along the surface.

2. Pencil scribing: After the aluminum profile is extruded, use a pencil to scribe the surface of the aluminum profile, and judge whether there is a thick pattern by the feel and the continuity of the scratch.

3. Spray paint test: automatically spray paint on the surface of aluminum profiles to simulate spraying. After the surface is dry, observe whether there are scribes, concave and convex lines, etc. on the surface. This method is suitable for the judgment of spray materials.
4. Alkali washing test: During the first inspection, take a 300mm length sample from the third rod. Soak the sample segment in the alkaline solution for 30-40 seconds, and the surface of the substrate after alkaline washing can see defects such as color separation, scribing and welding lines. This judgment method is suitable for oxide materials with relatively high surface requirements.

5. Surface grinding: During the first inspection, take a 300mm sample section and wipe it horizontally with an industrial scouring pad. After wiping, the surface of the substrate is easier to see slight defects. It is used to judge thin lines, concave bones that cannot be touched by hand, convex bones, and defects that cannot be judged by the above four methods.

The above five methods are commonly used in the first inspection of aluminum profiles, which can basically detect all defects on the surface of aluminum profiles.

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Post time: Jun-17-2022