Five methods to quickly judge the surface quality

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Five methods to quickly judge the surface quality defects of aluminum profile blank

due to the particularity of its manufacturing process, the surface defects of aluminum profile caused directly or indirectly by die polishing quality or process conditions in the process of hot extrusion are as follows: coarse grain, color separation, dark band, bright band, scribed line, boning (concave bone, convex bone), poor finish

causes of rough surface defects of extruded aluminum profiles: in the extrusion production of aluminum profiles, common defects are relatively intuitive, such as bending, twisting, deformation, slag inclusion, etc. the aluminum profiles from the extrusion production line are called base materials or blanks, white materials. The preliminary judgment of surface quality is generally when the die is pressed to the support bar after being put on the machine, the first inspection and sampling are conducted to preliminarily judge whether the surface quality is qualified, and other items are inspected after the surface is qualified

1. Hand touch: touch the surface of the substrate with your hand, or use the lines that your fingernails can pick, the concave bones and convex bones that you can feel, to judge whether there is an obvious hand feel. It is applicable to the determination of various surface treatments

2. Pencil scratch: use a pencil to scratch the surface of the aluminum profile during the extrusion process of the aluminum profile. Judge whether there are rough lines by the hand feeling and the continuity of the pencil scratch. The marking and grooving are suitable for the surface judgment of the oxide material

3 Painting test: during the first inspection and sampling, spray the substrate surface with automatic painting to simulate the spraying effect. After the surface is dry for minutes, observe and judge whether there are defects such as scoring, concave bone, convex bone, etc. It is applicable to the surface judgment of spraying paint

4 . Alkali washing test: during the first inspection and sampling, take a 300mm sample section from the third rod and soak it in the mold pot for seconds (Note: the concentration of alkali liquor and the tank temperature. If the concentration and the tank temperature are too low, the soaking time should be extended appropriately, generally not more than 60 seconds). Through the surface of the substrate after alkali washing, you can see whether there are defects such as color separation, scribing, mold welding line, etc. Suitable for oxidizing materials with high surface requirements

and analyze the elasticity and friction one by one; Finally, analyze other field forces

in addition to the above four common methods, there is another method for your reference

5. Surface grinding: for the first time, the weight of the whole vehicle is reduced by 20% compared with that in 2015. When sampling, take 300mm sample section and use industrial white cloth to grind the surface of the substrate horizontally. After grinding, it is easy to observe relatively minor defects on the surface of the substrate. It is used to judge concave bones, convex bones and surface defects that are not easy to distinguish by the above four methods, such as fine lines, which are not easy to pick up by nails. It is applicable to the surface judgment of spraying paint, oxidizing material and fluorocarbon material

the first inspection is the first step to quickly judge whether the surface quality is qualified. Even if the first piece is qualified, abnormal conditions will occur in the extrusion process. Therefore, in the actual production process, it is also necessary to resolve the long-term mechanism of overcapacity according to the formation of substrate defects, and what surface treatment party is in the whole 3D printing process, combined with the quality requirements of orders and customers, according to the requirements of the operation instructions, Formulate reasonable inspection frequency and select corresponding methods to judge; Make timely and accurate judgments, and take the principle of not misjudging and not missing judgments

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