How to prevent the extrusion lines on the surface of aluminum alloy profiles and what are the good methods

To achieve good control over the extrusion lines on the surface of aluminum alloy profiles, the first step is to identify the cause. In fact, the cause is well known, mostly due to problems with the extrusion die.
  The longitudinal convex or concave lines on the surface of extruded aluminum are a problem that exists in all aluminum extruded products, but the degree of existence varies. The reason for this is that the working belt of the extrusion die cannot achieve absolute smoothness, and the defects produced are mostly concave from the surface of the extruded product. The first type has a tactile feel, and the second type has no tactile feel but can be seen clearly with the naked eye. Usually, this is acceptable to customers; Another type is a raised vertical line with a tactile feel, which may not be obvious to the eye.  There are three main reasons for this:
  1. The surface of the mold is not smooth.
  2. The surface hardness of the mold is not sufficient, which makes it easy to stick aluminum or impurities.
  3. There are foreign objects stuck on the surface of the mold working belt.
  Preventive measures:
  1. Before heating the mold, check whether the working belt of the mold is scratched or smooth, which can effectively avoid sticking foreign objects;
  2. Before testing the new mold, it is necessary to confirm whether it has undergone nitriding treatment. The surface hardness of the working belt is high and uniform, which can prevent the working belt from being scratched;
  3. Before nitriding, it is necessary to check whether the working belt of the mold is processed evenly, whether the polishing is smooth, and remember to use the correct operation method during the polishing process;
  4. Check the surface of the material promptly after discharge to detect scratches and prevent the problem from escalating;