In the extrusion production of aluminum profiles, the common defects are more intuitive, such as bending, twisting, deformation, slag inclusion, etc.The defects of "adsorbed particles" are difficult to be found without careful observation or hand touch.Its harm is: in the production process of electrophoresis, spraying profiles, it is difficult to remove, affect the appearance of profiles, resulting in waste.
The main reasons for the formation of "adsorbed particles" are as follows:
1. The influence of the mold
In extrusion production, the die works under the condition of high temperature and high pressure, which will produce elastic deformation.The working belt of the die begins to be parallel to the direction of extrusion. After being subjected to pressure, the working belt deforms into a horn shape, and only the cutting edge of the working belt contacts the sticky aluminum formed by the profile, which is similar to the cutter crumbs of turning tools.In the forming process of aluminum adhesion, particles are constantly taken out by the profile and adhered to the surface of the profile, resulting in "adsorption particles".
2. Influence of extrusion process
The correct selection of extrusion process parameters is also an important factor affecting the adsorbed particles.Extrusion temperature is too high, extrusion speed is too fast, "adsorption particles" is more, the reason is because of high temperature, speed, profile flow speed increases, the degree of mold deformation increases, metal flow speed, metal deformation resistance is relatively weakened, more prone to form the phenomenon of sticking aluminum.
3. Influence of casting rod quality
The quality of casting rod is an important factor affecting the surface and extrusion forming of aluminum profiles.The formation of "adsorbed particles" has a great relationship with the quality of casting rod.The common structural defects of the casting rod are slag inclusion, loose, coarse grain, segregation, bright grain, etc. All these casting rod defects have one thing in common, that is, they are not welded well with the casting rod matrix, resulting in the discontinuity of the matrix flow, which is an important factor for the formation of "adsorbed particles".
"Adsorbed particles" is the major influencing factors of mould, casting, extrusion process from three aspects, the operation of the operating personnel level is also reflected in these three elements, on the basis of production practice, constantly to analyze problems, sum up experience, we can reduce or avoid "adsorbed particles", greatly improve the yield of profiles and the production efficiency.
