Aluminum profile: optimal cross-section

Aluminum extrusion

sometimes pressing aluminum profiles compared to extruding toothpaste from a tube. In some of these processes are similar, but the pressing of aluminum profiles with a complex cross-section and, in addition, High Quality, of course, much more difficult and it is very difficult. Pressing of aluminum requires high temperatures and pressures, their precise control and, naturally, sophisticated equipment - extrusion press.

How to make the aluminum profiles

An important part of this process is matrix. The simplest form of a matrix - a steel disc with a hole, контур которого совпадает с поперечным сечением профиля (рисунок 1).

pressovanie-alyuminiyaFigure 1

The process of molding itself is relatively simple. Нагретая заготовка (от 400 by 550 °С в зависимости от сплава) загружается в подогретый контейнер. When moving the ram into the container there is tremendous pressure and the material begins to flow through the matrix and to leave it has a profile cross section, which defines a matrix. For pressing the hollow sections used matrix with much more complex structure, than just a steel disc with a hole, especially for profiles with multiple cavities.

Pressing tool

Extrusion matrix not only form a cross-sectional profile. She is also a supporting structure, которая должна выдерживать полное усилие прессования и через вспомогательный прессовый инструмент (подкладки, больстер) передавать его на неподвижные конструкции пресса.

Working conditions of the extrusion die

these loads, according to the press, can reach 10000 tonnes, and the pressure on the mirror matrix – 8000 atmospheres. Therefore, the matrix is ​​made of high-strength, heat-resistant tool steels. Напряжения в матрице возрастают с увеличением ее размера (диаметра) и сложности. When the large matrix is ​​used for compression of high aluminum alloys, то нередко проявляется явление ползучести стали и ее малоцикловое разрушение (одна заготовка – один цикл).

Modern matrix for multi-cavity profiles are a complex combination of mandrels, forming the inner contours, and the feed channels, which is fed under high pressure metal. Between these functional elements should be enough space to accommodate the load-bearing elements of the necessary strength and rigidity. The lack of load-bearing capacity leads to early failure of the matrix, and lack of rigidity - to excessive elastic deformation of the matrix and, Consequently, large deviations from the specified dimensions of the cross-sectional profile and shape of the profile – longitudinal deflection, waviness, torsion.

Profile for good compaction

The size and shape of the cross-sectional profile can strongly influence, as the ability of the matrix to achieve the commanded pressing accuracy, and the reliability and durability of the matrix. Simple design rules of cross-sections of aluminum profiles, apparently, does not exist.

Ниже представлены некоторые практические рекомендации по проектированию профилей с конкретными «плохими» и «хорошими» примерами поперечных сечений (рисунки 2.1, 2.2 and 2.3), as well as drawing 3. According to these recommendations can be judged, why the profiles with one cross-section of a press easily, in others it is very difficult. Some of the recommendations may relate more to the profiles with a large cross-section, than to the profiles with a small cross-section.

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Figure 2.1

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Figure 2.2

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Figure 2.3

alyuminievye-profili-xoroshie-ploxie

Figure 3

Источник: Gitter R. § Seminar "EUROCODES – Background and Applications», Brussels, 2008