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FEM study of extrusion complexity and dead metal zone

Qamar S. Z.

Archives of Materials Science and Engineering

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2009

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Vol. 36, nr 2

110-117

EN

Purpose: Quality of the extruded product and efficiency of the manufacturing process can be seriously affected by inconsistent metal flow through the extrusion die. Metal flow problems can also significantly reduce die life. Various researchers have investigated the effect of profile complexity on extrusion pressure, product quality, die life, etc. However, the relationship between shape complexity and metal flow through the extrusion die has not been studied in detail. Cold extrusion experiments on some solid profiles and simulations using the finite element method (FEM) have been used in this work to investigate the effect of profile complexity on dead metal zone and metal flow. Design/methodology/approach: Cold extrusion experiments were performed using flat-face dies of different complexities. 3D finite element simulation was carried out using the commercial finite element packages ANSYS and ANSYS-LSDYNA. Findings: Findings of this FEM study are that there appears to be no definite correlation between dead metal zone (DMZ) size and the currently existing definitions of extrusion shape complexity. Factors such as die profile symmetry and extrusion ratio may also play significant role in the formation of DMZ and distortion of metal flow through an extrusion die. Practical implications: The study can be of direct utility in extrusion die design improvement, and reduction of extrusion defects related to metal flow. Originality/value: The paper provides basis for a deeper understanding of the factors involved in the formation and development of dead metal zone (and related metal flow problems) in metal extrusion.

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Basic solutions on shape complexity evaluation of STL data

Valentan B., Brajlih T., Drstvensek I., Balic J.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 26, nr 1

73-80

EN

Purpose: Purpose of this paper is to present basic solutions on shape complexity, based on basic information of the STL data. Design/methodology/approach: Paper presents a few methods of mathematically evaluating the complexity of the shape. Methods vary from very simple based on the number of triangles in STL file, STL file size and the parts volume, to the more complex mathematical evaluation based on the basic relations of the STL data. Findings: We discovered that evaluation of shape complexity based only on basic data of STL data gives us some basic results on part complexity and can be used for further researches. Research limitations/implications: For parts with large block volume/part volume ratio and thinner parts with free form surfaces only the first method is suitable and gives suitable results. Practical implications: In a rapidly developing field of manufacturing technologies choosing the optimal manufacturing procedure is a difficult and crucial decision. Usually the decision is based on experience evaluation that is fast and can be optimal. Usually, this method produces goods results, but in some cases this method can lead to cost increases and reduced economic efficiency without us even knowing that. Therefore, it is crucial, that a fast and simple solution is developed, by which the optimal way of manufacturing can be determined. Originality/value: Choosing maximum efficient manufacturing processes on base of part complexity is a new perspective in manufacturing, which, properly evolved and complied can cause revolution in manufacturing optimization, especially in hybrid manufacturing processes.

3

Evaluation of shape complexity based on STL data

Valentan B., Brajlih T., Drstvensek I., Balic J.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 17, nr 1-2

293--296

EN

Purpose: Purpose of this paper is to present a part complexity, based on basic information of the STL data. Design/methodology/approach: This paper presents a few methods of evaluating the complexity of the shape, based on the parts STL data. Methods vary from very simple based on the number of triangles in STL file and the parts volume, to the more complex mathematical determination based on the relations of the basic STL data. Findings: We discovered that evaluation of shape complexity based only on basic data of STL data gives us some basic view on part complexity. Research limitations/implications: For parts with large block volume/part volume ratio and thinner parts with free form surfaces only the first method is suitable and gives suitable results. Practical implications: The complexity of the shape of a part is an important factor for all manufacturing procedures. When using conventional machining, the parts complexity presents a key factor in determining the optimal way of manufacturing. Also, when using rapid tooling (for example silicon rubber moulding) the complexity of the part determines the parting plane layout and eventual tool construction (inserts, cores, etc.). Even when using certain rapid prototyping procedures, the support material consumption depends highly on the complexity of the part and together with the problem of optimal orientation and position of the part, significantly influences the manufacturing costs. At the end of the article a few test method are presented that try to determine the complexity regarding to the procedure by which the part will be manufactured. Originality/value: Choosing maximum efficient manufacturing processes on base of part complexity is a new perspective in manufacturing, which, properly evolved and complied can cause revolution in manufacturing optimization, especially in hybrid manufacturing processes.