| Summary: | 碩士 === 國立高雄應用科技大學 === 機械與精密工程研究所 === 102 === The main purpose of this study is to explore extrudibility of Al6061 aluminum alloy with hollow and complicated cross-section. AutoCAD software was used to draw complex hollow tube geometry and port-hole extrusion die and DEFORM 3D finite element simulation software was used to simulate the extrusion process. The product profile after extrusion and die stress were checked to optimum die design.
The original product thickness is 1mm; however it cannot be produced by port-hole extrusion process. In order to investigate whether the product thickness is the major factor to affect extrudibility or not, the product thickness has been enlarged into 2mm. The simulation result depicts that it cannot be extruded if based on the original die design concept. Therefore, in to solve the problem, a new die design is proposed. The concept is to align the maximum diagonal part of mandrel with the bridge of port-hole die. Then, the uniform material flow is investigated to enlarge the pocket geometry in lower die and reduce the cross section area of mandrel in upper die.
Using the final design of Type (3) dies to extrude 2mm thickness product where the simulation parameters are as follows: extrusion speed 1mm/sec, billet and die friction coefficient is 0.7 (no lubrication), billet mesh refinements are 3mm, 1.2mm and 0.8mm at three different stages, and temperatures are 250℃, 365℃ and 480℃. JIS-SKD61 die materials are used both for upper die and lower die. The simulation result depicts that the higher temperature, the lower die stress and extrusion load. Then, based on the die design concept of Type (3), a new die for 1mm thickness product with the same complicated geometry feature is designed as Type (4) which can be extruded successfully.
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