Browsing by Author "Delport, Lourens Daniel"
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- ItemMilling strategy induced shape deviation of thin-walled Ti-6Al-4V components(Stellenbosch : Stellenbosch University, 2017-03) Delport, Lourens Daniel; Oosthuizen, G. A.; Dimitrov, D. M.; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.ENGLISH ABSTRACT: Titanium and its alloys possess favourable characteristics and are thus increasingly used in the aerospace, biomedical and automotive industries. Difficulties due to these favourable characteristics result in various problems with final components manufactured from titanium alloys. These problems lead to high amounts of material waste, long machining times, high costs and safety issues. One of these problems identified in the industry was the shape deviation of thin-walled Ti-6Al-4V aerospace components during the machining process. This shape deviation leads to decreased dimensional accuracy of the final component which leads to increased scrap. A study was conducted on simplified components in order to determine the effects of cutting speed and wall thickness on the shape deviation. The aim of this study is to investigate the effects of axial depth of cut (ap) on the shape deviation of the simplified thin-walled Ti-6Al-4V components, machining process time, tool wear and cost. The main research objective is to find a balance between low machining cost and low shape deviation. The chosen benchmark components were CNC milled at three different axial depths of cut. These depths were 8 mm, 5.33 mm and 4 mm. Experiments consisted of 5 components at each depth of cut resulting in a total of 15 parts. All other machining parameters were kept constant. The components were measured using a Coordinate Measurement Machine (CMM) in order to determine the amount of shape deviation. Tool wear was measured after each finished part on an optical microscope. It was determined that the axial depth of cut has no significant effect on the tool wear. The shape deviation was however affected significantly by the axial depth of cut. The ap of 5.33 mm had the lowest shape deviation values. The time increased linearly with a decrease in ap and similarly the machining cost as a result of the little effect on tool wear. Plotting the machining cost and the shape deviation on the same graph made it revealed a point where the best balance between cost/time and shape deviation can be determined. This point coincided with an ap value of approximately 5.9 mm. It can, therefore, be concluded that the ap of 5.33 mm is the closest to this point is, therefore, the best balance between cost/time and shape deviation.
- ItemSuitable clamping method for milling of thin-walled Ti6Al4V components(Elsevier, 2017) Delport, Lourens Daniel; Conradie, Pieter Johannes Theron; Oosthuizen, Gert AdriaanThe use of Titanium alloys is becoming more widespread in the aerospace, automotive and medical industries due to its favourable mechanical and thermal characteristics. Reducing the number of defective parts will increase the overall efficiency of the machining operation and thereby contribute to a more sustainable manufacturing process. An industry problem where a thin-walled titanium alloy aerospace component has deformed during machining has been identified. The effects of clamping methods during the machining process on the accuracy of titanium parts will be investigated through FEM analysis and experiments.