Browsing by Author "Conradie, P. J. T."

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    Evaluation of communication systems for deep level mining monitoring applications
    (Stellenbosch : Stellenbosch University, Department of Industrial Engineering, 2011-09) Van Wyk, P. J. J.; Oosthuizen, G. A.; Conradie, P. J. T.
    Deep level mining companies face many problems affecting their development and profitability. One of these problems affecting growth is the lack of effective, yet economically viable, communication systems. This is especially necessary in rapidly expanding and changing environment mines. Resource companies need constantly growing revenues to remain competitive in the current mining industry. This paper identifies the constraints associated with applying communication systems in deep level mines, both the constraints affecting the physical machinery as well as constraints affecting the labourers installing, operating and maintaining the system. The existing communication systems are identified and then critically evaluated. The evaluation is done by identifying the advantages and disadvantages of each system, and by comparing the costs associated. The constraints play a prominent role in the evaluation phase as certain technologies immediately are discarded as possible selections when they clash with conflicting constraints. The results of the evaluation process are used to determine possible solutions with respect to communication problems faced in mining applications. Recommendations are made on the most efficient and cost effective technologies according to the results. These recommendations are used by mining companies to improve their current communication systems.
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    Evaluation of work piece temperature measurement techniques for milling of Ti6Al4V
    (Stellenbosch : Stellenbosch University, Department of Industrial Engineering, 2011-09) Conradie, P. J. T.; Oosthuizen, G. A.; Treurnicht, N. F.; Al Shaalane, A.
    Ti6Al4V is one of the most widely used titanium alloys in aerospace applications, but its machining remains a challenge. This is partly due to the lack of understanding of the thermal- and mechanical constraints during milling. Extensive research has been done in the past investigating catastrophic tool failure of various tool materials. However, not much research has been done to investigate the cause of work piece failure. The catastrophic effect of overheating the work piece and the resulting alpha case formation in titanium is well known. Current techniques of temperature measurement of the machined surface can be divided into two categories: contact- and optical methods. In this study these temperature measurement techniques were studied and evaluated. The response time of contact methods are found to be to relatively slow. The optical methods have the advantage of immediate response, allowing capture of intermittent heat generation as required in milling. The infrared camera temperature measurement experiments were conducted with a special setup in order to have a good visual of the temperature flow. The results of these experiments were found to correspond with literature.
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    Overview of work piece temperature measurement techniques for machining of Ti6Al4V
    (Southern African Institute for Industrial Engineering, 2012-07) Conradie, P. J. T.; Oosthuizen, G. A.; Treurnicht, N. F.; Al Shaalane, A.
    ENGLISH ABSTRACT: Ti6Al4V is one of the most widely used titanium alloys in aerospace applications, but its machining remains a challenge. Comprehensive research has been done in the past, mainly investigating tool failure of various materials. Less research has been done to investigate the thermal effect of machining on work piece quality, including fatigue performance. Temperature measurement is considered to be a key enabling technology. This study presents an overview of current temperature measurement techniques for machined and tool surfaces. Two categories of methods were investigated: slower contact, and faster optical methods. Optical fibre two colour pyrometry experiments are reported that demonstrate the technique’s adequate response time. The infrared camera temperature measurement experiments synchronised temperature measurement with visual observation, aimed at mechanism analysis. The results corresponded with the literature.