Browsing by Author "De Beer, N."

Now showing 1 - 4 of 4
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    An economic cost model for patient-specific intervertebral disc implants
    (Stellenbosch : Stellenbosch University, Department of Industrial Engineering, 2011-09) De Beer, N.; Bloem, N.
    Back pain is a common concern amongst a growing population across the world today. Depending on the severity of a patient’s condition, and after conservative treatment options have been exhausted, total disc replacement (TDR) surgery may be prescribed as a corrective treatment. Several existing artificial disc implants are available on the market and are manufactured in standard sizes by means of conventional manufacturing processes – which typically involves machining operations. During surgery, surgeons try to select the most suitable implant size to match the patient’s anatomy by pushing various trial sizes into the vertebral space before placing the final implant. This trial-and-error technique relies heavily on the level of experience of the surgeon and could lead to TDR device under sizing and inaccurate positioning of the implant, which could lead to implant subsidence and bone fracture. As various imaging, software and manufacturing technologies have developed, the option for patient-specific implants by means of Rapid Manufacturing is becoming a realistic alternative. Patient-specific implants offer several potential clinical benefits to the patient, but it is important to investigate its cost implications. This paper discusses a cost model for patient-specific disc implants, and the potential advantages as well as challenges of using customized implants within the South African context.
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    High-speed 5-axis machining for tooling applications
    (Southern African Institute for Industrial Engineering, 2012-11) Saxer, M.; De Beer, N.; Dimitrov, D. M.
    ENGLISH ABSTRACT: In the modern metalworking industry, production moulds often have complex geometry, with undercut regions, small corner radii, sharp edges, deep cavities, or large cores. Conventional manufacturing process chains to machine these complex features are often lengthy and inefficient due to multiple steps. This article presents current results obtained through industry projects and experimental work using 5-axis high-speed machining with high-end CAD/CAM systems to improve process efficiency. Cost optimisation and lead time shortening can be clearly shown. This is of particular importance for South African manufacturing companies, where multi-axis HSC technology although not totally unknown is significantly under-used.
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    An introduction to rapid casting : development and investigation of process chains for sand casting of functional prototypes
    (SAIIE, 2007) Dimitrov, D.; Van Wijck, W.; De Beer, N.
    ENGLISH ABSTRACT: This paper discusses the results obtained from studies on different Rapid Tooling process chains in order to improve the design and manufacture of foundry equipment that is used for sand casting of prototypes in final material. These prototypes are intended for functional and pre-production tests of vehicles. The Three Dimensional Printing process is used as core technology. Subsequently, while considering aspects such as time, cost, quality (accuracy and surface roughness), and tool life, a framework is presented for the evaluation and selection of the most suitable process chain in accordance with specific requirements. This research builds on an in-depth characterisation of the accuracy and repeatability of a 3D printing process.
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    Three dimensional printing in the South African industrial environment
    (Southern African Institute for Industrial Engineering, 2008-05) Dimitrov, D.; Schreve, K.; De Beer, N.; Christiane, P.
    ENGLISH ABSTRACT: The current development of the rapid prototyping industry in South Africa is characterised by the strong dominance and fast growth in sales of three dimensional printers. Although it reflects the international trend, it seems that the industrial community lacks a clear appreciation of the real strength of this technology, especially with respect to the large variety of devices available today on the market. This paper surveys the current state and capabilities of three dimensional printing (3DP). Based on its technical background – the ink-jet printing known from the printer and plotter industry – a classification structure is developed and proposed. Different printing techniques and process concepts, together with their advantages and limitations, are described and analysed. Typical examples from three completely different application areas – manufacturing, medicine, and architecture – are presented and discussed. Some basic considerations for an informed selection of the right technology for a particular application are then presented.