Browsing by Author "Hagedorn-Hansen, Devon"

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    A conceptual framework to increase competitiveness in a biltong factory
    (Southern African Institute for Industrial Engineering, 2018-11-09) Henning, Mieke; Hagedorn-Hansen, Devon; Von Leipzig, Konrad H.
    ENGLISH ABSTRACT: The global annual biltong market value was estimated at roughly R640 million to R1.1 billion in 2003. By 2015, biltong sales were reported to be more than R2.5 billion. To stay competitive as a biltong manufacturing company in an ever-changing landscape, the company’s success is determined by efficient operations. To achieve efficient operations, the accurate determination of performance measurements is of utmost importance. In world-class manufacturing facilities, one of the primary features of performance measurement is the measurement of cycle time. Although there is an emphasis, especially in Industry 4.0, on real-time data, the biltong factory where this study was conducted is still very much a manual operation. The focus of this study is, therefore, rather on performance measurements in order to achieve efficient operations and competitiveness. The aim of this study is to present different competitive advantage concepts in order to build a production management model. The biltong factory has not yet established cycle times for their production activities. A production management model has the potential to be used by the factory to manage their production processes more efficiently, and ultimately to increase their competitiveness.
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    The effects of developed selective laser melting strategies on titanium hybrid parts
    (Stellenbosch : Stellenbosch University, 2017-03) Hagedorn-Hansen, Devon; Oosthuizen, Gert Adriaan; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.
    ENGLISH ABSTRACT:Additive manufacturing (AM) is gaining popularity in industries such as the aerospace, medical, and tool-and-die industries. One of the major challenges faced by additive manufacturing technology is the high costs involved. In the case of selective laser melting (SLM), a metal powder bed fusion technology, warping due to residual stress could lead to the part being scrapped. SLM can be compared to a repetitive laser welding process whereby hundreds of layers are welded together in a specific shape to produce a 3-dimensional geometry. During the SLM process a thermal heat sink effect takes place between the base plate and the previously consolidated layers. This results in extremely large directional thermal gradients, which act in the direction of the scan track. These high thermal gradients cause the build-up of residual stresses, which can cause part deformation. The stress built up by the thermal shrinkage of the solidified melt pool induces a tensile stress at the top surface of the SLM part. These tensile stresses cause the part to curl upward, which is usually restrained by the base plate being anchored to the machine with screws. Sometimes the stress is so great that the base plate still warps and the screws break or get elongated past their elastic limit. To reduce the costs involved with SLM a process chain with subtractive manufacturing (SM) and additive manufacturing processes has been suggested. Process chains can incorporate a combination of manufacturing technologies in order to produce a product in the most resource efficient manner. Components produced using a combination of SLM and conventional machining are referred to as hybrid parts if the SLM section is fused to the machined section. The problems associated with the SLM technology, such as geometric deviation (warping) and porosity, are still applicable to the production of hybrid components. The purpose of this study was to determine whether different laser scan strategies can be developed to reduce geometric deviation and porosity in titanium hybrid parts. A new method called Hatch Pattern Designing was developed to bypass the default hatch strategies used by the Concept Laser machine. A new scan strategy was developed and compared to the patented Concept Laser Island scan strategy. Using the new scanning strategy on the experimental samples resulted in less geometric deviation and less porosity than those produced using the Concept Laser M2 Cusing machine’s default scan strategy.
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    Laser powder bed fusion of cemented tungsten carbide cutting tools
    (Stellenbosch : Stellenbosch University, 2022-04) Hagedorn-Hansen, Devon; Sacks, Natasha; Damm, Oliver; Matope, Stephen; Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering.
    ENGLISH ABSTRACT: Cemented carbides are extremely hard, wear resistant materials, and one of the most widely used tool materials in numerous manufacturing industries. Metal cutting tools are commonly manufactured from cemented carbides using standard powder metallurgy processes such as the press and sinter process. The tooling market is highly competitive and the companies with the best research and development departments have the competitive advantage when it comes to cutting edge technology. However, historically, the development process for a new cutting tool or production technology is a lengthy and costly venture. The use of laser powder bed fusion (L-PBF) for research, development, and small-batch production of cemented tungsten carbide cutting tools has not been extensively reported, and commercialisation does not seem apparent as yet. While the usage of L-PBF to produce cutting tools may be beneficial to advancing cutting tool technology, the process has many inherent drawbacks that affect part quality. However, there are many changes to the current L-PBF process that can be investigated to improve the final quality of L-PBF-produced tools before post-processing. The successful application of L PBF technology could help develop and manufacture cutting tools at an improved rate. The aim of this study was to determine and manage the influences of certain factors encountered during L-PBF of tungsten carbide cobalt (WC-Co) and their effects on specific cutting tool properties and cutting performance to produce L-PBF cutting tools that could be comparable to a conventionally produced tool. To accomplish this, three powders were analysed and investigated for their use in the L-PBF process. Then, characterisation of an existing cutting tool was performed to be used as a quality benchmark for L-PBF cutting tools. After a reasonable understanding of powders and conventional cutting tools was obtained, single track scans were performed on a tool steel base plate to understand adhesion and the feasibility of using a conventional base plate. The next stage of the study involved understanding the effects of different laser parameters and scanning strategies on the track morphology, density, hardness, and cobalt content of L-PBF produced WC-12wt%Co samples. Various parameter optimisation methods and strategies were tested and L-PBF-produced cutting tools were utilised in preliminary cutting tests to determine their cutting ability and to deduce which factors had the greatest effects on cutting contact time. The L-PBF scanning strategy was observed to be the most significant factor for successful cutting operations. A diagonal raster strategy with an 80-degree alternating rotation produced the best cutting inserts for the specific insert geometry and grade. Verification WC-12wt%Co inserts were produced with L-PBF for final cutting tests. These inserts were comparable to conventionally produced tungsten carbide inserts with respect to cutting performance indicators such as contact time and workpiece surface roughness. On average, after roughly 16M30S contact time, the L-PBF cutting tools exhibited 0.7 mm maximum flank wear versus 0.4 mm for similar conventional inserts. These results suggest that L-PBF could, one day, be a viable solution for research, developments, and small-batch production of WC-Co cutting tools.
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    Metacognitive learning : skills development through gamification at the Stellenbosch Learning Factory as a case study
    (Southern African Institute for Industrial Engineering, 2017) Henning, Mieke; Hagedorn-Hansen, Devon; Von Leipzig, Konrad
    ENGLISH ABSTRACT: South Africa has a high-cost, low-performance education system, which ultimately leads to unemployment and a skill shortage in the country. In order to bridge the skill shortage gap at a tertiary level, the Stellenbosch Learning Factory (SLF) was established. Learning factories involve experiential learning in a production environment through ‘learning by doing’. Gamification, one of the teaching methods used in the SLF, is investigated as a possible answer to South Africa’s educational problems. Learning factories can be used to train employees: the knowledge transfer resulting from real production conditions is favoured because process improvements can be implemented or practised without any real production downtime. The aim of this study was to determine the learning contribution of the games implemented at the SLF. This was accomplished by developing a three-dimensional matrix that employs a revised version of Bloom’s taxonomy to measure the learning success of the educational games at the SLF.
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    Resource-efficient process chains to manufacture patient-specific prosthetic fingers
    (SAIIE, 2016-05) Hagedorn-Hansen, Devon; Oosthuizen, G. A.; Gerhold, Tristan
    The high cost of quality prostheses, together with the lack of trained prosthetists, makes it challenging to obtain prosthetic devices in developing communities. Modern 3D digitising techniques and additive manufacturing (AM) technologies are gaining popularity in the bio-medical industry and, in the case of prosthesis production, reduce the need for a trained prosthetist. The objective of this research was to develop a new resource-efficient process chain for the manufacturing of prosthetic fingers using additive manufacturing technologies, and to compare it with the traditional (Sculptor) process chain. Fused deposition modelling (FDM), open-source FDM, 3-dimensional printing (3DP), and stereolithography (SLA) were evaluated in terms of their costs, time, material usage, and aesthetic quality. The surface qualities produced with the different additive manufacturing technologies were also compared. The results showed that 3DP was the preferred technology and was the best candidate for the production of prosthesis in terms of cost, quality, and time for developing communities. SLA produced the highest aesthetic quality prosthesis, but was the most expensive. It was concluded that using the additive manufacturing technology process chain to produce prosthetic fingers is faster and more cost effective than the traditional method.