Browsing by Author "Van Der Merwe, Andre F."

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    Production scheduling heuristics for frequent load-shedding scenarios : a knowledge engineering approach
    (Southern African Institute for Industrial Engineering, 2020-11-11) Dewa, Mncedisi T.; Van Der Merwe, Andre F.; Matope, Stephen
    ENGLISH ABSTRACT: Most industrial machinery and equipment used by the South African manufacturing sector is powered by either a direct current or an alternating current electricity supply. With the recent frequent power cuts caused by load shedding, operations managers have a difficult time trying to satisfy demand. Power cuts are a supplier-related operational disturbance that leads to production halts, increased downtime, and a significant compromise in delivery due date conformance. The paper presents heuristic rules of thumb that can be applied during the process planning and scheduling of orders during cases of frequent load shedding to maintain high levels of system reliability and productivity. Different load shedding scenarios are characterised, and an appropriate strategy for production planning and scheduling is outlined for each scenario. A knowledge engineering approach is employed in the study, with expert opinions derived from surveys and the literature employed to generate the strategies. These strategies are validated through a simulation study conducted in a small manufacturing firm.
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    System development for the five-axis extrusion of a photopolymer
    (Southern African Institute for Industrial Engineering, 2020-11-11) Kirkman, Daniel M.; Van Der Merwe, Andre F.; Campbell, Ian
    ENGLISH ABSTRACT: The development of a novel method of additive manufacturing involving the support-free extrusion of a photopolymer is discussed. The objectives of the paper are the presentation of mechanical and electrical hardware developments for a freeform additive manufacturing system, a discussion of the process developments that have taken place, and the presentation of the results from tests used to validate improvements to the system. Developments include the replacement of the UV light source with lasers, and the implementation of collision avoidance algorithms. The results include a significant increase in the speed of the extrusion process, and an improved toolpath viability achieved by the implementation of the collision avoidance algorithms.