South Africa is a developing country that invests billions of rands annually in the construction industry. This industry consumes resources and, inevitably, waste is generated during the process. Although numerous approaches have been developed to improve quality, efficiency, and effectiveness in this industry, lean principles offer the ability to minimise and/or eliminate non-value adding work, thus increasing value for the client. This paper highlights the lean construction tools currently used worldwide, and the benefits of adopting lean construction. The study surveyed publications on the application of lean principles in the construction industry, and identified tools yet to be implemented in the South African construction industry with specific reference to electrical and mechanical engineering services. The study used a systematic review methodology to identify different lean construction concepts, and developed a lean implementation framework. The framework was then evaluated using a local case focusing on electrical and mechanical engineering services in the construction industry. The improved framework after evaluation consists of eight steps.
Selective laser melting (SLM) is one of the most well-known additive manufacturing methods available for the fabrication of functional parts from metal powders. Although SLM is now an established metal additive manufacturing technique, its widespread application in industry is still hindered by inherent phenomena, one of which is high residual stresses. Some of the effects of residual stresses – such as warping and thermal stress-related cracking – cannot be corrected by post processing. Therefore, establishing input process parameter combinations that result in the least residual stress magnitudes and related distortions and/or cracking is critical. This paper presents the influence of laser power, scanning speed, and layer thickness on residual stresses, distortions and achievable density for maraging steel 300 steel parts in order to establish the most optimum input parameter combinations. An analysis of the interdependence between process outcomes shows that high residual stress magnitudes lead to high dimensional distortions in the finished parts, whilst porous parts suffer relatively lower residual stresses and associated distortions.
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