Papers & Articles


Introduction to RAPDASA
This presentation gives an overview of RAPDASA as a non-profit organization.
Assessment Of Surface Finish And Dimensional Accuracy Of Tools Manufactured By Metal Casting In Rapid Prototyping Sand Moulds

In this paper, an initial assessment of the quality parameters of the surface finish and dimensional accuracy of tools made by metal casting in rapid prototyping (RP) sand moulds is undertaken. A case study from a local tool room, dealing with the manufacturing of an aluminium die for the lost wax process, is employed. Modern techniques, including surface roughness analysis and three dimensional scanning, are used to determine and understand how each manufacturing step influences the final quality of the cast tool. The best surface finish obtained for the cast die had arithmetic average roughness (Ra) and mean average roughness (Rz) respectively equal to 3.23µm and 11.38µm. In terms of dimensional accuracy, 82% of cast-die points coincided with the Computer Aided Design (CAD) data, which is within the typical tolerances of sand cast products. The investigation shows that mould coating contributes slightly to the improvement of the cast tool surface finish. The study also found that the additive manufacturing of the sand mould was the chief factor responsible for the loss of dimensional accuracy. These findings indicate that machining will always be required to improve the surface finish and the dimensional accuracy of cast tools in RP sand moulds.

Adept Airmotive - Advanced aircraft piston engine
RAPDASA presented at the Aeronautical Society of South Africa. A case study was presented by Richard Schulz, director of Adept Airmotive. His topic, “Application of Rapid Prototyping in the development of the ADEPT Airmotive Engine” was very well received.
CRPM - 2010 Castings SA Publication
Laser Sintering is well known for insuring the quickest route from product idea to market launch. Innovative companies from a broad range of industries are using this technology today in every stage of the product life cycle for batch size optimised production.
CRPM - Medical Implants
The application of computer tomography (CT) scanning, computer aided design (CAD) and rapid/additive manufacturing (RM) has become a widely researched area in the field of medical implants in the last 5 years. This is primarily driven by advancements in RM technologies capable of fabricating in bio-inert materials such as Titanium.
CRPM - The Sky is the Limit
The Centre for Rapid Prototyping and Manufacturing (CRPM) at the Central University of Technology, Free State (CUT) specializes in Additive Manufacturing (AM). The CRPM was established in 1997 as a centre that does commercial work as well as research. Operating inside the Integrated Product Development Research Niche area, the research focuses on Rapid Prototyping, Rapid Manufacture, Rapid Tooling and Medical Product Development.
Decade of RAPDASA in SA
RAPDASA (Rapid Product Development Association of South Africa) was officially launched during the first annual international conference, held in 2000 at the CSIR, following a number of meetings held nationally, to establish a community of practice. RAPDASA embraces the complete product development value chain (starting from idea/concept, to design, prototype development into manufacturing and commercialization). RAPDASA aims to become a government-recognized activity or industry cluster/group, as it currently creates strategic links between academia, science councils and industry. It was started by volunteers, and is still being driven by individuals with a passion for innovative product development.
Establishment of RP or AM in SA
RAPDASA presented at the Aeronautical Society of South Africa. Prof. Deon de Beer, from the Department of Technology Transfer and Innovation at VUT presented his riveting perspective on “The Establishment of a Rapid Prototyping/Additive Manufacturing Capability in SA.”
Rapid Prototyping Technology in South Africa
The Institute for Inventors and Innovators (III) hosted a presentation themed “Rapid Prototyping Technology in South Africa” at Wits University on the 13th of April, 2011. Dr. Willie du Preez, from the CSIR Materials Science and Manufacturing presented on behalf of RAPDASA.
Residual Stress Measurements And Structural Integrity Implications For Selective Laser Melted Ti-6al-4v
Selective laser melting (SLM) of Ti-6Al-4V has significant potential in the aerospace and biotechnology industries. SLM employs a focused laser beam to melt successive layers of metallic powder into complex components. This process can result in the generation of high thermally-induced residual stresses. These residual stresses, together with micro-flaws/ pores from the inherent fabrication process, may lead to premature fatigue crack initiation and propagation at relatively low cyclic stresses. The hole-drilling strain gauge method was used to evaluate residual stresses within SLM Ti-6Al-4V specimens, with the intention of understanding the associated mechanisms for the successful application of SLM Ti-6Al-4V in industry.