By: Selina Rapulane 23 November 2022

From left: Mr Ngazibini Mayila, Ms Tsholofelo Nkaiseng, Ms Oriel Mhlongo, Ms Yvonne Shabanga and Mr Sarel Havenga at the RAPDASA Conference

On the 09 till 11 November, the Vaal University of Technology (VUT)’s researchers presented their research posters at the Rapid Product Development Association in South Africa (RAPDASA)’s 23rd Annual International Conference, held in Cape Town.

This event comes after the researchers were seconded in the Directional Composites through Manufacturing Innovation (DiCoMI) project which commenced in June 2022, and focused on Directional Fibre-Reinforced Polymer (DFRP) materials and combining different manufacturing techniques into a unique and innovative hybrid system.

The research focused on Directional Fibre-Reinforced Polymer (DFRP) materials and combining different manufacturing techniques into a unique and innovative hybrid system. During the Project, Ms Tsholofelo Nkaiseng and Ms Yvonne Shabanga, worked on the design of the production head and machine components, while Mr Ngazibini Mayila and Ms Oriel Mhlongo worked on material development and tensile testing.

The objective of each secondment was a staff skills-mobility exchange, where researchers gained valuable industry and academic experience on mainly additive manufacturing platforms. The secondees were expected to perform academic reporting, prototyping and finally to produce research outputs in the form of a journal or conference publication. All intellectual property accrued during that period was guided by the Intellectual Property policies of partner institutions and the Consortium Agreement.

The VUT researchers produced their research outputs in the form of a conference publication and presented it at the RAPDASA Conference as indicated below.

Ms Tsholofelo Nkaiseng

In her poster research, Ms Tsholofelo Nkaiseng characterized the material properties of polyamide with carbon, glass and aramid fibers under varying printing environment parameters. This was conducted by printing samples on the Markforged MKII and a custom open-sourced Imperial College London printer for tensile testing, flexural strength, and scanning electron microscopy. Her study proposed to identify the effects of varying printing parameters in an open and closed environment. In doing so, the results led to recommendations on the development of new materials for a broader scope of use beyond traditional engineering application.

In concluding her research, she mentioned that “Material characterization forms the basis of understanding the composition of polymer composites and their potential application for industries beyond traditional engineering applications. It also paves the way for the development of new polymer composites. Due to incomplete results, a comprehensive conclusion could not be made”.

Ms Yvonne Shabanga

Ms Yvonne Shabanga’s study focused on Fiber-reinforced polymer composite (FRPC) materials and the fact that they are used by many industries for their excellent mechanical properties, such as increased stiffness and strength. However, there is a lack of fabrication of such reinforced polymers in the form of 3D products due to the limited Fused Deposition Modelling (FDM) printers that has 3D fabrication capability as well as undefined process parameters.

The aim of her study was to produce and investigate carbon fibre (CF) reinforced specimens using the Markforged MKII machine and investigate the influence of fiber strategy on the dimension’s accuracy and mechanical integrity of produced specimens, using the best fiber strategy, as well as processing parameters for fabrication of 2D CF reinforced Nylon using two different custom-made FDM printers developed in the UK for comparison with that produced by Markforged MKII printer. Printing and investigation of 3D products using the developed processing parameters by the available FDM printer that was developed through DiCoMI project.

Ms Oriel Mhlongo

Furthermore, Ms Mhlongo stated in her research poster that, “The DiCoMI project was established to combine different manufacturing techniques into an innovative hybrid system by building a 5-axis printer which will perform both additive and subtractive processes. This study aims to compare investigated experimental characteristics of dog bone specimens from a collaborative research project by performing finite element analysis to determine how polymers are strengthened by carbon fibre-reinforcement”.

She added that the reason was to increase stiffness and strength in polymer materials. As part of a continuous DiCoMI project, in her study, a CAD dog bone model was simulated in Abaqus software where carbon fibre-reinforcement direction, applied load and selection of carbon fibre layers was specified. This was done to determine the response of the model to the applied load thus predict the stress-strain and elongation/deformation impact on the model.

Mr Ngazibini Mayila

In concluding the posters presentations, Mr Ngazibini’s research poster cited that continuous fibre-reinforced polymers (CFRP) have recently gained attention due to their excellent mechanical properties in Additive Manufacturing. It demonstrated that recent literature indicates that these reinforced materials can be directly compared with metal alloys; however, only a few studies have directly compared CFRP with metal.

“This study will compare CFRP and short CFRP fabricated on the FDM and then compare to metal. Mechanical testing will be performed on CFRP specimens. Results will be analyzed to provide future researchers with data that can be used to narrow the gap of material strength between metal alloys and polymers. As a result, cost-effective materials can be used as an alternative to metals”, it concluded.

His study aimed to perform mechanical testing that evaluated the reinforced material properties of CFRP to compare its increased strength against metal alloys. The researchers acknowledge that polymers cannot be directly compared with metal alloys; however, using CFRP may narrow the gap between these materials for cost savings/effectiveness and robustness.

Post their presentations, the researchers had one-on-one discussions with peers who had vested interest in their work – something they described as a great opportunity for them to further develop industry-academia cooperation.