The impact of additive fabrication technologies on Institutional Research Development and the SA product development community-the CRPM story

Published AticleThe Centre for Rapid Prototyping and Manufacturing (CRPM) made a humble start in 1997 as a spin-off from a proposed research activity in 1995, at a stage when Technikons were still being seen as occupational training institutions rather than higher education institutions and and as such, were not funded for research. Addressing an area of high importance to the South African industry, the research activity soon grew into a research unit, commercial centre / centre of excellence, technology transfer unit and innovation support centre. Above all, the research started to impact on product development practices to deliver improved products. The paper considers the development of the available technology platforms at the CUT'S CRPM to become a technology power-house on the African continent, and how it impacted on Institutional Research Development in South Africa

IMPLEMENTING THE SOUTH AFRICAN ADDITIVE MANUFACTURING TECHNOLOGY ROADMAP – THE ROLE OF AN ADDITIVE MANUFACTURING CENTRE OF COMPETENCE#

Published ArticleThe Rapid Product Development Association of South Africa (RAPDASA) expressed the need for a national Additive Manufacturing Roadmap. Consequentially, the South African Department of Science and Technology commissioned the development of a South African Additive Manufacturing Technology Roadmap. This was intended to guide role-players in identifying business opportunities, addressing technology gaps, focusing development programmes, and informing investment decisions that would enable local companies and industry sectors to become global leaders in selected areas of additive manufacturing. The challenge remains now for South Africa to decide on an implementation approach that will maximize the impact in the shortest possible time. This article introduces the concept of a national Additive Manufacturing Centre of Competence (AMCoC) as a primary implementation vehicle for the roadmap. The support of the current leading players in additive manufacturing in South Africa for such a centre of competence is shared and their key roles are indicated. A summary of the investments that the leading players have already made in the focus areas of the AMCoC over the past two decades is given as confirmation of their commitment towards the advancement of the additive manufacturing technology. An exposition is given of how the AMCoC could indeed become the primary initiative for achieving the agreed national goals on additive manufacturing. The conclusion is that investment by public and private institutions in an AMCoC would be the next step towards ensuring South Africa’s continued progress in the field

Using Idea-2-Product Labs® as a strategy for accelerating technology transfer

Technology transfer poses particular problems to developing countries whose governments cannot always afford to fund expensive high-tech solutions. This article reports on the Idea 2 Product Labs® concept that was developed in South Africa to offer a low-cost open-source alternative. The motivation behind the work was to put innovative new technologies into the hands of more people within a shorter timeframe than would otherwise be possible. The background, planning, objectives, outcomes and impact of the project are reported together with some conclusions on how this model could be adopted across a wider domain

Gynaecological product development facilitated through RP and Rapid Tooling

Published ArticleAtkinson distinguishes between four types of prototypes, categorised through its end-use: •Design or aesthetic prototypes •Geometrical prototypes •Functional prototypes •Technological prototypes Shigley and Mitchell define the design process according to the following six phases: Recognition of need Definition of problem Synthesis Analysis and optimization Evaluation Presentation The Centre for Rapid Prototyping and Manufacture (CRPM) of the Central University of Technology, Free State was asked to assist in the development of a newly developed gynaecological cream applicator. Apart from needing a freeform fabrication system to give form fit and function to the very complex design, the product needed Rapid Tooling / Rapid Manufacturing support to enable a first batch production for medical trials and evaluation. The paper will describe the total product development process alongside prototype categories described by Atkinson and design phases defined by Shigley and Mitchell (including some iterations enabled through timeous prototyping, including various Rapid Prototyping (RP) Technologies, soft tooling and vacuum casting). More importantly, results from Rapid Tooling for limited run production (due to the complexity of the product the cycle time of the Prototype Tool is fairly long), as well as the economical impact made possible through the support of CAD / CAM and RP Technologies, will be discussed

Parameters affecting spin casting of decorative and mechanical parts

Published ArticleSpin casting is widely used as a batch manufacturing process for decorative products. In the process, moulds are filled by taking advantage of the centrifugal effect, which is used to increase the pressure within the moulds, resulting in more detailed products. In this study, we analyse the different parameters that could affect the casting of mechanical parts through spin casting. Through this study, the user will be guided in the selection of parameters that will result in a certain degree of accuracy. The parameters were determined by performing numerous experiments using zinc alloy and tin-based pewter as casting materials. Results were obtained by casting approximately 15 000 parts in various positions, and at various clamping pressures, rotational speeds and temperatures in both the mould and the material. The experiments were undertaken by varying one parameter at a time, and with each set parameter repeated once, resulting in 100 test pieces per parameter for evaluation. From the results obtained, a series of critical factors and parameters, which are driven by part characteristics or features, has been studied. Contrary to following a modelling approach, the research was conducted following an action-research approach, with planned activities, but where actual results have defined the follow-up procedures. These guidelines will help industrial users ensure the accuracy of parts produced by spin casting. Also, since this project attempted to create a database of results that can be applied in future, it furthermore implies that the data created for the first time can be used in a numerical modelling approach in further / follow-up research. No such data was available from any previous research

Digital sculpture : technical and aesthetic considerations applicable to current input and output modes of additive fabricated sculpture

Published ArticleThis article examines the synergy between aesthetic and technical issues surrounding current input and output modes applicable to digital sculpture built by means of additive fabrication technologies. The scope is limited to select sculptural aspects that either transcend, question or fall short when measured against traditional manufacturing and aesthetic modes. Presented are a range of technical as well as aesthetic aspects that have impacted on this ''new form'' of sculpture delivery. It is indicated that irrespective of current strengths and weaknesses, for the evolving sculptor, an interactive creative partnership between technologies equally positions this ''new form'' of sculpture delivery as a leading role player towards defining a new digital aesthetic

Gb5® high modulus asphalt

With ever increasing volumes of traffic on South African roads, and particular that of heavy vehicles, the road building industry has recognized the need for specialised asphalt mixes to address the rutting and fatigue problems experienced currently. GB5 is a cost effective asphalt base mix, designed for high performance and long life, similar to stiff grade bitumen mixes (EME’s). This mix can be produced with most of the aggregate and bitumen road grade types available in South Africa that is currently being used in the production of hot mix asphalt. Usage of this mix will allow for reduced pavement thickness, increased longevity and decreased rutting. The GB5 alternative controls the volumetric properties by optimizing the combination of fine and coarse aggregates, resulting in an interactive network of particles in the mix to obtain a high stiffness modulus; at the same time uses modified bitumen, instead of high binder contents to obtain good fatigue properties. GB5 has already proven itself in France, where it was developed, under heavy traffic (more than 500 000 tons paved) where legal axle loading limits are significantly higher than those in South Africa. The extensive trials done in eThekwini Metro in KZN have shown that the GB5 technology has now successfully been transferred to South Africa.Papers presented at the 36th Southern African Transport Conference, CSIR International Convention Centre, Pretoria, South Africa on 10-13 July 2017.Transportation research board of the national academie

DIRECT METAL LASER SINTERING, USING CONFORMAL COOLING, FOR HIGH VOLUME PRODUCTION TOOLING#

Published ArticleExisting techniques to manufacture conventional tool steel inserts for the plastic injection moulding process are expensive and time-consuming. Complex mould inserts, difficult to manufacture with conventional processes, can be produced using Direct Metal Laser Sintering (DMLS) with Maraging tool steel (MS1). MS1 is an additive manufacturing (AM) material made available by Electro Optical Systems (EOS) GmbH. Contrary to material removal processes, DMLS can produce MS1 tool steel inserts directly from Computer-Aided Design (CAD) files suitable for high volume plastic injection moulding. Through DMLS it is possible to create conformal cooling channels inside the MS1 inserts that have advantages in reducing heat rapidly and evenly. This can result in a reduction of cycle times, cost per product as well as improving part quality by eliminating defects such as warpage and heat sinks. This paper will present a comparison between Finite Element Analysis (FEA) simulations of the injection mould inserts with actual mould trails of AM and conventional manufactured inserts. It also includes the design and manufacturing of conventional and DMLS inserts and compares the manufacturing costs and lead times. Using FEA simulations, the design of conformal cooling channels is optimised by comparing the mould temperature of different cooling channel layouts. Bestaande tegnieke vir die vervaardiging van matryse vir die plastiek-inspuit giet tegniek is duur en tyd rowend. Verder is dit nie altyd moontlik om konvensionele metodes vir die vervaardiging van matryse vir geomteries komplekse gietstukke te gebruik nie. Vir sodanige gietsukke kan invoegsels relatief vinnig vervaardig word, deur van direkte laser metal sinterings metodes (DLMS) met Maraging-staal (MS1) gebruik te maak. MS1 is ’n laag vervaardings materiaal wat onlangs deur Electro Optical Systems (EOS) GmbH beskikbaar gestel is. Dit is ’n pre-allooi, ultra hoë sterkte metaal met goeie meganiese eienskappe. In teenstelling met materiaal verwyderings prosesse (masjienerings prosesse), kan DMLS MS1 staal matryse of insetsels wat vir hoë volume produksie van plastiek gietsukke bruikbaar is, direk vanaf rekenaar-gesteunde ontwerp prosesse vervaardig word. Die gebruik van DMLS kan ook vir die ontwerp en vervaardiging van vorm getroue verkoelings kanale in matryse voorsiening maak, wat tot laer hitte asook die vinnige en eweredige verspreiding daarvan sal lei. Voorgenoemde behoort tot ’n aansienlike verlaging in produksie siklus tye te lei met ’n dien ooreenkomstige verlaging in die produksie koste asook ’n verbetering in die kwaliteit van die vervaardigde produkte a.g.v. die voorkoming van defekte soos kromtrekking en hitte-putte wat normaalweg deur oneweredige hitte verspreiding veroorsaak word

Using additive manufacturing with blow moulding to facilitate accurate consumer testing

A South African entrepreneur needed a fast and accurate route to consumer testing for a design of phlegm collection bottle for long-distance runners. Vaal University of Technology was presented with an initial product concept which had to be developed into a fully functional prototype required for field trials. The idea was converted into a practical product proposal and modelled using a 3D computer aided design (CAD) system. The CAD data were used for laser sintering of polyamide to produce an initial prototype for appearance and ergonomic evaluation. For product testing in the field, a short run of fully functional prototypes in thin-walled low density poly-ethylene (LDPE) was required. This required a further design iteration and the production of tooling for the blow moulding process. A novel hybrid modular approach to tool manufacture was followed, where the outer frame of the tools were machined in aluminium and the tool inserts were laser sintered in AlumideTM. Blow moulding trials were undertaken in LDPE which revealed a number of positive and negative issues. The rough surface of the tool inserts produced a desirable textured surface in the resultant blow-moulded bottles but also prevented a clean “shut-off” between the two halves of the tool. This allowed air to escape from the cavity along the split plane, creating unwanted holes in the bottles. In addition, the low thermal conductivity of AlumideTM resulted in an unwanted overheating of the tools. Strategies were identified to overcome these issues and these are explained in the paper

A CASE STUDY OF RAPID SAND CASTING DEFECTS

ArticleRapid sand casting is quickly transforming as an established method for the production of sand moulds and cores for metal casting applications by additive manufacturing processes. The case study investigated possible sand casting defects resulting from a local implementation of rapid sand casting referred to as Rapid Casting for Tooling (RCT). Poor workmanship of the RCT process chain was found to be the root cause of sand casting defects including cold lap, gas porosity and alignment faults