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Developing a tool supporting humans to design and evaluate CLB-based circuits requires a lot of know-how and research from different fields of computer science. In this work, the newly developed application q2d, especially its design and implementation will be introduced as a possible tool for approaching CLB circuit development with graphical UI support. Design decisions and implementation will be discussed and a workflow example will be given.

Thesis (D. Tech. ( Mechanical Engineering )) - Central University of technology, Free State, 2012 / In this study an alternative indirect Rapid Tooling process is proposed. It essentially consists of producing sand moulds by Additive Manufacturing (AM) processes followed by casting of tools in the moulds. Various features of this tool making method have been investigated. A process chain for the proposed tool manufacturing method was conceptually developed. This process chain referred to as Rapid Casting for Tooling (RCT) is made up of five steps including Computer Aided Design (CAD) modeling, casting simulation, AM of moulds, metal casting and finishing operations. A validation stage is also provided to determine the suitability of the tool geometry and material for RCT. The theoretical assessment of the RCT process chain indicated that it has potential benefits such as short manufacturing time, low manufacturing cost and good quality of tools in terms of surface finish and dimensional accuracy. Focusing on the step of AM of the sand moulds, the selection of available AM processes between the Laser Sintering (LS) using an EOSINT S 700 machine and Three Dimensional Printing using a Z-Corporation Spectrum 550 printer was addressed by means of the Analytic Hierarchy Process (AHP). The criteria considered at this stage were manufacturing time, manufacturing cost, surface finish and dimensional accuracy. LS was found to be the most suitable for RCT compared to Three Dimensional Printing. The overall preferences for these two alternatives were respectively calculated at 73% and 27%. LS was then used as the default AM process of sand moulds in the present research work. A practical implementation of RCT to the manufacturing of foundry tooling used a case study provided by a local foundry. It consisted of the production of a sand casting pattern in cast iron for a high pressure moulding machine. The investigation confirmed the feasibility of RCT for producing foundry tools. In addition it demonstrated the crucial role of casting simulation in the prevention of casting defects and the prediction of tool properties. The challenges of RCT were found to be exogenous mainly related to workmanship. An assessment of RCT manufacturing time and cost was conducted using the case study above mentioned as well as an additional one dealing with the manufacturing of an aluminium die for the production of lost wax patterns. Durations and prices of RCT steps were carefully recorded and aggregated. The results indicated that the AM of moulds was the rate determining and cost driving step of RCT if procurement of technology was considered to be a sunk cost. Overall RCT was found to be faster but more expensive than machining and investment casting. Modern surface analyses and scanning techniques were used to assess the quality of RCT tools in terms of surface finish and dimensional accuracy. The best surface finish obtained for the cast dies had Ra and Rz respectively equal to 3.23 μm and 11.38 μm. In terms of dimensional accuracy, 82% of cast die points coincided with die Computer Aided Design (CAD) data which is within the typical tolerances of sand cast products. The investigation also showed that mould coating contributed slightly to the improvement of the cast tool surface finish. Finally this study also found that the additive manufacturing of the sand mould was the chief factor responsible for the loss of dimensional accuracy. Because of the above, it was concluded that light machining will always be required to improve the surface finish and the dimensional accuracy of cast tools. Durability was the last characteristic of RCT tools to be assessed. This property was empirically inferred from the mechanical properties and metallographic analysis of castings. Merit of durability figures of 0.048 to 0.152 were obtained for the cast tools. It was found that tools obtained from Direct Croning (DC) moulds have merit of durability figures three times higher than the tools produced from Z-Cast moulds thus a better resistance to abrasion wear of the former tools compared to the latter.

Published Aticle / The 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.

Published Article / This paper is based on tests performed on die component specimens manufactured by EOS-DMLS (direct metal laser sintering) and LENS (laser engineered net shape) RP (rapid prototyping) technology platforms, as well as manufactured specimens machined out of preferred standard hot work steel DIN 1.2344. These specimens resemble typical components used in metal high pressure die casting tool sets. The specimens were subjected to a programme of cyclic immersion in molten aluminium alloy and cooling in water-based die release medium. The heat checking and soldering phenomena were analyzed through periodic inspections, monitoring crack formation and evidence of surface washout. At the end of the thermal tests, mechanical strength and hardness tests were performed to assess toughness and core resistance variations in relation to the initial conditions. Finally metallographic investigations were performed through optical microscopy on all the specimens considered. The outcomes of this research will be presented and used by the CSIR for further development and application of the assessed EOS-DMLS and LENS rapid prototyping technologies in rapid die manufacturing techniques and die design principles, including time and economic feasibility criteria to be applied when considering rapid die manufacture.

Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This project investigates the use of Rapid Prototyping (RP), with specific focus on Three Dimensional Printing (3DP), in the manufacture of complex shaped advanced composite parts, using variants of the Resin Transfer Moulding (RTM) method of composite manufacture. This study developed design guidelines, cost models and a process chain by studying data obtained by making example parts, from literature and consultation with industry. Advanced composite materials offer some of the best low weight and high specific strength properties for the solution of design problems. A major disadvantage of these processes, however, is the low production rates possible and the need of costly moulds. The 3DP technologies combined with the RTM composite process was found to enable a lowering of costs and increase in productivity if smaller batch sizes are considered. The most meaningful area of application for RP techniques seems to be for smaller and more complex components. The geometrical freedom allowed by RP technologies allowed the manufacture of parts which are challenging to manufacture by conventional technology such as CNC machining. Example part case studies were completed for a simple part utilising the one sided mould Resin Infusion RTM variant as well as for a complex part utilising the closed mould Vacuum Assisted Resin Transfer Moulding (VARTM) process variant. During these two case studies it was clear that proper part infusion with resin is critical for the manufacture of good quality composite parts free of voids and dry spots. It is possible to improve the resin infusion by correct placement of resin inlet and outlet ports as well as resin channels incorporated in the mould. Correct placement of these features for the case studies was obtained through simulations done with RTM-Worx software. Results also indicated that another useful application of RP technology to RTM is the manufacture of disposable cores for parts with thick cross sections. Resin channels were included on the surface of these cores to improve the mould filling with resin and consequently part quality. An early cost estimation model, based on the work of Veldsman (1995), was developed for the combined RP and RTM manufacturing process. This model may help designers to eliminate expensive design features and enables a quick cost comparison with competing processes. Drawbacks of applying RP techniques to RTM include the limited lifetime of moulds produced with 3DP and the size and accuracy limitations of the RP t echnology. / AFRIKAANSE OPSOMMING: Hierdie projek handel oor die toepassing van die drie-dimensionele druk metode van Snel-Prototipering (Rapid Prototyping) op die vervaardiging van komplekse gevorderde saamgestelde materiaal komponente met die Hars-Inspuit Giet (Resin Transfer Moulding) metode. Die projek behels die opstel van ontwerpsriglyne, koste-modelle en ’n proses-ketting deur data te bestudeer wat bekom is deur middel van die vervaardiging van eksperimentele parte, literatuurstudie asook raadpleging met individue in die industrie. Gevorderde saamgestelde materiale verskaf van die beste sterk, dog ligte oplossings vir sekere ontwerpsprobleme. ’n Ernstige nadeel van hierdie materiale is egter die stadige produksietempo moontlik en die vereiste van duur gietstukke. Die Snel- Prototipering metodes, gekombineerd met ’n saamgestelde materiaal vervaardigingsproses, maak laer kostes met beter produktiwiteit moontlik indien ontwerpers die part grootte- en akkuraatheidsbeperkings in ag neem. Die mees betekenisvolle area van toepassing blyk kleiner en meer komplekse komponente te wees. Die vryheid in geometrie wat moontlik gemaak word deur die Snel- Prototipering tegnologie laat die vervaardiging toe van parte wat uitdagend is om te vervaardig met konvensionele tegnologie soos CNC masjinering. ’n Gevallestudie is voltooi vir ’n eenvoudige part vervaardig met die enkelkant gietstuk vakuum-infusie weergawe van die Hars-Inspuit Giet metode asook vir ’n komplekse part wat vervaardig is met die geslote gietstuk Vakuum Hars-Inspuit Giet weergawe van die basiese metode. Dit het tydens die twee gevallestudies duidelik geword dat deeglike hars infusie van kritieke belang is vir die vervaardiging van goeie kwaliteit parte sonder enige droë kolle of lugruimtes. Dit is moontlik om die hars infusie te verbeter deur hars inlate en uitlate asook hars kanale in die korrekte posisies te plaas. Die korrekte posisies vir hierdie komponente is verkry deur middel van ’n reeks simulasies met die RTM-Worx sagteware. Resultate dui ook daarop dat Snel-Prototipering tegnologie handig te pas kom by die vervaardiging van verbruikbare kerne vir saamgestelde materiaal parte met groter diktes. Hars kanale kan maklik op die kerne se oppervlak geskep word om die hars verspreiding en gevolglik part kwaliteit te verbeter. ’n Vroeë kostevoorspellings model, gebaseer op werk voltooi deur Veldsman (1995), is saamgestel vir die gekombineerde Snel-Prototipering en Hars-Inspuit Giet proses. Hierdie model kan gebruik word om duur ontwerpsbesonderhede op parte te elimineer en om ’n vinnige koste vergelyking met ander vervaardigingsprosesse te toon. Nadele van die toepassing van Snel-Prototipering tegnieke op Hars-Inspuit Giet sluit die beperkte gietstuk-leeftyd en beperkte akkuraatheid in.

Thesis (PhD (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Information on the milling of Ti6Al4V is limited; with most studies concluding that it is not possible to obtain a significant increase in the material removal rate (Qw). Tool wear maps can be a diagnostic instrument for failure analysis. Cutting speed (vc), maximum un-deformed chip thickness (heMax) and the radial immersion percentage (ae/Ø %) are the key variables in understanding the milling of titanium alloys. The objective of this research study was to construct tool wear maps for the milling of Ti6Al4V. This will form the foundation of understanding the cutting demands on the tool, in order to analyse the main wear mechanisms. Remedial actions, which are developed by tool suppliers, can be considered and integrated via this understanding of the failure modes and related mechanisms. Firstly, experimental data from background studies, literature and industry on wear rates and wear mechanisms pertaining to the milling conditions was gathered to construct the tool wear map. Mathematical models describing the wear behaviour for these conditions were also investigated. Secondly, work piece failure maps have been superimposed onto the tool wear maps constructed to understand the global failure boundaries. Experimentation was carried out to validate the constructed maps. The tool wear map could then be used to discuss the observed effects and consider remedial actions. Cutting speed corresponds to the magnitude of the thermal load and heMax represents the mechanical load. The ae/Ø % defines the duration of the exposure to the thermal load at the edge of the cutting tool. This investigation has shown the following issues to be of importance when considering tool performance via the tool wear map approach: 1. The key to designing tool wear maps is to identify the most economic Scheduled Replacement Time (SRT) for the specific components. Knowing the correct SRT makes it possible to optimize the milling conditions so that the cutting tool wears gradually under the cutting conditions, and lasts longer than the economic SRT. 2. Increased vc will decrease tool life (TL). However, in low transverse rupture strength tools there may be a minimum vc below which mechanical overload may occur. Similarly, a local maximum TL (a sweet spot) may exist if there is a phase change in the work piece material. 3. Increased heMax will decrease TL. However, heMax must be kept below a maximum critical value to avoid mechanical overload, but above a minimum critical value to avoid work hardening. 4. Increased ae/Ø % will decrease TL. The best balance of high Qw and economic TL is found with ae/Ø between 30-40% for rough milling. In finish milling the radial cut is limited to 1 mm finishing stock of the work piece. This study revealed the following important factors when considering work piece failure in the milling of Ti6Al4V: 1. Increased vc will reduce the cutting resistance of the work piece and increase Qw. However, vc must be kept below a maximum critical value to avoid work piece material burn, but above a minimum critical value to avoid burring and poor surface finish, due to tool build-up and chip jamming. 2. Increased heMax will increase the cutting resistance of the work piece and increase Qw. The heMax must be kept below a maximum critical value to avoid poor surface finish, poor flatness and parallelism (due to work piece bending). Likewise, heMax must be kept above a minimum critical value to avoid work hardening and burring. The constructed tool wear maps are validated with experimental work. This research work identified safe zones to productively mill Ti6Al4V, while producing components with a sufficient surface integrity. / AFRIKAANSE OPSOMMING: Inligting rondom freeswerk van Ti6Al4V is beperk en volgens meeste studies is dit nie moontlik om ‗n wesenlike toename in die materiaal verwyderingstempo (Qw) te behaal nie. Snybeitel verwerings kaarte kan ‗n diagnostiese hulpmiddel wees tydens analisering van snybeitels. Snyspoed (vc), maksimum onvervormende spaanderdikte (heMax) en radiale snitdiepte persentasie (ae/Ø %) is die sleutel veranderlikes om die freeswerk van Ti6Al4V beter te kan verstaan. Die doel van die navorsingstudie was om snybeitel verweringskaarte vir die freeswerk van Ti6Al4V te bou. Die werk vorm ‗n fondasie om die eise van freeswerk op die snybeitel beter te verstaan. Sodoende kan die hoof verweringsmeganismes analiseer word. Regstellende aksies wat deur snybeitel vervaardigers ontwikkel is, was ondersoek en integreer met die huidige kennis rondom die falingstipe en verwerings meganismes. Aanvanklik was eksperimentele data van agtergrond studies, literatuur en industrie oor die verweringstempos en -meganismes rondom die freeswerk van Ti6Al4V versamel. Hiermee is verweringskaarte gebou. Wiskundige modelle wat die verwering kan beskryf was ook ondersoek. Daarna was werkstuk falingskaarte integreer met die ontwikkeling van die snybeitel verweringskaarte om sodoende die grense in geheel te verstaan. Eksperimentele werk was gedoen om die snybeitel verweringskaarte se uitleg te toets. Sodoende kon die snybeitel verweringskaarte gebruik word om die gedrag van die snybeitel te bespreek en regstellende aksies te ondersoek. Snyspoed (vc) stem ooreen met die grootte van die termiese lading en heMax verteenwoordig die grootte meganiese lading. Die ae/Ø % omskryf die tydperk van blootstelling aan die termiese lading op die snyrand. Die ondersoek het bewys dat die volgende faktore belangrik is wanneer snybeitel prestasie met die snybeitel verweringskaart evalueer word: 1. Die sleutel tot die ontwerp van snybeitel verweringskaarte is om die mees ekonomies beplande vervangingstyd (SRT) vir spesifieke komponente te identifiseer. Sodoende is dit moontlik om die frees toestande te optimaliseer, waaronder die snybeitels geleidelik sal verweer onder die eise en vir ‗n langer tydperk as die ekonomiese SRT sal kan sny. 2. Toename in vc sal snybeitelleeftyd (TL) laat afneem. Snybeitels met ‗n lae dwarsbreuksterkte, kan ‗n minimum vc hê waaronder meganiese oorlading plaasvind. Terselfdertyd, kan ‗n maksimum TL (‗n ―sweet spot‖) bestaan as daar ‗n fase verandering in die werkstuk materiaal plaasvind. 3. Toename in heMax sal TL laat afneem, maar moet laer as ‗n maksimum- en hoer as ‗n minimum kritiese waarde wees, om sodoende meganiese oorlading en werksverharding onderskeidelik te vermy. 4. Toename in ae/Ø % sal TL laat afneem. Die beste balans tussen TL en ae/Ø % is gevind met ae/Ø % tussen 30-40% vir growwe freeswerk. In afrondingsfreeswerk is die radiale snit beperk tot 1 mm van die oorblywende werkstuk. Die ondersoek het bewys dat die volgende faktore belangrik is wanneer werkstukfaling in ag geneem word met snybeitel verweringskaarte: 1. Toename in vc sal die werkstukweerstand geleidelik verminder en Qw laat toeneem. Ongelukkig is vc beperk tot ‗n maksimum kritiese waarde om werkstukfaling te voorkom weens ‗material burn‘. Die snyspoed moet ook hoër as ‗n kritiese waarde wees om werkstukklitsing en swak afronding weens spaander probleme te vermy. 2. Toename in heMax sal die werkstuk weerstand geleidelik vermeerder en Qw laat toeneem. Die heMax is beperk tot ‗n maksimum kritiese waarde om swak werkstuk afronding, weens die buiging van die werkstuk, te vermy. Terselfdertyd moet heMax hoër as ‗n kritiese waarde wees om werkstukverharding en -klitsing te voorkom. Die saamgestelde snybeitel verweringskaarte was bekragtig met eksperimentele werk. Die navorsingswerk het veiligheidsareas identifiseer om Ti6Al4V produktief te frees, sonder om die werkstukoppervlak krities te beïnvloed.