Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010 / ENGLISH ABSTRACT: Additive Manufacturing (AM) refers to the technologies that use Computer Aided Design (CAD) data to produce plastic, metal, ceramic, paper, wax or composite materials parts. Their ability to join thin layers of liquid, powder or sheet materials together permits the production of parts, which are difficult or even impossible to produce, using any other manufacturing method. Even though these technologies are still developing, they are considered a major breakthrough in industry. One of the main problems that is facing the improvement and the spread of AM technologies, and its benefits worldwide, is the lack of knowledge about them. Still a lot of countries, educational and industrial organizations do not even know about AM technologies. This lack of knowledge of such technologies is keeping their cost artificially high, which is limiting the access to more AM advanced technologies and materials. It also makes it difficult to market the technologies and those who do not use AM technologies yet become unable to compete against those who do. The numbers of AM systems are continually growing, their capabilities and applications are improving and their cost is decreasing. Today there are more than 40 companies that produce over 100 different systems in Canada, China, France, Germany, Israel, Italy, Japan, South Korea, Sweden and the United States. These systems vary in their strengths, defects, applications, functions and limitations. This growth has led to an increase in current and potential users of AM from both the manufacturing and educational sectors. These users are however facing increasing complex problems when it comes to selecting the most appropriate commercial system(s) to suit their needs. The aim of this study is to develop an AM system selection program. The program will serve both as an educational tool and a decision making support tool to assist any potential purchasers in both the educational and industrial sectors. The AM system selection program is divided into two sections: the learning section and the selecting section. The learning section introduces the AM technologies by imparting knowledge to the new users; moreover, it inspires them to start using these technologies to get their benefits. Having a background in AM technologies enables the new users to make educated decisions and to discuss technical issues about the systems with the providers. The selecting section offers a decision making support tool to help the users to decide which system best suits their needs. This study can contribute to the promotion of AM technologies and their benefits worldwide, especially for the countries and organizations that have not yet used such technologies. / AFRIKAANSE OPSOMMING: Toevoegende vervaardiging verwys na al die tegnologie wat rekenaargesteunde ontwerp data gebruik om plastiek, metaal, keramiek, papier, saamgestelde materiale en waks parte te vervaardig. Die vermoë van die tegnologie om dun lae vloeistof, poeier of plaatmateriaal op mekaar te verbind laat die vervaardiging van parte wat moeilik of selfs onmoontlik is, deur die gebruik van ander vervaardigingsmetodes. Alhoewel hierdie tegnologieë nog in ‘n ontwikkelingsfase is, word dit as ‘n reuse deurbraak vir die bedryf beskou. Die verbetering, verspreiding en voordele van die tegnologie word hoofsaaklik belemmer deur ‘n tekort aan inligting daaroor. Baie lande, akademiese en industrieële organisasies is nog nie eens bewus dat sulke tegnologieë bestaan nie. Die tekort aan inligting veroorsaak dat kostes hoog bly en verhoed die vinnige uitbreiding van nog meer gevorderde tegnologieë en materiale. Verder bemoeilik dit ook die bemarking van die tegnologieë. Die aantal toevoegende vervaardigingsmasjiene groei jaarliks met beter vermoëns, laer kostes en ‘n groter verskeidenheid van toepassings. Tans is daar meer as 40 vervaardigers wat meer as 100 verskillende masjiene vervaardig in Kanada, China, Frankryk, Duitsland, Israel, Italië, Japan, Suid-Korea, Swede en Amerika. Al die masjiene verskil ten opsigte van hul funksies, beperkings en ook ten opsigte van sterkte, materiale en toepassings van parte. Die groei het gelei tot ‘n toename in gebruik van die tegnologie deur huidige en potensiële nuwe gebruikers van beide die vervaardigings en akademiese sektore. Die keuse van ‘n geskikte sisteem wat aan al ‘n gebruiker se vereistes voldoen, raak elke dag meer kompleks. Die doel van hierdie studie is die ontwikkeling van ‘n seleksie program vir toevoegende vervaardigingmasjiene. Die program sal dien as ‘n opleidingshulpmiddel en as ‘n basis vir masjienseleksie deur potensiële kopers. Die program bestaan uit twee dele: die opleidingsgedeelte en die selekteringsgedeelte. Die opleidingsgedeelte beskryf die verskeie toevoegende prosesse en motiveer gebruikers om die tegnologie aan te skaf weens die voordele. ‘n Agtergrond oor die verskeie tegnologieë stel die gebruiker in staat om ingeligte besluite te neem en tegniese vrae te kan stel aan verskaffers. Die selekteringsdeel het ‘n besluitnemingstruktuur wat help om die regte masjien te kies ten opsigte van verlangde vereistes. Hierdie studie kan help met die bevordering van toevoegende tegnologieë en hul voordele, veral vir lande en organisasies wat nog nooit voorheen sulke tegnologieë gebruik het nie.

Thesis (MScEng)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: This report presents the application of the six sigma quality concept in solving a true business problem. Six sigma is a quality improvement and business strategy/tool developed by Motorola in the mid 1980s. It aims at delivering products and services that approach levels of near perfection. To achieve this objective a six sigma process must not produce more than 3.4 defects per million opportunities, meaning the process should be at least 99.9997% perfect [Berdebes, 2003]. Motorola's success with six sigma popularised the concept and it has now been adopted by many of the world's top compames e.g. General Electric, Allied Signal-Honeywell, etc. All the six sigma companies report big financial returns as a result of increased quality levels due to the reduction in the number of defects. 'General Electric reports annual benefits of over $2.5 billion across the organisation from six sigma' [Huag, 2003]. The six sigma concept follows a five step problem-solving methodology known as DMAIC (Define, Measure, Analyse, Improve, Control) to improve existing processes. Each of these steps makes use of a range of tools, which include quality, statistical, engineering, and business tools. This report first gives a theoretical presentation on quality and six sigma, attempting to answer the question 'What is six sigma'. A step-by-step guide on how to go through the DMAIC problem solving cycle is also presented. The six sigma concept was demonstrated by application to the colour removal process of a continuous processing plant manufacturing refined sugar. Colour removal is a very important process in sugar refining since the purpose of a refinery is to remove colour and other impurities from the raw sugar crystals. The colour removal process consists of three unit operations; liming, carbonation and sulphitation. Liming involves the addition of lime (calcium hydroxide) required for the formation of a calcium precipitate in the next unit operations. Carbonation is carried out in two stages; primary and secondary carbonation. Both stages involve the formation of a calcium carbonate precipitate, which traps colour bodies and other impurities. Sulphitation occurs in a single step and involve the formation of a calcium sulphite precipitate which also traps impurities. The pH and colour are the main variables that are being monitored throughout the colour removal process. Colour removal process Raw sugar Melting Carbonation Crystalli ~ Liming ~ c::J Secondary f+ Sulphitation .. Sugar sation Figure 1: Colour removal process The pH control of the two colour removal unit operations; carbonation and sulphitation, is very poor and as a result the colour removal achieved is below expectation. This compromises the final refined sugar quality since colour not removed in the colour removal processes ends up in the sugar. The first carbonation stage (primary) fails to lower the pH to the required specification and the second carbonation stage (secondary) is highly erratic, the pH fluctuating between too high and too low. The sulphitation process adds more sulphur dioxide than required and hence the pH is lowered below the lower specification limit. The six sigma DMAIC cycle was implemented in order to solve the problem of poor pH control. The Define phase defined the project and identified the process to be improved. The Measure phase measured the current performance of the process by collecting past laboratory data with the corresponding field instruments data. The data was used to draw frequency distribution plots that displayed the actual variation of the process relative to the natural variation of the process (specification width) and to calculate process capability indices. The Analyse phase analysed the data so as to determine the key sources of variation. The Improve phase used the findings of the analyse phase to propose solutions to improve the colour removal processes. The Control phase proposed a control plan so as to monitor and sustain the improvement gained. The key findings of the study are presented below: • Failure of the first carbonation stage to lower the pH to the required level is due to insufficient carbon dioxide gas supply. • The second carbonation reaction occurs very fast hence poor control will result in high variability. • The amount of colour removed is dependent on the input raw melt colour. • The histograms of the colour removal unit operations are off-centered and display a process variation greater than the specification width and hence a large proportion of the data falls outside the specification limits. • The % CaO and CO2 gas addition were found to be the key variables that control the processes centering on target. The % CaO having a stronger effect in the liming process and CO2 gas addition on the carbonation process. • The variation between the field instrument's pH and laboratory pH is the key variable that control the processes spread (standard deviation of the processes). • The processes Cpk values are less than C, (Cpk<Cp) meaning the processes can be improved by controlling the key variables that control centering (% CaO, CO2 gas addition). The processes capability indices are low, Cp<l meamng the processes are not statistically capable of meeting the required specifications at the current conditions. • Based on the findings of the study, the following deductions are made for the improvement of the colour removal processes in better meeting the required specifications. • Increase the CO2 gas supply to at least 4900 m31hr, calculated based on the fact that at least 140 rrr' gas is required per ton of solids in melt [Sugar Milling Research Institute Course Notes, 2002]. • Control the key variables identified to be the key sources of variation; % CaO, CO2 gas addition and variation between the field instrument's pH and laboratory pH. Reducing variation in the % CaO and increasing CO2 gas supply will improve the processes ability to maintain centering at the target specification. Maintaining a consistent correlation between the two pH readings; field instruments pH and laboratory pH will reduce the processes standard deviation and hence the processes spread. Reduction in the processes spread will minimize the total losses outside the specification limits. This will allow better control of the pH by getting rid of high fluctuations. • Control of the input raw melt colour is essential since it has an impact on the degree of decolourisation. The higher the input colour, the more work required in removing the colour. In improving the colour removal processes the starting point should be in ensunng process stability. Only once this is achieved, the above adjustments may be made to improve the processes capability. The processes capability will only improve to a certain extent since from the capability studies it is evident that the processes are not capable of meeting specifications. To provide better control and to ensure continuous improvement of the processes the following recommendations are made: • Statistical process control charts The colour removal processes are highly unstable, the use of control charts will help in detecting any out of control conditions. Once an out of control condition has been detected, necessary investigations may be made to determine the source of instability so as to remove its influence. Being able to monitor the processes for out of control situations will help in rectifying any problems before they affect the processes outputs. • Evaluation of capability indices- ISO 9000 internal audits Consider incorporating the assessment of the capability indices as part of the ISO 9000 internal audits so as to measure process improvement. It is good practice to set a target for Cp, the six sigma standard is Cp=2, this however does not mean the goal should be Cp=2 since this depends on the robustness of the process against variation. For instance the colour removal processes at the current operating conditions can never reach Cp=2. This however is not a constraint since for the colour removal processes to better meet pH specifications it is not critical that they achieve six sigma quality. A visible improvement may be seen in aiming for Cp=I. On studying the effects of CO2 gas addition the total data points outside specification limits reduced from 84 % to 33 % and by reducing the variation between field instruments pH and laboratory pH for the secondary pH the total data points out of specification reduced from 55 % to 48 %. These results indicate that by improving C, to be at least equal to one (Cp=l) the total data points outside specification can reduce significantly, indicating a high ability of the processes to meet specifications. Thus even if six sigma quality is not achieved, by focussing on process improvement using six sigma tools visible benefits can be achieved. / AFRIKAANSE OPSOMMING: Hierdie tesis kyk na die toepassing van die ses sigma kwaliteitskonsep om 'n praktiese probleem op te los. Ses sigma soos dit algemeen bekend staan is nie slegs 'n kwaliteitverbeteringstegniek nie maar ook 'n strategiese besigheidsbenadering wat in die middel 1980s deur Motorolla ontwikkel en bekend gestel is. Die doelstellings is om produkte en dienste perfek af te lewer. Om die doelwit te kan bereik poog die tegniek om die proses so te ontwerp dat daar nie meer as 3.4 defekte per miljoen mag wees nie - dit wil se die proses is 99,9997% perfek [Berdebes, 2003]. As gevolg van die sukses wat Motorolla met die konsep behaal het, het dit algemene bekendheid verwerf, en word dit intussen deur baie van die wereld se voorste maatskappy gebruik, o.a. General Electric, Allied Signal-Honeywell, ens. Al die maatskappye toon groot finansele voordele as gevolg van die vermindering in defekte wat teweeg gebring is. So by. beloop die jaarlikse voordele vir General Electric meer as $2.5 biljoen [Huag, 2003]. Die ses sigma konsep volg 'n vyf-stap probleem oplossings proses (in Engels bekend as DMAIC: Define, Measure, Analyse, Improve, Control), naamlik definieer, meet, analiseer, verbeter, en beheer om bestaande prosesse te verbeter. In elkeen van die stappe is daar spesifieke gereedskap oftegnieke wat aangewend kan word, soos by. kwaliteits-, statistiese--, ingenicurs-cn besigheids tegnieke. Die verslag begin met 'n teoretiese oorsig oor kwaliteit en die ses sigma proses, waardeur die vraag "wat is ses sigma" beantwoord word. Daama volg 'n gedetailleerde stap-virstap beskrywing van die DMAIC probleem oplossingsiklus. Die toepassing van die ses sigma konsep word dan gedoen aan die hand van 'n spesifieke proses in die kontinue suiker prosesserings aanleg, naamlik die kleurverwyderingsproses. Hierdie proses is baie belangrik omdat die doelstellings daarvan juis draai rondom die verwydering van nie net kleur nie maar ook alle ander vreemde bestanddele van die rou suiker kristalle. Die proses bestaan uit drie onafhanklike maar sekwensiele aktiwiteite waardeur verseker word dat die regte gehalte suiker uiteindelik verkry word. Tydens die eerste twee stappe is veral die pH-beheer onder verdenking, sodat die kleur verwydering nie die gewenste kwaliteit lewer nie. Dit bemvloed op sy beurt die gehalte van die finale produk, omdat die ongewenste kleur uiteindelik deel is van die suiker. Die pH inhoud is nie net nie laag genoeg nie, maar ook hoogs veranderlik - in beginsel dus buite beheer. Die DMAIC siklus is toegepas ten einde die pH beter te kan beheer. Tydens die definisiefase is die projek beskryf en die proses wat verbeter moet word identifiseer. In die meetfase IS die nodige data versamel om sodoende die inherente prosesveranderlikheid te bepaal. Die belangrikste bronne of veranderlikes wat bydra tot die prosesveranderlikheid is in die derde-- of analisefase bepaal. Hierdie bevindings is gebruik tydens die verbeteringsfase om voorstelle ter verbetering van die proses te maak. Die voorstelle is implementeer en in die laaste fase, naamlik die beheerfase, is 'n plan opgestel ten einde te verseker dat die proses deurentyd gemonitor word sodat die verbeterings volhoubaar bly. 'n Hele aantal veranderlikes wat elk bygedra het tot die prosesvariasie is identifiseer, en word in detail in die verslag beskryf. Gebaseer op die analise en bevindings van die ondersoek kon logiese aanbevelings gemaak word sodat die proses 'n groot verbetering in kleurverwydering getoon het. Die belangrikste bevinding was dat die huidige proses nie die vermoee het om 100% te voldoen aan die spesifikasies of vereistes nie. Die hoofdoel van die voorstelle is dus om te begin om die prosesveranderlikheid te minimeer of ten minste te stabiliseer - eers nadat die doel bereik is kan daar voortgegaan word om verbeteringe te implementeer wat die prosesvermoee aanspreek. Ten einde hierdie beheer te kan uitoefen en vanasie te verminder IS die volgende voorstelle gemaak: Statistiese beheer kaarte Die kleurverwyderingsproses is hoogs onstabiel. Met behulp van statistiese beheer kaarte is daar 'n vroegtydige waarskuwing van moontlike buite beheer situasies. Die proses kan dus ondersoek en aangepas word voordat die finale produkkwaliteit te swak word. • Evaluering van proses vermoee - ISO 9000 interne oudit Die assesering van die prosesvermoee behoort deel te word van die interne ISO oudit proses, om sodoende prosesverbeteringe gereeld en amptelik te meet. Die standaard gestel vir C, behoort gedurig aandag te kry - dit is nie goeie praktyk om bv. slegs 'n doelwit van C, = 2 soos voorgestel in ses sigma te gebruik nie, maar om dit aan te pas na gelang van die robuustheid van die proses wat bereik is. Daar is beduidende voordele bereik deur die toepassing van die DMAIC siklus. So het byvoorbeeld die persentasie datapunte buite spesifikasie verminder van 84% tot 33%, bloot deur te kyk na die effek wat die toevoeging van C02 gas tydens die proses het. Dit toon dus duidelik dat, alhoewel die proses huidiglik nie die vermoee het om te voldoen aan die vereistes van ses sigma nie, dit wel die moeite werd is om die beginsels en tegnieke toe te pas.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Any growing system is by definition in a transient phase, and consequently exhibits transient-, non-steady state-, unstable behaviour. Accordingly, this form of instability (systemic growth) is by and large conducive to the prosperity of said system. From a Control Systems perspective, transient behaviour that is not subjected to an adequate damping mechanism, does however lead to unavoidable adverse instability. Within the context of business systems, four distinct, yet interconnected entities (raw material, market demand, internal capability to deliver, and cash funds) serve as the damping mechanism to protect companies as a whole, against variation in any of the aforementioned entities. The level of damping afforded by the aforementioned entities is governed by its ability to decouple variation in one entity from undue variation in other entities. The higher the level of instability, the higher the associated level of damping required. The Thesis focuses on core instigators of negative instability within the context of Fast Growing Manufacturing Companies (FGMCs), and ultimately proposes a solution to prevent the regression from positive instability towards negative instability. / AFRIKAANSE OPSOMMING: Enige groeiende stelsel is per definisie in ’n oorgangsfase en vertoon gevolglik verbygaande-, niestabiele oorgangsgedrag. Dienooreenkomstig is hiérdie vorm van onstabiliteit (sistemiese groei) in die algemeen bevorderlik vir die welvaart van genoemde stelsel. Vanuit ’n Beheerstelsels oogpunt, lei oorgangsgedrag wat nie onderworpe is aan ’n voldoende dempingsmeganisme nie, egter tot onafwendbare negatiewe onstabiliteit. Binne ’n besigheidstelsel konteks dien vier afsonderlike, tog onderlingverbonde entiteite (roumateriaal, markaanvraag, interne bekwaamheid om te lewer, en kontantfondse) as die dempingsmeganisme om besighede holisties te beskerm teen variasie in enige van die voorgenoemde entiteite. Die dempingsvlak wat deur die voorgenoemde entiteite gegun word, word bepaal deur dié se vermoë om variasie in een entiteit te ontkoppel van variasie in ander entiteite. Hoe hoër die vlak van onstabiliteit, hoe hoër die vereiste vlak van demping. Die Tesis fokus op kern aanstigters van negatiewe onstabiliteit binne die konteks van VinnigGroeiende Vervaardigingsbesighede en stel uiteindelik ’n oplossing voor om die regressie vanaf positiewe onstabiliteit na negatiewe onstabiliteit te verhoed.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Applying the Industrial Engineering systems approach, this dissertation utilised the theories and propositions of previous studies to argue (model) the cause of financial herd behaviour and the subsequent momentum effect. From this, a hypothesis was postulated to test: whether momentum is a common attribute amongst top performing shares, whether technical analysis indicators can better identify the phenomenon, and whether the return from these shares would justify momentum as a viable investment strategy. A unique experiment derived from previous academic studies was adapted to explore the degree of the momentum phenomenon. This was done by ranking shares according to both technical analysis as well as pure price performance momentum criteria. Returns were translated as a rank in relation to the market as a whole, thereby minimising any effects that different market periods could have on a momentum return relationship. The degree of the relationship was evaluated by applying the alternative Spearman Rank Order Correlation Co-efficient in conjunction with a permutation test to determine the statistical significance of any trends. The viability of the phenomenon as an investment strategy was gauged by comparing annualised average returns against both the market capitalisation weighted JSE All Share Index as well as against an un-weighted representation of the market. The results revealed a seemingly unambiguous co-dependence between momentum and return with statistically significant trends being ever present. Applying the maximum taxes and trading costs revealed that the highest ranked momentum shares did indeed outperform both market benchmarks from the period of January 1990 to August 2009, suggesting the validity of the philosophy as an investment strategy. The outcome of the study in part rejected the null hypothesis, as technical indicators were unable to identify future top performing shares better, with price performance momentum measures delivering the superior returns. Future studies may include optimising the various technical indicators towards the JSE rather than using generic settings. Other interesting topics could include combining momentum with other investment strategies to investigate synergy and further pinpointing the source of the phenomenon. Over the past number of years, tighter controls and monitoring of investments has resulted in the documentation of the individual number of shareholders who are buying and selling shares. Utilising this data over the next number of years, an experiment could attempt to relate the number of individual investors trading in a particular share to herd behaviour and the subsequent momentum effect. / AFRIKAANSE OPSOMMING: Die verhandeling, binne die bedryfsingenieursstelsels benadering, gebruik teorieë en voorstelle van vorige studies om die gevolge van finansiële gedrag en die gevolglike momentum effek te bespreek. Uit die analise is ‘n voorstel saamgestel om die volgende te toets:Is momentum ‘n algemene verskynsel by aandele wat goed presteer, en kan tegniese analitiese indikatore die verskynsel beter verklaar, en dui die opbrengs van die aandele daarop dat momentum ‘n bruikbare beleggingsstrategie is. ‘n Unieke eksperiment uit vorige studies is aangepas om die aard van die momentum verskynsel te ondersoek. Dit was gedoen deur aandele volgens beide tegniese analise asook suiwer prestasie momentum kriteria te klassifiseer. Opbrengste is met die hele mark in konteks geplaas om sodoende enige impak van verskillende mark tye op die momentum opbrengs verhouding te elimineer. Die verband is opgestel deur die alternatiewe “Spearman Rank Order Correlation koëffisiënt” saam met permutasie toetse te gebruik om die statistiese belangrikheid van enige neigings uit te wys. Die geldigheid van die verskynsel as ‘n beleggingsstrategie is gemeet deur jaarlikse gemiddelde opbrengste teen beide die markkapitalisasie geweeg teen die JSE Alle Aandele Indeks sowel as ‘n ongeweegde verteenwoordiging van die mark te bepaal. Die resultate dui op ‘n interafhanklikheid tussen momentum en opbrengste met statistiese neigings altyd teenwoordig. Deur die maksimum belasting en verhandelingskoste toe te pas wys dit dat die hoogste momentum uitgewyste aandele die markriglyne uitpresteer het van Januarie 1990 tot Augustus 2009 wat die geldigheid van die benadering as ‘n beleggingsstrategie bevestig. Die studie verwerp die nul hipotese gedeeltelik in die sin dat dit nie toekomstige top presterende aandele kan uitwys nie, maar aan die ander kant gee prysprestasie momentum meting wel buitegewone opbrengs. Toekomstige studies mag die optimisering van verskeie tegniese indikatore van die JSE insluit, ‘n kombinasie van momentum met ander beleggingsstrategieë gebruik, en verder die bron van die verskynsel vas pen. Oor die afgelope aantal jare het beter beheer en die monitoring van beleggings die dokumentasie van individuele aandeelhouers moontlik gemaak. Hieride data sou kon gebruik word as ‘n toets om die korrelasie tussendie aantal aandeelhouers wat ‘n spesifieke aandeel verhandel en tropgedrag te bepaal en om dit te gebruik om die momentum effek beter te verklaar.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Small-scale farmers have the opportunity to gain access to markets through a contract farming arrangement. The key question is whether it is financially feasible for a small-scale farmer to enter into a contract. The objectives of this study were to develop a model that could be used to determine the financial feasibility of small-scale contract broiler farming in an intensive production system, compare three different genotypes namely: Cobb500 males X Hybro G females, Ross 308 males X Potchefstroom Koekoek females (crossbred) and the purebred Potchefstroom Koekoek, and evaluate current smallscale farmers’ broiler production by means of a case study. Financial performance indicators such as the net present value, cash flow and profit and loss statements were used to analyze the feasibility of all the scenarios. The model was built in Microsoft Excel. Five hundred, 1500 and 2500 birds/cycle scale of production were analyzed. Results revealed that based on the capital costs used, a 500 birds/cycle scale of production was uneconomical and that a farmer would have to receive R25.01/kg broiler meat in order to break even. The 1500 scale of production showed much better results. A farmer could break even at R17.51/kg meat. The capital investment cost of the 2500 scale of production was so high that the farmer would have had to sell his broiler meat for R18.54/kg. Performance traits of genotypes were collected through an experiment and data was statistically analyzed using ‘Statistica 9’. Results showed that there were significant differences between the cumulative feed intake, feed conversion ratios and the European production efficiency ratio of the different genotypes. No significant difference was found in the liveability of the genotypes. Data on performance traits was used as input into the model so that the economic feasibility of the genotypes could be compared. Results showed that a purebred Potchefstroom Koekoek genotype was not suitable for an intensive production system and that the crossbreed did not perform as well as the broiler breed, but that it would be worthwhile investigating the performance traits of the cross breed under less optimal conditions or in a free-range system. The lower capital costs necessary for a freerange system, together with the high premium paid for free-range broiler meat, may give admirable results in the economic feasibility of a small-scale broiler farm. / AFRIKAANSE OPSOMMING: Kleinboere het die geleentheid om deur kontrak boerdery toegang tot markte te verkry. Die vraag is egter of dit finansieël haalbaar is vir 'n kleinboer om kontraktueel verbind te word? Die doelwitte van die studie was om: ‘n model te ontwikkel wat gebruik kan word om die finansiële lewensvatbaarheid van' n klein-skaalse braaikuikenboer te bepaal onder 'n intensiewe produksiestelsel; verskillende genotipes naamlik: Cobb500 hane X Hybro G henne, Ross 308 hane X Potchefstroom Koekoek henne (kruising) en die suiwer Potchefstroom Koekoek te evalueer en die die huidige klein-skaal boer se braaikuikenproduksie deur middel van 'n gevallestudie te evalueer. Finansiële prestasie aanwysers soos die netto huidige waarde, kontantvloei, asook wins en verlies state was gebruik om die haalbaarheid van die verskeie gevalle te analiseer. Die model is op Microsoft Excel gebou. ‘n Produksie skaal van 500, 1500 en 2500 kuikens/siklus is ontleed. Resultate het getoon dat, gebaseer op die kapitale koste wat gebruik is, 'n produksie skaal van 500 kuikens/siklus onekonomies is en dat ʼn boer R25.01/kg sal moet ontvang om gelyk te breek. Die produksie skaal van 1500 kuikens/siklus het beter resultate getoon. 'n Boer kan gelyk breek teen R17.51/kg vleis. Die kapitale beleggingskoste van die produksie skaal van 2500 kuikens/siklus was so hoog dat die boer R18.54/kg sou moes ontvang het om gelyk te breek. Prestasie van genotipes is ingesamel deur middel van 'n eksperiment en data is statisties ontleed met behulp van Statistica 9. Resultate het getoon dat daar hoogs beduidende verskille tussen die kumulatiewe voerinname, voeromsetsverhoudings en Europese produksie effektiwiteits verhouding van die verskillende genotipes is. Geen beduidende verskil is gevind in die leefbaarheid van die genotipes nie. Inligting oor die prestasie eienskappe is gebruik as insette tot die model sodat die ekonomiese haalbaarheid van die genotipes vergelyk kon word. Resultate het getoon dat 'n suiwer Potchefstroom Koekoek genotipe nie geskik is vir 'n intensiewe produksie stelsel nie en dat die kruising nie so goed soos die braaikuiken gevaar het nie, maar dat dit die moeite werd sal wees om ondersoek in te stel na die produksie potensiaal van die kruis kuiken in minder optimale toestande, soos ‘n vryloop stelsel. Die laer kapitale koste en die hoë premie wat betaal word vir vryloop braaikuikenvleis mag geloofwaardige resultate op die ekonomiese haalbaarheid van 'n kleinskaalse braaikuikenboer toon.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: South Africa has potential to grow extensively as a country supplying components to the global aerospace industry supply chains, as well as directly to OEMs like Airbus, Boeing and Cessna which are first tier suppliers. The economic crisis had a significant impact on the growth of small to medium sized enterprises (SMEs), also in aerospace companies. Before the recession, SMEs did not see the necessity to become certified with internationally accredited quality standards, because there were an abundance of business opportunities. In the current restricted business climate SMEs are increasingly realising the importance of certification. The standard that aerospace companies need to comply with, is the AS 9100 standard. Compliance to AS 9100 was previously considered as a competitive advantage (order winner) but has become a necessary prerequisite (order qualifier) to be considered for a contract. In the aerospace industry accountability, traceability, documentation and quality of parts are of critical importance. Quality of products according to specification is crucial as it has a profound effect on safety. The tendency in improving of a company's processes is to scale down on superfluous documentation. In the case of aerospace companies, this is an extremely challenging goal because traceability is of such crucial importance in this sector in terms of aircraft structural system and –operational integrity. For the purpose of this study, a small to medium manufacturer of aircraft and defence system parts was studied and considered to be representative of the aerospace industry in South Africa. The research gap amongst SMEs was investigated by means of a case study at an SME in South Africa where an IT-based AS 9100 quality management system was designed, developed and implemented. The investigation includes the analysis of the research partner's quality documents, the steps in the design and development of the quality management system (QMS) and a description of the implementation thereof. This study aims to provide the focus group (SMEs) with more knowledge when developing their quality management systems for implementation of the AS 9100 requirement to compete in the aerospace industry. It describes the historic background and current use of the AS 9100 standard as background. The objective of the case study will be to determine the generic validity of the method to be able to implement AS 9100 at a small to medium sized aerospace supplier when using the same guidelines which are followed in this specific case. The method's value and success are determined by means of an external audit (certification audit) of the company used in the case study. The method makes specific use of an IT-based infrastructure to facilitate the reduction of unnecessary documentation. Experiences gained by the author in applying AS 9100 to upgrade local manufacturing companies to aerospace suppliers to Volvo Aero Company in Sweden are briefly discussed as well as the validity to make use of these generic steps. / AFRIKAANSE OPSOMMING: Suid-Afrika het die potensiaal om betekenisvol te groei as ʼn land wat komponente lewer aan internasionale lugvaart verskaffersnetwerke. Die ekonomiese krisis het 'n beduidende impak op die groei van klein tot mediumgrootte ondernemings gehad, asook in die lugvaart-industrie. Voor die resessie, het hierdie ondernemings nie die noodsaaklikheid om akkreditasie tot internasionale kwaliteitstandaarde te verkry na waarde geag nie, weens die genoegsame beskikbaarheid van sakegeleenthede. In die huidige ekonomiese klimaat word die belangrikheid van akkreditasie egter toenemend besef. Die standaard waaraan maatskappye in die lugvaartindustrie moet voldoen is die AS 9100 kwaliteitsbeheerstelsel. Voorheen is die akkreditasie tot hierdie standaard gesien as ʼn mededingende voordeel wanneer daar getender is vir ʼn kontrak. Deesdae word dit as ʼn noodsaaklike voorvereiste beskou, voordat die besigheid se aansoek om ʼn kontrak te verkry eers oorweeg sal word. In die lugvaartnywerheid is aanspreeklikheid, naspeurbaarheid en dokumentasie van kardinale belang. Die tendens in die verbetering van 'n maatskappy se prosesse is om af te skaal ten opsigte van onnodige dokumentasie. In die geval van lug- en ruimtevaartmaatskappye, is dit 'n uiters uitdagende doel, omdat naspeurbaarheid gedurende die komponent se leeftyd van deurslaggewende belang is in hierdie sektor. Vir die doel van hierdie studie is 'n klein- tot mediumgrootte vervaardiger van lugvaartkomponente wat dien as navorsingsvennoot, bestudeer. Hulle is beskou as verteenwoordigend van die lugvaartnywerheid in Suid-Afrika vir die doel van die studie. Die navorsingsgaping is geïdentifiseer as die implementering van ʼn gehaltebeheer stelsel wat voldoen aan die AS 9100 kwaliteitsbeheer standaard. Die gevallestudie van hierdie lugvaartvervaardiger sluit die bestudering van die ontwerp, ontwikkeling en implementering van ʼn IT-gebaseerde AS 9100 gehaltestelsel in. In die studie word die navorsingsvennoot se kwaliteitstelsel en dokumente ontleed, en die stappe in die ontwerp en ontwikkeling van die nuwe stelsel verduidelik. Die implementering en die validering van die stelsel deur die outeur, word beskryf en getoets deur middel van ʼn eksterne sertifiseringsliggaam. Hierdie studie poog om as riglyn te dien vir die fokus groep (klein- tot mediumgrootte ondernemings) en hul kennis van die AS 9100 standaard te verbreed. Hierdie kennis dra potensieel by tot die ontwikkeling van hul eie gehaltebestuur stelsels en die implementering van AS 9100 vereistes sodat akkreditasie tot die standaard verkry kan word en hul die lugvaartnywerheid kan betree. Die dokument beskryf die historiese agtergrond en huidige gebruik van die AS 9100 standaard. Die doel van die gevallestudie is om die generiese waarde van die metode vas te stel sodat ander klein tot mediumgrootte ondernemings in staat sal wees om dieselfde metode te volg om AS 9100 te implementeer. Die metode se geldigheid en sukses word bepaal deur middel van 'n eksterne oudit (sertifiseringsoudit) van die navorsingsvennoot in die gevallestudie. Die metode maak gebruik van 'n spesifieke IT-gebaseerde infrastruktuur om die vermindering van onnodige dokumentasie te fasiliteer. Ervarings en bevindings van ʼn soortgelyke studie in Swede, waar die outeur lid van die implementeringspan was, word ook kortliks bespreek om die geldigheid van die generiese stappe te bepaal en te beklemtoon.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Energy-related costs are increasing steadily. This is especially true in South Africa where we have been dealing with an energy crisis during the past couple of years. The increase in energy-related costs puts energy dependent industries under financial pressure. It is therefore imperative to find ways to improve the efficiency with which energy is being consumed in order to decrease the amount of money that has to be allocated to energy costs. The efficient consumption of energy at a facility is crucial and to increase that efficiency, Energy Management Programs (EMPs) should be implemented. An important component of EMPs is ascertaining the current energy consumption of a facility in order to identify areas where possible improvements can be made. This is done by completing an energy audit at the facility. After the energy audit has been completed and Energy Conservation Methods (ECMs) have been identified, the implementation of these methods should commence. The aim of this study is to determine how Industrial Engineering (IE) methods can play a more integral role in making South Africa more energy efficient. As part of this study, research was done to identify current EMCs being implemented in different areas and for different equipment in facilities. This information was compared to IE methods to identify the possible relationship between the ECMs and IE methods. Content analyses were completed on both IE and energy efficiency corpora using the Content Analysis Toolkit (CAT) program. These analyses identified important topics in these corpora and correlations between these topics in order to show correlations between the IE and energy efficiency fields. The most significant correlations identified, were between statistical methods and various energy efficiency topics. A case study was completed at a company in the Western Cape that manufactures electronic and integrated circuit products to implement the relevant ECMs. As part of the case study, an energy audit was completed at the facility. The implementation of a number of the ECMs has shown reductions in the daily kilowatt hours (kWh) consumptions. These reductions were obtained through the implementation of a Shut Down Management program, which highlights the importance of management in an energy conservation project. The application of optimisation algorithms for energy efficient design was examined through the optimisation of lighting design, using a Genetic Algorithm. It was found that a Genetic Algorithm is applicable to lighting design but requires further refinement in order to generate the most optimal design solutions. / AFRIKAANSE OPSOMMING: Kostes verbonde aan energieverbruik is voortdurend besig om toe te neem.Dit is veral relevant in Suid-Afrika waar ons tans ’n energiekrisis beleef. Hierdie toename in energieverwante kostes plaas energie-afhanklike industrieë onder groot finansiële druk. Dit is daarom belangrik om maniere te vind om energieverbruik meer effektief te maak sodat die bedrag geld wat aan energieverwante kostes toegestaan word, verminder kan word. Effektiewe energieverbruik by ’n fasiliteit is kritiek en om hierdie effektiwiteit te verbeter behoort ’n energiebestuursprogram by die fasiliteit geïmplimenteer te word. ’n Belangrike komponent van energiebestuursprogramme is die bepaling van die huidige energieverbruik en dit word gebruik om die areas te identifiseer waar moontlike verbeteringe aangebring kan word. Die energieverbruik word bepaal deur ’n energie-oudit. Nadat die energie-oudit voltooi en die energiebesparingsmetodes bepaal is, moet hierdie metodes by die fasiliteit geïmplementeer word. Hierdie studie probeer vasstel hoe bedryfsingenieurswesemetodes ‘n groter rol kan speel in die proses om Suid-Afrika meer energie-effektief te maak. Navorsing is gedoen oor energiebesparingsmetodes wat in verskillende areas en vir verskillende toerusting in fasiliteite geïmplementeer word. Hierdie inligting is daarna vergelyk met bedryfsingenieurswesemetodes om juis die moontlike verhouding tussen hierdie twee tipe metodes te identifiseer. Analises was gedoen in bedryfsingenieurswese en energie-effektiwiteitskorpusse met die gebruik van die ‘Content Analysis Toolkit’ program. Belangrike onderwerpe en verwantskappe tussen hierdie onderwerpe in die korpusse is identifiseer om sodoende korrelasies tussen die bedryfsingenieurswese- en energie-effektiwiteitsveld uit te lig. Die mees betekenisvolle korrelasies was tussen statistiese metodes en verskeie energieeffektiwiteitsonderwerpe identifiseer. ’n Gevallestudie is by ’n maatskappy in die Wes-Kaap wat geïntegreerde elektroniese stroombane vervaardig gedoen, om die relevante energiebesparingsmetodes te implementeer. ’n Energie-oudit is as deel van die gevallestudie by die fasiliteit gedoen. Die aantal energiebesparingsmetodes wat wel geïmplementeer is, het ’n verlaging in die kilowatture (kWh) teweeggebring. Hierdie verlagings is verkry deur die implementering van ’n afskakelingsbestuursprogram wat die belangrikheid van bestuur in ’n energiebesparingsprogram uitlig. Die toepaslikheid van optimiseringsalgoritmes vir energie-effektiewe ontwerp is getoets deur die optimisering van ’n liguitlegontwerp met behulp van ’n genetiese algoritme. Daar is gevind dat ’n genetiese algoritme wel toegepas kan word, maar dat dit verbeteringe benodig.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The aim of this thesis is to address the need for sustainable development within waste management. It explores how sustainability can be assessed and used as the basis for high level decision making within waste management. Stellenbosch University (SU) was used as a case study to demonstrate how information can be gathered and used for decision support. The literature reviewed, showed a wide area of focus within which sustainability is defined and how businesses and organisations shift towards a model of corporate responsibility. The concept of sustainability was then presented within waste management. Life Cycle Assessment (LCA) and Multi-Criteria Decision Analysis (MCDA), were presented as management tools that could facilitate the assessment and decision making process within a sustainable waste management framework. The two management tools, Sustainable Life Cycle Analysis (SLCA) and Analytical Hierarchal Process (AHP) (branches of LCA and MCDA respectively), were used to develop a framework to be applied to SU Waste Management System. By integrating the two tools, a framework was established that could measure the sustainability of current waste management practices and provide a decision support tool. The framework was validated by applying it to the Stellenbosch University waste system. The framework that was developed delivered a set of sustainable results from which decision makers could base policy decisions. The framework then facilitated the decision making process and a sustainable waste management policy was selected. The application modelled the decision makers preferences and resulted in a policy being selected which favoured high levels of recycling and waste prevention. The results represented an approach which, when compared to the current practice, was more expensive but more environmentally friendly and socially acceptable. The findings provide an exciting basis for future research, where decisions are based on sustainable principles. The framework has potential to be expanded into other areas of management and is not limited to a university environment. / AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is om die behoefte aan volhoubare ontwikkeling binne afvalbestuur aan te spreek. Die tesis ondersoek hoe die volhoubaarheid in afvalbestuur bepaal kan word, en hoe dit dan gebruik kan word as basis vir beleid besluitneming binne afvalbestuur. Die Universiteit Stellenbosch (US) is as ’n gevallestudie gebruik om te demonstreer hoe inligting versamel kan word en as ondersteuning vir beleidbesluitneming gebruik kan word. Die literatuurstudie dek ’n wye veld waarbinne daar op volhoubaarheid gefokus word. Dit wys ook hoe maatskappye en organisasies na ’n model van korporatiewe verantwoordelikheid beweeg. Die konsep van volhoubaarheid word dan binne die mileu van afvalbestuur aangebied. Die Lewenssiklus Assesering (LSA) en Multi-Kriteria Besluitnemings Analise (MKBA) wat gebruik is, kan dien as bestuur hulpmiddel om die assessering van, en besluitneming binne ’n volhoubare afvalbestuur te vergemaklik. Vanuit die twee hulpmiddels, is Volhoubare Lewens Siklus Analise (VLSA) en Analitiese Hierargiese Proses (AHP), gebruik om ’n raamwerk te ontwikkel wat toegepas is op die US. Deur die twee hulpmiddels te integreer kan ’n raamwerk geskep word wat die volhoubaarheid van die huidige afvalbestuur praktyke en wat kan dien as ‘n ondersteunende hulpmiddel met die besluitnemingsprosesse. Die waardasie van die raamwerk wat ontwikkel was, het ‘n stel volhoubare resultate opgelewer, wat besluitnemers gebruik het om hul beleidsbesluite op te baseer. Die besluitnemers se voorkeure is gebaseer op die bevindinge van die VLSA en het bepaal watter beleid gekies is. Die bevindinge het ’n duurder, maar meer omgewingsvriendelike en sosiaal aanvaarbare beleid verteenwoordig. Hierdie bevindinge bied ’n opwindende basis vir toekomstige navorsingwerk, waar besluitneming op volhoubare beginsels gebaseer is. Die raamwerk het potensiaal vir uitbreiding na ander gebiede van bestuur en is nie beperk tot ’n universiteitsomgewing nie.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The aerospace- and automotive industries have an urgency to save space and reduce weight, as well as a need to increase fuel efficiency and reduce emissions. This has led to the use of lightweight structural materials, such as Ti6A14V alloy, which is the most widely used titanium alloy in the aerospace industry. This alloy has an exceptional strength-to-density ratio. The work also covers studies on tool steel 40CrMnMo7 that is used in applications in the tooling-, aerospace and automotive industry. In the quest for improved performance new alternative methods of efficiently machining these materials are investigated. One of the important criteria during machining of these materials is their machinability. This study discusses current research in high performance machining strategies and techniques for advanced materials such as Ti6Al4V and 40CrMnMo7. The properties that make these materials advantageous for the use in the aerospace- and automotive industry also make them difficult to cut. The widespread application of Ti6Al4V in the aerospace industry has encouraged investigations into cooling strategies or -techniques to maintain and improve tool life. Ti6Al4V has a low thermal conductivity causing the heat generated during machining to accumulate on the cutting edge of the tool. During various experiments the application of external compressed air blow cooling (dry cutting), flood cooling, high pressure through spindle cooling (HPTSC) and modifications thereof were investigated. The research project also evaluated the performance of a coating (TiAlN) and various coating treatments. The objectives of the HPTSC modifications were to improve the coolant stream impingement on the tool surface, effectively compressing the thermal barrier, and to reduce the chip-tool contact area. This would lead to a decrease in tool heating and wear. The modified techniques failed to increase tool life but showed signs of increased heat removal capability under the given conditions. It was observed that air blow cooling (dry cutting) delivered the best results when considering cutting materials, coating, coating treatment and cooling strategies or –techniques throughout the experiments conducted. / AFRIKAANSE OPSOMMING: Die Ruimte-en motor-industrie het 'n dringendheid om ruimte te bespaar en gewig te verminder, sowel as 'n behoefte om brandstofdoeltreffendheid te verbeter en emissies te verminder. Dit het gelei tot die gebruik van liggewig strukturele materiale, soos Ti6A14V Allooi , wat die mees gebruikte titanium allooi in die Ruimte is. Hierdie allooi het 'n uitsonderlike krag-tot-digtheid-verhouding. Die studie dek ook gereedskapstaal 40CrMnMo7 wat in die gereedskap, Ruimte-en motor-industrie aangewend word. In die soeke na verbeterde prestasie word nuwe alternatiewe metodes om effektief bewerking van hierdie materiaal ondersoek. Een van die belangrikste kriteria tydens bewerking van hierdie materiaal is die bewerkbaar daarvan. Hierdie studie bespreek die huidige navorsing in hoë prestasie bewerking strategieë en tegnieke vir gevorderde materiale, soos Ti6Al4V en 40CrMnMo7. Die eienskappe wat hierdie materiaal voordelig maak vir die gebruik in die lug-en Ruimte-en motor-industrie, maak dit terselfdetyd moeilik om te sny. Die wydverspreide toepassing van Ti6Al4V in die lug-en Ruimte industrie moedig ondersoeke aan na koelstrategieë of -tegnieke om die instrumentlewe te handhaaf en te verbeter. Ti6Al4V het lae termiese geleidingsvermoë wat veroorsaak dat die hitte, wat gegenereer word tydens bewerking, versamel op die voorpunt van die instrument. Tydens verskillende eksperimente was die toepassing van eksterne saamgeperste lugblaas-verkoeling (droë sny), vloed verkoeling, hoë-druk-deur-die-spil-afkoeling (HPTSC) en aanpassings daarvan geondersoek. Die navorsingsprojek het ook die prestasie van 'n bedekkingslaag (TiAlN) en verskeie bedekkingslaagbehandelings geëvalueer. Die doelwit van die HPTSC aanpassing was om die koelmiddelstroom beklemming op die instrument oppervlak te verbeter, en effektiewelik die termiese versperring saam te pers, asook die skerf-teenoorinstrument kontak te verminder. Dit sou lei tot 'n afname in die instrumentverwarming en -slytasie. Die gewysigde tegnieke het daarin misluk om die instrumentlewe te verhoog, maar het tekens getoon van 'n toename in hitte verwydering vermoë onder die gegewe omstandighede. Dit is dus waargeneem dat lugblaasverkoeling (droë sny) die beste resultate gelewer het in die oorweging van sny materiale, bedekkingslaag, bedekkingslaagbehandelings en verkoeling strategieë of -tegnieke wat regdeur die eksperimente uitgevoer was.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: There is a need for a coarse-to-fine positioning system as per a case study presented by the project collaboration partner, the Technical University of Chemnitz. The case study involves the picking and placing of piezo-ceramic micro parts into milled micro cavities. The focus of the project is the creation and development of a systematic approach for the design and the implementation of a coarse-to-fine positioning system for micro material handling. A second focus is to determine the applicability of the system for highly accurate and repeatable micro drilling and micro-milling. A systematic approach entails combining innovation management (assists in overall project structure), systems engineering (assists in specific design steps and tools) and research questions. Micro-milling was achieved, however the system proved unsuitable for highly accurate and repeatable micro drilling. The coarse-to-fine positioning system was successfully designed, built, and tested for accurate micro material handling. / AFRIKAANSE OPSOMMING: Daar bestaan ’n behoefte aan ’n grof-tot-fyn-posisioneringstelsel - soos blyk uit die gevallestudie uiteengesit deur die samewerkende projekvennoot, die Tegniese Universiteit van Chemnitz. Die gevallestudie behels die uitsoek en plasing van piezo-keramiek partikels in gefreesde mikroholtes. Hierdie projek het gefokus op die skepping en ontwikkeling van ’n stelselmatige benadering tot die ontwerp en implementering van ’n grof-tot-fyn-posisioneringstelsel vir mikromateriaalhantering en mikromasjienering. ’n Stelselmatige benadering behels dat innovasiebestuur (hulp met die algehele projekstruktuur), stelselingenieurswese (hulp met spesifieke ontwerpstappe en -hulpmiddels) en navorsingsdoelwitte gekombineer word. Die geïmplementeerde stelsel is eksperimenteel getoets en daar is bevind dat dit aan die spesifikasies en vereistes voldoen.