Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In a move towards cleaner and more sustainable energy systems, hydrogen as an energy carrier and
hydrogen fuel cells as energy converters are receiving increasing global attention. Considering the
vital role that platinum plays in the operation of hydrogen fuels cells, South Africa stands to gain
enormously as the world’s leading platinum group metals supplier. Therefore, in order to benefit
across the whole value chain, it is imperative to develop the capability to manufacture hydrogen fuel
cell stacks locally.
This project addresses this imperative, in part, by building a framework to evaluate the
manufacturing performance of one of the more costly components of the hydrogen fuel cell stack.
More specifically, this project builds a cost evaluation model (or cost model) for the manufacture of
bipolar plates using micro milling. In essence, the model characterises manufacturing cost (and time)
as a function of relevant inputs.
The model endeavours to be flexible in accommodating relevant contributing cost drivers such as
tool life and manufacturing time. Moreover, the model lays the groundwork, from a micro milling
perspective, for a comparison of different manufacturing methods for bipolar plates.
The approach taken in building the cost model is a fundamental one, owing to the lack of historical
cost data for this particular process. As such, manufacturing knowledge and experimentation are
used to build the cost model in a structured way.
The process followed in building the cost model begins with the formulation of the cost components
by reviewing relevant examples from literature. Thereafter, two main cost drivers are
comprehensively addressed. Tool life is characterised experimentally as a function of cutting
parameters and manufacturing time is characterised as a function of relevant inputs. The work is
then synthesized into a coherent cost model.
Following the completion of the cost model, analysis is done to find the near-optimal combination of
machine cutting parameters. Further, analysis is done to quantify the sensitivity of manufacturing
cost to design changes and production volumes. This attempts to demonstrate how typical
managerial issues can be addressed using the cost model format.
The value of this work must be seen in terms of its practical contribution. That is, its contribution to
the development of the capability to manufacture hydrogen fuel cells locally. By understanding the
effect of relevant input factors on manufacturing cost, ‘upstream’ design and development activities
can be integrated with ‘downstream’ manufacturing activities. Therefore, this project supports the
development of manufacturing capability by providing a mechanism to control cost throughout the
process. / AFRIKAANSE OPSOMMING: In die soeke na skoner, meer volhoubare energie bronne word die fokus op waterstof, as energie
draer, en waterstof brandstofselle, as energie omskakelaars, al meer verskerp. Deur die sleutelrol
van platinum in die werking van waterstof brandstofselle in ag te neem, word Suid-Afrika, as die
wêreld se grootste platinum verskaffer, in `n uitstekende posisie geplaas om voordeel te trek uit
hierdie geleentheid. Om dus as land voordeel te trek uit die proses in geheel, is dit van kardinale
belang om die vermoë te ontwikkel om waterstof brandstofsel stapels op eie bodem te vervaardig.
Hierdie projek adresseer gedeeltelik hierdie noodsaaklikheid, deur `n raamwerk te bou wat die
vervaardigingsoptrede van een van die meer duursame komponente van die waterstof brandstofsel
stapel evalueer. Meer spesifiek, bou hierdie projek `n koste evaluerings model (of koste model) vir
die vervaardiging van bipolêre plate deur die gebruik van mikro-masjienering. In wese kenmerk
hierdie model vervaardigings kostes (en tyd) as `n funksie van relevante insette.
Hierdie model poog om buigsaam te wees met die in ag neming van relevante bydraende
kostedrywers soos buitelleeftyd en vervaardigingstyd. Daarbenewens lê hierdie model die
grondwerk, vanuit `n mikro masjienerings oogpunt, vir die vergelyking van verskillende
vervaardingings metodes vir bipolêre plate.
Die benadering wat gevolg word in die bou van die koste model is fundamenteel as gevolg van die
gebrek van historiese data vir hierdie spesifieke proses. As sodanig word vervaardigings kennis en
eksperimentering gebruik om die koste model in `n gestruktueerde wyse te bou.
Die proses gevolg in die bou van die koste model begin met die formulering van die koste
komponente deur die hersiening van relevante voorbeelde vanuit die literatuur. Daarna word twee
hoof koste drywers deeglik geadresseer. Buitelleeftyd word ekperimenteel gekenmerk as funksie van
masjieneringsparameters en vervaardigingstyd word gekenmerk as `n funksie van relevante insette.
Die werk word dan gesintetiseer in `n samehangende koste model.
Wat volg op die voltooiing van die koste model is `n analise om die optimale kombinasie
masjieneringsparameters te vind. Daaropvolgens word analises gedoen om die sensitiwiteit van
vervaardigingskoste onderworpe aan ontwerpsveranderings en produksie volumes te kwantisfiseer.
Dit poog om te demostreer hoe tipiese bestuursproblem geadresseer kan word deur die koste model
formaat te gebruik.
Die waarde van hierdie werk moet in die lig van die praktiese bydrae daarvan gesien word,
menende, die bydrae tot die ontwikkeling van die vermoë om waterstof brandstofselle in Suid-Afrika
te vervaardig. Deur die effek van relevante inset faktore op vervaardigingskoste te verstaan, kan
‘stroom-op’ ontwerp en ontwikkelings aktiwiteite geïntegreer word met ‘stroom-af’ vervaardigings aktiwiteite. Dus, hierdie projek ondersteun die ontwikkeling van vervaardigingsvermoëns deur `n
meganisme te voorsien om kostes oor die omvang van die proses te beheer.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20319 |
| Date | 03 1900 |
| Creators | Essmann, Erich C. |
| Contributors | Dirkse van Schalkwyk, T. G., Stellenbosch University. Faculty of Engineering. Dept. of Industrial Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 136 p. : ill. |
| Rights | Stellenbosch University |
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