Spelling suggestions: "subject:"6process optimisation"" "subject:"_process optimisation""
1 |
Process Optimisation - An empirical study of process optimisation in FinlandHeinonen, Annika January 2012 (has links)
The objective of this master’s thesis is to determine methods for improving a company’s business processes without investing in new technology and whether a relatively small company can benefit from investing in technology. This study determines the meaning of process optimisation and how it should be conducted. Using existing theory and the case of a logistics company operating in Finland, this research attempts to identify hindrances and find opportunities for the company to develop their processes through process optimisation without technology. Different public bodies in Finland (such as the Finnish government and Statistics Finland) have stated that Finnish logistics requires development and have recommended new technology as a solution to the issue. However, the lack of information on the Finnish logistics business sector makes such statements by public bodies difficult to analyse. Process optimisation has been revealed to be more complex than expected. Many theories available today examine and recommend different technological solutions to execute companies’ work processes. However, a theory is needed on how process optimisation can be carried out at a company lacking technology. Process optimisation consists of process modelling and process analysis. Process modelling appears to be the most significant and crucial aspect of process optimisation. Order-to-delivery processes cannot be optimised within a company if the company does not understand the entirety of such processes. Knowledge of the process has been highlighted as being key to understanding a company’s processes at a high level. The case company in this study showed that process optimisation is possible without implementing new technology; instead, optimisation required additional human capital and a stronger focus on a company’s internal business processes. Technology-based solutions for process optimisation are tempting to implement as doing so may be believed to save time, but no automated solution is able to reveal a company’s critical information if the company does not know what it is looking for and cannot identify its problem areas. This research includes a single case study. The results indicate that whether a relatively small company could benefit from investing in technology is unclear, and the lack of research on process optimisation at Finnish companies resulted in limited findings and analysis. Several different scientific articles presented technology implementation successes and failures, but did not reveal information on the steps taken by the companies.
|
2 |
Optimisation of conditions for the resolution of 1,2-epoxyoctane in a bioreactor / I. le RouxLe Roux, Ilani January 2003 (has links)
Due to recent legislation requiring the determining of the pharmacokinetic effect of both
enantiomers separately, of any new racemic drug before commercialisation, much research is
done to improve and optimise methods for obtaining chirally pure compounds important for the
pharmaceutical industry, for example epoxide precursors.
To date most experiments regarding the biocatalytic chiral separation of 1,2-epoxyoctane has
been done in batch processes. The aim of this study was to optimise the enantioselective
hydrolysis of 1,2-epoxyoctane by Rhodosporidiurn tondoides in both a batch and continuous
process. The batch process was optimised in terms of stir speed, biomass (cell) concentration
and reaction time, while the flow-through reactor (continuous process) was optimised with
regards to the flow rate as a function of the pressure and the amount of chitosan and biomass in
the reactor.
Initial inconsistencies of epoxide concentrations in preliminary studies were found to be due to
adsorption by reaction and sampling vessels, and the lower than expected solubility of 1,2-
epoxyoctane (3.85 mM instead of 6 mM as reported by previous investigators).
The results from the batch process suggest that as the reaction time increases, the % ee-epox
increases initially, but decreases after 40 minutes. Optimum yield in terms of % ee-epox were
obtained at medium stir speed (400 rpm) and biomass (cell) concentration (13 %). Below these
values the % ee-epox increases with an increase in stir speed and/or biomass concentration.
Above these values however, the increased stir speed and/or biomass concentration causes
abrasion between cells, which negatively affects the % ee-epox. The % ee-diol reached a steady
state after 10 minutes, and the effect of the different operating conditions on % ee-diol was
negligible.
In the flow-through reactor chitosan was used as a spacer material (antifouling agent) to help
decrease the fouling due to biomass deposition. The use of chitosan as a spacer ensured
higher and stabilised flow rates for extended periods of time. In initial studies 0.5 g chitosan
increased the flow rate by 34 % with a resistance removal of 25 %. For 1 g chitosan these
values were 130 % flow increase and 57 % resistance removal. The flow rate was optimised in
relation to the chitosan amount, biomass (cell) amount and pressure. The maximum flow rate
was obtained at a pressure of 40 kPa, using the minimum amount of cells (0.4 g) and a
maximum amount of chitosan (1.6 g) / Thesis (M.Sc.)--North-West University, Potchefstroom Campus, 2004.
|
3 |
Optimisation of conditions for the resolution of 1,2-epoxyoctane in a bioreactor / I. le RouxLe Roux, Ilani January 2003 (has links)
Due to recent legislation requiring the determining of the pharmacokinetic effect of both
enantiomers separately, of any new racemic drug before commercialisation, much research is
done to improve and optimise methods for obtaining chirally pure compounds important for the
pharmaceutical industry, for example epoxide precursors.
To date most experiments regarding the biocatalytic chiral separation of 1,2-epoxyoctane has
been done in batch processes. The aim of this study was to optimise the enantioselective
hydrolysis of 1,2-epoxyoctane by Rhodosporidiurn tondoides in both a batch and continuous
process. The batch process was optimised in terms of stir speed, biomass (cell) concentration
and reaction time, while the flow-through reactor (continuous process) was optimised with
regards to the flow rate as a function of the pressure and the amount of chitosan and biomass in
the reactor.
Initial inconsistencies of epoxide concentrations in preliminary studies were found to be due to
adsorption by reaction and sampling vessels, and the lower than expected solubility of 1,2-
epoxyoctane (3.85 mM instead of 6 mM as reported by previous investigators).
The results from the batch process suggest that as the reaction time increases, the % ee-epox
increases initially, but decreases after 40 minutes. Optimum yield in terms of % ee-epox were
obtained at medium stir speed (400 rpm) and biomass (cell) concentration (13 %). Below these
values the % ee-epox increases with an increase in stir speed and/or biomass concentration.
Above these values however, the increased stir speed and/or biomass concentration causes
abrasion between cells, which negatively affects the % ee-epox. The % ee-diol reached a steady
state after 10 minutes, and the effect of the different operating conditions on % ee-diol was
negligible.
In the flow-through reactor chitosan was used as a spacer material (antifouling agent) to help
decrease the fouling due to biomass deposition. The use of chitosan as a spacer ensured
higher and stabilised flow rates for extended periods of time. In initial studies 0.5 g chitosan
increased the flow rate by 34 % with a resistance removal of 25 %. For 1 g chitosan these
values were 130 % flow increase and 57 % resistance removal. The flow rate was optimised in
relation to the chitosan amount, biomass (cell) amount and pressure. The maximum flow rate
was obtained at a pressure of 40 kPa, using the minimum amount of cells (0.4 g) and a
maximum amount of chitosan (1.6 g) / Thesis (M.Sc.)--North-West University, Potchefstroom Campus, 2004.
|
4 |
Investigation on the multiscale multiphysics based approach to modelling and analysis of precision machining of metal matrix composites (MMCs) and its application perspectivesNiu, Zhichao January 2018 (has links)
Over the last two decades or so, metal matrix composites (MMCs) have been drawing the attention of the industry due to their potentials in fulfilling demands for high performance industrial materials, products and advanced engineering applications. On the other hand, the high precision machining is becoming one of the most effective methods for enabling these difficult-to-machine composites to be applied particularly in precision engineering. Therefore, in-depth scientific understanding of MMC precision machining is essential and much needed so as to fulfil the gap between fundamental issues in precision machining of MMCs and their industrial scale applications. This thesis focuses on development of a multiscale multiphysics based approach to investigating the machinability of particulate MMCs and the machining process optimisation. In order to investigate the surface generation in relation to the process variables, this PhD study covers the key fundamental issues including chip formation process, dynamic cutting force, cutting temperature partition and tool wear by means of combining modelling, simulation and experimental study. The chip formation mechanisms and the minimum chip thickness in precision machining of SiCp/Al and B4Cp/Al MMCs by using PCD tools are investigated through a holistic approach. Minimum chip thickness (MCT) value is firstly identified based on the modified mathematical model. The certain threshold of the uncut chip thickness, i.e. chips starting to form at this chip thickness point, is then established. The chip formation process including the matrix material breakage, particles fracture, debonding, sliding or removal and their interfacial interactions are further simulated using finite element analysis (FEA). The minimum chip thickness and chip formation simulations are evaluated and validated via well-designed experimental trials on a diamond turning machine. The chips and surface profiles formed under varied process variables in periodic material removals are inspected and measured in order to obtain a better understanding on MMC chip formation mechanisms. The improved dynamic cutting force model is developed based on the micro cutting mechanics involving the size effect, undeformed chip thickness effects and the influence of cutting parameters in the micro scale. Cutting process variables, particle form, size and volume fraction at different scales are taken into account in the modelling. The cutting force multiscale modelling is proposed to have a better understanding on the MMCs cutting mechanics and to predict the cutting force accurately. The cutting forces are modelled and analysed in three cutting regimes: elastic recovery zone, ploughing zone and shearing zone. A novel instantaneous chip thickness algorithm including real chip thickness and real tool trajectory is developed by taking account of the tool runout. Well-designed cutting trials are carried out under varied process variables to evaluate and validate the force model. In order to obtain the actual cutting forces accurately, transfer function technique is employed to compensate the measured cutting forces. The cutting force model is further applied to correlate the cutting tool wear and the prediction of the machined surface generation. Multiphysics coupled thermal-mechanical-tribological model and FE analysis are developed to investigate the cutting stress, cutting temperature, tool wear and their intrinsic relationships in MMCs precision machining process. Heat generation, heat transfer and cutting temperature partition in workpiece, chips and cutting tool are simulated. A modified tool wear rate model is proposed, tool wear characteristics, wear mechanisms and dominate tool wear are further investigated against the real machining process. Cutting tool wear is monitored and assessed offline after machining experiments. The experimental study on the machined surface generation is presented covering cutting force, tool wear, tool life, surface roughness and machining efficiency. Process optimisation is explored by considering the variation of cutting parameters, cutting tool conditions and workpiece materials in order to achieve the desired outcomes and machinability.
|
5 |
Knowledge based system implementation for lean process in low volume automotive manufacturing (LVAM) with reference to process manufacturingMohamed, N.M.Z.Nik, Khan, M. Khurshid 04 August 2011 (has links)
Yes / Global manufacturing industry mostly depends on new product development and processes to
become competitive. The product development process for automotive industry is normally
complicated, lengthy, expensive, and risky. Hence, a study of lean manufacturing processes for
low volume manufacturing in automotive industry is proposed to overcome this issue by
eliminating all wastes in the lengthy process. This paper presents a conceptual design approach to
the development of a hybrid Knowledge Based (KB) system for lean process in Low Volume
Automotive Manufacturing (LVAM). The research concentrates on the low volume processes by
using a hybrid KB system, which is a blend of KB system and Gauging Absences of Pre-requisites
(GAP). The hybrid KB/GAP system identifies all potential waste elements of low volume process
manufacturing. The KB system analyses the difference between the existing and the benchmark
standards for lean process for an effective implementation through the GAP analysis technique.
The proposed model explores three major lean process components, namely Employee
Involvement, Waste Elimination, and Kaizen (continuous improvement). These three components
provide valuable information in order for decision makers to design and implement an optimised
low volume manufacturing process, but which can be applied in all process manufacturing,
including chemical processing.
|
6 |
Process Parameter Optimization of a Polymer Derived CeramicCoatings for Producing Ultra-High Gas BarrierChanna, I.A., Shah, A.A., Rizwan, M., Makhdoom, M.A., Chandio, A.D., Shar, Muhammad A., Mahmood, A. 27 October 2021 (has links)
Yes / Silica is one of the most efficient gas barrier materials, and hence is widely used as anencapsulating material for electronic devices. In general, the processing of silica is carried out at hightemperatures, i.e., around 1000◦C. Recently, processing of silica has been carried out from a polymercalled Perhydropolysilazane (PHPS). The PHPS reacts with environmental moisture or oxygen andyields pure silica. This material has attracted many researchers and has been widely used in manyapplications such as encapsulation of organic light-emitting diodes (OLED) displays, semiconductorindustries, and organic solar cells. In this paper, we have demonstrated the process optimization ofthe conversion of the PHPS into silica in terms of curing methods as well as curing the environment.Various curing methods including exposure to dry heat, damp heat, deep UV, and their combinationunder different environments were used to cure PHPS. FTIR analysis suggested that the quickestconversion method is the irradiation of PHPS with deep UV and simultaneous heating at 100◦C.Curing with this method yields a water permeation rate of 10−3g/(m2·day) and oxygen permeationrate of less than 10−1cm3/(m2·day·bar). Rapid curing at low-temperature processing along withbarrier properties makes PHPS an ideal encapsulating material for organic solar cell devices and avariety of similar applications. / King Saud University
|
7 |
Gestion de robots mobiles et redondants et collaboratifs en environnement contraint et dynamique / Management of mobile and collaborative robots in cluttered and dynamic environmentBusson, David 26 November 2018 (has links)
L’utilisation de robots collaboratifs dans l’industrie de production est en plein essor. Ces robots, dont la puissance est limitée, sont dotés de capteurs leur permettant de détecter la présence d’obstacles, afin de garantir la sécurité des humains se trouvant aux alentours. On s’intéresse dans cette thèse à l’utilisation de systèmes redondants, collaboratifs et mobiles (bras articulés montés sur plateformes mobiles), dans un environnement de production aéronautique peuplé d’humains, pour la réalisation d’opérations d’assemblage. Du point de vue des process, l’utilisation de ces systèmes, souvent beaucoup moins imposants et rigides que leurs homologues non collaboratifs, est jalonnée de défis. La grande souplesse mécanique et les faibles couples qui les caractérisent peuvent induire des imprécisions de positionnement et une incapacité à soutenir l’intensité d’une interaction physique. Ce contexte induit également un besoin d’autonomie de ces systèmes, qui sont amenés à travailler dans des environnements en perpétuelle évolution. Dans cette thèse, une formulation de la redondance cinématique est d’abord présentée. Le formalisme associé permet de simplifier l’exploitation de la liberté que ces systèmes possèdent sur le choix des postures à utiliser pour réaliser des tâches de placement statique de l’effecteur. Ce formalisme est ensuite exploité pour améliorer et caractériser le comportement en déformation et la capacité d’application d’efforts des systèmes redondants sériels. Enfin, le sujet de la planification des mouvements de systèmes robotisés dans un environnement dynamique et encombré est considéré. La solution présentée adapte l’algorithme bien connu des Probabilistic RoadMaps pour y inclure une anticipation des trajectoires des obstacles dynamiques. Cette solution permet de planifier des mouvements sécuritaires, peu intrusifs et efficaces, jusqu’à la destination. / Industrial applications involving collaborative robots are regarded with a growing interest. These power-limited systems are embedded with additional sensing capabilities, which allow them to safely work around humans and conquer new industrial grounds. The subject of managing redundant, collaborative and mobile systems, for assembly operations within a human-populated aircraft production environment, is addressed in this thesis. From a process perspective, the use of these smaller and less stiff counterparts of the non-collaborative robots comes with new challenges. Their high mechanical flexibility and weak actuation can cause shortcomings in positioning accuracy or for interaction force sustainment. The ever-changing nature of human-populated environments also requires highly autonomous solutions. In this thesis, a formulation of positional redundancy is presented. It aims at simplifying the exploitation of the freedom redundant manipulators have on static-task-fulfilling postures. The associated formalism is then exploited to characterise and improve the deformational behaviour and the force capacity of redundant serial systems. Finally, the subject of planning motions within cluttered and dynamic environments is addressed. An adaptation of the well-known Probabilistic RoadMaps method is presented – to which obstacles trajectories anticipation has been included. This solution allows to plan safe, efficient and non-intrusive motions to a given destination.
|
8 |
The control of selectivity in partial oxidation of hydrocarbonsAworinde, Samson Mayowa January 2018 (has links)
No description available.
|
9 |
Mail-Returns Process Optimization Using Lean Thinking Principles at The Swedish Tax AgencySabri, Yasmine January 2011 (has links)
Lean Thinking has been widely implemented in various industries in the production context. Lately a number of companies in the service sector have developed lean systems within their organisations to improve efficiency, productivity, and quality of their services. In our study we are putting forward an approach for operational excellence using Lean Thinking principals in the public service context. The study was performed at the Swedish Tax Agency and the main process examined was mail-returns handling process, the main goal was to improve business process by eliminating non value adding activities within the mail-returns handling process. A thorough investigation of the Swedish Tax Agency process was carried out, primary (core) business process was identified. We examined the supporting processes and how they can affect the primary process performance, and we defined the activities associated with mail-returns handling process and the costs incurred, which led to having a fact-sheet that examined the entire process. Process mapping for the current state was carried out and Root Cause Analyses was performed. We identified root causes of the problem and process elements with high improvement potential, and we presented an optimisation proposal for the current state. Based on the optimisation proposal, an improvement proposal for the whole process was developed. Some of the notable attributes of this redesigned strategy were substantial cost savings and reduced process time. The proposal was approved by the Swedish tax agency and practical implementation is initiated.
|
10 |
ADDITIVE MANUFACTURING OF PURE COPPER USING ELECTRON BEAM MELTING (EBM)Chinnappan, Prithiv Kumar, Shanmugam, Vishal January 2022 (has links)
Pure copper (Cu) has the properties of high optical reflectivity and surface tarnishing as well as excellent thermal and electrical conductivity. Accordingly, laser-based additive manufacturing (AM) techniques confront various difficulties to produce thismaterial. In contrast, the electron beam melting (EBM) process is paving to become an excellent method to manufacture AM parts from such materials. This is since theelectron beam is not influenced by the optical reflectivity of the material. Furthermore, EBM works under vacuum that can protect the powder material from oxidization. In addition, the high working temperature and preheating process for each layer canensure a uniform heat input and a much lower cooling rate. Hence, the EBM processcan significantly prevent the parts from delamination failure caused by residual stress. Accordingly, this research work is intended to investigate the EBM processability and geometrical freedom/accuracy of EBM made copper components. The 99.95% pure Cu powder with a particle size range of 45-100μm are used to produce samples. All the samples are built with a certain layer thickness of 50μm with altering parameters, including the processing temperature, line offset, focus offset, beamspeed, and beam current. It is found that the processing temperature of 500°C leadsto low density and severe lateral melting/sintering. Accordingly, the temperature is lowered to 450°C, 400°C, 350°C, and 310°C to control the excessive lateral melting. Since dense parts could only be produced above 400°C, this work focuses on developing 400°C processing temperature with different line offset, focus offset, beamspeed, and beam current. However, it is observed that the processing window of the EBM process is rather narrow, too high or too low energy input could both result in a porous part with severe distortion. After many experimental optimizations runs, the combination of the optimum parameters is reached which can deliver parts with over 99% density and a good geometrical stability. After optimization, the benchmark partsare designed and manufactured according to electrical and thermal applications (using the optimum parameters). Afterwards, the corresponding geometrical freedomand accuracy of the copper components made by EBM is assessed and discussed. / Ren koppar (Cu) har egenskaper som hög optisk reflektivitet och ytans anlöning samt utmärkt termisk och elektrisk ledningsförmåga. Följaktligen möter laserbaserad additiv tillverkning (additive manufacturing, AM) olika svårigheter när det gäller att producera detta material. Däremot är elektronstrålesmältning ("electron beam melting", EBM) på väg att bli en utmärktmetod för att tillverka AM-delar av sådana material. Detta beror på att elektronstrålen inte påverkas av materialets optiska reflektivitet. Dessutom arbetar EBM under vakuum som kan skydda pulvermaterialet från oxidering. Dessutom kan den höga arbetstemperaturen och förvärmningsprocessen för varje lager säkerställa en jämn värmetillförsel och en mycket lägre kylningshastighet. EBM-processen kan därför i hög grad förhindra att delamineringsfel orsakade av restspänningar uppstår. Syftet med detta forskningsarbete är därför att undersöka EBM-processbarheten och den geometriska friheten/precisionen hos EBM tillverkade kopparkomponenter. Det 99,95 % rena Cu-pulvret med ett partikelstorleksområde på 45-100 μm används för att producera prover. Alla prover är byggda med en viss tjocklek på 50 μm med ändrade parametrar, inklusive bearbetningstemperatur, linjeförskjutning, fokusförskjutning, strålhastighet och strålström. Det har visat sig att bearbetningstemperaturen på 500°C leder till låg densitet och allvarlig lateral smältning/sintring. Följaktligen sänks temperaturen till 450°C, 400°C, 350°C och 310°C för att kontrollera den överdrivna laterala smältningen. Eftersom täta delar endast kunde produceras över 400°C, fokuserar detta arbete på att utveckla 400°C bearbetningstemperatur med olika linjeförskjutning, fokusförskjutning, strålhastighet och strålström. Det observeras dock att bearbetningsfönstret för EBMprocessen är ganska smalt, för hög eller för låg energitillförsel kan båda resultera i en porösdel med allvarlig förvrängning. Efter många experimentella optimeringskörningar uppnås kombinationen av de optimala parametrarna som kan leverera delar med över 99% densitet och en god geometrisk stabilitet. Efter optimering designas och tillverkas benchmarkdelarna i enlighet med elektriska och termiska applikationer (med optimala parametrar). Därefter bedöms och diskuteras motsvarande geometriska frihet och noggrannhet hos kopparkomponenterna tillverkade av EBM.
|
Page generated in 0.0936 seconds