Dissertations / Theses on the topic 'Quality of castings'
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Dewhirst, Brian A. "Optimization of the heat treatment of semi solid processed A356 aluminum alloy." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-111705-111503/.
Full textKeywords: microstructure; casting; Fluid Bed; Quality Index; Aluminum; A356; heat treatment; SSM; Semi Solid Metal Includes bibliographical references. (p.105-106)
Khaled, Iman. "A study of some of the foundry processing factors influencing the quality of titanium alloy investment castings." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5989/.
Full textPolyakova, Irina. "Untersuchung der kognitiven Modellierung zur Gussstückqualitätsverbesserung." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-130996.
Full textДячок, Дарія Романівна. "Оптимізація технологічного процесу відтворення художніх виробів у металі." Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/43657.
Full textBachelor’s dissertation: 86 pages, 20 figures, 30 tables, 16 references. The purpose of the work – optimize the technological processes of reproduction in metal copies, two works of art, according to the available non metallic originals. Research methodology – production of silicone and plaster molds with different variants of the foundry system; production of plaster-silica molds, their calcination and pouring at different temperatures; control of quality parameters of castings (surface roughness and the presence of casting defects). Results of the work and their novelty – theoretically and practically established the suitability of silicone molds for the manufacture of high-quality castings from low-melting (tin-lead) alloys; the parameters of technological processes of reproduction in metal copies of art products are investigated; made a series of high-quality art castings from tin-lead and copper alloy. The main indicators – as a result of work the optimum parameters of technological processes of manufacturing of art products are defined. A 0.099 kg Viking figure made of tin-lead alloy and 0.073 kg L63 brass was cast, as well as a 0.468 kg Celt statue made of L63 brass. The products do not have casting defects, the surface roughness does not exceed 12,5 microns and 6,3 microns, Areas of application – art and jewelry casting of unique products. Economic efficiency – UAH 214,137.4. Predictive assumptions about the development of the object of study – by analogy with the studied technological processes, the development of plans for the manufacture of similar size and complexity of cast art products in small scale production.
Krejčí, Martin. "Nedestruktivní zkoušení odlitků ozubených kol." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228720.
Full textMahapatra, Rama Ballav. "Mould behaviour and product quality in continuous casting of slabs." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/29214.
Full textApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Cao, Xinjin. "Heat treatment of liquid metal : precipitation and sedimentation processing of liquid Al-11.5Si-0.4Mg alloy." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369168.
Full textBommaraju, Ramaprasad V. "Mold behavior, heat transfer and quality of billets cast with in-mold electromagnetic stirring." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28628.
Full textApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Slagter, Alejandra. "Advanced Inspection of Surface Quality in Continuously Cast Products by Online Monitoring." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70634.
Full textBouhouche, Salah. "Contribution to quality and process optimisation in continuous casting using mathematical modelling." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2009. http://nbn-resolving.de/urn:nbn:de:swb:105-6900128.
Full textBouhouche, Salah. "Contribution to quality and process optimisation in continuous casting using mathematical modelling." Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966041208.
Full textSaleem, Saud. "On the surface quality of continuously cast steels and phosphor bronzes." Doctoral thesis, KTH, Metallernas gjutning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187718.
Full textQC 20160527
Oscilation mark formation during continous casting of steel
Bakir, Berna. "Defect Cause Modeling With Decision Tree And Regression Analysis: A Case Study In Casting Industry." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608427/index.pdf.
Full textPelayo, Chagoya Graciela. "Development of a knowledge based system for the control of 319-Al melt quality and prediction of casting characteristics." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62264.pdf.
Full textPinheiro, Carlos A. M. "Mould thermal response, billet surface quality and mould-flux behaviour in the continuous casting of steel billets with powder lubrification." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq27226.pdf.
Full textДинник, Оксана Дмитрівна, Оксана Дмитриевна Дынник, Oksana Dmytrivna Dynnyk, and А. Морщ. "Розробка методики оцінювання якості продукції ливарного виробництва." Thesis, Видавницто СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/20981.
Full textДинник, Оксана Дмитрівна, Оксана Дмитриевна Дынник, Oksana Dmytrivna Dynnyk, and І. Максименко. "Конструктивні і технологічні чинники формування якості продукції ливарного виробництва." Thesis, Видавницто СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/20948.
Full textBjurenstedt, Anton. "On the influence of imperfections on microstructure and properties of recycled Al-Si casting alloys." Doctoral thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Material och tillverkning – Gjutning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36963.
Full textGenom att återvinna aluminium kan stora energibesparingar göras eftersom återvinning kan förbruka så lite som 5% av den energi som behövs för produktion av primär aluminium. Vid gjutning av högkvalitativa aluminiumprodukter krävs förståelse för defekter i mikrostrukturen och denna kunskap är extra viktig vid användning av återvunnen aluminium, som i regel innehåller mer defekter än primär aluminium. Defekterna består bland annat av Si, Fe och Mn samt oxider. Si behövs för gjutbarhet men kan också initiera brott. Järnrika intermetaller kan ha olika morfologier som generellt påverkar gjutna komponenter negativt. Oxider, som kan utgöra sprickor, är gäckande då de är svåra att kvantifiera. Denna avhandlings syfte är att öka kunskapen om defekter i gjutna komponenter av återvunnen aluminium. Experiment utfördes med avancerad laborationsutrustning så som röntgenfotografering av prover under stelning och dragprovning i svepelektronmikroskop. Experiment utfördes också i industrimiljö. Experimenten visade att kärnbildningstemperaturen steg för primära α-Fe intermetaller med ökade andelar av Fe, Mn och Cr. Resultaten tyder starkt på att primär α-Fe kärnbildas på oxider och att de växer i fyra olika morfologier. Lägre kärnbildningstäthet av α-Fe främjade snabbare tillväxt av kristaller med håligheter men högre kärnbildningstäthet främjade långsammare tillväxt av massiva kristaller. Resultaten visade också att minskad storlek av eutektiskt Si och β-Fe intermetaller ledde till förbättring av dragprovsresultaten, främst brottförlängningen. I legeringar med β-Fe ledde transversellt orienterade intermetaller till makrosprickor vilka kan initiera brott. I legeringar med primär α-Fe var det främst kluster av intermetaller som orsakade makrosprickor. I utmattningsprovning orsakade modifiering av β-Fe till α-Fe förflyttning av sprickinitieringen från oxider och porer till α-Fe, vilket resulterade i en reducerad utmattningshållfasthet. Oxiderna i Al-Si-legeringar fortsätter att gäcka; ingen korrelation mellan försök att kvantifiera oxiderna och draghållfasthet kunde påvisas.
Abdalrahman, Khalid Haroun Mohamed [Verfasser], and Eckehard [Akademischer Betreuer] Specht. "Influence of water quality and kind of metal in the secondary cooling zone of casting process / Khalid Haroun Mohamed Abdalrahman. Betreuer: Eckehard Specht." Magdeburg : Universitätsbibliothek, 2012. http://d-nb.info/1053914369/34.
Full textAbdalrahman, Khalid Haroun Mohamed Verfasser], and Eckehard [Akademischer Betreuer] [Specht. "Influence of water quality and kind of metal in the secondary cooling zone of casting process / Khalid Haroun Mohamed Abdalrahman. Betreuer: Eckehard Specht." Magdeburg : Universitätsbibliothek, 2012. http://nbn-resolving.de/urn:nbn:de:gbv:ma9:1-2685.
Full textRen, Qizheng. "The Application of Gage R&R Analysis in s Six Sigma Case of Improving and Optimizing an Automotive Die Casting Product’s Measurement System." TopSCHOLAR®, 2015. http://digitalcommons.wku.edu/theses/1536.
Full textRozman, Jiří. "Nástroje jakosti pro hodnocení tlakově litých odlitků z Al slitin." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230926.
Full textJaradeh, Majed. "The Effect of Processing Parameters and Alloy Composition on the Microstructure Formation and Quality of DC Cast Aluminium Alloys." Doctoral thesis, KTH, Materialvetenskap, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4205.
Full textQC 20100901
Abdullah, Eva. "Untersuchungen zwischen Belastungen und Belastbarkeiten beim Herstellen tongebundener Formen." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2014. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-151086.
Full textMercklé, Jean. "Stratégies de détection de rupture de modèle appliquées à la recherche et à la localisation des défauts sur des produits sidérurgiques." Nancy 1, 1988. http://www.theses.fr/1988NAN10047.
Full textLin, Chih-Chiang, and 林志強. "The effect of recasting on the quality of pure titanium castings." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/67922730275809799574.
Full text高雄醫學大學
牙醫學研究所碩士班
95
Objective: Molten titanium is highly reactive with common mold materials at elevated temperatures. There has been no paper published related to the recasting of pure titanium. It is probably due to the techniques for precise casting of pure titanium having yet to be developed perfectly. The aims of this investigation were to evaluate the possibility of casting the reused pure titanium by adding unreactive zirconia into the commercial magnesia-based investment material, and further more, to discuss the effects of recasting on the quality of pure titanium castings. Materials & Methods: According to the results of our previous study, an automatic argon-casting machine (Castmatic-S, Iwatani Co.), the trial investment: commercial magnesia-based investment (Selevest CB, Selec Co.) with 5% zirconia powder added, and the pure titanium ingots (CPT Dental titanium, Ohara Co.) were used to cast titanium castings. The initial casting used totally new pure titanium ingots. After casting, the surplus metal (sprue and button) removed from previous castings was carefully cleaned, weighed and combined with an appropriate amount of new ingots to maintain an approximate 50/50 ratio for the next use to produce the second castings. In this investigation, totally two groups were set and each group contained 5 casting MOD-inlay samples and 3 tensile bars. The success rate of complete casting was compared between two groups. The existence of internal porosity in these samples was evaluated with traditional dental x-ray machine. The average marginal discrepancy on a metal die was measured by 3D coordinate measuring machine. We also measured the average surface roughness of castings by surface roughness tester and the change of hardness from the surface to the center of the castings by microhardness tester. An x-ray diffractometer was used to evaluate the interfacial reactivity between the molten titanium and investment. The composition of castings was analyzed by EPMA and the tensile strength was tested by Instron. The data collected was analyzed with two sample t-test (p<0.05); one-way ANOVA/ Tukey-Kramer HSD test (p<0.05) and Pairwise correlations (p<0.05). Result: The success rate of complete casting reached 100% in all groups. Little small internal porosity was found in both groups. The average marginal discrepancy and surface roughness showed no significant difference between two groups (p>0.05). In hardness aspect, the VHN of initial casting samples and recasting ones all tended to decrease from the outer layer to the deeper part. And in both groups, an almost constant VHN, without significant difference, starting from the depth of 220μm down to the center was found. The results of XRD and EPMA analysis bothshowed the dominant component of recasting samples was still α-Ti. And the tensile strength of recasting samples was founded significantly higher than that of the initial ones (p<0.05). Conclusion: Recasting of the pure titanium seems possible and workable. According to the result, we suggest grinding away at least 220μm thickness from the surface of the surplus metal used for repeated casting is necessary. It’s helpful in removing most of the reaction layer covering the samples. In this study, we recast the pure titanium just for one generation and chose the previous trial investment performing best to reduce the level of chemical reactivity. For understanding weather recasting through more than one generation and choosing different commercial investment materials and casting machines will lead to similar results to our study or not, more further investigations are required.
Chen, J. S., and 陳建興. "On the Process Evaluation and Quality Control of the Production of A356 Wheel Castings." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/55179280884423431273.
Full text國立臺灣大學
機械工程學系
85
abstract The production processes of A356 Al-wheels in a specific foundry was evaluated in this study. The process standardization was proposed for that specific foundry based upon the evaluation results. A rotary impeller degasser is currently used for the degassing treatment in the foundry. The degassed melt contained commercially accepted low gas level. However, the gas content of the melt increased gradually with increasing holding time, and the gas content reached an unacceptable level after holding for over 90 minutes. The microstructures of the Al-wheels currently produced in the foundry were thoroughly analyzed with the results indicating that substantial shrinkage porosity was present in the central portion of the rim section of the Al-wheels. Failing to maintain a directional solidification pattern and/or high enough temperature gradients were found to be responsible for the formation of the porosity defect. Modifying the ingate design and employing forced cooling at the central rim section were suggested for the elimination of this porosity defect. Furthermore, the feasibility of reducing the section thickness of the as-cast Al-wheels was evaluated in this study by using tensile and impact properties as the criteria. The results show that the original thickness of rim section of 10- 15㎜ can be reduced to around 9㎜. Also, accompanying with the reduction of section thickness, the T6 solution time at 540℃ can be shortened to 2-4hr from original 6hr and still obtains improved properties.
Chen, Xiang-Yong, and 陳向詠. "The Application of CAE to the Riser Design of High Quality Furan Resin Mold Gray Cast Iron Castings." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/14780256317620260527.
Full text逢甲大學
機械工程學所
91
The objective of this study is focus on the manufacturing of sound furan resin mold castings, by utilizing the foundry-use Computer Aided Engineering (CAE) technology to investigate the influence of riser design on furan resin mold casting. Both simulation and analysis will first be conducted, and then experimental results will also be adopted for comparison and validation. Besides, the hardness distribution of the castings will be tested, so we can know the influences of different riser designs on hardness distribution. The casting shapes are rectangular and circular and with dimensions of 300L×150W×50H mm and 240ψ×50H mm respectively. The pouring material is FC350 and uses the pressurized gating system. First, utilizing Chvorinov’s rule to design the initially riser. The parameter of design including the size and location of the riser. Then building the 3D model and run simulation on foundry-use CAE. At last, pouring all the different riser design castings and compare with the results of CAE simulation in order to investigate the feeding performance and yield of castings. So the technology on optimize the riser design of furan resin mold castings by using CAE simulation will be established. Besides, we choose the risers which are Modulusriser/Moduluscast=1 to do hardness distribution test on top plane and three different sections of the castings and then to investigate the influence of different riser designs on the hardness distribution of castings. The results of this study indicate that:(1)When we use top riser on furan resin mold castings and Modulusriser / Moduluscast>1, we can get sound castings. Using foundry-use CAE could raise the yield of the rectangular castings from 54.9% to 63.7% and the circular castings from 51% to 61%. (2) When we use side riser on furan resin mold castings and Modulusriser / Moduluscast>0.86, we can get sound castings. Using foundry-use CAE could raise the yield of the rectangular castings from 54.9% to 69.3% and the circular castings from 51% to 67.6%. (3)For rectangular castings, the yield of side riser design is 5.6% higher than top riser design. For circular castings, the yield of side riser design is 6.6% higher than top riser design. It means that side riser has better feeding performance and yield than top riser. (4)The regions of the castings that are far away from the riser have higher hardness and the regions that are close to the riser have lower hardness. (5)Top riser design castings have larger hardness variation than side riser design castings. (6)The regions that close to the gate have higher hardness because of higher cooling rate. Besides, set the side riser on the longer side(300 mm length side) of the rectangular castings will have better hardness distribution.
Polyakova, Irina. "Untersuchung der kognitiven Modellierung zur Gussstückqualitätsverbesserung." Doctoral thesis, 2012. https://tubaf.qucosa.de/id/qucosa%3A22898.
Full textLim, Tiong-wei, and 林長偉. "Quality evaluation of AZ91D recycling magnesium alloy in die-casting process." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/86721732930185342635.
Full text國立臺灣科技大學
機械工程系
95
In general die casting factory, large volume of recycling AZ91D magnesium alloy materials were used. Although the recycled manufacturing supplier’s materials meet the standard norm, due to the difference of recycled material used the quality of the die casting parts was influenced widely and the understanding of the causes are limitedly. The main purpose of this research is to understand the influences of recycling AZ91D magnesium alloy to the mechanical property and corrosion resistance of the die casting parts. By choosing three existing reputed brand AZ91D material, to compare with own manufacturing magnesium alloy by using 100% pure magnesium, mixture of 30% pure magnesium with 70% recycling magnesium, mixture of 70% pure magnesium with 30% recycling magnesium, and 100% recycling magnesium. Different testing specimens are made by ingot without fabrication and by die-casting process. Through the analysis of chemical compositions, metallography, tensile strength test, impact test, hardness test and corrosion resistance testing, we try to clarify the characteristic of different combination of magnesium. From the analysis of a large number of test data, we realign that the main compositions like Al, Mn, Zn, Si, Fe, Ni, Cu, etc. which can influence the properties of the die-casting parts. Besides, the pollution of casting oxides, plunger lubrication oil and die release agents during die-casting process and the impurities of flux and residue during smelting are also influence the properties of the parts. To widen the use of all recycling AZ91D magnesium alloy can significantly reduce the manufacturing cost. The results detained in this study can be offered to the recycled material manufacturer and die casting factory for reference.
Shen, Po-Chien, and 沈伯鍵. "An Investigation on Process Quality Improvement for Melt-Casting of Explosive." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/f4pt39.
Full text義守大學
機械與自動化工程學系
107
At present, the production of large-calibre ammunition in military Arsenals is mainly based on the method of melt casting and pressing the explosives. The melt-casting shells must eliminate bubbles and porosity by probing process, and then it is solidified by the cooling process. The purpose of this study is to explore the best filling methods and equipments, and to improve the safety of production processes and equipment, so we can produce smoothly ammunition and reduce ammunition defects and critical factors in the production process. The Old equipment adopts single machine mode and manual operation. All operations that include equipment temperature changes and operating parameters are monitored by operators, which cause unstable process quality. Therefore, this study greatly reduce interference of the human factors and misjudgment and stabilize production quality by replacing the old production process and equipment upgrade, and monitor and set the operating parameters and temperature of the whole line by computer graphics control. At the same time, the equipment adopts the latest international explosion-proof standard IECEx(International Engineering Consortium for Explosive Atmospheres)Certification to improve the operators safety and reduce the risk of any accidents by explosives. This key point of study focuses on the probing depth. The study plans to use Composition B (RDX/TNT 60/40) as the melt-casting explosive and 105mm High Explosive Anti-Tank-Tracer (105mm HEAT-T) as a sample. First, we fix theequipment operating temperature and probing time data in the process of melting and filling. Second, we will study and test on the influence of the depth of the probing for the bubbles and the porosity on the inside of the projectile, and use X-ray to inspect the internal filling defects of the projectile. The result of the best probing depth setting is 75 mm.
LEE, SANG-HUNG, and 李尚紘. "Combining Taguchi and DMAIC approaches to improve aluminum die-casting quality." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87452695735679575096.
Full text國立勤益科技大學
工業工程與管理系
101
The research will combine Taguchi and DMAIC approach, applies to Aluminum Casting so as to establish best parameters module, process improvement and reduce defects. First of all, Casting is the key target as set in order to increase profit and capability for competition as the company is looking for; secondly, we will apply Taguchi Method and combine 5 steps DMAIC of 6Sigma to improve casting process for product of Power Tools Industry than old fashion Try and Error so as to generate cost reduction, improve quality of product and capability for competition in the end. The result of experiment comes up Cpk value dramatically up to 1.89 was 0.11; porosity defect down to 4% was 34%; in terms of cost improvement, the cost saving from quality aspect, the cost saving was $231,000 before implementing the process ,and the cost saving was $1,155,000 after implementing the process. In other words, the best parameters identified through this study do improve the quality of aluminum die casting product.
Wu, Chin-Chang, and 吳錦昌. "A Study of Centrifugal Casting Process Quality Improvement through Six Sigma Approach." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/37277196572016780928.
Full text國立雲林科技大學
工業工程與管理研究所碩士班
100
Casting is the basic of traditional industries, the products widely applies in defense, medicine, steel, cement, petrochemical, electric power, shipbuilding, electronic, machinery, construction and so on. With the globalization of the competitive market, the casting already has been in the open international environment, with the newly-emerging nation develops fast, like the China and Southeast Asia where by the extremely low labor cost superiority caused the greatest impact on the domestic casting industry. The current important topic is how to promote the quality to reduce the cost in face the globalization of the competitive market. The casting divide into both normal and special that the centrifugal casting is one of special methods and can be saving-material, cost-effective. The research applies Six Sigma DMAIC methodology to improve the centrifugal casting process quality. First of all, we identified the critical quality characteristics and evaluate the measurement system, as well as find out the key factors which affect the process and will be optimize by the design of experiment. The result shows the defect rate was reduced 9.4%, effectively improve the process quality, and save production costs.
Kao, Kai-Wei, and 高楷為. "Applying Quality Engineering Methods to Reduce Sand Inclusions in Investment Casting Industry." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/4q54p6.
Full textYang, He-Kai, and 楊賀凱. "Supporting Quality of Service and Mobility Management of Media Casting over Wireless Networks." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/22416354018316039251.
Full text國立臺灣大學
資訊管理學研究所
94
With the widely deployed wireless networks, people have another choice to access the Internet. Therefore, many applications originally provided on wired networks will be used over wireless environment, and multimedia services may be the most popular one in the near future. Delivering multimedia content via multicast in our system saves unnecessary bandwidth wastage and uses limited wireless resource more efficiently. Besides, we compress video content through the adaptive mechanism─scalable video coding according to the video quality users need. However, nodes in wireless networks move anytime and multimedia services may disconnect during handoff, mobility management issues must be considered when providing seamless services. Moreover, real-time applications are sensitive to delay and jitter, Quality of Service (QoS) guarantee need to be provided. We propose “pre-download” scheme in order to pre-construct multicast tree, then MN will not suffer from delay and could always get basic quality content during handoff. Besides, our most important contribution is to design “preemption” scheme. Through the flexibility provided by scalable video coding, we let handoff MN preempt others’ high quality enhancement layer (EL) stream to continually download basic quality content when system resource insufficient. Therefore, we not only favor handoff MN than new arrival one to keep handoff dropping probability low but also utilize the channel. In the end, we propose concept of Full quality Utilization (FU) on admission control unit to manage the resource adaptively. We evaluate both our mobility management scheme and MAC mechanism used to provide QoS on AP (IEEE 802.11e MAC). In the simulation results, our scheme outperforms previous work favor handoff MN by bandwidth reservation on three important performance metrics : utilization、new blocking probability and handoff dropping probability.
Farahani, Alavi Forouzandeh. "In-line Extrusion Monitoring and Product Quality." Thesis, 2010. http://hdl.handle.net/1807/29967.
Full textKumar, Sunil. "An expert system to diagnose quality problems in the continuous casting of steel billets." Thesis, 1991. http://hdl.handle.net/2429/1671.
Full textLungu, Chozi Vincent. "Sustainable production of quality bronze alloy bearings in under-resourced small scale casting facilities." Thesis, 2020. https://hdl.handle.net/10539/31286.
Full textThere are good reasons to keep the local economy of the Copper belt in Zambia growing. Mining consumables and spares that can be manufactured locally such as bronze sleeve bearings is one way of doing so and can benefit local people a great deal. Bronze sleeve bearings of a fit for purpose quality can to a large extent be cast in a small under-resourced foundry (SURF) sustainably. Sustainability implies survival requiring both consistency of output and cost effective selection and use of secondary materials and aiming for products suited to the market. There is therefore a combination of both technical and economic or business questions. The research examined challenges encountered in a typical SURF and sought to offer a solution for cost effectively producing near net size finished bronze sleeve bearings of a composition that achieves the required mechanical properties to replace directly machined varieties. It was aimed therefore to produce fit for purpose sleeve bearing that represented value for money and were cost effective. Within this thesis focus was on one selected candidate bronze foundry, Fox Foundry, situated in Kitwe on the Copper belt of Zambia. To establish the fit for purpose standard, the methodology employed sampling of used bronze bearings considered successful in service from producers and various users. These were tested for chemical, mechanical and metallurgical properties. Experimental castings were made using a permanent mould at Heroes Foundry and the University of Johannesburg. Factors examined for the experimental castings were; temperature, composition, feeding, pouring and mass. A matrix design approach was also employed to optimise on the number of experimental runs required as opposed to using conventional factorial method. The resulting microstructure from each experimental cast was the response variable determined. Test results of the bronze bearings considered successful in service (or OEM) showed irregular microstructure, inconsistent mechanical properties and unacceptable porosity levels. Chemical composition results indicated no control on levels of alloying elements and that had an impact on microstructure and properties dependent on it. Results from experimental castings on the other hand showed that a consistent and optimal microstructure was key in producing a successful bearing as it was the basis of all secondary properties. It can be concluded that a SURF such as Fox Foundry of Kitwe can successfully produce near net sleeve bearing requiring little or no machining providing basic elements of quality in materials and processes are adhered to during production. Whilst SURFs have a low fixed capital base the costs of energy use and metal procurement are an important contributor to competitiveness and should be monitored carefully.. A training programme developed for a typical SURF which when implemented can complement the important measures of material and process quality control and energy conservation to ensure a first time casting fit for purpose ivThe work undertaken in here is dedicated to enterprises and individuals serving in the foundry sector particularly in Zambia contributing tirelessly to improving local economic conditions where they are based.
CK2021
Weijia, Shi, and 施韋嘉. "A Study of Machining Dimension Stability and Casting Defects with Quality Control and Analysis." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/65194510524823018245.
Full text中州科技大學
機械與自動化工程系
103
Abstract In recent years, fraction defective rate of machining company casting products can be broadly divided into three types, (1) castings (2) tool wear (3) poor processing, resulting in defective products. Tangible losses such as heavy industry, painting, renewal or even scrapped and intangible losses that must spend a higher cost with the company. Also delayed delivery will decrease the credibility of the company. In order to enhance and improve the company's casting and machining production quality and efficiency. Studied and analyzed the reasons of defective products by researcher’s machining company on quality control currently. Investigating the company's casting products by statistical analysis could observe improvement measures of the production of castings. The manufacturing process with a variety of test problems caused by bad itemized proposes possible improvement measures. The implementation of the pursuit of quality spirit expected the product is good quality enough, that enhance the company's external competitiveness. The main conclusions of this study are as follows: (1) Casting their possible causes are hard spots, sand holes, lack of materials and crack defects. (2) Tool wear and tear can be caused by fracture and wear. (3) Machining workpiece can be caused by over-cutting and impact. (4) Process capability of horizontal machine processing were higher than the capability of the vertical machine. (5) Process capability of night shift staffs is higher than the ability of process the day shift personnel. Keywords: Machining Dimension Stability, Casting Defects, Quality Control and Analysis
Chien, Chuan-kuo, and 錢傳國. "Building of a Quality System for the Casting Industry:the case of A Mechanical Company." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/65458148022136186362.
Full text國立高雄大學
高階法律暨管理碩士在職專班(EMLBA)
100
Casting industry is called 3K industry in Taiwan because its work circumstance with the potential danger : kitsui、kitanai and kiken (in Japaness) etc. What is the direct way to improve the work circumstance and uncertain quality is that building up a set of good system for improvement and standard flow. Making use of standard flow prevents and improves the potential danger of work circumstance to standardize the process and increase the product quality. Taiwan manufacturing level obtains a good evaluation from the international, specially mechanical equipment. In order to satisfy the customer requirement and maintain the competitiveness, constant improvement is essential for Work hour Reduction, Standard production system and Quality stability advance. This research, consists Quality Program of Machinery Enterprise Company Building of Tainan Taiwan, Fusion MIL-Q-9858A(U.S.A MILITARY SPECTFICATION) Quality Program, MIL-STD-45662 Quality Program, ISO 9001:2008 Quality Program, provides standard flow to Organization operation, Standard for production flow, competitiveness to production quality, and provides the requirement for Domestic and foreign nation armament, Ships component and mechanical equipment process. It takes the huge expense on Building Quality system for Casting industrial. This research takes the case of Building Quality system of A machine corporation(casting), to share with same area of company(casting) and the others for reference to achieve the effect of “To yield twice the result with half the effort” and system building economization.
Chiao, Tsai-Meng, and 蔡孟樵. "The Effect of Dispersion and Defoaming-use Surfactant on the Various Properties of Coating and Casting Surface Quality for the Evaporative Pattern Casting Process." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/62245164386069421779.
Full text逢甲大學
機械工程學所
99
Evaporative Pattern Casting process is a special method of casting. In this process, the coating properties (permeability, adhensive property, crack resistance, erosion resistance, foaming property, and settlement property), have a significant affect on casting surface quality. The objective of this research is to investigate the effect on the coating properties and casting surface quality of adding dispersion-use and deforming-use surfactant to the coating. Firstly, to adopt the coating without surfactant addition (Type1) to investigate the various properties (permeability, adhensive property, crack resistance, erosion resistance, foaming property, and settlement property), and regarded as the comparsion basis for experiment follows. Secondly, by adding different proportions dispersion-use surfactant (0.5%, 1%, 2%, 3%, 4%, 5%), (Type 2 ~ Type 7)to the coating, and to investigate the effect on the coating properties. Thirdly, to use a fixed percentage of dispersion-use surfactants (1%) then they were added with different proportions of deforming-use surfactants (0.01%, 0.02%, 0.03%), (Type 8 ~ Type10), and also to investigate the effect on the coating properties. Finally, by using the previous three type coatings to the actual pouring, and to find the effect of coating types on the surface quality of aluminum alloy casting. The experiment results show that coatings with dispersion-use surfactant have better settlement property and permeability compared to the coatings without surfactant, but have the same crack resistance、erosion resistance、adhensive property ,foaming property. It is regarded as the result of bubble forming effect by the dispersion-use surfactant. Coatings with fixed (1%) dispersion-use surfactant but with different defoaming-use surfactant are compared with coating without surfactant (Type1). When the defoaming-use surfactant increased, the permeability、erosion resistance、settlement property、surface quality became better. Moreover when compared with coatings only with dispersion-use surfactant(Type2~Type7), the erosion resistance、adhensive property、foaming property、surface quality were better. Therefore, the above experiment results show that, coating (Type10) with defoaming-use surfactant (0.03%) and dispersion-use surfactant (1%) is the best coating one .
Huang, Jong-Yu, and 黃炯瑜. "The Effects of Casting Condition on the Dimensional Accuracy and Surface Quality of EPC Process." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/20318581515401146877.
Full text逢甲大學
機械工程研究所
85
ABSTRACT The shape design, making condition , and casting condition etc., of the pattern used in the EPC process, will affect the quality and dimensional accuracy of the casting after poured. So that how to control and how to make the pattern to have the various good characteristics, and how to control the casting condition, in order that the castings have good quality and dimension accuracy after poured, is a very important thing. This study is to probe into the relationships among the shape design and making condition of pattern, the casting condition, and the surface quality and dimensional accuracy of casting. By using the self-designed and manufactured metal dies to produce patterns. And the casting ccoating, vibration time, vacuum degree, pouring temperature, etc. Finally, the onditions include thickness of dimensional accuracy of castings such as surface roughness, surface quality, dimensional accuracy, is concerned. Then we can establish the data base of the optizimed pattern shape design and condition of pattern making, and the casting condition of the castings with good quality. According to the experiment, it is concluded that when the pattern bead is B type, vibration time is longer, vacuum degree is medium, pouring temperature is lower, the casting after poured have better surface quality. When the pattern bead is B type, coating thickness is thicker, vibration time, vacuum degree, pouring temperature are lower, the casting after poured have better dimensional accuracy. When the pattern bead is B type, coating thickness is medium, vacuum degree is higher, vibration time, pouring temperature are lower, the casting after poured have better surface roughness. Keywords: EPC process, Shape design, Pattern making condition, Casting condition, Surface quality, Dimensional accuracy, Surface roughness
Bouhouche, Salah [Verfasser]. "Contribution to quality and process optimisation in continuous casting using mathematical modelling / vorgelegt von Salah Bouhouche." 2002. http://d-nb.info/966041208/34.
Full textMeenken, Thomas. "Analysis of the cooling capacity of water as a function of its quality during DC casting." Thèse, 2003. http://constellation.uqac.ca/750/1/17771752.pdf.
Full textLi, Cheng-Lung, and 李正隆. "The Quality Change Of Molten Aluminum Alloy After Flowing Through The Ceramic Foam Filter In Gravity Casting." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/35553263310024679491.
Full text國立聯合大學
材料科學工程學系碩士班
101
Ceramic foam filter is normally applied in the design of runner system in aluminum gravity casting. The purpose of using this filter is to reduce the velocity of liquid aluminum under the so-called critical gating velocity (e.g., 0.5 m/s for aluminum alloys). After liquid aluminum flows through the foam filter, its static pressure energy is recovered from kinetic energy. The foam filter then can be used for stabilizing the aluminum flow during the filling of mold cavity. The so-called bi-film defect, deriving from the surface turbulence and the entrapment of oxide films during filling process, can thus be avoided. The purpose of this study was to understand the change of profile and melt quality of liquid aluminum after flowing through the foam filter in various runner system designs. Three types of bottom gating runner systems were designed. For observing the flow going through the ceramic foam filter, water analogy method, dyed water filling test in a transparent PMMA material mold, was applied. This flowing profile had been used for the validating the result of computational modeling. In the casting experiment, the aluminum casting sample in the outlet region of the foam filter was sectioned. These specimens then did re-re-melt reduced pressure test (re-melt RPT). The bulk density of the specimens was measured by Archimedes method. By comparing the density differences between the original degassed liquid aluminum and the casting specimens, the contamination of hydrogen of the liquid aluminum after flowing through the filter was measured. "Area normalized" Bifilm index map was proposed to quantify the content of bifilm defects within the casting samples.
Wu, Tsung-Yen, and 吳宗諺. "The Effects of Casting Parameter of the In-mold Process on the Quality of Ductile Cast Iron." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/41600212990785076011.
Full text逢甲大學
機械工程學所
94
The objective of this research is to focus on the manufacturing of furan resin mold ductile cast iron by using the In-mold Process. Casting parameters (addition amount and grain size of nodulant, pouring temperature, the use of cloth filter etc.,) on the mechanical properties (tensile strength , elongation , hardness , impact value etc.,) and metallographic microstructures (nodularity, count of nodule , matrix etc.,) of the ductile cast iron were investigated in this research. The results of this study indicate that : (1) when the addition amount of nodulant is 1.0wt%, the tensile strength is the best 500MPa . When the addition amounts of nodulant are 0.9wt% and 0.8wt%, the tensile strength decreases to 403 MPa and 358 MPa, respectively. The results of tensile strength variation are matched with the metallographic microstructrure results of nodularity and matrix. (2) The grain sizes of nodulant are coarse (>6.35mm), medium (5.66~6.35mm), fine (<5.66mm). With the coarse type, the nodulant can not melt fully;and with the fine type, the molten iron can not enter to the reaction chamer sufficiently;therefore using the medium type of nodulant can obtain the best casting quality. (3) When the pouring temperature is 1500℃, the tensile strength of casting is better than the other two pouring temperature (1470,1440℃). (4) The mechanical properties of using the cloth filter are better than without cloth filter. (5) When the addition amount of nodulant is 1.0wt% and the grain sizes of nodulant are medium (5.66~6.35mm) and the pouring temperature is 1500℃ , the impact value is lowest . (6) When the addition amount of nodulant is 1.0wt% and the grain sizes of nodulant are medium (5.66~6.35mm) and the pouring temperature is 1500℃, the hardness is highest .
Cho, Wang-tzu, and 卓琬姿. "Improving the Process Quality of Investment Casting Industry via Six Sigma-A Case Study of B Company." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/666m6z.
Full text國立雲林科技大學
工業工程與管理系
103
Chinese's manufacturing sector, the most important competition in the market, subject to the same competition, in order to break through price competition, improve product quality and highest priority, therefore, the importance of the quality of attention. Business managers can no longer be past the old norms to judge the quality problem, you should have to face up to the current quality problems, introducing appropriate improvement methods. With the advancement of technology faces major companies, the relative quality of the process followed to enhance, reduce product defect rate has become valued by many businesses. There are good and stable quality control process, product defect rate will therefore reduce, you can really meet customer demand and reduce the company's production costs. In order to get the best quality, enterprises should select the most appropriate quality management system tools to assist businesses stable quality, streamline processes, improve efficiency and reduce the cost of the optimal strategy. And promote Six Sigma, it is to obtain one of the best quality management system tools. By pushing Six Sigma, to achieve enterprise restructuring physique, improve profitability, enhance the quality of the best state. In this study, the case of traditional lost-wax casting industry company B as the main object of study, and to collect the relevant literature, the application of Six Sigma improvement techniques to improve the quality of our products problem cases of sand hole defect rate, in order to improve customer satisfaction, reduce product defect rate and save production costs. The results showed that the use of Six Sigma quality improvement techniques and with the SOP and experimental design, which can effectively reduce product defect rate, 21.38% rate of improvement before adverse reduced to 5.4%, reduced scrap and rework costs by the monthly average of 1.07 million to 430 000, Sigma index increased from 2.3 to 3.1; case if the company continued to apply six Sigma DMAIC approach to improve the overall quality of the process, will enhance the company's competitiveness and cost savings. Keywords: Six Sigma, Investment Casting, defection rate, DOE
Lee, Gumn-Ben, and 李冠伻. "The Influence of Furan's Molding Parameters to the Properties of Mold and the Quality of the Casting." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/70601773757709248212.
Full text國立臺灣師範大學
工業教育研究所
88
Abstract The continuous discovery of new materials and methods has brought about a lot of change in the foundry industry. For instance, the emerging of the Furan No Bake process has gradually not only become the principal method for large-sized castings, but also been accepted extensively in the foundry industry with its characteristics of convenience and cleanliness. In the purposes of finding out the best combination of new sand and reclamation sand, and then reaching the demand of the most economical making process and the best quality for casting, this experiment has attempted to discuss some property changes of Furan No Bake process, such as the influence of mold hardn- Ess, dry compression, dry shear, surface stability, permeability , grainfineness, LOI and so on. Furthermore, by using the ladder molding, pouring gray cast iron and nodular graphite cast iron, the surface quality of casting and micrograph in ladders have been analyzed. Also, with different cooling temperatures being put on ladders, we could acquire the needed information about hardness. The conclusions of the experiment are as follows: The kind of Furan sand uses 100% new sand, 50% new sand plus 50% reclamation sand, 50% reclamation sand. Furan resin uses 0.5%, 1.0%, 1.5% in FNB process, and the time to hardness is set to 60 mins. Uses 1.5% Furan resin. The 100% new sand is the best for hardness, surface stability and permeability, when 1.5% Furan resin is used getting the larger hardness 70. when 1.5% Furan resin is used getting the smaller surface stability 6.54%, when 0.5% Furan resin is used getting the best permeability is 719. When 1.5% Furan resin is used, getting large dry compr- ession of 50% new sand plus 50% reclamation sand. The value is 1.28Mpa. Because the 100% reclamation sand remains the fronter hardness surface, in 60% furan resin, the value of the grain finess is 15.73. The largest value of the L.O.I. is 1.3%, and of the shear is 0.224MPa. The surface quality of casting is best with the combination of 50% new sand, 50% reclamation sand and 1.5% of the furn binder, along with being pouring from the thin ladders. Pouring height uses above 30cm location with many gas holes on the surface. The micrograph of gray cast iron turns out to type C graphite, and type B graphite in thick ladders and thin ones, respectively. The graphite diverges are evenly from the thick ladders and the thin ones’ micrograph are dendrite. The nodularity rating and the nodule count of nodular graphite cast iron are represented in the thin ladders, whcih are higher than those are visible in the thick ones.The micrograph in the thin ladders contains much more Pearlite as well. The hardness of the thin ladders casting is larger than thick ones. The Brinell Hardness Number for thick ladders of gray cast iron is HB105 in average; whereas for thin ladders is HB108 in average. The hardness for thick of nodular graphite cast iron is HB81 in average; whereas for thin is HB87 in average. The Brinell Hardness Number for gray cast iron at thicker side of ladders is larger, HB107.in average.The hardness for gray cast iron, the thinner side is larger on reversed side, HB109 in average. The Brinell Hardness Number for nodular graphite cast iron, reversed side is larger, HB82 in average.The hardness for nodular graphite cast iron, reversed side is larger, HB88 in average.
Camisani-Calzolari, Ferdinando Roux. "Quality prediction and control of continuously cast slabs." Thesis, 2003. http://hdl.handle.net/2263/24938.
Full textThesis (PhD (Electronic Engineering))--University of Pretoria, 2008.
Electrical, Electronic and Computer Engineering
PhD
unrestricted
Pinheiro, Carlos A. M. "Mould thermal response, billet surface quality and mould-flux behaviour in the continuous casting of steel billets with powder lubrication." Thesis, 1997. http://hdl.handle.net/2429/8560.
Full text