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Master of Agribusiness / Department of Agricultural Economics / Bryan Schurle / The milling of wheat into white flour is a high volume, low margin business. Flour is a commodity. Competition is fierce. Over the past several years, there have been several mergers and acquisitions leading to fewer, but larger flour mills. The number of companies in the flour milling business has diminished as well. Flour sold in small packages on the grocery store shelf is but a small part of the business these days. Most flour is sold to commercial bakers in large bags or bulk trucks. The process of milling wheat into white flour consists of numerous variables within an extensive collection of equipment. It is the job of the miller to minimize the negative impact of these variables or at least hold constant as many of these variables as possible while achieving the best efficiency possible. To lessen the effect of these numerous variables on a large extensive system makes for a well running operation. When efficiency is achieved, a flour milling operation can be a profitable venture. A number of the variables that influence efficiency are affected by the amount of flour storage that a flour mill has. This thesis examines the benefits of flour storage as related to flour process efficiencies in milling. With flour mills operating at large output capacities, it is necessary for a flour mill to have adequate bulk flour storage bins as well as the right amount of warehouse space. Changes from one type flour to another in a flour mill require some time and an abundance of intervention by a skilled operator or miller. Having the proper amount of storage space makes it possible to minimize changes as well as the opportunity to optimize production of each specific flour type that is processed on the mill. To justify capital project money to invest in the proper amount of storage can be a challenge. Warehouse space and bulk flour storage can be expensive, and it is difficult to quantify how theoretical improvements will increase production and quality in the end product of flour. Using regression methods, production data obtained from an average sized commercial flour mill was used to estimate the increase in extraction due to a longer length of run allowed by the addition of storage space. By increasing the time a mill stays on a specific wheat mix to a minimum of twenty hours, there is a theoretical increase in extraction of 1.02 percentage points, resulting in wheat savings of over $500,000 per year. This resulting savings on the raw input material showed that capital expenditures on storage can be justified. A positive net present value and good internal rate of return show that the increased efficiency due to longer lengths of run justified the additional expense of the additional storage capacity. As volatility and the price per bushel of grain continue to increase, having the proper plant infrastructure with regard to storage space is of the utmost importance. Other benefits of storage will be realized as well in the area of flour quality and customer service.

Master of Agribusiness / Department of Agricultural Economics / John A. Fox / The cost of wheat is the largest input cost for a flour mill, and as a result, profitability in wheat flour milling is determined in large part by milling efficiency – i.e., the amount of flour extracted per unit of wheat milled. In this project the objective was to quantify the influence of several measurable variables on flour mill efficiency. Data was collected from two commercial milling units of similar size. Linear regression was then used to estimate the relationship between flour yield and variables measuring grain characteristics and environmental factors. The analysis suggests that increasing ambient temperature and the occurrence of downtime both have a significant negative effect on flour yield. A significant difference in flour yield efficiency was also found between the two mills.

The surface quality is identified by surface roughness parameters. The average surface roughness (Ra) is used in this study, as it is the most commonly used roughness parameter in the industry. A particular curved cavity of a forging die is selected for the experimental study. Different milling methods are tested. The comparison studies are conducted between 3-axes and 5-axes milling, linear and circular tool path strategies and down and up milling. According to the experimental study, appropriate method is determined for the milling of a particular curved cavity of a forging die. The experimental analysis based on design of experiments (DOE) has been employed by considering cutting speed, feed per tooth and stepover parameters. Multiple linear regression technique is used by which a mathematical formula has been developed to predict the Ra values for milling parameters. The results of the mathematical formula are controlled by conducting test experiments and good correlations are observed between the results of the formula and the results of test experiments.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2009. / The titanium alloys have found wide application in the aerospace, biomedical and automotive industries. Soaring fuel prices and environmental concerns are the fundamental drivers that intensify the demand situation for titanium. From a machining viewpoint, one of the challenges companies face, is achieving high material removal rates while maintaining the form and function of the part. The ultimate aim for a machining business remains to make parts quickly. Conventional cutting speeds range from 30 to 100 m/min in the machining of Ti-6Al-4V. Milling this alloy faster however is challenging. Although titanium is becoming a material of choice, many of the same qualities that enhance titanium‟s appeal for most applications also contribute to its being one of the most difficult materials to machine. The author explored the potential for Polycrystalline diamond (PCD) inserts in high speed milling of Ti-6Al-4V, by trying to understand the fundamental causes of tool failure. The objective was to achieve an order of magnitude increase in tool life, while machining at high speed, simply by reducing some of the failure mechanisms through different cutting strategies. Tool wear is described as a thermo-mechanical high-cycle fatigue phenomenon. The capability of a higher material removal per tool life is achieved in the case of PCD inserts compared to Tungsten carbide (WC). The average surface roughness produced was relatively low. The collected chips were also analyzed. The work demonstrated progress over the performance reported in current literature. The work confirms that there is a region where a sufficiently high temperature in the cutting zone may contribute to extended tool life, provided that the tool material can withstand these extreme conditions.

Submitted by PAULO ROBERTO GOMES ALVES null (pauloalves@grad.itapeva.unesp.br) on 2016-03-19T13:35:12Z No. of bitstreams: 1 ANÁLISE DO ACABAMENTO SUPERFICIAL E DA POTÊNCIA CONSUMIDA NA USINAGEM DE FRESAMENTO FRONTAL E CILÍNDRICO TANGENCIAL DA MADEIRA DE EUCALIPTO.pdf: 4159341 bytes, checksum: 1aece2dc81a26f1c87e9e4d59ff0dd54 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-22T13:52:55Z (GMT) No. of bitstreams: 1 alves_prg_dr_guara.pdf: 4159341 bytes, checksum: 1aece2dc81a26f1c87e9e4d59ff0dd54 (MD5) / Made available in DSpace on 2016-03-22T13:52:55Z (GMT). No. of bitstreams: 1 alves_prg_dr_guara.pdf: 4159341 bytes, checksum: 1aece2dc81a26f1c87e9e4d59ff0dd54 (MD5) Previous issue date: 2016-02-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A expansão tecnológica e de mercado da madeira e produtos derivados de madeira industrializada, fazem com que as pesquisas dos processos que envolvem esse material sejam cada vez mais necessárias. O fresamento é um processo de usinagem muito utilizado na indústria, quando se pretende obter um acabamento superficial de qualidade. O presente trabalho teve por objetivo avaliar o desempenho do processo de usinagem de madeiras das espécies de Corymbia citriodora e Eucalyptus saligna, realizado em centro de usinagem CNC, através da análise do acabamento superficial e da potência consumida em operações de fresamento frontal e cilíndrico tangencial. As madeiras foram usinadas de forma tangencial em movimentos concordante e discordante, com profundidade de corte (ap) de 1,0 mm; de forma frontal nas direções perpendicular e paralelo em relação às fibras com (ap) de 5,0 mm. Como condições de usinagem, empregaram-se quatro velocidades de corte (Vc) 5,9; 8,4; 10,9; 13,4 m/s, e quatro velocidades de avanço (Vf) 3,0; 5,0; 7,0 e 9,0 m/min. Utilizou-se para os ensaios uma fresa helicoidal de metal duro maciço com três dentes e diâmetro de 16,0 mm. Foram analisados os resultados de Rugosidade Média (Ra) obtidos através de rugosímetro e potência consumida captada por sensor de efeito Hall, e verificado a integridade das superfícies fresadas através de microscópio eletrônico de varredura (MEV). Os resultados foram analisados pelo software Minitab e tratados estatisticamente através da análise de variância ANOVA e teste de Tukey. Concluiu-se que as melhores qualidades superficiais registradas ocorreram para as menores velocidades de avanço, maiores velocidades de corte, no fresamento tangencial para o corte discordante, no fresamento frontal para o corte paralelo às fibras da madeira. Para a potência média consumida, o menor valor médio ocorreu para as maiores velocidades de corte e a espécie citriodora, obteve melhor qualidade superficial quando comparado com a espécie saligna. / The technological expansion and market wood and derived from wood products industrialized make research processes involving this material are increasing necessary. Milling is a machining process commonly used in the industry, when applying for a surface finish quality. This study was to evaluate the performance of wood machining process of species Corymbia citriodora and Eucalyptus saligna realized out in CNC machining center, through the analysis of surface finish and the power consumed in tangential front and cylindrical milling operations. The woods were used tangentially on down-milling and up-milling movements, cutting depth of 1.0 mm; the front in parallel and perpendicular directions in relation to the fibers with cutting depth of 5.0 mm. As machining conditions, we used four cutting speeds of 5.9, 8.4, 10.9 and 13.4 m/s, and four feed speeds 3 5, 7 and 9 m/min. It was used for testing a helical cutter solid tungsten carbide tool with three teeth and diameter of 16 mm. The results were analyzed Roughness Average (Ra) obtained from roughness and power consumed captured by Hall effect sensor and the integrity of the machined surfaces obtained by scanning electron microscope. These results were analyzed by Minitab software and statistically analyzed by ANOVA and Tukey test. It is concluded that the best recorded surface qualities were obtained for lower feed rates, higher cutting speeds, the tangential milling cutting for up-milling in front for cutting parallel to the wood fibers. For the average power consumed, the lowest average value occurred for higher cutting speeds and the species citriodora, obtained better surface quality when compared with the species saligna. / CAPES: 00.889.834/0001-08

Made available in DSpace on 2014-10-09T12:47:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:49Z (GMT). No. of bitstreams: 1 08280.pdf: 6192071 bytes, checksum: 8b416b6373619895be5ca4e67e02afe0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:96/11795-7

Made available in DSpace on 2014-10-09T12:47:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:08:49Z (GMT). No. of bitstreams: 1 08280.pdf: 6192071 bytes, checksum: 8b416b6373619895be5ca4e67e02afe0 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:96/11795-7

This master thesis is dealing with the design of the frame and working axis of the desktop milling machine. The theoretical part is in the form of a research of the construction of small machine tools. Practical part concerns the idea for a design of the working axis, as well as the design of the frame construction. Practical part also contains the selection of the main and most important components.

This master thesis deals with the constructional design of small CNC milling machine with a sliding table. The first part of the work describes small CNC milling machines currently available on the market. Based on the result of the literature review, the small CNC milling machine was constructed with respect to the currently available trends, including sizing and drawing documentation of the machine.