6 resultados para turning
em Repositório Institucional da Universidade Estadual de São Paulo - UNESP
Resumo:
In the current economic scenario, it is important to the incessant search for improvements in production quality and also in reducing costs. The great competition and technological innovation makes customers stay more and more demanding and seek multiple sources of improvement in production. The work aimed to use the general desirability to optimize a process involving multiple answers in machining experiment. The process of cylindrical turning is one of the most common processes of metal cutting machining and involves several factors, in which will be analysed the best combination of the input factors in machining process, with variable response to surface roughness (Ra) and cutting length (Lc) that vary important answers to measure process efficiency and product quality. The method is a case study, since it involves a study of a tool well addressed in the literature. Data analysis was used in the process of doctoral thesis of Ricardo Penteado on the theme using metaheuristicas combined with different methods of bonding for the optimization of a turning process of multiple responses, then used the desirability and analysis tool. Joint optimization by desirability, the method proposed the following combination of input variables, variable cutting speed at 90 m/min ( -1 level), the breakthrough in 0, 12 mm/revol. ( -1 level), the machining depth should be in 1.6 mm (level 1), gum used must be the TP2500 ( -1 level), in abundant fluid (level 1) and laminated material (level 1) to the maximization of the cutting length (Lc) and minimization of roughness (Ra)
Resumo:
We know that the Earth goes through natural cycles that influence its climate and the development of their societies. In recent decades, climate changes and nature began to call world attention to the unbridled exploitation that was carried by the current economic system, causing unrest among scientific, social, political and economic world. The theory that man causes a warming in global temperatures by the release of greenhouse gases made the headlines of major newspapers in the world. From there, it was only a matter of time before environmental concerns became ownership of capital by its excessive appropriation. The fear of nuclear threat by the bombs of Hiroshima and Nagasaki left in fanfare the world, which together with the devastating impact of the exploitation of man and nature gave birth to the Environmental Revolution, a way of trying to change the development patterns of the time and behavior of the population. However, based on the historical form of capitalist domination, this was another measure that was apossada the economic system being transformed into economic value and political exchange. The origin of the conventions, meetings, conferences, parliaments set up to discuss environmental issues, eventually became forums of political and economic talks focused on environmental governance, valuing an asset that is public and everyone. Environmental and climate issue now has a value, thus turning the agenda on the agenda of the United Nations (UN) for its political and economic regulation in the form of global agreement. Given the need for understanding the climate issue, was born the Conference of the Parties (COPs), a regulatory body for climate negotiations, surrounded interests, complexities, conflicts and disagreements between the parties countries, which becomes clear when we analyze their agreements...
Resumo:
Machining processes are one of the most important manufacturing processes in the modern world. In these processes, there are many elements which will influence in the final result of the machined part. Among them, the tools are the principal factor of the rising cost, because its global influence on the process. In aeronautical industries, this can be more evidenced due the need to machining several alloys, between them, aluminum alloys. These alloys have to demonstrate a specific surface finishing to be used in aircraft's fuselage. This kind of industry is one of the segments which is still rising in Brazil, and they are looking viable alternatives in the manufacturing processes of materials, due the need to produce more and more parts and equipment, with costs increasingly reduced. The purpose of this project is the development of a ceramic with differentiated properties. The ceramics were developed using a pre-sintering at 1200 °C, with posterior sintering at 1600°C, and subjected to dry turning process on aluminum alloy 6005. The characterizations showed that ceramics presented with toughness on the center of 1700 MPa and on the surface of 1950 MPa, density 98,5 ±0,14. g/cm³. Ceramics were grinded and faceted, according to ISO standard 1832, and subjected to turning tests in a ROMI lathe brand, model GL240M, using cutting speeds of 500, 800 and 1000 m/min with different feed rates. The machining results showed low occurrence of flank wear to all cutting speeds, and better surface finishing average values of Ra = 0,4935 μm and Rt = 8,112 μm. In general, it could be seen that the tool presents important potential to machining 6005 alloy, and that the use of correct parameters can decrease and/or eliminate subsequent processes, providing important reductions in costs related to the machining processes
Resumo:
The housing issue in Brazil is'nt a recent problem and has been discussed, worked and questioned in the institutional framework, especially with regard to the critical considerations on the topic and urban problems involved. We as milestones in the Brazilian housing policy the National Housing Bank - BNH, 1964, the height of the military regime in Brazil, and the Minha Casa, Minha Vida, in 2009. Both have questions that approach and distance themselves regarding changes in the Brazilian housing policy, where we have the emergence of new forms of knowledge production and housing consumption. Thus we have a number of advances in ways of acquiring social housing, even at different times, it is characterized as capitalist forms of this issue. Thus the spatial process of housing developments arising from these programs reflect the change in space - time that they lay down, turning the urban space of the cities in this case the city of Presidente Prudente / SP
Resumo:
Machining is one of the most commonly manufacturing processes used in the modern world, consuming millions of dollars annually. Because of this, it is crucial for the automotive industry to reduce costs on their heat-resistant alloy machining processes, such as compacted graphite iron (CGI), which has shown an increasing trend of its application in diesel engine blocks, brakes disks, among other applications, due to its superior mechanical properties to gray cast iron. Despite this advantage, its use is still limited due to its difficulty of machining, moreover, cutting tools are displayed as the main factor in increasing the machining cost. Seeking an alternative to a better machinability of CGI, this paper aims to study two types of ceramic tools developed in Brazil, and benchmark their performance by dry turning. For this, were used CGI class 450 and two tools: ceramic of silicon nitride (Si3N4) and alumina-based (Al2O3), with a cutting speed (Vc) of 300, 400 and 500 m / min; feed (f) of 0.2 mm / rev and depth of cut (ap) of 0.5 mm, using three replicates and starting with new cutting edges. The results showed that the Al2O3 tool had the best performance in Vc of 500 m / min, while the Si3N4 tool had the best results in Vc of 300 m / min. This can be explained by the tool of Si3N4 based include soft intergranular phase, called amorphous, while alumina has higher abrasion resistance due to its high refractoriness. The results make it clear that the tools have significant potential for machining of compacted graphite iron, being necessary a strict control of the cutting parameters used
Resumo:
This paper presents a proposal to redesign a physical therapy device for patients with quadriplegia, called parapodium. With the help of the Association of Parents and Exceptional Friends of Guaratinguetá, it was possible to know the currently used device and from this it was conceived changes, allowing the increase of freedom of its central portion, in the down and across positions with mechanical drive . This adaptation is to introduce improvements in the routine of physical therapy professionals and reduce ergonomic problems resulting from repetitive strain during the transfer of patients to the parapodium. In addition to providing greater security for patients who require the use of this equipment. The proposed device comprises: wheel, gearbox and brake systems used for actuation, allowing a degree of turning of the rear post, along an axis which is fixed to the gearbox and the rear structure that permits posterior movement. The mechanism allows the rear post rotate from 0 ° to 90 °. The estimated cost to make the proposal is lower than the marketed parapodiuns, reaching the device's functional expectations