Influência da utilização do fluido de corte com adição de grafeno na temperatura de usinagem e formação de rebarba no processo de micro fresamento

As time passed, humanity needed the development of new materials used in various activities. High strength materials such as titanium and Inconel for example, had been studied because they are widely used for implants in biomedicine, as well as their use in aerospace and automotive industries. Because of its thermal and mechanical properties, these materials are considered difficult to machine, promoting a rapid wear of cutting tools, primarily caused by the high temperatures in machining. With the development of new materials has emerged the need of developing new manufacturing processes. One of today’s innovative processes is the micro-manufacturing. Being a process with a defined cutting tool geometry, burr formation is a constant and undesirable phenomenon formed during the machininig process. Being detrimental to the manufacturing process, overspending deburring operations are constantly employed leading to increase the aggregate cost to the manufactured material. Assembly components are also impaired if there is no control of the burr, with consequences including the disposal of components due to the occurence of this phenomenon. This paper presents the study of micro-milling Inconel 718, investigating influential parameters in the formation of burrs in order to minimize the occurrence of this phenome non. Different feed rates per tooth and cutting speed are evaluated, and different cutting fluids with different methods of applying the fluid. Adding graphene to cutting fluids was considered as a variable to be investigated, which is considered an excellent solid lubricant, in addition to increasing the thermal conductivity of the cooling solution (AZIMI; MOZAF FARI, 2015). The micro-milling temperature was evaluated in the present work. It was observed a new phenomenon that causes the machined surface temperature decreases below room temperature when using the solution water + oil. This phenomenon is explained in further chapters. In order to unravel this phenomenon, a new test was proposed and, from this test, it can be concluded, comparatively, which cutting fluid has a better cooling property.Using cutting fluid with different thermal properties has shown influence when analy zing burr formation and reducing machining temperature.

O processo de subjetivação profissional durante os estágios supervisionados em psicologia

Internship is legally understood in Brazil as an overseen educational activity to be developed in a work setting aiming to prepare students to make productive work. According to the federal law number 11.788/08, its main aim is to provide students with competences directly related to the professional activity in a curricular context and to make students develop themselves to live as citizens and to work professionally. With a focus on the professionalizing internship, this research aimed at understanding the professional subjectiveness process of Psychology undergraduates at a public university in the state Minas Gerais during their internship and according to a critic perspective in schooling psychology. The importance of studying psychologist academic training above all the relationship between theory and practice is on the fact that the internship is his/her initial contact with the professional experience itself after four years of theoretical studies. Understood as a way of appropriating and internalizing theoretical and practical dimensions related to the psychologist profession and constructed by the individual, the concept of professional subjectiveness is viewed in the light of the cultural-historical theory, that is, as a result of the human being social constitution. Three Psychology s intern students and their respective overseers were interviewed during their internship period to talk about the process of professional constitution at this phase of the academic training. To do so, oral history proved to be an important methodological support, for it offers a means of giving voice to common people and letting them signify their multi-circumstantial experiences. Results reiterate the presence of subjectivity in the dynamics of an undergraduate training, but they showed that it is permeated by social relations established in his/her personal life story and professional trajectory, stemming from the professional choice, the relationship between intern and overseer, the professional activity properly considered, the psychotherapy, the rules, and from the institutionalization of knowledge, among others aspects that guide the professional subjectiveness during the internship. We verified that the training of a Psychology undergraduate includes multiple determinations that exceed the academic setting because it points out the breaking down of the professional dimensions and personal one dichotomy.