Orientador: Anselmo Eduardo Diniz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-07-23T21:54:22Z (GMT). No. of bitstreams: 1 Matsumoto_Hidekasu_D.pdf: 9333077 bytes, checksum: 51f227c51103bc62610f0c64d486742b (MD5) Previous issue date: 1998 / Resumo: Neste trabalho procurou-se estudar a viabilidade de se tornear aços no estado endurecido utilizando máquinas de projeto mecânico convencional (sem mancais hidrostáticos e com um certo desgaste) comandadas numericamente, com a finalidade substituir as operações de retificação. Para tanto, usinou-se dois tipos de corpos de prova, de aço ABNT 52100 temperado e revenido com dureza média de 60 HRc (Rockwell C), com ferramentas de corte de PCBN (65% de CBN) e cerâmica mista ('Al IND. 2¿ 'O IND. 3¿ + TiC) encontradas no mercado. Monitorou-se os ensaios via corrente do motor principal e emissão acústica, com a finalidade de determinar o momento da substituição da ferramenta de corte. Após a análise dos resultados, chegou-se às seguintes conclusões: a) é possível substituir as operações de retificação por torneamento com máquina de projeto mecânico convencional, uma vez que se obteve qualidade IT5 e rugosidade menor que Ra = 0,6 'mu¿m, com vidas das ferramentas suficientemente longas para determinadas aplicações; b) os métodos de análise dos sinais de emissão acústica e corrente do motor utilizados, não se mostraram adequados para indicar o momento da troca da ferramenta; c) em geral, a ferramenta cerâmica apresentou vida média maior que a ferramenta de PCBN, porém com uma dispersão também maior / Abstract: The main goal of this work is to study the feasibility of turning hardened steels using a lathe with a conventional mechanical design (without hydrostatic bearings), aiming to replace grinding operations. For this purpose, two kinds of quenched and tempered 52100 steel workpieces were machined, with average hardness of 60 HRc, using PCBN (65% of CBN) and mixed ceramic ('Al IND 2¿¿O IND. 3¿ + TiC) tools. Both the electrical current of the main motor and the acoustic emission were monitored, aiming to automatically establish the moment to replace the tool. After the result analyses, the following conclusions were drawn: a) it is possible to replace grinding operations by turning with a conventional mechanical design lathe, since the workpiece quality obtained was within IT5 and the surface roughness was below Ra = 0.6 ' 'mu¿m, with tool life long enough for this kind of applications; b) the tool life monitoring through acoustic emission and electrical current of the main motor did not show to be suitable to establish the moment to replace the tool; c) in general, mixed ceramic tool had longer average toollife than PCBN tool, but presented larger scatter / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

The thesis is focused on concept of manufacturing technology for rotary part in case of mass production. The main aim was established suitable manufacturing technology for rotary part, choosing lathe machine, cutting tools and creating of NC program. The part of diploma thesis contains configuration of lathe machine in software Sinumerik. Document includes also the basic rules for developing NC program for two channels lathe.

In this diploma thesis, literary research about drilling and coating technology focused on PVD coatings was performed. Furthermore, there is an overview of cutting materials. In the experimental part of the work, the attention is dedicated to tests of twist drills from cemented carbide and high-speed steel materials. For these drills, the feed force Ff and the cutting moment Mc were measured when drilling into austenitic stainless steel. At the end of this work, the technical and economic evaluation of the practical part is presented.

Thesis is focused on ceramic cutting tools in terms of their labeling, composition, use and production of well-known manufacturers cutting tools. Part of this work is comparison of the selected range of manufacturers.

Master´s thesis deals with modern cutting tools for grooving and cutting-off. The main part of this project is analysis of forces in the process of grooving by using two types of chip breaker and their influence on the shape of the chip.

No / Extensive research has been performed to investigate effective techniques, including advanced sensors and new monitoring methods, to develop reliable condition monitoring systems for industrial applications. One promising approach to develop effective monitoring methods is the application of time-frequency analysis techniques to extract the crucial characteristics of the sensor signals. This paper investigates the effectiveness of a new time-frequency analysis method based on Empirical Model Decomposition and Hilbert transform for analyzing the nonstationary cutting force signal of the machining process. The advantage of EMD is its ability to adaptively decompose an arbitrary complicated time series into a set of components, called intrinsic mode functions (IMFs), which has particular physical meaning. By decomposing the time series into IMFs, it is flexible to perform the Hilbert transform to calculate the instantaneous frequencies and to generate effective time-frequency distributions called Hilbert spectra. Two effective approaches have been proposed in this paper for the effective detection of tool breakage. One approach is to identify the tool breakage in the Hilbert spectrum, and the other is to detect the tool breakage by means of the energies of the characteristic IMFs associated with characteristic frequencies of the milling process. The effectiveness of the proposed methods has been demonstrated by considerable experimental results. Experimental results show that (1) the relative significance of the energies associated with the characteristic frequencies of milling process in the Hilbert spectra indicates effectively the occurrence of tool breakage; (2) the IMFs are able to adaptively separate the characteristic frequencies. When tool breakage occurs the energies of the associated characteristic IMFs change in opposite directions, which is different from the effect of changes of the cutting conditions e.g. the depth of cut and spindle speed. Consequently, the proposed approach is not only able to effectively capture the significant information reflecting the tool condition, but also reduces the sensitivity to the effect of various uncertainties, and thus has good potential for industrial applications.

Sandvik Coromant in Gimo is in need of a good quality evaluation method of adhesion for PVD layers; since the existing testing method is located in Sandvik Coromant’s other location in Västberga. Different micro-blasting methods were investigated in this thesis and the results show that some of the methods could potentially be used for evaluation of adhesion, more specifically the wet blasting methods, M1 and M2. The results also show that the investigated geometry received varying adhesion quality when lower etching bias in the PVD process was used and when different sides was pointing upwards in the PVD furnace. Further investigation will have to be made in order to fully implement micro-blasting as a testing method in production.

Titanium alloys are major materials used in the airplane industry, and prospects show that airplane production will double in the next 20 years. Consequently, the demand for cutting tools for machining of titanium alloys will increase. The primary problem when machining titanium alloys is their low thermal conductivity. Crater wear is the main factor limiting tool life, and is generally caused by thermal diffusion due to high temperatures in the tool-chip interface. This master’s thesis was performed in collaboration with Sandvik Coromant, with the prospect to increase knowledge of how diffusion and chip formation influences crater wear progression. The aim was to study tool wear of cutting tools when turning Ti–6Al–4V. This was done by testing two different rake face geometries, both coated and uncoated, at cutting speeds of 30–115 m/min. Diffusion was investigated to learn about the impact it has on crater wear. Chips were examined to investigate chip formation and shear strain. The coated modified rake face insert showed less crater wear only for the initial few seconds of machining. Uncoated inserts with a modified rake face showed higher diffusion rate and faster crater wear progression than did standard inserts. The standard inserts showed twice as long tool life as did the modified inserts. No significant differences in the chip formation mechanism were found between modified and standard inserts. Cracks were found within shear bands that were thinner than usual, which suggest that the generation of cracks allows less shear deformation.

WC-Co cutting tools are widely used in the machining industry. The application of diamond coatings on the surfaces of the tools would prolong the cutting lifetime and improves the manufacturing efficiency. However, direct chemical vapor deposition (CVD) of diamond coatings on WC-Co suffer from severe premature adhesion failure due to interfacial graphitization induced by the binder phase Co. In this research, a combination of hydrochloric acid (HCl) and hydrogen (H2) plasma pretreatments and a novel double interlayer of carbide forming element (CFE)/Al were developed to enhance diamond nucleation and adhesion. The results showed that both the pretreatments and interlayers were effective in forming continuous and adhesive nanocrystalline diamond coatings. The method is a promising replacement of the hazardous Murakami's regent currently used in WC-Co pretreatment with a more environmental friendly approach.<p> Apart from coatings, diamond can be fabricated into other forms of nanostructures, such as nanotips. In this work, it was demonstrated that oriented diamond nanotip arrays can be fabricated by ion beam etching of as-grown CVD diamond. The orientation of diamond nanotips can be controlled by adjusting the direction of incident ion beam. This method overcomes the limits of other techniques in producing nanotip arrays on large areas with controlled orientation. Oriented diamond nano-tip arrays have been used to produce anisotropic frictional surface, which is successfully used in ultra-precision positioning systems.<p> Diamond-like carbon (DLC) has many properties comparable to diamond. In this thesis, the preparation of á-C:H thin films by end-Hall (EH) ion source and the effects of ion energy and nitrogen doping on the microstructure and mechanical properties of the as-deposited thin films were investigated. The results have demonstrated that smooth and uniform á-C:H and á-C:H:N films with large area and reasonably high hardness and Youngs modulus can be synthesized by EH ion source with a low ion energy. The EH ion beam deposition of carbon-based thin films have potential applications such as protective coatings on high capacity magnetic memory disk, for which coating uniformity and smoothness cannot be achieved by the traditional sputtering methods.

WC-Co cutting tools are widely used in the machining industry. The application of diamond coatings on the surfaces of the tools would prolong the cutting lifetime and improves the manufacturing efficiency. However, direct chemical vapor deposition (CVD) of diamond coatings on WC-Co suffer from severe premature adhesion failure due to interfacial graphitization induced by the binder phase Co. In this research, a combination of hydrochloric acid (HCl) and hydrogen (H2) plasma pretreatments and a novel double interlayer of carbide forming element (CFE)/Al were developed to enhance diamond nucleation and adhesion. The results showed that both the pretreatments and interlayers were effective in forming continuous and adhesive nanocrystalline diamond coatings. The method is a promising replacement of the hazardous Murakami's regent currently used in WC-Co pretreatment with a more environmental friendly approach.<p> Apart from coatings, diamond can be fabricated into other forms of nanostructures, such as nanotips. In this work, it was demonstrated that oriented diamond nanotip arrays can be fabricated by ion beam etching of as-grown CVD diamond. The orientation of diamond nanotips can be controlled by adjusting the direction of incident ion beam. This method overcomes the limits of other techniques in producing nanotip arrays on large areas with controlled orientation. Oriented diamond nano-tip arrays have been used to produce anisotropic frictional surface, which is successfully used in ultra-precision positioning systems.<p> Diamond-like carbon (DLC) has many properties comparable to diamond. In this thesis, the preparation of á-C:H thin films by end-Hall (EH) ion source and the effects of ion energy and nitrogen doping on the microstructure and mechanical properties of the as-deposited thin films were investigated. The results have demonstrated that smooth and uniform á-C:H and á-C:H:N films with large area and reasonably high hardness and Youngs modulus can be synthesized by EH ion source with a low ion energy. The EH ion beam deposition of carbon-based thin films have potential applications such as protective coatings on high capacity magnetic memory disk, for which coating uniformity and smoothness cannot be achieved by the traditional sputtering methods.