In machining, tool life is the chief determinant of cost, tool changing frequency, machining efficiency, and machining precision. Application of a proper cutting edge with optimized geometry and suitable edge properties is an effective way to improve tool performance and machining quality. The majority of the reported work is limited to the effect of edge geometry on tool life. In this thesis, cutting edges were prepared using three different methods which were evaluated in terms of tool edge geometry produced, tool surface quality and topographies, edge hardness and residual stresses. Furthermore, the influence of cutting edge preparation techniques on the tool performance of uncoated tungsten carbide cutting inserts with different average cutting edge rounding (S¯), different form factor (K), as well as the different edge preparation methods used underwent experimental investigation through the orthogonal turning of AISI 4140 alloy steel. Results show that the performance of the prepared edge depends on the combined effect of micro-geometry and edge properties. For symmetric edges (K=1), the preferable range for S¯ was found to be 20 µm to 30 µm. Drag finishing was determined to be the best edge preparation process which is able to produce cutting edges with the best performance. The experimental investigations provided guidelines and evidence for future study of the cutting tool life and wear behavior of prepared cutting inserts and PVD-coated carbide inserts. / Thesis / Master of Applied Science (MASc)

The cutter is a fundamental machine tool used extensively throughout manufacturing industries. The performance and quality of the cutter have a direct influence upon the cutting precision, product quality and production rate. Invigorating the domestic cutter industry and establishing a characteristic syscxtem of cutter technology requires that new technology be imported, the constraints of previous experience be overcome, a fundamental research and development capability be developed and new machine tool materials be adopted Two basic approaches exist when considering geometrical models of the cutter. In the first approach, developing new cutters and establishing an optimal set of cutter design parameters is performed in accordance with general cutting theory and the operational functions of the machine tool. Meanwhile, in the second approach, the structural requirements and design parameters of an ideal cutter are used to establish a geometrical cutter model which describes the various contours of the cutter. Developing an accurate geometrical model is an essential prerequisite to realizing the com-puter-aided design of a cutter, and is necessary in order to apply the theory of cutter design and manufacturing theory to the practical manufacturing proc-ess. Moreover, the geometrical model provides the basis for interference checking and manufacturing error analysis. Modern cutter design and manufacturing technologies integrate the results from a diverse range of previous studies, including those performed within the fields of fundamental mathematical theory, computer-aided ap-plication technology, modern design technology, material science and manufacturing technology. In each field, technological progress is reliant upon the development of mathematical theory. In the present study, differen-tial geometry, conjugate theory, engagement relationship theory, coordinate transfer and numerical methods are used to develop a systematic method for the design, simulation, manufacturing and compensation of special revolving cutters. Using the proposed mathematical models, this paper presents real-izable and effective manufacturing models for these revolving cutters. Fur-thermore, the Taguchi method and power signal analysis techniques are em-ployed to investigate the effects of different cutting-edge curves on the cut-ting characteristics of Inconel tool material. The basic research activities performed within the present study can be summarized as follows: 1.The study develops geometrical models for the cutting-edge curves and flute designs of ball-end cutters, truncated-cone ball-end cutters and toroid-cone shape cutters. Applying the inverse-envelope theory, a geometrical model for the cross-section of the grinding wheel used to grind the required helical groove on the cutter is developed. Further-more, the relative positions and velocities of the grinding wheel and workpiece during the NC manufacturing of the cutter are developed and investigated via a process of computer simulation. Finally, a compensation method is developed which resolves the problems of residual revolution surface and localized non-existence of the cutting-edge. The theoretical models and results provide a valuable source of reference for the NC manufacturing of revolving cutters. 2.A series of experiments are performed to investigate the effects of the cutting-edge geometry on the machining performance when machining Inconel 718. The Taguchi method is adopted to determine the set of optimal machining parameters for a variety of cutting-edge types, in-cluding those of the truncated-cone ball-end cutter, the plane type, the S type and the traditional type. The results of these experiments serve as a valuable reference for the automated machining of aero-materials. 3.Study the design and manufacture of the cutting-edge curve, flute sur-face and the coning angle of the grinding wheel for both the rotating burr and the revolving cutter, and discuss the difference of the related geometrical models. Also, the practical cutting-edge curve and the feeding rate of the relative movement for the cutter of the two and half axes processes of the NC machine have been discussed.

<p>This thesis presents the proof-of-concept of electro-erosion edge (EE) honing as a novel edge preparation process that is based on micro-shaping of the cutting edges of metal cutting tools by electro discharge machining (EDM). This process in its simplest form is first applied to straight edge high speed steel cutting tools which results in a four-fold enhancement in the lives of these tools as compared to the sharp unprepared ones. In the next step the EE-honing application is expanded to hone carbide tools of a complex geometry through the innovative idea of using foil counterfaces. Foil counterface ensures the uniform processing of the entire edge length irrespective of macrogeometric complexities such as curvilinear cutting edges and nose radii. By employing this technique, cutting tools of a complex geometry can be prepared with only 13% edge radius variation which is significantly lower than 40% variation reported for conventional edge preparation processes. ED-machining of cemented carbides necessitates the systematic identification of optimal process parameters to preserve process stability and surface integrity. It is shown that by the application of optimal EE-honing process parameters, EE-honed tools achieved the same life of conventionally prepared ones with the same radii. The advent of advanced edge preparation techniques like EE-honing process has led to the emergence of engineered cutting edge microgeometries most of which cannot be represented by a single edge radius value. In this regard, a novel idea of using parametric quadratic curves for comprehensive cutting edge characterization is presented in the next part of this thesis. The free-knot B-spline approximation enables the unique identification of cutting edge separation points from the clearance and rake faces. Subsequent to the edge identification, quadratic parametric polynomials are employed to characterize the cutting edge by four characterization parameters. These parameters are contour-based and easy to visualize. As the final part of the thesis, the EE-honing process is simulated numerically to gain a better insight into the process. Simulation can model the generation of symmetrical and asymmetrical edges and predict edge geometry with the maximum of 14% error.</p> / Doctor of Philosophy (PhD)

No / Wheel structure has a critical influence on grinding performance especially active cutting edge density. Experiments were carried out to find out the relationshipbetween active and staticcutting edge density. It was found that there are many more active cutting edges in grinding than expected based on chip thickness formulae mainly due to wheel deflection in grinding.

Cutting forces and vibrations are essential parameters in the assessment of a cutting process. As the energy consumption in the machining process is directly affected by the magnitude of the cutting forces it is of vital importance to design cutting edges and select process conditions that will maintain high tool performance through reduced energy consumption. The vibrations are often the cause of poor results in terms of accuracy, low reliability due to sudden failures and bad environmental conditions caused by noise. The goal of this work is to find out how the cutting edge and cutting conditions affect the entry conditions of the machining operation. This is done utilizing experimental methods and appropriate theoretical approaches applied to the cutting forces and vibrations. The research was carried out through three main studies beginning with a force build-up analysis of the cutting edge entry into the workpiece in intermittent turning. This was followed by a second study, concentrated on modelling of the entry phase which has been explored through experiments and theory developed in the first study. The third part was focused on the influence of the radial depth of cut upon the entry of cutting edge into the workpiece in a face milling application. The methodology for the identification of unfavourable cutting conditions is also explained herein. Important insights into the force build-up process help addressing the correlation between the cutting geometries and the rise time of the cutting force. The influence of the nose radius for a given cutting tool and workpiece configuration during the initial entry is revealed. The critical angle i.e. the position of the face milling cutter that results in unfavourable entry conditions has been explained emphasizing the importance of the selection of cutting conditions. Finally, the theoretical methods utilized for the evaluation of the role of cutting edge geometry within entry phase dynamics has been explored. This has revealed the trends that are of interest for selection of cutting conditions and cutting edge design.

<p>This thesis investigates how to reach and recruit cutting-edge users to user experience studies. The recruitment of cutting-edge users is difficult since these users usually are not registered in recruitment databases. Cutting-edge users are advanced, early-adopters of technology and sometimes referred to as opinion leaders. Telecom research projects performed at Ericsson Research involve products and services 2-3 years ahead of the market; early-adopters and cutting edge users are therefore an important user group.</p><p> </p><p>To test recruitment methods a user experience study was performed of Ericsson Labs developer portal. Ericsson Labs offers Application Programming Interfaces for mobile and web applications development. Internet marketing theories were used to form a recruitment method. Respondents were recruited from the Ericsson Labs user database and they were contacted individually via email. The users were invited to share their thoughts and ideas about the portal to help improve and possibly influence the direction of the site.</p><p> </p><p>This thesis also assessed different online qualitative research methods applied for user experience research. Online focus groups such as bulletin boards were used to interact with users in addition to individual chat and voice interviews. Performing user experience research on the Internet is a cost-efficient way to interact with users in geographically dispersed areas.</p><p> </p><p>The findings from the study show that recruitment is hard; it is especially difficult to recruit active and conversational respondents from a user database. Providing incentives and using personal communication were shown to be successful strategies to convince users to participate in a study.</p>

This thesis investigates how to reach and recruit cutting-edge users to user experience studies. The recruitment of cutting-edge users is difficult since these users usually are not registered in recruitment databases. Cutting-edge users are advanced, early-adopters of technology and sometimes referred to as opinion leaders. Telecom research projects performed at Ericsson Research involve products and services 2-3 years ahead of the market; early-adopters and cutting edge users are therefore an important user group.   To test recruitment methods a user experience study was performed of Ericsson Labs developer portal. Ericsson Labs offers Application Programming Interfaces for mobile and web applications development. Internet marketing theories were used to form a recruitment method. Respondents were recruited from the Ericsson Labs user database and they were contacted individually via email. The users were invited to share their thoughts and ideas about the portal to help improve and possibly influence the direction of the site.   This thesis also assessed different online qualitative research methods applied for user experience research. Online focus groups such as bulletin boards were used to interact with users in addition to individual chat and voice interviews. Performing user experience research on the Internet is a cost-efficient way to interact with users in geographically dispersed areas.   The findings from the study show that recruitment is hard; it is especially difficult to recruit active and conversational respondents from a user database. Providing incentives and using personal communication were shown to be successful strategies to convince users to participate in a study.

Este trabalho buscou analisar dois materiais para fabricação de navalhas para corte de sucata, de forma a identificar aquele que melhor atenda às solicitações de desgaste dentro de um custo competitivo. Foram realizados testes comparativos de desempenho entre navalhas de aço AISI S1 e SAE 4340, sendo este último o material base utilizado atualmente para a fabricação de navalhas para corte de sucata na Gerdau Aços Especiais Charqueadas. O estudo foi realizado durante o processamento de sucata em uma Prensa Tesoura Harris BSH 1123, sendo que as medições de desgaste foram realizadas nas arestas de corte com a utilização de um relógio comparador. Os resultados mostram que o aço ferramenta, apesar de seu elevado custo e necessidade de maior controle durante o tratamento térmico, é superior em todos os aspectos, apresentando a metade do desgaste do aço ligado quando utilizado nas mesmas condições e trazendo benefícios operacionais como a redução do tempo de troca das navalhas, sendo o material mais indicado para este fim. / Performance trials were carried out to identify the most suitable material for the manufacturing of blades for scrap cutting considering resistance for wear specifications as well as competitive cost. The materials tested were AISI S1 and SAE 4340, being the latter the material currently used for this application at Gerdau Aços Especiais Charqueadas. The study was conducted during scrap processing in a Harris BSH 1123 shearing press. In order to measure the cutting edge wear, a dial gauge was employed. The results show that the tool steel, despite its higher cost and more complex heat treatment process, is superior for all analyzed aspects, presenting less than half of the wear shown by the low alloyed steel when processing scrap under the same conditions. Other additional operational benefits also were obtained as a decrease in the set up time, being the material of choice for this task.

Este trabalho buscou analisar dois materiais para fabricação de navalhas para corte de sucata, de forma a identificar aquele que melhor atenda às solicitações de desgaste dentro de um custo competitivo. Foram realizados testes comparativos de desempenho entre navalhas de aço AISI S1 e SAE 4340, sendo este último o material base utilizado atualmente para a fabricação de navalhas para corte de sucata na Gerdau Aços Especiais Charqueadas. O estudo foi realizado durante o processamento de sucata em uma Prensa Tesoura Harris BSH 1123, sendo que as medições de desgaste foram realizadas nas arestas de corte com a utilização de um relógio comparador. Os resultados mostram que o aço ferramenta, apesar de seu elevado custo e necessidade de maior controle durante o tratamento térmico, é superior em todos os aspectos, apresentando a metade do desgaste do aço ligado quando utilizado nas mesmas condições e trazendo benefícios operacionais como a redução do tempo de troca das navalhas, sendo o material mais indicado para este fim. / Performance trials were carried out to identify the most suitable material for the manufacturing of blades for scrap cutting considering resistance for wear specifications as well as competitive cost. The materials tested were AISI S1 and SAE 4340, being the latter the material currently used for this application at Gerdau Aços Especiais Charqueadas. The study was conducted during scrap processing in a Harris BSH 1123 shearing press. In order to measure the cutting edge wear, a dial gauge was employed. The results show that the tool steel, despite its higher cost and more complex heat treatment process, is superior for all analyzed aspects, presenting less than half of the wear shown by the low alloyed steel when processing scrap under the same conditions. Other additional operational benefits also were obtained as a decrease in the set up time, being the material of choice for this task.

Este trabalho buscou analisar dois materiais para fabricação de navalhas para corte de sucata, de forma a identificar aquele que melhor atenda às solicitações de desgaste dentro de um custo competitivo. Foram realizados testes comparativos de desempenho entre navalhas de aço AISI S1 e SAE 4340, sendo este último o material base utilizado atualmente para a fabricação de navalhas para corte de sucata na Gerdau Aços Especiais Charqueadas. O estudo foi realizado durante o processamento de sucata em uma Prensa Tesoura Harris BSH 1123, sendo que as medições de desgaste foram realizadas nas arestas de corte com a utilização de um relógio comparador. Os resultados mostram que o aço ferramenta, apesar de seu elevado custo e necessidade de maior controle durante o tratamento térmico, é superior em todos os aspectos, apresentando a metade do desgaste do aço ligado quando utilizado nas mesmas condições e trazendo benefícios operacionais como a redução do tempo de troca das navalhas, sendo o material mais indicado para este fim. / Performance trials were carried out to identify the most suitable material for the manufacturing of blades for scrap cutting considering resistance for wear specifications as well as competitive cost. The materials tested were AISI S1 and SAE 4340, being the latter the material currently used for this application at Gerdau Aços Especiais Charqueadas. The study was conducted during scrap processing in a Harris BSH 1123 shearing press. In order to measure the cutting edge wear, a dial gauge was employed. The results show that the tool steel, despite its higher cost and more complex heat treatment process, is superior for all analyzed aspects, presenting less than half of the wear shown by the low alloyed steel when processing scrap under the same conditions. Other additional operational benefits also were obtained as a decrease in the set up time, being the material of choice for this task.