Vid skärande bearbetning av material för att framställa olika produkter med önskade egenskaper orsakas förslitningar av verktygen som är viktiga att fotografera och analysera för att uppskatta livslängden. Detta kräver erfaren personal med precision som är svår att upprepa där automation kan vara en lösning för att avlasta personal från ett monotont arbete.  Syftet med studien är att bidra med kunskap om hur man kan fotografera förslitningen av verktyg med hjälp av automation och ge förslag på en lösning. För att komma med ett lösningsförslag har en nulägesanalys genomförts med hjälp av observationer och intervjuerhos Sandvik Coromant, litteratursökning för att undersöka vad som gjorts inom området redan och simuleringar.  Resultatet blev ett konstruktionsförslag för en kamerafixtur och cykeltider för att fotografera samtliga förslitningsområden för de testade verktygen i ett simuleringsprogram. Om lösningsförslaget ska implementeras i verkligheten kommer den behöva testas för att med säkerhet kunna fotografera med tillräckligt bra fokus och ljussättning samt att kamerafixturen inte blir för skakig vid rörelse med roboten. / The use of cutting tools in cutting processing cause tool wear which need be analysed and photographed to predict tool life. To analyse the tool wear you need technicians with experience with precision that is hard to repeat in which automation could be a solution.  The purpose of this study is to contribute with knowledge on how you could photograph tool wear using automation and suggest a solution. This was done with a current situation analysis with the use of observation and interview of the technicians at Sandvik Coromant. A literature study was conducted to gather information about what has been done earlier in this field. Later a suggestion on the design of the camera fixture was made and simulated in a simulation program with the robotic cell to ensure it is possible to implement in real life.  The result from the study suggests that the camera fixture with the current robotic cell is capable of automatically photograph the tool wear of the tested tools. If the suggested camera fixture should be implemented in real life it needs to be tested with the camera to confirm it gets good enough focus and lightning inside the CNC-machine. It also needs to be tested so it does not wobble to much with the usage of the robot.

No description available.

The physical and mechanical characteristics of carbon fiber reinforced polymers (CFRP) and Ti6Al4V make them widely used in the aerospace industry. The hybrid structure of CFRP/ Ti6Al4V material has been used in the new generation of aircraft manufacturing. The drilling process of these materials is often associated with unfavorable machining defects such as delamination, burr formation, reduced surface integrity, and tensile residual stresses. These machining defects are attributed to high thermal load, continuous chip morphology, and poor chips evacuation efficiency. Vibration-assisted drilling (VAD) uses an intermittent cutting process to control the uncut chip thickness and chip morphology. VAD has potential advantages include low thermal load, high chips evacuation effectiveness, and longer tool life. This thesis presents an experimental investigation into the effect of VAD machining parameters on the cutting energy, CFRP delamination, surface integrity, geometrical geometry, Ti6Al4V burr formation, induced residual stresses, and tool wear during the drilling process of CFRP, Ti6Al4V, and CFRP/Ti6Al4V stacked materials. Moreover, a kinematics model is developed to link the observed results to the independent machining parameters (i.e., cutting speed, feed rate, modulation amplitude, and modulation frequency). The experimental work covers a wide range of machining parameters using four levels of frequencies (83.3, 125, 1500, and 2150 Hz). The VAD results show up to 56 % reduction in the cutting temperature with a significant enhancement in the CFRP entry and exit delamination, geometrical accuracy, surface integrity, and burr formation. The use of VAD also generates compressive stresses, hence improving the part fatigue life. / Thesis / Doctor of Philosophy (PhD)

The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.

Limitation of conventional machining equipment has become a growing concern over the past two decades due to the demands for greater machining accuracy in today’s manufacturing. The development of micro-machining has therefore attracted significant attention; it signifies the advancement of national economy as well as the level of accuracy manufacturing industry could achieve. While the connection between tool lifespan, cost of machining and throughput is well established, the factor of tool lifespan appears to have more significance since the miniaturization of tool could lead to further performance concerns such as its lack of strength and durability. On the other hand, raising feed rate and spindle rotation speed are the two common approaches for increasing manufacturing throughput. Such approaches tend to cause an increase in the thrust force subjecting the tool to greater stress, which is the main cause of tool wear and even tool failure. Through literature review and preliminary experiments, it was found that spot-drill is often done prior to micro-drilling since it prepares a pre-drill countersunk hole that helps the alignment of tool for subsequent micro-drilling. Although such pre-drill step does improve the micro-drilling operation, the fundamental issue of tool diameter difference still remains. Often the tool used for pre-drill has a bigger diameter than the one for micro-drilling although a significant difference is always something to be avoided. This is because the difference has to be picked up by the tool used for micro-drilling and is directly linked to the wear caused by increased thrust force. In this research the operation of micro-drilling is investigated via mathematical models. Such operation is further broken down into various steps and stages so more detailed description can be achieved. The findings are then further enhanced by simulation based on the 3D model of micro-drilling. Three materials were selected for this research: Al 6061T, Al/Cu metal alloy panel and Carbon fibre reinforced composites. Such a selection enables the study of individual characteristics of different materials and the variation in respective thrust forces. Finally, Conclusions present the summary of the main findings from micro-drilling process analysis based on research and investigation shown in earlier chapters. By combining actual measurements on micro-drilling and mathematic model this research hopefully would improve the understanding towards micro-drilling processes.

<p>Predmet istraživanja ove disertacije predstavlja unapređenje, modelovanje i optimizacija procesa elektroerozivne obrade (EDM) savremenih inženjerskih materijala. Prvo su predstavljene dve inovativne metode: EDM u dielektrikumu sa pome&scaron;anim prahom i EDM sa pomoćnom elektrodom, a zatim i njihova kombinacija. Za generisanje matematičkih modela primenjene su metodologija odzivne povr&scaron;ine i alati ve&scaron;tačke inteligencije. U nastavku su postavljeni optimizacioni procesi određivanja ulaznih parametara sa jednom i vi&scaron;e funkcija cilja koji su re&scaron;eni primenom klasičnih metoda optimizacije. U zavr&scaron;nom osvrtu sprovedena je verifikacija dobijenih modela i optimalnih ulaznih parametara elektroerozivne obrade.</p> / <p>The subject of the research of this dissertation is the improvement, modeling and optimization of the electrical discharge machining (EDM) of advanced engineering materials. First, two innovation methods are presented: EDM in powder mixed dielectric fluid and EDM with assisted electrode and that their combination. The method of response surface and artificial intelligence tools were applied to generate mathematical models. The optimization problems of determining the input parameters with single and multiple target functions are solved by the application of classical optimization methods. Finally, verification of the obtained models and optimal input parameters of electrical discharge machining was carried out.</p>

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The aim of this work is to determine the life of twist drills used for dental implantology when drilling bovine tibia bones and to study the influence of the cutting conditions. The inputs variables considered were the cutting tool material, the feed velocity and the spindle speed. The outputs variables monitored were the number of drilled holes, the workpiece temperature, the thrust force and the tool wear. The tests were carried out in a CNC machine center and the cutting parameters were varied following a 23 experimental design. Three types of uncoated tool materials were used, a martensitic stainless steel (M340/Böhler), an austenitic stainless steel (AISI 316L) and a ceramic (zircon stabilized with Y2O3). The tool lives were expressed by the number of drilled holes considering a limit of the workpiece temperature of 47ºC, used as the end of tool life criterion. The temperatures were monitored by using three thermocouples of the type T (cupper-constantan) inserted in the work material samples, positioned very close to the drill wall. The thrust force was measured with a Kistler rotating dynamometer. A data acquisition board and a computer were used for automation of the measurement system. A mixture of 20% of car radiator fluid and water was applied as coolant (irrigation) with a flow rate of 160 ml/min. The results showed that the martensitic stainless steel outperformed the austenitic stainless steel and the ceramic material. The lowest temperatures and a conformity state at the clinic standard for thrust force values were obtained with the highest cutting parameters (45 mm/min and 2500 rpm). It was observed that the higher feed velocity promoted a temperature drop, while the higher spindle speed decreased the thrust force. / O objetivo deste trabalho é determinar a vida de brocas para implantodontia através de furação em tíbia bovina e estudar a influência das condições de corte utilizadas. As variáveis de entrada do trabalho foram o material de ferramenta, a velocidade de avanço e a rotação. E as variáveis de saída monitoradas foram o número de furos realizados, a temperatura próxima à parede óssea, a força de avanço e o desgaste das ferramentas. Os testes foram executados em um Centro de Usinagem variando os parâmetros de corte seguindo um planejamento experimental 23. Três tipos de materiais de ferramenta não revestidos foram utilizados, um aço inoxidável martensítico (M340/Böhler), um aço inoxidável austenítico (AISI 316L) e um cerâmico (zircônia estabilizada com Y2O3). A vida da ferramenta foi expressa pelo número de furos realizados considerando como critério de fim de vida a temperatura na peça igual a 47ºC. As temperaturas foram monitoradas pelo uso de três termopares do tipo T (cobre-constantan) inseridos no corpo-de-prova e posicionados próximo à parede do furo. A força de avanço foi medida com um dinamômetro rotativo Kistler. Uma placa de aquisição de dados e um computador foram utilizados para a automação do sistema de medição. Uma mistura de 20% de líquido de arrefecimento automotivo foi utilizada como refrigerante (irrigação) a uma vazão de 160 ml/min. Os resultados mostraram que o aço inoxidável martensítico superou o aço inoxidável austenítico e o material cerâmico. Menores temperaturas e um estado de conformidade aos padrões clínicos para valores de força de avanço foram obtidos com os maiores parâmetros de corte (45 mm/min e 2500 rpm). Observou-se que velocidade de avanço alta promove principalmente a queda da temperatura, enquanto a rotação elevada à queda na força de avanço. / Mestre em Engenharia Mecânica

This master's thesis deals with the broaching technology. Theoretical part includes the essay about the technology, tools and machines used for broaching. Theoretical part also describes the analysis of the broaching machine testing. Practical part is focused on the collecting, comparing and analysis of the data. These data have been collected during and after the broaching process. The supplier of the new analysed broaching machine is Stenhoj Hydraulik and the older machine has been made by Arpini. The measurements show that the increased number of broached pieces influence the cutting force and the quality of the surface due to wear of the tool which has been also monitored. The measuring dimension through the ball is almost constant. In the conclusion we evaluated the economical aspect of the results.

The thesis is focused on testing of the cutting tools for machining on five axis machine tools and possibility of implementation of designed experiments in this area. The theoretical section focuses attention on analysis of specific features during five axis machining, including chip cross section and particularity of tool testing under high speed cutting conditions with consideration of dynamic stability of cutting tools. In the thesis force loading of the tool is discussed as well as its measurement process, considering force development caused by tool wear and data analysis. Description of designed experiment and its application to the area of tool testing is included as well. All theoretical predictions are followed by experimental verifying by extensive number of experimental tests, including evaluation of cutting tool condition, influence of hard coatings on cutting power of the tools, etc. For each of testing conditions are designed specific methods of processing of gathered data as well as evaluation of power of the cutting tools. Gathered data were processed by means of statistical evaluation and by statistical methods of designed experiments. The thesis contains also the extensive number of records and analysis, documented by means of light microscopy as well as electron microscopy.

Die Dissertation befasst sich mit der Optimierung des Schneidprozesses bei der Gesteinsgewinnung und der Erarbeitung eines Modells zur Prognose der relevanten Arbeitsgrößen unter Berücksichtigung der Abnutzung der Schneidwerkzeuge. Die Untersuchungen wurden mit Rundschaftmeißeln unterschiedlicher Verschleißzustände durchgeführt. Gegenstand der Untersuchungen waren die von den Schneidparametern abhängigen Größen wie Schneidkräfte, spezifische Energie, Staubmengenanteil und Stückigkeit des gewonnenen Gesteins. Es wurden die Auswirkungen des Meißelverschleißes auf die optimalen Schneidparameter festgestellt, denen beim Einsatz einer Gewinnungsmaschine oder bereits in der Konstruktionsphase des Gewinnungsorgans Rechnung getragen werden sollten.