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Title: Numerical models for the assessment of the cylinder-kit performance of four-stroke internal combustion engines
Creator: Panayi, Andreas Petrou
Date: 2009
Collection: Electronic Theses & Dissertations

Title: Ring pack behavior and oil consumption modeling in ic engines
Creator: Ejakov, Mikhail Aleksandrovich
Date: 1998
Collection: Electronic Theses & Dissertations

Title: Dissolution wear : decomposition of tool material, and concentration profile into chip
Creator: Wong, Tim Kong-Ping
Date: 2004
Collection: Electronic Theses & Dissertations

Title: Topographic imaging of tool wear in multilayer coated inserts
Creator: Olortegui-Yume, Jorge A.
Date: 2004
Collection: Electronic Theses & Dissertations

Title: Local tool wear profiles prediction using physics-based models
Creator: Olortegui-Yume, Jorge A.
Date: 2009
Collection: Electronic Theses & Dissertations

Title: Inter-assemblage variability and hunter-gatherer settlement systems : a perspective from the Saginaw Valley of Michigan
Creator: Robertson, James Andrew
Date: 1987
Collection: Electronic Theses & Dissertations

Title: Technomorphology, tool use and site function in the Italian Upper Paleolithic
Creator: Donahue, Randolph E.
Date: 1986
Collection: Electronic Theses & Dissertations

Title: Development and analysis of a fire ring wear model for a piston engine
Creator: Chung, Yooseok
Date: 1992
Collection: Electronic Theses & Dissertations

Title: Local determination of tool wear during turning operations
Creator: Dogruyol, Bulent
Date: 1985
Collection: Electronic Theses & Dissertations

Title: Fundamental tool wear study in turning of Ti-6Al-4V alloy (Ti64) and nano-enhanced Minimum Quantity Lubrication (MQL) milling
Creator: Nguyen, Trung Kien (Of Michigan State University)
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Titanium (Ti) alloy, in particular Ti-6Al-4V (Ti64), has been widely used in a variety of industries such as automobile, aerospace, chemistry, biomedicine and other manufacturing industries because of their desirable and unique mechanical properties. The well-known properties of Ti alloys include light-weight, excellent strength even at elevated temperatures, resistance to corrosion and biocompatibility, which cannot be collectively and comprehensively satisfied by any other alloys in some...
Show moreTitanium (Ti) alloy, in particular Ti-6Al-4V (Ti64), has been widely used in a variety of industries such as automobile, aerospace, chemistry, biomedicine and other manufacturing industries because of their desirable and unique mechanical properties. The well-known properties of Ti alloys include light-weight, excellent strength even at elevated temperatures, resistance to corrosion and biocompatibility, which cannot be collectively and comprehensively satisfied by any other alloys in some applications. In machining of Ti alloys, however, the low thermal conductivity and high hardness exposes cutting tools to high temperatures and cutting forces, which often fracture the cutting tools catastrophically. More importantly, the high chemical solubility of cutting tools causes the high chemical wear leading to accelerated wear on cutting tools, especially when cutting at high speeds. Polycrystalline diamond (PCD) and uncoated carbide tools are the most widely used tool materials for machining Ti alloys. In order to find the main reason for this puzzling behavior, this study revisits the fundamental wear mechanisms in rake and flank faces using PCD and carbide tools in dry turning of Ti64 alloy. The original microstructure of work material was characterized using Orientation Image Microscope (OIM) to explain the correlation of the wear pattern with the observed microstructure. Based on the microstructure and the tool wear patterns, this study claims that wear damages are caused primarily by the heterogeneity coming from not only the presence of both hexagonal closed packed) and  (body centered cubic) phases but also the hard orientation of the phases. In addition to the heterogeneities, the adhesion layer detaching parts of the tool material also contributes to flank wear.This thesis also considers improving tool life by adopting new lubrication techniques. In particular, Minimum Quantity Lubrication (MQL)-based machining process was chosen as it has many merits over not only conventional flood cooling machining but also dry machining. However, few disadvantages make the MQL-based machining process impractical to be adopted in many industrial production settings for more aggressive cutting conditions. At high cutting speeds, for example, a minute amount of oil used in MQL will simply evaporate or disintegrate as soon as the oil droplets strike the tools already heated to high temperatures. Lamellar structured solid lubricants (graphite and hexagonal boron nitride) in a platelet form have been mixed with a typical vegetable MQL oils to mitigate this major deficiency of MQL process. When the mixture of oil and these platelets are applied, the platelets are expected to provide additional lubricity even after the oil droplets have been disintegrated at high temperature. Thus, the enhancement achieved by adding these platelets allows us to expand the processing envelope of MQL. In this research project, a comprehensive study on the effect of the diameter and thickness of platelets was carried out. The results showed that the presence of nano-platelets in the MQL oil decreased the tool wear and improved the tool life compared to traditional MQL with pure oil as well as dry machining 1045 steel and Ti64 not only by providing lubricity at high temperature cutting condition but also by reducing the micro-chipping and tool fracture.
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Title: Tool wear mechanism of difficult-to-cut materials
Creator: Nguyen, Dinh Son (Graduate of Michigan State University)
Date: 2020
Collection: Electronic Theses & Dissertations
Description: "Titanium alloys (Ti), Cast Graphite Iron (CGI), Carbon Fiber Reinforced Plastics (CFRP) and CFRP/Ti Stack are difficult-to-cuts materials which have been extensively used and attracted attention in aerospace, automobile, chemistry, biomedicine, sport and other industrials. These materials have distinguished properties, i.e. Ti is a light-weight metal (4.3 g/cm3 in density) which has a low thermal conductivity, 6.7 W/m.K (50.8 W/m.K for steel), CGI has superior physical and mechanical...
Show more"Titanium alloys (Ti), Cast Graphite Iron (CGI), Carbon Fiber Reinforced Plastics (CFRP) and CFRP/Ti Stack are difficult-to-cuts materials which have been extensively used and attracted attention in aerospace, automobile, chemistry, biomedicine, sport and other industrials. These materials have distinguished properties, i.e. Ti is a light-weight metal (4.3 g/cm3 in density) which has a low thermal conductivity, 6.7 W/m.K (50.8 W/m.K for steel), CGI has superior physical and mechanical properties compared to gray cast iron which is commonly used in the automotive industry, CFRP and CFRP/Ti are light-weight materials with high corrosion resistance, and better mechanical properties. However, the common drawback of these materials is their poor machinability.The first part of this study examines the flank wear mechanism in machining Titanium alloy Ti-6Al-4V (Ti64). Titanium alloys typically do not contain hard inclusion phases typically observed in other metallic alloys. However, characteristic scoring marks, in addition to more distinctive micro- and/or macro-chipping, are ubiquitously observed on the flank faces of cutting tools when machining titanium alloys, which is the direct evidence of abrasive wear. Thus, an important question lies with the nature of the hard phases present in the titanium microstructure. In this work, we present a comprehensive study that examines the microstructural impact on flank wear attained by turning various Ti-6Al-4V bars having different microstructures with uncoated carbide tools. In particular, four samples with elongated, mill-annealed, solution treated & annealed and fully-lamellar microstructures were selected. After turning each sample, the inserts were observed with confocal laser scanning microscopy (CLSM) and analyzed to determine the flank wear behavior in relation to the four distinct microstructures. To do so, the microstructure was examined to distinguish the phases present using scanning electron microscopy (SEM) and the content and topography of each phase was examined to relate to the flank wear and its behavior. The flank wear is also affected by interface conditions such as temperature and pressure, which were estimated using finite element analysis (FEA) models. The temperature and pressure dependence of abrasion models enable the flank wear rates to be estimated for each microstructure and are compared with the experimentally measured wear data.Secondly, the tool wear mechanism of cBN inserts is examined after it is machined. In the literature, it was reported that the presence of a MnS layer at the interface between cBN inserts and the flake graphite iron (FGI) workpiece enhances the machinability of FGI. This work presents the results of our experimental investigation on the differences in the layer formation between CGI and FGI. Straight turning experiments were carried out with both FGI and CGI with various cubic boron nitride (cBN) grade inserts in dry conditions at high cutting speeds (mostly > 400m/min). The evolutions of both flank and crater wear were investigated and assessed. When cutting FGI, speckles of MnS, not as a layer, were present on the cBN inserts, mainly from the MnS inclusions in the FGI microstructure smearing on the cBN inserts. However, the total area of MnS speckles did not increase as the turning process progressed, questioning the formation of the extensive MnS layer protecting the insert. When turning CGIs, both Mn and S were present but not as MnS on the cBN inserts. Therefore, the presence of the MnS layer cannot be claimed as a main reason for the machinability difference between FGI and CGI. However, it is interesting to note that, instead of MnS layer, Al2O3 layer is formed from Al2O3 binder in cBN inserts on the rake side, when cutting at high cutting speeds, which functions as the solubility barrier on the cBN. The machinability difference comes from the fact that the Al2O3 layer formed when turning FGI is much more stable compared to that formed when turning CGI.The third part of the study investigates the effect of ply angle on tool wear when edge-trimming carbon fiber reinforced plastics (CFRP) with particular ply angles of 0, 45, 90, and 135° via up-milling operations. The edge-trimming experiments were conducted with micro-grain tungsten carbide endmills at a constant feed of 0.3 m/min under two cutting speed conditions, 1000 RPM (19.9 m/min) and 6000 RPM (119.7 m/min). A laser confocal microscope was used to measure the flank wear land, edge radius, and worn area in order to evaluate the impact of ply angle quantitatively. A qualitative analysis was also conducted using the scanning electron microscopic (SEM) images of the tool edges to delineate the wear mechanisms as well as the machined surfaces of each ply to characterize the machined surfaces at various cutting distances. The 45° plies resulted in the most extensive flank wear. The 90° plies yielded the worst edge radius rounding and largest worn tool area at both cutting speeds. The SEM images of the machined surfaces enabled determination of the number of exposed fibers and their exposed length, which directly impacts the extent of flank wear. Edge rounding may be related to more aggressive 2-body abrasion on the cutting tools by the broken ends of the carbon fibers interacting with the cutting edge. The 0° ply angle has the least amount of tool wear for all three measurements due to the minimal interactions between the carbon fibers and cutting edge with the delamination in the chip formation.The fourth part of the study investigated the effectiveness of several superhard ceramic coatings on carbide drills when drilling carbon fiber reinforced plastics (CFRP) composite/Ti-6Al-4V alloy (titanium or Ti) stacks. The drilling experiments of CFRP/Ti stack were conducted with diamond-like coating (DLC) coated, alternating layers of the nanocomposite of AlCrN & Si3N4 and TiN or (AlCrSi/Ti)N coated, and uncoated tungsten carbide drills. Tool wear evolution of each drill was measured qualitatively as well as quantitatively using the scanning electron and confocal laser scanning microscopes (CLSM) by interrupting after making a certain number of holes. Based on the drilling experiments, the performance of each coating when drilling CFRP/Ti stack are discussed. Among these coated and uncoated drills, uncoated and DLC coated drills failed before making 5 holes while (AlCrSi/Ti)N coated drills performed the best, making more than 80 holes. The DLC coating, despite of high hardness of DLC coating, does not provide any significant protection especially when drilling Ti layer.Based on the success of nanocomposite in drilling CFRP/Ti stack, the comparative study in turning Ti64 was carried out with of several coatings: BAM coated, AlTiN coated, ZrN coated, (AlCrSi/Ti)N coated, and uncoated tungsten carbide inserts. Those experiments were conducted at three speeds, 61, 91, and 122 m/min, and then tool wear was analyzed quantitatively and qualitatively using advanced SEM and confocal techniques. The results show superior performance of (AlCrSi/Ti)N coated inserts at low speed, 61 m/min; its tool life was at least 3 times longer compared to uncoated carbide tools while the tool life from other coatings did not improve considerably for any cutting the speed.Finally, the last part focused on the wear evaluation of dry, minimum quantity lubrication (MQL) and MQL with nanofluid in turning the most common titanium (Ti) alloy, Ti-6Al-4V, in a solution treated and aged (STA) microstructure. In particular, the nanofluid evaluated here was vegetable (rapeseed) oil mixed with small concentrations of exfoliated graphite nanoplatelets (xGnP). This work focuses on the turning process, which imposes a challenging condition to apply oil droplets directly onto the tribological surfaces of a cutting tool due to the uninterrupted engagement between tool and work material. A series of turning experiments was conducted with uncoated carbide inserts while measuring the cutting forces with a dynamometer under various conditions. The inserts were retrieved intermittently to measure the progress of flank and crater wear using confocal microscopy. This preliminary experimental result shows that MQL and in particular MQL with the nanofluid improve the machinability of Ti alloys even for turning process. However, to attain the best performance, the MQL conditions such as nozzle orientation and the concentration of xGnP must be optimized."--Pages ii-iii.
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Title: Tool wear mechanisms in turning TI-6AL-4V using tungsten carbide and polycrystalline diamond inserts
Creator: Schrock, David James
Date: 2013
Collection: Electronic Theses & Dissertations
Description: The objective of this work is to identify some of the tool wear mechanisms at the material level for the machining of titanium and to provide some understanding of these mechanisms for use in physics based tool wear models. Turning experiments were conducted at cutting speeds of 61m/min, 91m/min, and 122m/min on Ti-6Al-4V, an alloy of titanium, using two different grades of tungsten carbide cutting inserts and one grade of polycrystalline diamond inserts. Three-dimensional wear data and two...
Show moreThe objective of this work is to identify some of the tool wear mechanisms at the material level for the machining of titanium and to provide some understanding of these mechanisms for use in physics based tool wear models. Turning experiments were conducted at cutting speeds of 61m/min, 91m/min, and 122m/min on Ti-6Al-4V, an alloy of titanium, using two different grades of tungsten carbide cutting inserts and one grade of polycrystalline diamond inserts. Three-dimensional wear data and two-dimensional wear profiles of the rake face were generated using Confocal Laser Scanning Microscopy to quantify the tool wear mechanisms. Additionally, the microstructure of the deformed work material (chip) and un-deformed parent material (work piece) were studied using Orientation Imaging Microscopy (OIM). Observations from tool wear studies on the PCD inserts revealed the presence of two fundamentally different wear mechanisms operating at the different cutting speeds. Microstructural analyses of the chip and the work material showed phase dependent tool wear mechanisms for machining titanium. There is a high likelihood of phase change occurring in the work material during machining, with a transformation from the alpha phase to the beta phase. The observed dramatic increase in wear is attributed to a combination of increased diffusivity in the beta phase of the titanium alloy in conjunction with a higher degree of recrystallization of the prior beta phase upon cooling. Results of other observations such as the influence of carbide grain size on tool wear are also discussed.
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Title: A study of tool wear in turning of pure aluminum and drilling of CFRP/titanium stacks
Creator: Wang, Xin
Date: 2012
Collection: Electronic Theses & Dissertations
Description: Tool wear in turning of pure aluminum and drilling of carbon fiber reinforced plastics (CFRP)/titanium (Ti) stacks was investigated due to their importance in modern manufacturing. Although pure aluminum is a ductile metal while CFRP contains brittle carbon fibers, there exist also few important similarities which impact tool wear. For instance, neither work material contains inclusions harder than the tool material. Thus, in both cases, the abrasive wear mechanism, which comes from the hard...
Show moreTool wear in turning of pure aluminum and drilling of carbon fiber reinforced plastics (CFRP)/titanium (Ti) stacks was investigated due to their importance in modern manufacturing. Although pure aluminum is a ductile metal while CFRP contains brittle carbon fibers, there exist also few important similarities which impact tool wear. For instance, neither work material contains inclusions harder than the tool material. Thus, in both cases, the abrasive wear mechanism, which comes from the hard inclusion abrading the tool surface, cannot explain the tool wear. Thus, selecting a tool material solely based on higher hardness does not always provide a longer tool life. This study presents a new explanation for tool wear with these work materials based on our experiments.Fine and coarse grain tungsten carbide-cobalt tools were used for turning commercially pure aluminum. Two types of tool wear were observed on both grades of tools. The first type of wear was due to carbide grain pullout from the surface by adhesion. The abrasion by the pull-out grains was the second type of wear observed. Larger flank wear was observed on the fine grain carbide than the coarse grain carbide despite the higher hardness of the fine grain carbide. The increase in tool wear was explained by the higher probability of a finer carbide grain being pulled out of the matrix compared to a coarser carbide grain.The evolution of Built up edge (BUE) in aluminum turning was studied. It was shown that the BUE decreased after the cobalt binder on the surface of the tool was removed by wear. The influence of oxidation in the formation of BUE is also discussed.In the CFRP/Ti stack drilling study, three types of experiments were carried out: CFRP-only drilling, titanium-only drilling and combined CFRP/Ti stack drilling. The tool wear were investigated on uncoated WC-Co drills, diamond coated drills, AlMgB14 (BAM) coated drills and nano-composite coated drills. There were two significant findings in the CFRP-only drilling study. First, edge rounding was found to be the main tool wear mode for all types of drills. A hypothesis was developed to explain the cause of edge rounding wear in CFRP machining. In metal machining, the wear on the cutting edge is normally prevented by a stagnation zone. However, the fracture-based chip formation in cutting CFRP prevented the formation of a stagnation zone. Rapid wear rounds off the cutting edge. Second, the tool wear measurements in the CFRP drilling experiment did not match the abrasive wear resistance of the drills. Instead, the results from tribo-meter tests correlated well with the tool wear in the CFRP drilling. Therefore, it is believed that tribo-meter testing can be used to rank suitable tool materials for CFRP drilling without carrying out extensive drilling experiments.In Ti-only drilling, edge chipping and coating flake off were the dominant wear types. The diamond coating, which is effective in drilling CFRP-only, flaked off due to Coefficient of Thermal Expansion (CTE) mismatch and graphitization. Finally, it was found that CFRP/Ti stack drilling was mainly a combination of the gradual wear in CFRP drilling and the coating flaking off and edge chipping in Ti drilling. Study of the individual work materials provided understanding of the combined wear mechanisms. This allows for future improvement of tools used in the machining of CFRP/Ti stack drilling.
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Title: Tool wear analysis in various machining processes and study of minimum quantity lubrication (MQL)
Creator: Park, Kyung Hee
Date: 2010
Collection: Electronic Theses & Dissertations
Description: The tool wear analysis on the multilayer coated carbide inserts in turning and milling of AISI 1045 steels was performed using advanced microscope and image processing techniques. In turning process, the flank wear evolution, surface roughness and groove sizes on the coating layers were analyzed to understand the flank wear mechanism(s) involved. The dominant wear phenomenon was abrasion and, after carbide was exposed, adhesion took over. For flank wear prediction, 2-body abrasion model was...
Show moreThe tool wear analysis on the multilayer coated carbide inserts in turning and milling of AISI 1045 steels was performed using advanced microscope and image processing techniques. In turning process, the flank wear evolution, surface roughness and groove sizes on the coating layers were analyzed to understand the flank wear mechanism(s) involved. The dominant wear phenomenon was abrasion and, after carbide was exposed, adhesion took over. For flank wear prediction, 2-body abrasion model was used along the interface conditions from finite element (FE) model, which provides the temperature on the cutting tool. In a face milling study, multilayer cutting tools, double (TiN/TiAlN) and triple (TiN/Al2O3/TiCN) layered coated carbide, processed by physical vapor deposition (PVD) and chemical vapor deposition (CVD) respectively, were evaluated in terms of various cutting conditions. Similar to the turning case, abrasion was found to be the most dominant tool wear mechanism in milling. Edge chipping and micro-fracture were the tool failure modes. Overall, the double layer coating was superior to the triple layer coating under various cutting conditions due to the benefit coming from the coating deposition processes themselves. On the other hand, drilling of carbon fiber reinforced polymer (CFRP)/titanium (Ti) stacks has been performed using carbide and PCD drills. The dominant wear mechanism for carbide tools was the abrasion by fibers in CFRP drilling and Ti adhesion, covering entire cutting edge while the main wear behavior of PCD drill was edge chipping. The adhesion of titanium seems to be the most important factor in tool wear and micro-chipping because the adhered titanium seems to be brushed away by the fibers in CFRP when drilling the composites, which accelerates tool wear in drilling of stacks. PCD drills have more wear resistance than carbide drills only in terms of the flank wear land. However, due to the inherent brittleness of PCD drills, chipping was observed at the tool edge when drilling titanium. Finally, for a better understanding of Minimum Quantity Lubrication (MQL) and its effective use in practical industrial applications, MQL parameters such as droplet sizes, the droplet distributions and wetting angles of various types of lubricants were investigated. The measurement method of droplet size and distribution was proposed using confocal laser scanning microscopy (CLSM) and wavelet transform. In addition, the empirical droplet size estimation equation was also introduced for extremely small droplets, which are difficult to be measured. The distribution of the droplets has been also studied to determine the MQL optimal nozzle-workpiece distance and the nozzle discharge pressure. To extent the applicability of MQL to more aggressive machining conditions, a potential additive to MQL lubricant, which is a mixture of exfoliated nano-graphene particles and vegetable oil, have developed. Oil based lubricant, especially nano-enhanced vegetable oil, showed a better wettablility and tribological behavior. MQL-ball milling tests with nano-graphene enhanced lubricant were performed to show a remarkable performance improvement in reducing both central wear and flank wear as well as edge chipping.
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