Tool Material Selection Research Articles

Modeling the effect of compacted graphite iron microstructure on cutting forces and tool wear

The characteristic mechanical (and physical) properties of compacted graphite iron (CGI) are contingent upon its unique microstructure. To model and simulate compacted graphite iron (CGI) in machining meaningfully, the metal's microstructure should not be overlooked throughout the process.In this work, modeling the microstructure of CGI in machining is implemented using a commercial general-purpose finite element package; ABAQUS/EXPLICIT (v 6.8). Segmental chip is modeled by the introduction of a new chip formation modeling technique. The cohesive zone elements are used to model the graphite–matrix interface. The methodology pursued to implement the finite element model is based upon an iterative interaction between comprehensive metallurgical investigations and finite element formulation of the problem in hand. Metallurgical examination of fractured and machined chips is not solely performed as a tool of validation, but rather as a tool of modeling.Vital model inputs are based upon metallurgical investigations of fractured CGI samples and machined chips. Subsequent comparisons between (1) simulated chips and (2) cutting forces trends, to experimental findings are used to validate the finite element model. The effects of cutting forces and temperature are comprehensively investigated to elaborate on their effects on tool wear. The effect of cutting speed (and feed rate) on cutting forces and cutting temperature determine the type of tool wear in CGI machining. Variation of the cutting speed triggers the deviation from mechanical to thermal tool wear mechanisms. This behavior is captured through the investigation of the cutting forces and simulated temperature trends in the finite element model. Other important findings are documented to serve as an optimization technique for tool material selection and machining conditions of compacted graphite iron (CGI) for which automotive and locomotive industries are of significant need to date.

Cutting tool material selection using grey complex proportional assessment method

In today’s metalworking industry, many types of materials, ranging from high carbon steel to ceramics and diamonds, are used as cutting tools. Because of the wide range of conditions and requirements, no single cutting tool material meets all the needs of machining applications. Each tool material has its own properties and characteristics that make it best for a specific machining application. While evaluating a cutting tool material for a machining operation, the applicability is dependant on having the correct combination of its physical properties. Thus, it is extensively important to select the most appropriate cutting tool material with the desired properties for enhanced machining performance. This paper considers an exhaustive list of 19 cutting tool materials whose performance are evaluated based on ten selection criteria. The grey complex proportional assessment (COPRAS-G) method is then applied to solve this cutting tool material selection problem considering grey data in the decision matrix. Synthetic single crystal and polycrystal diamonds emerge out as the best two choices. Oil quenched tool steel (AISI O2) and powder metal tool steel (AISI A11) may also be used as the suitable cutting tool materials. Sialon and sintered reaction bonded silicon nitride are the worst chosen cutting tool materials.

Improved tool wear properties in sheet metal forming using Carbide Steel, a novel abrasion resistant cast material

This work presents a comparative study regarding wear behavior between a novel abrasion resistant cast iron, “Carbide Steel” and a number of conventional tool materials frequently used in the automotive industry. Carbide Steel is basically a high-Cr white cast iron heavily alloyed with cemented carbide. The high chromium content and additional alloying elements like WC, TiC or NbC results in a material containing a large portion of hard, wear-resistant carbides with a composition different from conventional white irons normally used in wear applications. Characteristic properties for the material are: superior as-cast properties, improved wear resistance and hardness. The as-cast hardness of Carbide Steel is comparative to hardened steel but depending on desirable properties of the wear part the alloying content can be varied within a wide range. An interesting aspect of the material is potential for sustainable manufacturing, due to the fact that the critical alloying elements are added in the form of recycled carbide inserts. The experimental work was carried out in a U-bending test equipment to simulate conditions in a stamping process. One type of sheet material was used and seven different conventional tool materials were evaluated. The selection of tool materials ranged from white cast irons to tool-steels and powder steels. The wear patterns were analyzed and expressed in percentages of reduction of weight of the test specimens, galling tendency and temperature variations during the experiments. All parameters were correlated to the number of strokes. The press force was measured and a friction coefficient was calculated. An important conclusion from the experimental work is that Carbide Steel has a significantly higher wear resistance compared to the other conventional tool materials evaluated. Galling is also significantly reduced when using Carbide Steel. The volume part of carbides and the relative size of the same play a significant role in the process leading to less galling and wear, when using Carbide Steel as a tool material.

Architects’ considerations while selecting materials

When selecting materials for a building, architects are guided not only by structural and functional requirements but also consider aspects relating to the sensory effect and experience. The material information and selection tools available for architects are, however, often dominated by technical material data without providing systematic knowledge on experience aspects of materials. Hence, no comprehensive material information is available to the architect. This paper aims to identify, organize, and map the different elements contributing to the material selection process for buildings, and generate a schematic of basic material selection considerations for an architectural design project. The paper discusses the findings of three studies investigating architects’ materials selection process at different stages of the design process. As a result, architects’ materials selection considerations are identified and organized according to four categories: Context, Manufacturing, Material aspects, and Experience. These considerations are discussed in relation to each other as well as in reference to material selection research in architecture and industrial design. The results confirm the importance of aspects relating to experience in an architectural material context and emphasize the need for further research and information on the topic of material experience in architecture.

Review: friction stir welding tools

Friction stir welding (FSW) is a widely used solid state joining process for soft materials such as aluminium alloys because it avoids many of the common problems of fusion welding. Commercial feasibility of the FSW process for harder alloys such as steels and titanium alloys awaits the development of cost effective and durable tools which lead to structurally sound welds consistently. Material selection and design profoundly affect the performance of tools, weld quality and cost. Here we review and critically examine several important aspects of FSW tools such as tool material selection, geometry and load bearing ability, mechanisms of tool degradation and process economics.

Belief network-based acoustic emission analysis for real time monitoring in CIM environment

Machining is the most important part of the manufacturing process. Machining deals with the process of removing material from a work piece in the form of chips. Machining is necessary where tight tolerances on dimensions and finishes are required. The common feature is the use of a cutting tool to form a chip that is removed from the work part, called Swarf. Every tool is subjected to wear in machining. The wear of the tool is gradual and reaches certain limit of life which is identified when the tool no longer produce the parts to required quality. There are various types of wear a single point cutting tool may be subjected to in turning. Of these, flank wear on the tool significantly affects surface roughness. The other types of tool wears are generally avoided by proper selection of tool material and cutting conditions. On-line surface roughness measurements gained significant importance in manufacturing systems to provide accurate machining. The acoustic emission (AE) analysis is one of the most promising techniques for on-line surface roughness monitoring. The AE signals are very sensitive to changes in cutting process conditions. The gradual flank wear of the tool in turning causes changes in AE signal parameters. In the present work, investigations are carried for turning operation on mild steel material using high speed steel (HSS) tool. The AE signals are measured by highly sensitive piezoelectric element; the on-line signals are suitably amplified using a high gain pre-amplifier. The amplified signals are recorded on to a computer and then analyzed using MATLAB. A program is developed to measure AE signal parameters like ring down count (RDC), signal rise time (SRT) and root mean square (RMS) voltage. The surface roughness is measured by roller ended linear variable probe, fitted and moved along with tool turret on a CNC lathe machine. The linear movements of probe are converted in the form of continuous signals and are displayed on-line in the computer. This paper proposes to monitor tool wear and surface roughness by acoustic emissions using belief networks. The feature vectors of AE analysis and machining time were used to train the network. The overall success rate of detecting tool wear and surface roughness is high with low error. Key words: Acoustic emission, surface roughness, turning, belief network.

Tool development based on modelling and simulation of hot sheet metal forming of Ti–6Al–4V titanium alloy

In the aero engine industry alternative manufacturing processes for load carrying aero engine structures imply fabrication. The concept of fabrication involves simple forgings, sheet metals and small ingots of e.g. titanium alloys which are welded together and heat treated. In the concept phase of the product development process, accurate evaluations of candidate manufacturing processes with short lead times are crucial. In the design of sheet metal forming processes, the manual die try out of deep drawing tools is traditionally a time consuming, expensive and inexact process. The present work investigates the possibility to design hot forming tools, with acceptable accuracy at short lead times and with minimal need for the costly die try out, using finite element (FE) analyses of hot sheet metal forming in the titanium alloy Ti–6Al–4V. A rather straightforward and inexpensive approach of material modelling and methods for material characterisation are chosen, suitable for early evaluations in the concept phase. Numerical predictions of punch force, draw-in and shape deviation are compared with data from separate forming experiments performed at moderately elevated temperatures. The computed responses show promising agreement with experimental measurements and the predicted shape deviation is within the sheet thickness when applying an anisotropic yield criterion. Solutions for the hot forming tool concept regarding heating and regulation, insulation, blank holding and tool material selection are evaluated within the present work.

Implementation and Evaluation of an Image Analysis System for Determining Viability of Pollen Grains in Temperate Rice

Geographical and climatic factors limit the production of temperate rice (Oryza sativa L.) in Chile. Large thermal fluctuations of air and water temperatures affect the viability of pollen, causing high levels of spikelet sterility (”blanking”), resulting in reduced yields per hectare. Counting viable pollen grains, at the time of anthesis, may allow determining, ahead, whether there will be yield losses by spikelet sterility; besides, knowing the potential pollen viability serves as a powerful tool for material selection in breeding programs, and for determining which management factors may influence ”blanking”. If performed manually, counting total and viable pollen grains can be extremely tedious, producing highly variable results. The present work had for objectives to develop and evaluate a system, based on imagery analysis, for counting total and viable pollen in rice anthers. At the time of anthesis, three panicles were collected from plot treatments of two field experiments in which the effects of different management factors (variety, water height, N rate, and spatial arrangement) on spikelet sterility were evaluated. Two spikelets and four anthers were sampled from each panicle; pollen grains were extracted from anthers and photographed. Manual and digital counts were made on the images to determine total and viable pollen. Digital count was performed with the software SigmaScan Pro, setting some parameters on the imagery before counting. Precision and accuracy of the digital method were estimated. The results indicated that the digital pollen count showed a very good precision and accuracy and could be used to estimate pollen viability, and as a response variable to compare management treatments.

Tool Wear Prediction when Maching Ti6Al4V Using Different Tool Materials

The tool life is different when using different tool materials machine Ti6Al4V under different cutting conditions. Based on the experiments of cutting Ti6Al4V using different tool materials, the tool wear prediction model is established with BP neural network theory. The wear prediction model is verified by further experiments. The results show that there is a valid prediction interval when using BP neural network predicts tool wear. When the cutting speed is in the vicinity of the training sample data, the relative error of the tool wear prediction and experimental results is less than 10%, which can meet the actual production. The tool wear prediction model is helpful for cutting tool material selection, cutting speed optimization and predomination the time of changing tool accurately when cutting titanium alloy.

Electrochemical Spark Micromachining: Present Scenario

The electrochemical spark process, alternately known as the electrochemical discharge process or sparkassisted chemical engraving process, is emerging as a viable machining process. Though it emerged accidentally, has been found to be useful in the machining of wide variety of materials. The process has received global attention mainly because of its applicability to electrically non-conducting materials. Many researchers have investigated the process, especially its spark formation mechanism, its hydrogen gas evolution together with its bubble formation mechanism, and its material-removal mechanism. With our intensive experimental research investigations, we have tried to understand the underlying phenomena during the process. With this information, we announce its application to the micromachining of a wide range of materials, including copper, tungsten, molybdenum, glass, quartz, and silicon, among others. With the careful design of the experimental setup, tool material selection, power supply selection, and the in-house development of an automated 5-DOF machine, we have been able to achieve micro-level machining, deposition, and surface modification. These phenomena can be achieved simultaneously or one at a time. Simultaneous surface treatment, micromachining, and copper deposition on a silicon wafer, are achieved using this process. A novel metrology technique based on replica making using polymeric material is devised to measure the depth and width of the microchannels produced using ElectroChemical Spark MicroMachining (ECSMM). This metrology technique is prominent in the study of surface morphology.

W-05 Significance of Materials Selection Tools in Undergraduate Engineering Education

W-05 Significance of Materials Selection Tools in Undergraduate Engineering Education

Selection of Tool Materials and Cutting Parameters Optimization for Turning Nickel-Based Powder Metallurgy Superalloy

Powder metallurgy (PM) nickel-based superalloy is regarded as one of the most important aerospace industry materials. A series of turning tests in a wide range of speeds with different inserts were carried out to select the proper tool material. Then, the effect of cutting parameters on the cutting force, cutting temperature and tool wear was investigated for the selected insert. The effect of cutting parameters on the tool wear was examined through SEM and TEM micrographs. The experiential functions of tool life, cutting force and cutting temperature were developed. Finally, the cutting parameters in PM nickel-based superalloy dry turning were optimized based on tool life-efficiency contour analysis. The present approach and results will be helpful for understanding the machinability of PM nickel-based superalloy during dry turning for the manufacturing engineers.

A New Multipulse Technique for Probing Electron Trap Energy Distribution in High- $\kappa$ Materials for Flash Memory Application

A new discharge-based multipulse technique has been developed in this paper, which overcomes the shortcomings of the existing techniques, such as the charge pumping, charge injection and sensing, and two-pulse C-V techniques. It captures the energy signature for electron traps across high-κ materials and can be a useful tool for material selection during technology development. Trap distributions in HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , AI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , and HfAlO have been compared to identify the effects of material variation. It is observed that hafnium gives the shallow traps at about 0.45 eV above the silicon conduction band bottom (Si E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CB</sub> ), and the deep traps at 0.8 eV below the Si E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CB</sub> are caused by aluminum. HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> combines the features in HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and AI <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . A peak near the Si E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CB</sub> has been observed in all the three materials.

Diffusion and oxidation wear of PCBN tool based on thermodynamics

The rules of diffusion wear and oxidation wear for PCBN cutting tools were analyzed based on thermodynamics theory. Dissolution concentrations in typical normal workpice materials of PCBN tool material at different temperature were then calculated. Diffusion reaction rules in high temperature were developed and analyzed using the Gibbs free energy criterion. The machining tests were conducted using the PCBN tools at different cutting speeds of 50, 95,100 and 180 m/min, feed of 0.1, 0.2 and depth of cut of 0.1, 0.8, 1, and 1.5 mm respectively on a PUMA300LM numerically-controlled lathe. It was found that the theoretical results were uniform with the experimental data, and the results will provide useful references for tool material design and selection.

Experimental Study on Wear Mechanism of Cutting Tool and Cutting Temperature in High Speed Machining Superalloy

Two kinds of Cemented carbide tools were used to turn Iron-based superalloy GH2132 at 80m/min-210 m/min under dry cutting condition. Infrared thermometer was used to measure cutting temperature, Tool wear was observed by SEM, and oxygen element distribution of tool surface was analyzed by EDS. Adhesive wear oxidation wear were the main wear mechanisms of the coated cemented carbide tool, Adhesive wear, abrasive were the main wear mechanisms of the carbide tool. Oxidation wear occurs above a certain temperature about 430°C, the higher the temperature the more serious the oxidation wear is. The results might be helpful to guiding the design and selection of tool materials and control of tool wear in high speed machining processes.

Digital tools for material selection in product design

The increasing number of normalized materials, promoters and users led to a significant amount and diversity of databases and software for material selection, presenting differentiating abilities for the materials selection process. The aim of the present study is the critical analysis of the digital tools for material selection, trying to answer to a few important questions, such as What kind of digital tools exist? How do they work? What properties determine the selection? and What kind of information results from the selection? To materialize this useful and innovative investigation, a bibliographical search was carried out on selection methods, databases, and software for material selection. About three hundred software, databases and website references were collected and, after a previous analysis, 87 were selected for this study. All the relevant information about digital tools was organized in tables, including the name, user conditions, number of materials, “materials family or class”, selection paths, website address, resulting information and a descriptive text. The digital tool’s data on the tables were comparatively analysed. The capabilities and limitations of the existent digital tools, together with the aspects to be developed, are discussed. The availability of the information here reported will be very helpful for designers, engineer students and all kind of professionals performing materials selection for product design.

Thermodynamical matching of alumina-based composite ceramic tools with typical workpiece materials

Cutting temperature always highly reaches to over 1,000°C during high speed. Diffusion of tool material element may have important influence on tool wear at such high temperature. The advanced ceramic cutting tools have very good wear resistance, high refractoriness, good mechanical strength, and hot hardness. In this paper, the rules of diffusion wear for alumina-based ceramic cutting tools are proposed and analyzed based on thermodynamics theory. Dissolution concentrations in typical normal workpiece materials of ceramic tool materials at different temperatures are then calculated. Diffusion reaction rules in high temperature are developed and analyzed using Gibbs free energy criterion. The machining tests were conducted using the alumina-based composite ceramic tools at different cutting speeds of 10, 150, and 250 m/min, feed of 0.2 and 0.3, and depth of cut of 1, 2, 2.5, and 5 mm, respectively, on PUMA300LM numerically controlled lathe. It was found that the theoretical results were uniform with the experimental data; the results will provide useful references for tool material design and selection.

Computer aided material selection for circular tubes designed to resist axial crushing

We consider optimal design of cylindrical shells under axial compression. The main motivation is the comprehensive study of Weaver and Ashby [Material limits for shape efficiency. Progress in Materials Science 1997;41:61–128] concerning tubes designed to resist local buckling, global buckling and yield. In this paper we add another mode to this set of possible failure mechanisms, namely axial crushing. This failure-mode turns out to be dominate for many materials in several relevant load-cases. In many cases, taking this mode into account changes the optimal design substantially. By analyzing the formulae for the failure-modes we obtain piecewise defined functions describing the optimal cross-section and the minimum mass of the tube. Combined with advanced computer aided material selection tools like the Cambridge Engineering Selector (CES), these functions enable us to identify the best possible materials which give the lightest possible tubes.

Chipped Stone Debitage, Material Selection, and Expedient Tool Production in Southeast Michigan

This article summarizes the results of exploratory analyses on material sources and debitage attributes from chipped stone artifacts at sites identified and sampled by the Eastern Michigan University Field School along the Huron River Valley in southeast Michigan. Several hypotheses are tested with chipped stone debitage assemblages from 35 prehistoric sites to better understand material selection, expedient versus formal tool manufacturing, and the influence of material availability and mobility in chipped stone processing within the region. The distribution of debitage attributes (reduction stage, technology, condition, and size) are first compared by material source and quality. Then, the distributions of materials and debitage attributes are compared among small limited-use sites and two early Late Woodland small settlements. The results indicate a heavy reliance on poorer quality local cherts, and a focus on expedient tool manufacturing with both the local poorer quality and the nonlocal higher quality sources. There were no major differences in debitage assemblages between the limited use sites and the settlements.

New materials and surface finishing methods for cold forging tools

Regarding the ever increasing demand for net shaping, research on innovative technologies on tool material and design becomes an important factor for the overall efficiency and competitiveness. The tools in cold forging have to withstand damaging mechanisms of both fatigue and wear, which may act concurrently at different locations on the tool surface. Therefore, process specific tool material selection and local surface treatment of the tools already at the design stage becomes crucial. In this respect, industrial ceramics, offering a better solution against conventional tool steels in terms of wear resistance, occupies the first part of the research presented in this paper. A ceramic adapted tool design with the consideration of thermal effects has been given. Whereas, the second part of the research deals with the locally optimised surfaces of steel tools in terms of fatigue and wear resistance. Three different surface treatment methods are applied on cold forging tools and the results on tool life have been given.