Showing papers in "International Journal of Machine Tools & Manufacture in 1998"
TL;DR: There are many different rapid prototyping (RP) technologies available as discussed by the authors, and a taxonomy is also suggested, along with a preliminary guide to process selection based on the end use of the prototype.
Abstract: Until recently, prototypes had to be constructed by skilled model makers from 2D engineering drawings. This is a time-consuming and expensive process. With the advent of new layer manufacturing and CAD/CAM technologies, prototypes may now be rapidly produced from 3D computer models. There are many different rapid prototyping (RP) technologies available. This paper presents an overview of the current technologies and comments on their strengths and weaknesses. Data are given for common process parameters such as layer thickness, system accuracy and speed of operation. A taxonomy is also suggested, along with a preliminary guide to process selection based on the end use of the prototype.
865 citations
TL;DR: In this paper, the fundamental principles of ultrasonic machining, the material removal mechanisms involved and the effect of operating parameters on material removal rate, tool wear rate and workpiece accuracy are reviewed, with particular emphasis on the machining of engineering ceramics.
Abstract: Ultrasonic machining is of particular interest for the cutting of non-conductive, brittle workpiece materials such as engineering ceramics. Unlike other non-traditional processes such as laser beam, and electrical discharge machining, etc., ultrasonic machining does not thermally damage the workpiece or appear to introduce significant levels of residual stress, which is important for the survival of brittle materials in service. The fundamental principles of ultrasonic machining, the material removal mechanisms involved and the effect of operating parameters on material removal rate, tool wear rate and workpiece accuracy are reviewed, with particular emphasis on the machining of engineering ceramics. The problems of producing complex 3-D shapes in ceramics are outlined.
416 citations
TL;DR: Hard roller burnishing as mentioned in this paper transforms tensile residual stresses present in the surface zone after hard turning into compressive residual stresses, and has no effect on the formation of white layers.
Abstract: In a hard roller burnishing operation, a hydrostatically borne ceramic ball rolls over the component surface under high pressures The roughness peaks are flattened and the quality of the workpiece surface is improved When combined with hard turning, this process provides a manufacturing alternative to grinding and honing operations The studies determined optimum working parameter ranges Parameter settings were shown to be non-critical in this process, since constant surface qualities were attainable over wide setting ranges A second phase of the studies examined the improvements obtained for various original roughnesses Reductions of 30 to 50 % in mean peak-to-valley height Rz are, for example, achievable, depending on the original roughness Structure analyses and residual stress measurements were used to examine the effects of the process on the workpiece surface zone Hard roller burnishing transforms tensile residual stresses present in the surface zone after hard turning into compressive residual stresses Hard roller burnishing has no effect on the formation of white layers in the surface zone
151 citations
TL;DR: In this paper, an analysis of the chatter behavior for a slender cutting tool in turning in the presence of wear flat on the tool flank is presented in the context of cutting force and contact force.
Abstract: An analysis of the chatter behavior for a slender cutting tool in turning in the presence of wear flat on the tool flank is presented in this research. The mechanism of a self-excited vibration development process with tool wear effect is studied. The components contributing to the forcing function in the turning vibration dynamics are analyzed in the context of cutting force and contact force. A comparison of the chatter stability for a fresh cutting tool and a worn cutting tool is provided. Stability plots are presented to relate width of cut to cutting velocity in the determination of chatter stability. Machining experiments at various conditions were conducted to identify the characteristic parameters involved in the vibration system and to identify the analytical stability limits. The theoretical result of chatter stability agrees qualitatively with the experimental result concerning the development of chatter stability model with tool wear effect.
140 citations
TL;DR: In this article, an approach to modeling the ductile-mode removal in rotary ultrasonic machining is proposed, and the results of the pilot experiments to verify the model are discussed.
Abstract: In rotary ultrasonic machining of ceramic materials there exist two modes of material removal: brittle fracture mode and ductile mode. Two models were developed based on the assumption that the brittle fracture is the dominating mode of material removal, and were published previously. This paper presents the follow-up work on modeling of the ductile-mode material removal in rotary ultrasonic machining. After a brief review of the ductile phenomena in ceramic machining, an approach to modeling the ductile-mode removal in rotary ultrasonic machining is proposed. Then, magnesia stabilized zirconia is used to demonstrate the model's capability of predicting the material removal rate from the process parameters and the material property of the workpiece. Finally, the results of the pilot experiments to verify the model are discussed.
129 citations
TL;DR: In this paper, the failure mechanisms of micro-end-mills were studied during the machining of aluminum, graphite electrodes and mild steel workpieces, and the cutting force variation was monitored, i.e., the relationship between the utilization-related changes at the tool structure (wear), and the outcomes (increasing cutting force which means raising stress on the tiny shaft).
Abstract: Unpredictable tool life and premature tool failure are major problems in micro-machining. In this study, the failure mechanisms of micro-end-mills were studied during the machining of aluminum, graphite electrodes and mild steel workpieces. Hundreds of machining operations were performed, and the pictures of cutting edges were taken with a scanning electron microscope to identify fatigue and extensive stress-related failure mechanisms. Also, the cutting force variation was monitored, i.e. the relationship between the utilization-related changes at the tool structure (wear), and the outcomes (increasing cutting force which means raising stress on the tiny shaft). Inspection of the cutting force variation patterns of large numbers of micro-end-mills indicated that tool failure occurs with chip clogging, fatigue and wear-related excessive stress depending on the characteristics of the workpiece. Two tool breakage prediction methods were developed by considering the variation of the static part of the feed direction cutting force. These methods used segmental averages and wavelet transformation coefficients. The accuracy of the proposed approaches were tested with experimental data and the agreement between the predictions and actual observations are reported.
124 citations
TL;DR: In this paper, a surface topography simulation model is established to simulate the surface finish profile generated after a turning operation, which incorporates the effects of the relative motion between the cutting tool and the workpiece with the effect of tool geometry.
Abstract: In this paper, a surface topography simulation model is established to simulate the surface finish profile generated after a turning operation. The surface topography simulation model incorporates the effects of the relative motion between the cutting tool and the workpiece with the effects of tool geometry to simulate the resultant surface geometry. It is experimentally shown that the surface topography simulation model can properly simulate the surface profile generated by turning operations. The surface topography simulation model is used to study the effects of vibrations on the surface finish profile. It is found that the vibration frequency ratio is a more important vibration parameter than the vibration frequency on the characterization of the surface finish profile. The vibration frequency ratio is the ratio between the vibration frequency and the spindle rotational speed.
123 citations
TL;DR: In this paper, a rotational tool with controlled feed has been used to improve the performance of electrochemical spark machining (ECSM) for nonconducting materials, such as ceramics and composites.
Abstract: Machining of electrically non-conducting materials, i.e. ceramics, composites, etc., is still a major problem. Electrochemical spark machining (ECSM) is found to be a potential process for machining these materials. However, ECSM has its own inherent problems too. So far, only non-rotational tools with gravity feed have been used 'by previous researchers, but the performance of such tools has been reported to be poor. In the present work, electrochemical spark drilling (ECSD) experiments have been conducted using various tool kinematics with a view to enhancing the process capabilities. Use of a rotational tool with controlled feed has been found to improve the process performance. Significant improvement in the “limiting value” of the machined depth during ECSD has been observed while using a tool with orbital motion. Geometrical parameters and surface integrity of the machined specimens have also been studied and presented.
117 citations
TL;DR: In this article, a simulation system for machining with ball-end milling cutters is presented, where the geometry of the workpiece, the cutter, and the cutter/workpiece engagement is modeled using a geometric simulation system.
Abstract: A simulation system is developed in this paper, which deals with the geometry and mechanics of machining with ball-end milling cutters. The geometry of the workpiece, the cutter, and the cutter/workpiece engagement is modeled using a geometric simulation system. This module uses a commercial solid modeler (ACIS) as a geometric engine and automatically extracts the critical geometric information required for the physical simulation system. To calculate the instantaneous cutting forces, a new mechanistic force model is developed. This force model takes into account the variations of the cutting coefficients along the cutting edge, and considers the variations of the rake angle and the chip flow direction on the rake face. The calibration of the developed model is performed for half-immersion ball-end milling operation. The applicability of the developed system is verified experimentally for various up-hill angles. It is shown that as the up-hill angle increases, the ball-nose tip engagement decreases which in turn significantly affects the magnitude of the resultant forces. Also, lower cutting forces and powers are experienced if cutting with the vicinity of the tool tip is avoided.
117 citations
TL;DR: This paper deals with the possibility of measuring surfaces of medium finished parts using a vision system and briefly reviews a few approaches and examines one — texture unit spectra — in more detail.
Abstract: Conventional measurement of finish using stylus instruments has been in vogue for over half a century. Though these instruments have excellent capabilities and wide range, they are normally used for inspecting machined surfaces of good finish. Further the procedure is a post process approach which is not amenable for automation. In the recent past, higher levels of automation in the shop floor has focused the attention on the application of fast, reliable and cost effective procedures for evaluating surfaces of medium finished parts.This paper deals with the possibility of doing this using a vision system. It briefly reviews a few approaches and examines one — texture unit spectra — in more detail.
115 citations
TL;DR: In this article, the authors present a new six-degree-of-freedom measurement system (6DMS) which employs three parallel laser beams to detect three relative linear distances of a moving body by Doppler effect.
Abstract: This paper presents a new six-degree-of-freedom measurement system (6DMS) which has the capability to measure simultaneously all six motion errors of a linear stage This system employs three parallel laser beams to detect three relative linear distances of a moving body by Doppler effect so that the positioning, yaw and pitch errors can be separated With an additional beam splitter and two quadrant photodetectors to detect the lateral shifts of the returned beams, the remaining two straightness errors and roll error can be obtained at the same time In comparison with the HP5528A system, the accuracy of the positioning error is about 001 μ m to the range of 10 m, the straightness error is about 1 μ m within the measuring range of ±01 mm, and angular errors are all about 1 arcsec within the range of ±50 arcsecs This system is simple in principle and can be easily equipped to any moving stages, such as linear stages, X – Y tables, CMMs, and machine tools
TL;DR: In this paper, the authors introduce the concept and framework of a teleservice engineering system for the life cycle support of manufacturing equipment and products, which involves the fundamental methodologies that deal with machine performance assessment techniques, self-maintenance machine mechatronics, and remote diagnostics.
Abstract: This position paper introduces the concept and framework of a teleservice engineering system for the life cycle support of manufacturing equipment and products. The proposed system involves the fundamental methodologies that deal with machine performance assessment techniques, self-maintenance machine mechatronics, and remote diagnostics. In addition, a concept on digital service enterprise will be introduced. These methodologies will support remote users and facilities to ensure the performance of consumer products, manufacturing equipment, quality of operations, and productivity of the plant, in particular, for those users and facilities located in remote locations. Finally, research challenges and opportunities are discussed.
TL;DR: The Fast Support Layout Optimization (FSLO) model proposed in this paper uses a finite element analysis (FEA) model to characterize workpiece stiffness and then uses the FEA model to determine support locations that will minimize the maximum displacement to tolerance ratio of a set of workpiece features subject to a system of machining loads.
Abstract: Machining-fixture supports are used to increase workpiece rigidity. A critical problem of machining-fixture design is where to place a fixed number of supports in order to minimize workpiece deformation during machining. This paper presents the Fast Support Layout Optimization (FSLO) model. The objective of the FSLO model is to determine support locations that will minimize the maximum displacement-to-tolerance ratio of a set of workpiece features subject to a system of machining loads. The FSLO model utilizes a Finite Element Analysis (FEA) model to characterize workpiece stiffness. Solution of the FSLO model improves an existing support layout by systematically altering the boundary conditions applied to the FEA model. The FSLO model is unique in that its solution time is both very small and insensitive to the size of the FEA model, the sizes of machined features considered, and the sizes of the candidate regions of the supports. In addition to describing the formulation of the FSLO model, this paper describes a set of experiments that were used for its verification.
TL;DR: In this paper, the authors introduced a wavelet transform technique based on the detection of the multi-scale view of the components of a signal, which can be used for space-frequency localization and analysis of roughness and waviness motifs.
Abstract: This work introduces a wavelet transform technique based on the detection of the multi-scale view of the components of a signal . The main advantages of wavelet transform over the existing signal processing techniques are its space-frequency localization and multi-scale analysis of roughness and waviness motifs. After an extensive review of the mathematical and signal processing fundamentals of the wavelet technique, numerical implementations are carried out to explore the potential applications of wavelet transform and its inverse transform multi-scale analysis of roughness and local morphological characterization by the detection of the roughness singularities and 21) motif size of an engineered surface.
TL;DR: Higher removal torques and higher percentages of bone-to-implant contact for implants blasted with 25 and 75 μm sized blasting particles than with as-turned or 250 μm blasted implants are demonstrated.
Abstract: 318 threaded implants with a diameter of 3.7 mm, length 6 to 7 mm and a pitch-height of 0.6 mm were inserted in 56 New Zealand white rabbits. Implants of varying surface roughness were produced by a blasting procedure using 25m 75m and 250 μm sized particles. As- machined, (i.e turned) implants served as controls. The implant surface roughness was measured with the confocal laser scanner (TopScan 3D), and appropriate software was used for visual and numerical characterization. After implantation time of 4 weeks, 12 weeks or 1 year, the animals were euthanized. The implants were evaluated with respect to the peak removal torque, the percentage of bone-to-implant contact. The results from the animal experiments demonstrated, generally, higher removal torques and higher percentages of bone-to-implant contact for implants blasted with 25 and 75 μm sized blasting particles than with as-turned or 250 μm blasted implants. The corresponding average height deviation for the 4 surfaces was 1 μm 1.5 μm 0.7 μm and 2.0 μm When comparing the 25 and the 75 μm blasted implants it was found that 75 μm blasted screws showed the strongest bone fixation.
TL;DR: In this article, existing models of a mill stand as well as of the rolling process in the open literature are presented, which are formulated to investigate chatter as the consequence of the interaction between the structural dynamics of the mills and the dynamics of a rolling process.
Abstract: In the past, many different modes of vibration and causes of rolling chatter have been presented, yet no complete and clear picture of the basic mechanics emerged. In order to control chatter in cold rolling operations, a much better understanding of the basic mechanics of the problem is required. To provide, therefore, a ground work for developing such a basic understanding, in this paper, existing models of a mill stand as well as of the rolling process in the open literature are presented. In addition, existing chatter models, which are formulated to investigate chatter as the consequence of the interaction between the structural dynamics of the mills and the dynamics of the rolling process, are also reviewed.
TL;DR: In this paper, the authors proposed a tool breakage detection and wear estimation method using acoustic emission (AE) signals using adaptive resonance theory and Abductory Induction Mechanism (AIM).
Abstract: Acoustic Emission (AE) signals have been used to monitor tool condition in conventional machining operations. In this paper, new procedures are proposed to detect tool breakage and to estimate tool condition (wear) by using AE. The proposed procedure filters the AE signals with a narrow band-width, band-pass filter and obtains the upper envelope of the harmonic signal by using analog hardware. The envelope is digitized, encoded and classified to monitor the machining operation. The characteristics of the envelope of the AE were evaluated to detect tool breakage. The encoded parameters of the envelope of the AE signals were classified by using the Adaptive Resonance Theory (ART2) and Abductory Induction Mechanism (AIM) to estimate wear. The proposed tool breakage and wear estimation techniques were tested on the experimental data. Both methods were found to be acceptable. However, the reliability of the tool breakage detection system was higher than the wear estimation method.
TL;DR: In this article, the thermal characteristics of a spindle bearing system with a tilting axis were investigated using finite element method to improve the performance of the spindles bearing system.
Abstract: High cutting speeds and feeds are essential requirements of a machine tool structure to accomplish its basic function which is to produce a workpiece of the required geometric form with an acceptable surface finish at as high a rate of production as is economically possible. Since bearings in high speed spindle units are the main heat source of total cutting system, in this work, the thermal characteristics of the spindle bearing system with a tilting axis were investigated using finite element method to improve the performance of the spindle bearing system. Based on the numerical results, a specially designed prototype spindle bearing system was manufactured. Using the manufactured spindle bearing system, the thermal characteristics were measured and compared to the numerical results. From the comparison of the numerical results with the experimental results, it was found that the finite element method predicted well the thermal characteristics of the spindle bearing system.
TL;DR: In this paper, the extruding action of the rake and the flank have been considered, the possibility of the major cutting-edge chip-breaking in ZVD has been verified, the chisel-edge chips formation in vibration drilling has been analyzed, and theoretical chip graphs have been drawn.
Abstract: Up to the present, all published vibration drilling chip-breaking theories have considered that for zero-phase-difference axial vibration drilling (ZVD), major cutting-edge chip-breaking was impossible, and have not discussed the chisel-edge chip. In this paper, the extruding action of the rake and the flank have been considered, the possibility of the major cutting-edge chip-breaking in ZVD has been verified, the chisel-edge chip formation in vibration drilling has been analyzed, and theoretical chip graphs have been drawn. The new chip-breaking theory has been confirmed by vibration drilling experiments using aluminum and stainless steel.
TL;DR: In this paper, a root locus plot analysis of time delayed systems is presented as a new and practical perspective on regenerative machine tool chatter, which is a well known phenomenon, occurrence of which is undesired in manufacturing.
Abstract: The paper contains a practical perspective on regenerative machine tool chatter. Chatter is a well known phenomenon, occurrence of which is undesired in manufacturing. Aggressive machining conditions, in the sense of removing more metal rapidly, usually cause chatter. In most cases, these conditions can be determined a priori to the operation. A chatter stability study and its reasoning based on root locus plot analysis of time delayed systems is presented as a new and practical perspective in the field. At the junction of root locus and chatter concepts an area of particular interest to the authors arises: a new method for active vibration suppression, the Delayed Resonator. It is an active vibration absorber tuning of which is achieved utilizing a simple time delayed feedback. The cross linking between the Delayed Resonator study and the subject matter, machine tool chatter, is exciting to share. This is the primary motivation in pursuing this study. One of the highlights of the work appears at the phenomenon called Dual Frequency Delayed Resonator. This feature has been conjectured in the literature using the well known “stability lobes”, but never discussed with detail.
TL;DR: In this article, the concept of equivalent orthogonal cutting conditions, applied to modeling of the mechanics of ball end milling, is extended to include the dynamics of cutting forces.
Abstract: This paper presents a dynamic force model and a stability analysis for ball end milling. The concept of the equivalent orthogonal cutting conditions, applied to modeling of the mechanics of ball end milling, is extended to include the dynamics of cutting forces. The tool is divided into very thin slices and the cutting force applied to each slice is calculated and summed for all the teeth engaged. To calculate the instantaneous chip thickness of each tooth slice, the method of regenerative chip load calculation which accounts for the effects of both the surface undulations and the instantaneous deflection is used. To include the effect of the interference of the flank face of the tool with the finished surface of the work, the plowing force is also considered in the developed model. Experimental cutting forces are obtained using a five-axis milling machine with a rotary dynamometer. The developed dynamic model is capable of generating force and torque patterns with very good agreement with the experimental data. Stability of the ball end milling in the semi-finishing operation of die cavities is also studied in this paper. The tangential and radial forces predicted by the method of equivalent orthogonal condition are fitted by the equations F t = K t ( Z ) bh av and F r = K r ( Z ) F t , where b is the depth of cut and h av is the average chip thickness along the cutting edge and Z is the tool axis coordinate. The polynomial functions K t ( Z ) and K r ( Z ) are the cutting force constants. The interdependency of the axial and radial depths of cut in ball end milling results in an iterative solution of the characteristic equation for the critical width of cut and spindle speed. In addition, due to different cutting characteristics of the cutting edge at different heights of the ball nose, stability lobes are represented by surfaces . Comparison of the time domain simulation for the shoulder removal process in die cavity machining with the analytical predictions shows that the proposed method is capable of accurate prediction of the stability lobes.
TL;DR: In this article, a unique experimental investigation has been carried out to statistically determine the optimum build parameters to be used with the use of Taguchi Method, as to improve the SLA product quality.
Abstract: In recent years, Rapid Prototyping Technology (RPT) has been implemented in many spheres of industry, particularly in the area of product development. Existing processes provide the capability to rapidly produce a tangible solid part, directly from three dimensional Computer-Aided Design (CAD) data, from a range of materials such as photocurable resin, powders and paper. In many situations, the desired end product of a developmental cycle is a metallic object that is dimensionally stable and of high accuracy, whether it is a component or a tool. However, in most cases, models built in the acrylic based resin in the StereoLithography process has not yielded the desired quality and this has led to a shift in the use of this resin to some more expensive ones that have longer build time. A unique experimental investigation has been carried out to statistically determine the optimum build parameters to be used with the use of Taguchi Method, as to improve the SLA product quality. Two new hatch styles have been developed in this study which has resulted in the overall improvement of the part surface finish.
TL;DR: In this article, a finite element analysis (FEA) has been applied to model and simulate the chip formation and the shear localization phenomena in the metal cutting process, and the updated Lagrangian formulation of plane strain condition is used in the study.
Abstract: The finite element analysis (FEA) has been applied to model and simulate the chip formation and the shear localization phenomena in the metal cutting process. The updated Lagrangian formulation of plane strain condition is used in this study. A strain-hardening thermal-softening material model is used to simulate shear localized chip formation. Chip formation, shear banding, cutting forces, effects of tool rake angle on both shear angle and cutting forces, maximum shear stress and plastic strain fields, and distribution of effective stress on tool rake face are predicted by the finite element model. The initiation and extension of shear banding due to material's shear instability are also simulated. FEA was also used to predict and compare materials behaviors and chip formations of different workpiece materials in metal cutting. The predictions of the finite element analysis agreed well with the experimental measurements.
TL;DR: This paper shows that a 20 percent overlap gives a good trade off between having good repeatability and obtaining a large field of view with a minimum number of data sets.
Abstract: It is difficult in interferometric metrology to maintain high spatial resolution over a large field of view Interferometric microscope measurements yield high resolution, but only over a small area Other conventional interferometric systems can measure large areas, but they fail to provide the necessary spatial resolution High spatial resolution over a large field-of-view (FOV) can be obtained by stitching together multiple high spatial resolution measurements of adjacent areas of a measured surface The measurements can be fit together in a global sense, or by matching the piston and tilt over the overlap region Care must be taken in the stitching process to make sure the measurements are precisely overlapped to minimize errors The larger the overlap the easier it is to match data sets, but of course more data sets are required to get a given field of view This paper shows that a 20 percent overlap gives a good trade off between having good repeatability and obtaining a large field of view with a minimum number of data sets Typical measurement results are shown for stitching as many as 285 sub-regions
TL;DR: In this paper, a mathematical model for machining of FRPs was developed based on the anisotropic theory of plasticity and the Lagrangian formulation-based transient elasto-plastic finite element analysis has been adopted.
Abstract: An initial attempt has been made to develop a mathematical model for machining of FRPs. The anisotropic theory of plasticity has been utilized. The analysis is carried out for four different FRP materials and for four different fibre orientation angles. A total Lagrangian formulation-based transient elasto-plastic finite element analysis has been adopted.
TL;DR: In this article, a software method to compensate for the contour error in repeated machining process is proposed, where the profile of the first machined part is measured by a coordinate measuring machine, and the tool path is modified by a compensation algorithm, and then, is represented by a series of linear segments.
Abstract: This paper proposes a software method to compensate for the contour error in repeated machining process. In the proposed method, the profile of the first machined part is measured by a coordinate measuring machine. Based on the measured data, the tool path is modified by a compensation algorithm, and then, is represented by a series of linear segments. Finally, the compensated tool path is fed to the CNC machine tool for the machining of subsequent parts. Mathematical analysis and experimental evaluation are presented in this paper.
Abstract: The present study aims to investigate the residual stresses and surface hardening in ground components caused by the coupled effect of thermo-plasticity and phase transformation. A feasible numerical method was developed to accommodate appropriately the phase transformation in a workpiece experiencing critical temperature variation during grinding. The change of material properties was modelled as a function of temperature history. It found that if material properties are temperature-independent, the residual stresses in both the grinding direction and that perpendicular to it are tensile. The maximum residual stress in this case does not vary with the further increment of grinding heat. When material properties are temperature-dependent, however, the rise of grinding temperature promotes surface hardening and increases the maximum residual stress. The study showed that the volume growth associated with phase change plays an important role in the formation and nature transition of residual stresses. Nevertheless, residual stresses in the no-martensite zone is nearly unaffected by surface hardening and volume change. This paper offers insight into the understanding of surface hardening mechanism introduced by grinding.
TL;DR: In this article, the effects of wheel wear and wheel characteristics on grinding performance are simulated and compared with experimental results, and the results show that grinding performance is strongly affected by dressing conditions immediately after dressing.
Abstract: A method of simulating dressing and grinding was described in Parts I and II of this paper. In Part IV, the effects of wheel wear and wheel characteristics on grinding performance are simulated and compared with experimental results. The results show that grinding performance is strongly affected by dressing conditions immediately after dressing. As grinding continues, the grinding power, and also the surface roughness, tends to converge towards similar values for all dressing conditions when the same grinding conditions are employed. Results from the simulation show that the influence of wheel wear is affected by the wheel fracture characteristics. The convergence of the grinding behaviour shown in the simulation and experiments suggests that stable grinding performance in a wheel redress life cycle may be achieved by selecting dressing conditions, taking account of the grinding behaviour.
TL;DR: In this article, the scale-of-interaction criterion for establishing functional correlations is presented as a criterion for evaluating data acquisition systems and is also used as the basis for simulating interactions with the surface.
Abstract: The scale-of-interaction is presented as a criterion for establishing functional correlations. It is also used in simulating interactions with rough surfaces. Fractal analysis by the patchwork method is discussed and is used as the basis for evaluating data acquisition systems. The patchwork method is also used as the basis for simulating interactions with the surface. The essence of the simulation is to understand macroscopic, apparently continuous, interactions as the sum of a large number of discrete interactions at some appropriately fine scale. The simulations shown here use topographic data acquired from engineering surfaces.
TL;DR: In this article, the influence of surface properties on film adhesion of PVD-coated carbides was investigated and residual stress measurements and SEM pictures were used to characterize surface properties.
Abstract: Today's research activities are concentrated on improving the properties of cutting tools by optimizing manufacturing technologies, by alloying of special cutting materials and by coating of tools. As a result of the poor machinability of new cutting materials, grinding processes get more difficult. Especially in grinding of new WC-carbide and cermet compositions, high mechanical and thermal loads influence the surface topography and surface integrity of the tool. In particular, the coating adhesion depends on the surface structure of the substrate. Variations of subsurface properties cause distinct differences to interface strength and tool life. Influences of surface properties on film adhesion of PVD-coated carbides were investigated. Considered topics are the influence of grinding, micro blasting and water peening of carbides on surface topography and surface integrity as well as effects on film adhesion of (Ti,AI)N-coatings. Residual stress measurements and SEM-pictures were used for characterization of surface properties. Film adhesion was analysed by scratch and indentation tests. Due to increasing interface strength of micro blasted tools a superior wear behaviour in dry machining was observed.