Stochastic Diagnostics of Tool and Workpiece Interaction

4842937 Method of depositing a wear-protective layer on a cutting tool and wear protective layer produced by the method : Hans-Robert Meyer, Hans-Joachim Wiemann, Hamburg, Federal Republic Of Germany assigned to Ernst Winter & Sohn (GmbH & CO)

Wear resistance of hot forging tools surfaced by welding

One of the major cost components in tool economics is the cost incurred due to deviation in workpiece quality as a result of poor tool-cutting conditions. Commonly, the operating conditions of a culling tool may be restored via regrinding during periodic intervals of the tool's life. This paper proposes that optimal regrinding interval ought to be determined with respect to the optimal number of regrindings. The product of these two values defines the economic life of a tool. The objective function is the minimization of the sum of the expected costs of failure, regrinding, tool purchase, machining, and deviation in workpiece quality. The cost of deviation in workpiece quality is modelled using Tagucbi's loss function. The effect of cutting speed on tool regrinding interval is also explored.

Nowadays, in order to reach minimum production cost in machining operations, various optimization methods have been proposed. Since turning operation has different parameters affecting the workpiece quality, it was selected as a complicated manufacturing method in this paper. To reach sufficient quality, all influencing parameters such as cutting speed, federate, depth of cut and tool rake angle were selected as input parameters. Furthermore, both surface roughness and tool life were considered as the objectives. Also, ST37 steel and M1 high speed steel (HSS) were selected as workpiece material and tool, respectively. Subsequently, grey relational analysis was performed to elicit optimal values for the mentioned input data. To achieve this goal, first, degree of freedom was calculated for the system and the same experiments were performed based on the target values and number of considered levels, leading to calculating grey relational generating, grey relational coefficient and grey relational grade. As the next step, the grey relational graph was sketched for each level. Finally, optimum values of the parameters were obtained for better surface roughness and tool life. It was shown that the presented method in the turning operation of ST37 led to high surface quality and tool life.

The demand for good surface quality and good fatigue resistance of engineering components is becoming ever greater. Mechanical surface treatments are performed to improve the surface properties and quality of cylindrical workpieces. In this article, the surfaces produced by two different surface treatment methods are evaluated in terms of their surface integrity. The processes are diamond burnishing and ultrasonic burnishing. Both diamond burnishing and ultrasonic burnishing are fast, simple and economical cold-working processes that provide good surface quality and hardness. This paper examines the residual stresses, the changes in the surface quality and the changes in the surface hardness of the workpieces that have been finished via diamond burnishing and ultrasonic burnishing processes. It is extremely important to know what effect the methods have on the residual state of the material. The results demonstrate that it is possible to achieve reductions of as much as 78% to 94% in surface roughness (Ra) via the diamond burnishing and ultrasonic burnishing processes.

Effect of texture parameters on cutting performance of flank-faced textured carbide tools in dry cutting of green Al2O3 ceramics

Micro-wear in micro-grinding process is very important to research the micro-tools wear and the service life prediction of the micro-tools. The wear mechanism of electroplated diamond micro-grinding tool is analyzed in this paper. The geometric and mathematical modeling is established in allusion to the composite mechanism in micro-grinding zone and the main characteristics of the wear forms. The prediction model of micro-wear is established by considering the size effect and the minimum chip thickness. Experiments with different grinding parameters in micro-grinding soda lime glass are carried out to confirm the validity of the model. The influence of the worn micro-grinding tools are proposed by analyzing the diameter of grinding head, the ratio of wear and fracture grains, the surface roughness of the specimens, and different grinding parameters. The test results show that the grinding head diameter decreases rapidly and sharply first and then decreases slowly and steadily. The wear is more slowly with better surface quality. The wear rate and the ratio of wear and fracture grains increase with the increasing of grinding and feed speeds, and the ratio has a linear trend integrally. It provides the experimental reference and the theoretical basis for improving the grinding performance and extending the service life of micro-grinding tools.

The textbook examines in detail the structure of the modern machine-building complex of Russia, outlines aspects of technological preparation of production and resource-saving technologies, classification, labeling and properties of basic structural materials, provides a methodology for system analysis of technological processes, processing methods and methods, describes traditional and modern technological processes for manufacturing machine parts. When considering each method and method of processing, the main emphasis was placed on the description of the main processing schemes, technological features and capabilities of the method. The technological requirements imposed by the method on the blanks are described. Practical recommendations on the choice of the processing method and mode are given. Meets the requirements of the Federal State Educational Standard of Higher Education of the latest generation of teaching the general professional discipline "Technological processes of machine-building production" for the training areas 15.00.00 "Mechanical Engineering" and 22.00.00 "Technology of metals". It is intended for students of engineering universities of technological specialties.

Purpose of the study: to consider technological processes for processing cutting fluids. Scientific hypothesis: it is necessary to change and improve the technological processes themselves in order to comprehensively and most fully process raw materials during the production process, thereby reducing the volume of waste, converting them into forms that are least harmful to the environment. Industry has a significant negative impact on the environment, characterized by the release of hazardous substances and the accumulation of both liquid and solid toxic waste. The need to protect the environment leads to significant changes in general approaches to ensuring the environmental efficiency of production and the introduction of systems for integrated processing of raw materials.

Surface quality monitoring for process control by on-line vibration analysis using an adaptive spline wavelet algorithm

The machining process of aluminum alloy usually produces built-up edge and tool sticking problems due to their low hardness and large plastic deformation, which may further affect the machined surface quality and tool life. This paper aims to investigate the influence of different cutting fluids on the machined surface quality and tool life during the milling process of 7050 aluminum alloy. A novel cutting fluid (QC-2803) was considered in the study, which is synthesized by addition of alkyl alcohol amide and chlorinated polyolefin, and the traditional cutting fluid (CCF-10) was used as the control group. The physical and chemical properties of two cutting fluids were characterized. The milling process of 7050 aluminum alloy was carried out under two different cutting fluid conditions. The machined surface morphology, cutting force and tool wear morphology were observed during the process. Results show that the surface tension of the novel cutting fluid is significantly lower than that of the traditional cutting fluid, which makes it easier to produce a lubricating film between the aluminum alloy and tool, and further benefits the machined surface quality and tool life. As a result, the surface roughness and cutting force are reduced by ~20.0% and ~42.9%, respectively, and the tool life is increased by 25.6% in the case of the novel cutting fluid (QC-2803). The results in this paper revealed the important laws of cutting fluid with metal surface quality, cutting performance and tool wear, which helps to control the machined surface quality and tool life by the selection of cutting fluid during metal milling.

Application of niobium carbide based cutting materials for peripheral milling of CFRP

Surface quality is a major factor affecting the performance of a component. The machined surface quality is strongly influenced by the external loads during the fixturing and machining processes. In machining process development, it is highly desirable to predict the quality of a machined surface. For this purpose, an integrated finite element analysis (FEA) model of the entire fixture-workpiece system is developed to investigate the influence of clamping preload and machining force on the surface quality of the machined workpiece. The effects of fixture and machine table compliance (from experimental data), and the workpiece and its locators/clamps contact interaction, and forced vibration, on the machined surface quality are taken into account. This simulation model provides a better understanding of the causes of surface error and a more realistic prediction of the machined surface quality. The deck face of a V-type engine block subjected to fixture clamping and a face milling operation is given as an example. A comparison between the simulation result and experimental data shows a reasonable agreement.

The present research of cold-beating formation mainly focused on roller design and manufacture, kinematics, constitutive relation, metal flow law, thermo-mechanical coupling, surface micro-topography and microstructure evolution. However, the research on surface quality and performance of workpieces in the process of cold-beating is rare. Cold-beating simulation experiment of 1020 steel is conducted at room temperature and strain rates ranging from 2000 to 4000 s−1 base on the law of plastic forming. According to the experimental data, the model of strain hardening of 1020 steel is established, Scanning Electron Microscopy(SEM) is conducted, the mechanism of the work hardening of 1020 steel is clarified by analyzing microstructure variation of 1020 steel. It is found that the strain rate hardening effect of 1020 steel is stronger than the softening effect induced by increasing temperatures, the process of simulation cold-beating cause the grain shape of 1020 steel significant change and microstructure elongate significantly to form a fibrous tissue parallel to the direction of deformation, the higher strain rate, the more obvious grain refinement and the more hardening effect. Additionally, the change law of the work hardening rate is investigated, the relationship between dislocation density and strain, the relationship between work hardening rate and dislocation density is obtained. Results show that the change trend of the work hardening rate of 1020 steel is divided into two stages, the work hardening rate decreases dramatically in the first stage and slowly decreases in the second stage, finally tending toward zero. Dislocation density increases with increasing strain and strain rate, work hardening rate decreases with increasing dislocation density. The research results provide the basis for solving the problem of improving the surface quality and performance of workpieces under cold-beating formation of 1020 steel.

In this paper, a method of intensive quenching in water salt solutions, known as the IQ-2 process, is considered. To realize the IQ-2 process, water salt solutions were used, including with NaNO3, Na2CO3, NaCl, CaCl2, MgCl2, Ca(OH)2, and others salts. It is shown that the effectiveness of intensive quenching can be improved via the use of water salt solutions of optimal concentration. In order to prevent the corrosion of steel parts, a small amount of Ca(OH)2 was added to water salt solutions of sodium and calcium chloride to create a pH of 8 to 12. The proposed technology is less expensive compared to conventional quenching methods while providing the same or better end results in terms of increasing the service life of steel parts and tools and components made of powder metal materials. It is shown that the intensive quenching of tools by water salt solutions of optimal concentration increases the service life of tools by 1.5 to 2 times as compared with the oil quenching process.