PRELIMINARY ANALYSIS OF THE MODERNIZATION OF METAL-CUTTING MACHINES

The method of modernization and analysis of the choice of the electric motor are shown. It has been established that it is expedient to carry out modernization based on a feasibility study in several stages with the development and approval of technical documentation at each stage

Effect of chamfer width and chamfer angle on tool wear in slot milling

The tool geometry is generally of great significance in metal cutting performance. The response surface method was used to optimize chamfer geometry to achieve reliable and minimum tool wear in slot milling. Models were developed for edge chipping, rake wear, and flank wear. The adequacy of the models was verified using analysis of variance at a 95% confidence level. Each response was optimized individually, and the multiple responses were optimized simultaneously using the desirability function approach. The Monte Carlo simulation method was applied to tolerance analysis. All milling tests were conducted at dry conditions; the chamfer width and the chamfer angle varied between 0.1 and 0.3 mm, and 10 and 30°, respectively. Optimal chamfer geometry for minimizing chipping and rake wear was small chamfer width and chamfer angle. The flank wear reached the minimum value for the tool with 0.18 mm chamfer width and 10° chamfer angle. The obtained composite model predicted good edge strength and minimum overall wear when the chamfer was 0.1 mm wide at a 10° angle. Thermal cracks were observed on the tools. They were small on the edges with the finest and least negative chamfer but were more significant on the more negative and greater chamfer. A great chamfer width and chamfer angle also resulted in insufficient chip evacuation. The results show how the edge geometry affects the tool’s reliability and wear and may help manufacturers minimize tool cost and downtime.

Predicting Cutting Force and Primary Shear Behavior in Micro-Textured Tools Assisted Machining of AISI 630: Numerical Modeling and Taguchi Analysis

The cutting tool heats up during the cutting of high-performance super alloys and it negatively affects the life of the cutting tool. Improved tool life can enhance both the machinability and sustainability of the cutting process. To improve the tool life preferably cutting fluids are utilized. However, the majority of cutting fluids are non-biodegradable in nature and pose harmful threats to the environment. It has been established in the metal cutting literature that introducing microgrooves at the cutting tool rake face can significantly reduce the coefficient of friction (COF). Reduction in the COF promotes anti-adhesive behavior that improves the tool life. The current study numerically investigates the orthogonal cutting process of AISI 630 Stainless Steel using different micro grooved cutting tools. Results of the numerical simulations point to the positive influence of micro grooves on tool life. The results of the main effects found that the cutting temperature was decreased by approximately 10% and 7% with rectangular and triangular micro grooved tools, respectively. Over machining performance indicated that rectangular micro groove tools provided comparatively better performance.

Assessment of a Heterogeneous Environment

An approach to the assessment of a heterogeneous environment in accordance with the proposed concept of a heterogeneous environment is described. The classification of industrial heterogeneous media by technological feature is proposed. The processes described by the proposed approach include the process of metal cutting, surface plastic deformation, chemical-thermal treatment, formation of coatings, welding, most of the processes that change the level and gradient of hardness and internal stresses in the surface layer of the material. Application of the proposed principles makes it possible to find new directions in the study of such processes.

Development of a Method for Obtaining a Wear-Resistant Coating for a Cutting Tool

The article presents a method for producing a nanostructured wear-resistant high-hard coating with high physicomechanical and strength characteristics, resistance to shock and vibration loads. The result is an increase in adhesion between the substrate and the coating, as well as an increase in microhardness. One of the common methods of metal cutting is band-cutting machines that use closed band saws as cutting tools. Since materials with high physicomechanical characteristics (hardness, strength, etc.) are increasingly being used in modern production, which significantly complicates the cutting process and makes increased demands on the cutting tool. To expand the range of processed materials for which the productive use of band-cutting machines is possible, it became necessary to create a band saw with higher cutting characteristics. At the same time, the specificity of the working conditions of the band saw shows that the blade should have such characteristics as increased vibration resistance, resistance to alternating and dynamic loads, and the cutting part of the saw should have increased resistance to shock, dynamic, alternating loads, have high hardness, as well as increased wear resistance.

Testing Tool Material on Scratch Tester

In manufacturing industry cutting tools are considered as the backbone of the metal cutting operation. In metal cutting operation there is relative motion between the tool and the workpiece. As the tool material is harder than the workpiece material, there is deformation of the workpiece which acts as a base for the formation of chips. If we observe the process of metal cutting, we can easily find out that there is a considerable amount of heat generated during the machining operation. As there is a point of interface between the tool and the workpiece, there is absorption of generated heat into both the tool as well as work material. Due to the absorption of the heat there is distortion in the tool material. In this research article we have taken the base parameters as speed, load and stroke and the output parameter is taken as the load which breaks the coating of the tool. Keywords: tool coating, scratch tester, speed, stroke, coating.

Optimization of Wire Cut Electro Discharge Machining Process Parameters for Aluminium 6082 by using Taguchi Technique

The manufacturing industry is changing very drastically in all the aspect regarding the manufacturing technology as well as the quality concern as per as the quality is considered. Quality is becoming a significant trend in todays growing automobile industry. In the field of metal cutting operations, the surface roughness is becoming more dominant parameter as per as the quality of the component is considered. Electrical discharge machining is becoming a most powerful non conventional machining which is being widely used in the field of machining. Most specifically our work was conducted on the electrical discharge wire cut machining for achieving the desired surface roughness (Ra) and adequate material removal rate (MRR). The input parameter for our research work were selected as Peak current, pulse on time & pulse off time while the output parameter was selected as MRR and the surface roughness. Aluminum 6082 Grade material is used as a specimen and the research methodology implemented for the research work is taguchi and Anova. Keywords: Wire cut EDM, Taguchi, MRR surface roughness, Anova.

Optimization of two support spindle shaft on nonlinear elastic supports by rigidity characteristics

One of the main structural elements of metalworking machines is the spindle assembly (spindle), which is used to hold cutting tools or workpieces. The rigidity of the spindle assembly plays a decisive role in ensuring the accuracy and efficiency of the machine as a whole. The assessment of the spindle shaft stiffness is carried out on the basis of the analysis of the static bending of the spindle shaft, which made it possible to formulate and solve the problems of optimizing the spindle shaft according to the stiffness characteristics for two supporting structures on nonlinear elastic supports. To determine the stiffness of roller bearings, the work uses the dependence obtained on the basis of solving the problem of contact interaction of an elastic steel cylinder with curvilinear elastic steel half-spaces. For the considered design scheme, the optimization goals were chosen for the conditions of the smallest displacement of the end section of the spindle shaft console, the achievement of the minimum angle of rotation in this section or the minimum of their normalized superposition, which ensures maximum rigidity in the processing zone. Consideration has also been given to minimizing the swing angle at the front support to maximize bearing life. Mathematically, the problem is presented in the form of minimizing one of the 4 proposed objective functions by changing the variable parameters - the length of the cantilever and the value of the inter-support distance, represented as dimensionless quantities - the cantilever coefficient and the inter-support distance coefficient. Minimum and maximum values ​​of the cantilever length and shaft span were considered as constraints on the variable parameters. Varying the console coefficients and the inter-support distance was carried out by the method of sequential enumeration within the specified constraints, the solution of optimization problems is presented in a graphical form. The solution to the problem of shaft bending was carried out on the basis of the equation of the bent axis of the beam in the framework of the Euler - Bernoulli hypotheses and presented in an analytical form together with analytical dependencies for calculating the radial stiffness of a roller bearing as a function of the supporting force acting on it. The algorithm for solving optimization problems is implemented in the MatLAB package. Optimal solutions have shown that the minimum of the combined functions, consisting of the sum of the relative deflection values ​​at the end of the console and the angles of rotation at the end of the console and on the front support, is achieved at the same variable parameters as the minima of the angles of rotation at the end of the console and on the front support. The proposed approach to the design of the shafts of spindle units of metal-cutting machines, which are optimal in terms of rigidity characteristics, forms a tool for a reasonable choice of bearings and design parameters of spindle shafts.

Nonlinear repetitive control of the metal cutting machine feed module with saturated input

The article discusses the methodology for constructing an automatic control system for the feed module of the cutting tool for lathes in the presence of input saturation. The presence of the saturation function is due to restrict unwanted movements of the feed module actuator. The generator for periodic signals, the hyperstability criterion, L-dissipativity conditions and an implicit reference model are used as the solution methods for structural synthesis of the control system. At the stage of simulation, the functioning quality of the developed control system is illustrated.

Prediction and Analysis of the Surface Roughness in CNC End Milling Using Neural Networks

In the metal cutting process of machine tools, the quality of the surface roughness of the product is very important to improve the friction performance, corrosion resistance, and aesthetics of the product. Therefore, low surface roughness is ideal for mechanical cutting. If the surface roughness of the product can be predicted, not only the quality of the product can be improved but also the processing cost can be reduced. In this study a back propagation neural network (BPNN) was proposed to predict the surface roughness of the processed workpiece. ANOVA was used to analyze the influence of milling parameters, such as spindle speed, feed rate, cutting depth, and milling distance. The experimental results show that the root mean square error (RMSE) obtained by using the back propagation neural network is 0.008, which is much smaller than the 0.021 obtained by the traditional linear regression method.