THE EFFECT OF CUTTER PATH STRATEGIES ON SURFACE ROUGHNESS WHEN MACHINING TITANIUM ALLOY

The article deals with the comparison and evaluation of finishing cutter path strategies when applied to one of the difficult to cut material such as Ti-alloy. The titanium alloy has been increasingly used for high performance application for oil and gas, aerospace, energy, medical and automotive industries. The importance of milling strategies outgoing from their impact on the economic aspects of production, realized using CNC machines. A planar sample was designed for the purposes of the experiment, enabling finishing cutter path strategies for shaped surfaces. Three cutting strategies were involved and compared- spiral, constant Z and line feed. For assessment of the effect of the cutting strategies three different feed rate were used. Comparison of simulated cutter path strategies and machined surface were visually inspected as well as measured surface roughness were evaluated. The constant Z cutting path strategy was found as suitable cutting strategy from point of view of surface roughness.

Experimental Study of Tool Wear when Milling Tropical Wood with Various Tool Materials

The paper presents a study on the performance of cutter tip for wood milling process. The tests were performed with the tropical wood samples which were milled in the double sided wood planer, the measured micro-geometrical parameters encompassing the linear wear and tooltip radius. The study primarily contributes to developing a far better understanding of the physical nature of cutting tool wear in response with the growing concern of many researchers. Given this basis, it does not only assist the selection of reasonable cutting tool but also enable the detection of the patterns in the cutting tool wear process. In terms of tool wear and bluntness, there has been a number of researches taking account into the physical nature of cutting tools, - providing basis for selection of cutting tools apart from clarification of the current pattern of tool wear and bluntness. The load applied to the cutter during wood milling is the load that changes marks periodically. When starting to work after tool sharpening and finishing, the first stage changes the microscopic geometry - tool run-in process (rapid initial wear), followed by constant conditions of wear before a rapid wear which leads to failure at last. The objective of this study is to determine the influence of the cutting path to the tooltip radius and linear wear of the cutting edge. The paper employs method of least squares and variance analysis in application of the Minitab software to determine regression equations for relation of the tooltip radius and linear wear to the relative cutting length. The ultimate goal is to predict the life of cutting tool when milling tropical wood.

Experimental study on cutting factors of multi-layer machining for large aerospace thin-walled structural parts

Large aerospace thin-walled structures will produce deformation and vibration in the machining process, which will cause machining error. In this paper, a cutting experimental method based on multi-layer machining is proposed to analyze the influence of cutting tool, cutting path, and cutting parameters on machining error in order to obtain the optimal cutting variables. Firstly, aiming at the situation that the inner surface of the workpiece deviates from the design basis, the laser scanning method is used to obtain the actual shape of the inner surface, and the method of feature alignment is designed to realize the unification of the measurement coordinate system and machining coordinate system. Secondly, a series of cutting experiments are used to obtain the machining errors of wall thickness under different cutting tools, cutting paths, and cutting parameters, and the variation of machining errors is analyzed. Thirdly, a machining error prediction model is established to realize the prediction of machining error, and the multi-objective optimization method is used to optimize the cutting parameters. Finally, a machining test was carried out to validate the proposed cutting experimental method and the optimal cutting parameters.

An Optimal Algorithm for Planning Shearer Trailing Drum Cutting Path

The intelligent adaptive cutting of the shearer is one of the key technologies to realize the intelligent working face. However, since the “memory cut” technology is the mainstream technology, which cannot actively adapt to the coal seam variations, the trailing drum usually cuts at a fixed height without a planned cutting path. This paper analyzes the shearer’s location characteristics before and after the advancement to propose a complete calculation method for the advancing path of the shearer, which simulates all of its possible advancing paths for subsequent n cuttings. The multitree and depth-first search algorithms are utilized to filter out the optimal advance path under different mining requirements. Simultaneously, this paper indicates that the vertical curvature of the armored face conveyor (AFC) should be considered in the calculation process of the optimal advancing path at different positions of the working face to obtain the shearer’s planned cutting path for subsequent n cuttings. The proposed algorithm in this paper has apparent advantages over the “memory cut” technology and provides a good solution for the intelligent planning of cutting and pitch steering of the shearers.

Dynamic Update Method of Working Face Geological Model Driven by Multi-Source Data

In order to build a high-precision dynamic geological model to serve the intelligent mining, working face is explored step by step through the comprehensive prospecting technology. A multi-source data fusion method was applied to realize mutual verification, supplement, fusion and interpretation of non-uniform heterogeneous geological data to obtain a high-precision geological data volume. Also, the dynamic update model method was proposed to update 3D geological model of working face quickly so that the accuracy of the geological model can be improved effectively. Furthermore, cutting path planning technology was developed based on the dynamic geological model. The field test showed that the cutting path planning based on the high-precision dynamic geological model can improve the coal mining efficiency and improve the fusion efficiency between geology and coal mining systems. Dynamic update of multi-attribute geological information should be studied and developed to improve the automatic level of mining driven by geological data.

Full coverage cutting path planning of robotized roadheader to improve cutting stability of the coal lane cross-section containing gangue

The purpose of this work is to improve the cutting stability of robotized roadheader through the full coverage cutting path planning of the coal lane cross-section containing gangue. Cutting gangue will bring serious pick wear and severe vibration, which will reduce the service life of robotized roadheader. Therefore, the strategy that avoiding the gangue and cutting the remaining coal-rock was recommended. Firstly, the environment grid map of the cross-section containing gangue was established and the grid attribute was assigned. To describe the arbitrary position of gangue, a random generation method was developed. On this basis, the combination of biologically inspired neural network (BINN) and floating template method was proposed to overcome the shortcomings of traditional BINN and the full coverage cutting path planning simulation was carried out. The simulation shows a better result that the average repetition rate is approximately 10% under the condition that the cutting coverage rate is more than 95%. Finally, the cutting experiment of the coal-rock sample containing gangue on the robotized roadheader cutting platform was performed. Based on the infrared thermography and cutting signal obtained by the previous round cutting, the cutting path of the second round was planned and the cutting experiment was conducted. The experiment results show that the cutting temperature rise and the cutting vibration of the second round cutting can be effectively reduced by approximately 60% and 90%, which demonstrated that the cutting stability of the cross-section containing gangue can be effectively improved by the cutting path planning strategy of avoiding gangue.

Determination of optimal coordinates for switching processing cycles on metal-cutting machines

Introduction. One of the ways to improve the efficiency of processing on machines is to coordinate the CNC program with the changing properties of the dynamic cutting system. If this takes into account the tool wear and the associated with it changes in the parameters of the dynamic cutting system, then the cutting speed to ensure the minimum wear rate is reduced along the cutting path. The corresponding feed rate is reduced even faster, since it is necessary to ensure a constant deformation displacement of the tool relative to the workpiece. The evolution of the properties of the cutting process (for matching with which the trajectories of the operating elements of the machine are corrected) depends on the power of irreversible transformations of the energy supplied to cutting. This reduces the processing efficiency. Therefore, a new for the considered subject area problem of determining the coordinates of the tool movement relative to the workpiece is formulated, starting from which further processing is economically inexpedient. In this case, it is necessary, after processing the next part, to ensure the replacement of the tool and carry out its changeover. Subject. A metal-cutting machine of a turning group, the trajectories of the executive elements of which are controlled, for example, by a CNC system. The purpose of the work. Mathematical simulation and methods for determining the coordinates at which it is necessary to replace the tool. Method and methodology. The necessary conditions for the optimality of determining these coordinates are proved. Mathematical tools are provided that allow calculating the coordinates at which the given manufacturing costs take the minimum value according to the given trajectories. The probabilistic characteristics of evolutionary trajectories are taken into account. Results and discussions. The analysis of the efficiency of using the technique in industry depending on the cost of the machine and tool together with its replacement and readjustment is given. The proven optimality conditions and the given mathematical tools complement the knowledge about the optimization of controlled machining processes on machines. Conclusions. The results of the study show new options for the organization of tool replacement, aimed at improving the efficiency of processing by software methods using a CNC system.