Papers by Keyword: Tool Wear

Abstract: Accurate prediction of tool Remaining Useful Life (RUL) is essential for reliable and cost-effective milling, particularly when machining commercially pure titanium (CP-Ti), where tool wear is highly irregular. In industrial practice, continuously varying cutting conditions further complicate tool condition monitoring and life prediction. This paper proposes a vibration-based monitoring framework for RUL prediction under strongly variable milling conditions. A hybrid deep learning model based on CNN–BiLSTM is developed to capture the non-stationary relationship between vibration signals and tool degradation. Performance is compared between a spindle-mounted, non-invasive sensor and a tri-axial accelerometer mounted on the machine table, and the benefit of sensor fusion is assessed. Results show that spindle vibration correlates strongly with tool degradation and achieves predictive performance close to that of multi-sensor configurations, while requiring minimal instrumentation. The proposed approach remains robust under variations in both operating conditions and wear mechanisms, enabling reliable RUL estimation in non-stationary milling environments.

Abstract: Composite fiber products and components are widely used in various industries, from highly stressed structural elements in the aerospace industry to sports equipment. In order to achieve the desired final shape, these materials are often subjected to various machining methods. Due to the inhomogeneous structure of composites and the different physical and mechanical properties of the matrix and reinforcement, specific problems arise during machining, such as delamination, intensive tool wear, increased temperature in the cutting area, or poor surface finish.This work deals with the observation of delamination size, wear, and cutting forces when drilling holes in carbon composites with tools with different rake angles. The result of this work is a recommendation for the geometry of tools for drilling this type of carbon composite.

Abstract: The research is concerned with obtaining basic knowledge in the field of machining biocomposite materials with hemp fibers and a matrix in the form of a mixture of polyester and methyl methacrylate resin in a secret ratio. The research was focused on milling technology, or rather side milling. For the needs of the research, 3 milling tools were selected with which experimental measurements were performed. Each tool was different in its type of sharpened geometry, both standard and specialized, including one coated. The experimental measurements focused on the size and course of wear of the cutting edge of the tools, the roughness value of the machined surface and the size and type of delamination of the upper and lower layers of the biocomposite material under investigation. The obtained results helped to evaluate the machinability of the selected hemp biocomposite and at the same time determined the future direction of research with regard to the design of a suitable cutting geometry of the tool and the overall optimization of the machining process during side milling.

Abstract: Many of the previous studies on cutting properties have compared various steels with a same heat treatment, and there are almost no studies that focus on the differences in heat treatments of a same material. In this report, the influence of different heat treatments on tool wear of high-carbon steel (C55) is experimentally investigated in turning process. This study focused on three heat treatments: quenching and tempering, normalizing, and spheroidization annealing. We divided flank wear into 3 areas (corner, middle area and groove wear) for observation and analyzed each characteristic. It is found that for C55, regardless of heat treatment types, wear at the corner of the insert tip is highly dependent on cutting speed, whereas the dependence is lower where it is far away from the corner. This result is considered to be due to the adhesion that occurs while cutting. Therefore, selecting the cutting speed that minimizes flank wear at the corner can control tool wear and extend tool life. In terms of real-time monitoring for tool replacement, the correlation coefficient between the flank wear and the sensing data (spindle current, feed-axis servo motor current, and cutting sound) is also considered to depend on the adhesion condition at the insert tip. If adhesion occurs, the correlation coefficient is not stable and it’s likely to be difficult to predict wear trend to check the end of a tool life. Adhesion makes tool wear prediction using the sensing data difficult.

Abstract: Tool life is recognized as a critical factor in finishing a fine surface as well as high machining accuracy in cutting operation. The tool wear progress, therefore, should be evaluated in cutting simulation before the operation. This paper presents an analysis of tool wear rate during a rotation of tool in fly cutting as a manner of gear machining. The distribution of tool wear rate is analyzed with the stress and the temperature on the rake face based on a tool wear characteristic equation. The cutting force is estimated in a chip flow model, which piles up the orthogonal cuttings in the plane containing the cutting and the chip flow directions. The chip flow direction is determined to minimize the cutting energy. Then, the cutting temperature is analyzed numerically in the finite volume method, where the mechanical energy is converted to the heat generation in the shear zone and the rake face. In the fly cutting, the stress and temperature change with the uncut chip thickness and the tool-chip contact area during a rotation. Therefore, the instantaneous tool wear rates are analyzed for the rotation angles by the stress and the temperature distributions. This paper demonstrates an example of the tool wear analysis in cutting processes of a carbon steel. A cutting test was conducted to identify the force model with the orthogonal cutting data used in the analysis. Then, the temperature and tool wear distributions on the rake face are analyzed with the uncut chip thicknesses and the tool-chip contact areas.

Abstract: Because of their extraordinary qualities, titanium alloys are very sought-after materials that can be applied to a wide range of sectors. Excellent mechanical and chemical qualities, including a high strength-to-weight ratio and resistance to corrosion, are present in it. The special properties of these alloys make machining them extremely difficult. As frequent tool wear occurs throughout the machining process, Computer Numerical Control (CNC) milling has become a potential method for machining titanium alloys due to its precision and versatility. This review article provides a comprehensive overview of the development of titanium alloy CNC milling, with an emphasis on the effects of cutting tool geometries and materials on machining efficiency. The process examines several aspects of cutting circumstances, including depth of cut, speed, feed rate, and lubrication techniques, and optimizes machining parameters and procedures to achieve the best results. Surface integrity and quality, surface roughness, residual stresses, and microstructural changes brought about by CNC milling are the main points of evaluation.

Abstract: In machining of difficult-to-cut materials, increase of temperature in tool tip is one of the main reasons resulting in short tool life. Heat can promote adhesion wear and diffusion wear at rake face, accelerate thermal plastic deformation. Furthermore, heat could also accelerate flank wear and promote adhesion wear at flank face. As a result, machining precision of tool will become worse. The common method applied to reduce temperature of tool tip is cutting with coolant supply. Conventional coolant supply is only effective to cool down areas around cutting zone with low pressure when cutting speed is low. When higher cutting heat is generated, the fluid can be vaporized to form a high-temperature steam barrier and most of the fluid suppled does not penetrate in the area adjacent to cutting zone. However, high pressure coolant might overcome the disabilities of flood coolant in milling. Present relevant research focused on effect of ultra-high pressure coolant (UHPC) on rake face mainly. In this study, to improve the machining efficiency (processing time) by using end mill, a prototype of end mill with internal coolant nozzles (both rake side and flank side) was designed and CFD (Computational Fluid Dynamics) simulations were conducted to find out the relatively effective coolant supply method for coolant penetrating in cutting zone of flank face mainly. Beyond that, effects of UHPC on rake face were also examined. During the latest experiments, tool wears, cutting length and roughness of work material were measured under both dry and wet cutting conditions. For wet cutting, three kinds of coolant supply method were applied: flank face only, rake face only and both rake face and flank face. For each method, coolant was supplied under the pressure of 3MPa, 7MPa, 14MPa and 20MPa. Tool wear was significantly reduced, and roughness was improved by high pressure coolant supply.

Abstract: Carbon Fiber-Reinforced Polymer (CFRP) has been in great demand in the aerospace and automotive industries due to its exceptional strength-to-weight ratio. Machining CFRP is a challenge as dry machining results in high cutting temperature especially with high cutting speeds that compromise the glass transition temperature (Tg) and degrades the matrix resin epoxy. A sustainable cutting environment such as chilled air is utilized as an alternative cutting media in reducing the heat generated during machining process to reduce the tool wear and improved the surface quality of the CFRP. Therefore, this research is conducted to study the progression of uncoated tungsten carbide (WC-Co) tool wear when milling CFRP in a three different cutting conditions which are dry, coolant and chilled air with a constant cutting parameter. The CFRP was milled with a constant speed of 170 m/min, feed rate of 2100 mm/min and 1 mm depth of cut for a total of 6000 mm machining length. It was found that milling in chilled air resulted in the highest flank wear of 0.110 mm, which is higher compared with dry and coolant cutting condition. This is contributed by the additional abrasion of CFRP dust-like chips on the cutting edge of the carbide tool. The presence of the chilled air during milling of CFRP aided in maintaining the surface hardness thus resulted in increasing of tool wear as compared with dry and coolant cutting conditions.

Abstract: The aim of this study is predict tool wear in the fine-blanking process using a tribometer tester with ASTM G99-17 standard. Then, the result of wear volume and tool life were confirmed with finite element simulation and experiment. The punch material used in fine blanking process was selected to be hight speed steel JIS.SKH51 with surface coating thickness 4 µm of TiCN, the work piece material was used as hot-rolled steel JIS.SPHD P/O, with a thickness of 8 mm. The experimented and simulated results were found that the pressure, and sliding velocity were increase in term of linear curve with slope K = 2.09x10^-6 and K = 2.07x10^-6 ,respectively, and the hardness of material was increase in term of power at 1.983 and slope of K = 2.14 x10^-6. These three factors were effect to the wear volume and tool life, simultaneously, the summation of three factors will average as K = 2.10 x10^-6. From comparison of the applied wear equation model with tribology tester the simulated and experimented results were similarly equal with 0.05 by significance at 95% reliability confident. The resulted were precisely confirmed according to the previous research.

Abstract: Hard materials are widely used in industry due to qualities such as strong fatigue strength and the ability to maintain strength at a high temperature. Still forming certain raw materials into the appropriate shapes is the challenge in subtractive manufacturing industries and these materials are categorized as hard to machine material. To solve this problem Heat Assisted Machining (HAM) is an emerging and most dominating method, which requires an external heat source subjected to the workpiece either before or during the machining to increase the ductility. As a result, the workpiece yield and shear strength are reduced. This is an advanced technique to enhance the tool’s life, and productivity. The present paper provides in-depth knowledge of thermal assisted machining process where various heat sources are used like laser, plasma, LPG, Induction heating and etc. The comparison analysis between various heat sources is made and their impact on various parameters like tool wear, material removal rate, surface roughness, stability and etc. were illustrated and provide the novel approach for selecting the correct heat-assisted technique which is used for turning process in order to increase the machining process.