Elsevier BVActa Medica Okayama2590-1230292026Unified 2D polygon-based CAM framework integrating tool path generation, machinability evaluation, and cutting-force simulation108948ENKazukiKanekoFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityHirotoTakayasuGraduate School of Science and Engineering, Ibaraki UniversityAtsuyaSuzukiMechanical Systems Engineering Program, Okayama UniversityHiroyukiKodamaFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityThis study proposes a unified two-dimensional (2D) polygon-based computer-aided manufacturing (CAM) framework that enables tool path generation, machinability evaluation, material removal simulation, and cutting-force prediction within a single computational environment. The proposed method represents three-dimensional geometries as aggregates of orthogonal 2D polygon sets, obtained by slicing the model in the xy-, yz-, and zx-parallel planes and superposing the three polygonal datasets. A novel convolutional offsetting algorithm is developed to perform three-dimensional inflation and shrinkage by incorporating adjacent cross-sectional relationships, thereby achieving accurate 3D offsets independent of the slicing orientation. The inflated 2D polygons are directly utilized to generate contour and scanning tool paths, and sequential inflation–shrinkage analysis enables visualization of unmachinable regions for tool accessibility evaluation. Furthermore, the framework integrates an instantaneous cutting force model that accurately predicts the cutting force waveform by detecting intersections between the cutting edge points and 2D polygon aggregations. The system is experimentally validated via ball-end milling. The results demonstrate that tool paths can be generated in under one minute using only a CPU. Furthermore, the simulated cutting forces closely align with experimental measurements. These findings demonstrate that the proposed 2D polygon-based framework provides an efficient and extensible foundation for integrating mechanical simulation and tool-path generation.No potential conflict of interest relevant to this article was reported.Fuji Technology Press Ltd.Acta Medica Okayama1883-80221952025Study on an Effective Coolant Supply Method in the Side Plunge Grinding Process939948ENLingxiaoGaoGraduate School of Natural Science and Technology, Okayama UniversityTaichiFujimotoGraduate School of Natural Science and Technology, Okayama UniversityHiroyukiKodamaFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityKazuhitoOhashiFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityGrinding is widely used for finishing components with journal and thrust surfaces, such as crankshafts. Side-plunge grinding enables the simultaneous finishing of thrust and cylindrical surfaces in a single plunge. However, compared to cylindrical grinding, it involves a larger contact area between the grinding wheel and the workpiece, leading to increased heat generation. In particular, poor coolant penetration near internal corners can degrade surface quality, potentially causing stress concentrations and cracks. To enhance coolant effectiveness in side-plunge grinding, this study installs a high-pressure nozzle that supplies coolant from the side of the grinding wheel. The effectiveness of this setup is experimentally verified. Additionally, the distribution of coolant flow within the contact area between the grinding wheel and the workpiece is measured to determine the optimal nozzle position for efficient coolant delivery. The nozzle’s performance is evaluated by measuring the workpiece surface temperature using a wire/workpiece thermocouple, the amount of coolant discharged from the grinding wheel, and the residual stress distribution. The results show that coolant penetrates the grinding wheel and effectively reaches the grinding zone, enhancing the cooling effect. This study clarifies the relationship between effective coolant supply and the position of the side nozzle. Considering physical constraints, such as potential interference during grinding, the optimal nozzle location is as close as possible to both the edge of the grinding wheel and the workpiece. This positioning ensures maximum coolant delivery, reduces grinding temperature, and helps suppress drastic variations in residual stress.No potential conflict of interest relevant to this article was reported.日本機械学会Acta Medica Okayama2187-9761919462025ボールエンドミルの突き出し長さに応じた切削条件補正システムの開発24-00128ENHiroyukiKODAMAFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityYukiMORIYAGraduate school of Environmental, Life, Natural Science and Technology, Okayama UniversityTatsuoMORIMOTOGraduate school of Environmental, Life, Natural Science and Technology, Okayama UniversityKazuhitoOHASHIFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityIn the field of die and mold machining, determining appropriate cutting conditions is crucial. Factors such as tool geometry, machining path, work material characteristics, machining efficiency, and finishing accuracy must be taken into consideration. However, the current method of determining cutting conditions relies heavily on the intuition and experience of skilled engineers, and there is a need for a system to replace such knowledge. One of the critical factors affecting machining accuracy and efficiency is the tool overhang length, which is directly related to tool geometry. Unfortunately, there is no clear guideline for its determination. In a previous study, researchers developed a system to quickly derive cutting conditions using a data mining method and Random Forest Regression (RFR) applied to a tool catalog database. In this study, we constructed a new cutting condition compensation system based on the existing model, which accounts for the tool overhang length. The results of cutting experiments under high aspect ratio overhang lengths confirm that the correction coefficients proposed by the system are significant.No potential conflict of interest relevant to this article was reported.Fuji Technology Press Ltd.Acta Medica Okayama1883-80221932025Study on the Grinding Temperature of Workpiece in Side Plunge Grinding Process337345ENLingxiaoGaoGraduate School of Natural Science and Technology, Okayama UniversityMotokiKuidaGraduate School of Natural Science and Technology, Okayama UniversityHiroyukiKodamaFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityKazuhitoOhashiFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityGrinding is used to finish thrust metal attachment parts, such as crankshafts, which have both journal and thrust surfaces. In side plunge grinding, a thrust surface and a cylindrical surface of a shaft workpiece with collars are finished in a single plunge grinding process. However, the surface quality near the ground internal corner, where grinding fluid may not penetrate, can deteriorate, causing high residual stress and cracks owing to grinding heat. While it has been reported that quality issues at the inner corners of the ground surface can be mitigated by reducing the grinding point temperature through efficient cooling fluid supply, the mechanisms of grinding phenomena and heat generation in side plunge grinding are not yet fully understood. In this study, the variations in the grinding temperature at the thrust surface of a workpiece with a collar were experimentally investigated using a wire/workpiece thermocouple to clarify these phenomena. The results revealed a significant increase in the grinding temperature at the corners of the grinding zone. However, it slightly decreases as the thermocouple output approaches the center of the workpiece, indicating a slight effect of the grinding speed. The surface temperature of the workpiece in side plunge grinding is primarily influenced by the wheel depth-of-cut in the thrust direction. Additionally, the effect of workpiece rotational speed and grinding infeed speed on temperature distribution has been demonstrated.No potential conflict of interest relevant to this article was reported.Japan Society of Mechanical EngineersActa Medica Okayama1881-30541912025Development of tool life prediction system for square end-mills based on database of servo motor current valueJAMDSM0001ENHiroyukiKODAMAFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityMakotoSUZUKIGraduate school of Environmental, Life, Natural Science and Technology, Okayama UniversityKazuhitoOHASHIFaculty of Environmental, Life, Natural Science and Technology, Okayama UniversityAccurate prediction of tool life is crucial for reducing production costs and enhancing quality in the machining process. However, such predictions often rely on empirical knowledge, which may limit inexperienced engineers to reliably obtain accurate predictions. This study explores a method to predict the tool life of a cutting machine using servo motor current data collected during the initial stages of tool wear, which is a cost-effective approach. The LightGBM model was identified as suitable for predicting tool life from current data, given the challenges associated with predicting from the average variation of current values. By identifying and utilizing the top 50 features from the current data for prediction, the accuracy of tool life prediction in the early wear stage improved. As this prediction method was developed based on current data obtained during the very early wear stage in experiments with square end-mills, it was tested on extrapolated data using different end-mill diameters. The findings revealed average accuracy rates of 71.2% and 69.4% when using maximum machining time and maximum removal volume as thresholds, respectively.No potential conflict of interest relevant to this article was reported.Fuji Technology Press Ltd.Acta Medica Okayama1883-80221752023Effect of Vibration Behavior in Low-Frequency Vibration Cutting on Surface Properties of Workpiece434448ENHiroyukiKodamaOkayama UniversityShotaMatsunoOkayama UniversityNaoyukiShibataOkayama UniversityKazuhitoOhashiOkayama University The objective of this study was to determine the effect of vibration behavior on workpiece surface properties in low-frequency vibration cutting. The effects of the parameters that determine vibration behavior on surface roughness were quantitatively evaluated through a comparison with other cutting conditions. Furthermore, by clarifying how the surface properties of the workpiece, such as roughness, roundness, and cross-sectional curves, change depending on the vibration behavior, a search for optimal conditions for low-frequency vibration cutting was conducted. The best surface properties were obtained under the condition of spindle rotation per vibration E=4.5. By using a value close to the minimum possible spindle rotation R=0.5 when the workpiece is retracted, it is expected to be effective in suppressing the variation in surface roughness at each phase angle; this variation is characteristic of low-frequency vibration cutting. Workpieces machined under low-frequency vibration conditions such as (E=2.5, R=1.0) and (E=3.5, R=1.0) were found to form characteristic surface patterns on the workpiece surface owing to a phenomenon in which the depth of the cut to the workpiece changes.No potential conflict of interest relevant to this article was reported.ElsevierActa Medica Okayama0141-6359652020Thermal influence on surface layer of carbon fiber reinforced plastic (CFRP) in grinding5363ENHiroyukiKodamaOkayama UniversityShingoOkazakiOkayama UniversityYifanJiangOkayama UniversityHiroyukiYodenIndustrial Technology Research Institute of Okayama Prefectural GovernmentKazuhitoOhashiOkayama UniversityIn this study, we investigated thermal influence on surface layer of CFRP in grinding with heat conduction analysis using grinding temperature at wheel contact area on dry and wet condition. Moreover, the thermal affected layer was analyzed through an experiment to examine the temperature of glass transition and thermal decomposition of the matrix resin that composes the CFRP used in this study. The influence of thermal effect on grinding of CFRP was verified based on observation of ground surface finish after grinding using SEM and the measurement of surface roughness. From the measurement result of DSC (Differential Scanning Calorimetry)，TG-DTA (Thermogravimetry-Differential Thermal Analysis), It was found that the thermal affected layer of CFRP includes a layer in which the matrix resin is changed in quality by exceeding the glass transition temperature and a layer in which the matrix resin is thermally decomposed by exceeding the thermal decomposition temperature. In addition, it was found that the surface roughness was significantly reduced if the thermal affected layer with thermal decomposition was generated. In each grinding atmosphere, it tended to increase of grinding temperature at wheel contact area with increasing in the setting depth of cut. In the case of dry grinding, grinding temperature at wheel contact area increased up to t thermal decomposition temperature of the matrix resin. However, in the case of the wet grinding, grinding temperature at wheel contact area did not increase until thermally decomposition temperature. From the result of simulation about thermal affected layer, influence of grinding heat increased with increasing in the setting depth of cut. Ultimately, the thermal affected layer with thermal decomposition was generated in dry grinding. Moreover, from the results of SEM observation, it was confirmed that the surface finish properties deteriorated significantly due to thermal decomposition of the matrix resin in the case of Δ = 400 μm in the setting depth of cut at fiber angle θ = 0°. On the other hand, it was confirmed that the micro damage of carbon fiber was occurred in wet grinding at each setting depth of cut.No potential conflict of interest relevant to this article was reported.