The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of w...The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of wear zone of each end mill were analyzed, and three tool wear criterions of small-diameter end mills were defined. With the uEye camera, macro lens and 3-axis micro milling machine, it was proved the feasibility of measuring flank wear with the milling tests on a 45# steel workpiece. The design of experiment （DOE） showed that Vc was the most remarkable effect factor for the flank wear of small-diameter end mill. The wear curve of the experiments of milling was very similar to the Taylor curve.展开更多
Five-axis ball-end milling is commonly used to machine the complex surfaces. Local tool interference phenomenon which often occurs in five-axis milling should be urgently solved. In this paper, a simplified method to ...Five-axis ball-end milling is commonly used to machine the complex surfaces. Local tool interference phenomenon which often occurs in five-axis milling should be urgently solved. In this paper, a simplified method to detect the occurrence of local tool interference and modify tool position is proposed. First, the detection matrix is established to detect local tool interference at all the cutter location points on tool path simultaneously in five-axis ball-end milling of complex surfaces. The algorithm of detection matrix based on point arithmetic is simple. Secondly, the new coordinates of the modified interfering-free points are obtained precisely by using the genetic algorithm. The feasibility of the method is validated by simulation in Matlab. This research is benefit to simplify the calculation of local tool interference detection and tool position modification.展开更多
目的评价常用的安宁疗护筛查工具识别急诊科患者安宁疗护需求的准确性。方法计算机检索中国知网、万方数据库、中国生物医学文献数据库、PubMed、Cochrane Library、Embase、CINAHL、Web ofScience等数据库,从建库至2023年11月所有有关...目的评价常用的安宁疗护筛查工具识别急诊科患者安宁疗护需求的准确性。方法计算机检索中国知网、万方数据库、中国生物医学文献数据库、PubMed、Cochrane Library、Embase、CINAHL、Web ofScience等数据库,从建库至2023年11月所有有关安宁疗护筛查工具应用于急诊科患者的研究,由2名研究者独立进行文献筛选、资料提取和文献质量评价,采用Stata 15.0软件对资料数据进行Meta分析。结果共纳入20篇文献,包含20122例患者,一共涉及6种筛查工具,其中最常用的是惊讶问题(Surprise Questions,SQ)(n=9),其次是急诊安宁疗护快速筛查工具(the Palliative Care and Rapid Emergency Screening,P-CaRES)(n=7)及急诊科姑息治疗和临终关怀需求筛查工具(the Screen for Palliative and End-of-life care needs in the Emergency Department,SPEED)(n=2)。9项研究通过评估SQ预测患者病死率从而确定安宁疗护需求,总体而言,SQ预测病死率的敏感度为0.72(0.59,0.82),特异度为0.74(0.62,0.84),均为中等。SQ预测长期病死率(1年内、2年内)的敏感度0.75(0.64,0.84)高于预测短期病死率(1个月内、3个月内)的敏感度0.65(0.35,0.86)。此外,就1年内急诊入院或频繁急诊科就诊而言,SQ敏感度为0.72(0.41,0.90)、特异度为0.52(0.32,0.72)。P-CaRES预测安宁疗护需求合并敏感度为0.73(0.57,0.85)、特异度为0.64(0.48,0.77)。结论用于急诊科安宁疗护筛查的工具中SQ应用最广泛,其次是P-CaRES,两种工具在预测患者未来1年病死率方面均具有中等敏感度和特异度,但该结论仍需高质量、大样本研究进一步验证。展开更多
In this article, the results obtained from a study carried out on the some elements-incorporated diamond-like carbon (DLC) films are reported. All the films were deposited using plasma-based ion implantation (PBII) te...In this article, the results obtained from a study carried out on the some elements-incorporated diamond-like carbon (DLC) films are reported. All the films were deposited using plasma-based ion implantation (PBII) technique. The deposited films were annealed at 400℃, 650℃ and 900℃ in an air atmosphere for 1 hour. The effects of adding hydrogen, silicon/oxygen and silicon/nitrogen into the DLC film on chemical composition, friction coefficient and corrosion resistance were investigated. The films coated micro end mills performance was also assessed. The results indicate that all the films showed almost constant atomic contents of C, Si, O and N until annealing at 400℃. However, the films were completely destroyed at 650℃ with the increased Si and O contents, while the C content decreased. The incorporation of silicon/oxygen and silicon/nitrogen into the DLC exhibited lower values of friction coefficients than the hydrogenated DLC (DLC and H-DLC) before and after annealing at 400℃, whereas all the films presented the same values of friction coefficients after annealing at 650℃ due to the completely destroy of the films. Furthermore, the incorporation of silicon/nitrogen into the DLC also exhibited better corrosion resistance and unbroken micro end mills performance on their surfaces. Thus, the incorporation of silicon/nitrogen into the DLC film can be considered beneficial in improving the micro end mills performance.展开更多
基金Supported by the Ministerial Level Advanced Research Foundation(51318020309)
文摘The objective of this study was to develop an online tool-wear-measurement scheme for small diameter end-mills based on machine vision to increase tool life and the production efficiency. The geometrical features of wear zone of each end mill were analyzed, and three tool wear criterions of small-diameter end mills were defined. With the uEye camera, macro lens and 3-axis micro milling machine, it was proved the feasibility of measuring flank wear with the milling tests on a 45# steel workpiece. The design of experiment （DOE） showed that Vc was the most remarkable effect factor for the flank wear of small-diameter end mill. The wear curve of the experiments of milling was very similar to the Taylor curve.
基金Funded by the National Natural Science Foundation of China (No.51575321)the Major Science and Technology Innovation Project of Shandong Province (No.2018CXGC0804)Taishan Scholars Program of Shandong Province (No.ts201712002)
文摘Five-axis ball-end milling is commonly used to machine the complex surfaces. Local tool interference phenomenon which often occurs in five-axis milling should be urgently solved. In this paper, a simplified method to detect the occurrence of local tool interference and modify tool position is proposed. First, the detection matrix is established to detect local tool interference at all the cutter location points on tool path simultaneously in five-axis ball-end milling of complex surfaces. The algorithm of detection matrix based on point arithmetic is simple. Secondly, the new coordinates of the modified interfering-free points are obtained precisely by using the genetic algorithm. The feasibility of the method is validated by simulation in Matlab. This research is benefit to simplify the calculation of local tool interference detection and tool position modification.
文摘目的评价常用的安宁疗护筛查工具识别急诊科患者安宁疗护需求的准确性。方法计算机检索中国知网、万方数据库、中国生物医学文献数据库、PubMed、Cochrane Library、Embase、CINAHL、Web ofScience等数据库,从建库至2023年11月所有有关安宁疗护筛查工具应用于急诊科患者的研究,由2名研究者独立进行文献筛选、资料提取和文献质量评价,采用Stata 15.0软件对资料数据进行Meta分析。结果共纳入20篇文献,包含20122例患者,一共涉及6种筛查工具,其中最常用的是惊讶问题(Surprise Questions,SQ)(n=9),其次是急诊安宁疗护快速筛查工具(the Palliative Care and Rapid Emergency Screening,P-CaRES)(n=7)及急诊科姑息治疗和临终关怀需求筛查工具(the Screen for Palliative and End-of-life care needs in the Emergency Department,SPEED)(n=2)。9项研究通过评估SQ预测患者病死率从而确定安宁疗护需求,总体而言,SQ预测病死率的敏感度为0.72(0.59,0.82),特异度为0.74(0.62,0.84),均为中等。SQ预测长期病死率(1年内、2年内)的敏感度0.75(0.64,0.84)高于预测短期病死率(1个月内、3个月内)的敏感度0.65(0.35,0.86)。此外,就1年内急诊入院或频繁急诊科就诊而言,SQ敏感度为0.72(0.41,0.90)、特异度为0.52(0.32,0.72)。P-CaRES预测安宁疗护需求合并敏感度为0.73(0.57,0.85)、特异度为0.64(0.48,0.77)。结论用于急诊科安宁疗护筛查的工具中SQ应用最广泛,其次是P-CaRES,两种工具在预测患者未来1年病死率方面均具有中等敏感度和特异度,但该结论仍需高质量、大样本研究进一步验证。
文摘In this article, the results obtained from a study carried out on the some elements-incorporated diamond-like carbon (DLC) films are reported. All the films were deposited using plasma-based ion implantation (PBII) technique. The deposited films were annealed at 400℃, 650℃ and 900℃ in an air atmosphere for 1 hour. The effects of adding hydrogen, silicon/oxygen and silicon/nitrogen into the DLC film on chemical composition, friction coefficient and corrosion resistance were investigated. The films coated micro end mills performance was also assessed. The results indicate that all the films showed almost constant atomic contents of C, Si, O and N until annealing at 400℃. However, the films were completely destroyed at 650℃ with the increased Si and O contents, while the C content decreased. The incorporation of silicon/oxygen and silicon/nitrogen into the DLC exhibited lower values of friction coefficients than the hydrogenated DLC (DLC and H-DLC) before and after annealing at 400℃, whereas all the films presented the same values of friction coefficients after annealing at 650℃ due to the completely destroy of the films. Furthermore, the incorporation of silicon/nitrogen into the DLC also exhibited better corrosion resistance and unbroken micro end mills performance on their surfaces. Thus, the incorporation of silicon/nitrogen into the DLC film can be considered beneficial in improving the micro end mills performance.
