单晶金刚石刀具后刀面沟槽磨损的石墨化生成过程分析

单晶金刚石刀具切削单晶硅时后刀面会发生剧烈沟槽磨损,严重影响零件加工质量和刀具寿命。为了从金刚石石墨化转变角度揭示沟槽磨损生长扩展机制,建立了金刚石刀具后刀面具有初始沟槽的分子动力学模型,模拟了切削单晶硅时初始沟槽处的工件材料流动行为与金刚石刀具晶体结构变化情况。结果表明,初始沟槽的存在改变了工件材料的流动状态;并且这种材料流动引起了刀具初始沟槽附近温度和能量的变化,温度升高了8%,势能提高了1.4%;通过分析金刚石刀具晶体结构发现,初始沟槽处的刀具材料发生了石墨化转变,并通过计算采样点处原子间键角,得到了石墨化转化率随着切削的进行不断升高,并最终趋于恒定的规律,当切削进入到稳定切削阶段时,石墨化转化率约为6%。     

如何教好金属切削机床课程

金属切削机床是现代机械制造业中最重要的加工设备。对机械制造工艺与设备专业来说，金属切削机床课程是很重要的一门专业课。如何教好这门课，本文提出了自己的见解。     

Real-Time Tool Detection for Workflow Identification in Open Cranial Vault Remodeling

Deep learning is a recent technology that has shown excellent capabilities for recognition and identification tasks. This study applies these techniques in open cranial vault remodeling surgeries performed to correct craniosynostosis. The objective was to automatically recognize surgical tools in real-time and estimate the surgical phase based on those predictions. For this purpose, we implemented, trained, and tested three algorithms based on previously proposed Convolutional Neural Network architectures (VGG16, MobileNetV2, and InceptionV3) and one new architecture with fewer parameters (CranioNet). A novel 3D Slicer module was specifically developed to implement these networks and recognize surgical tools in real time via video streaming. The training and test data were acquired during a surgical simulation using a 3D printed patient-based realistic phantom of an infant’s head. The results showed that CranioNet presents the lowest accuracy for tool recognition (93.4%), while the highest accuracy is achieved by the MobileNetV2 model (99.6%), followed by VGG16 and InceptionV3 (98.8% and 97.2%, respectively). Regarding phase detection, InceptionV3 and VGG16 obtained the best results (94.5% and 94.4%), whereas MobileNetV2 and CranioNet presented worse values (91.1% and 89.8%). Our results prove the feasibility of applying deep learning architectures for real-time tool detection and phase estimation in craniosynostosis surgeries.     

实际工况下的包络环面蜗杆设计参数优化

平面二次包络环面蜗杆因具有承载能力大,润滑性能好,传动效率高等优点而得到广泛应用,但这种蜗杆传动对误差和受载变形的影响敏感.在实际工况条件下,作者基于传动副的实体模型,采用3-D接触有限元方法综合分析了平面二次包络环面蜗杆的母平面倾斜角β、蜗杆分度圆直径系数k1、主基圆直径系数kb和I传动比对传动副啮合性能和承载能力的影响,认为选取较大的母平面倾斜角β和较大的蜗杆分度圆直径系数k1对传动副的传动质量有利.这为在工程实际中结合具体工况优选设计参数提供了参考依据.     

工具钢——碳钢复合板爆炸焊接试验研究

针对T10工具钢与碳钢（A3钢）复合板爆炸焊接试验中易出现的列纹、嘣块以及四周不易焊合现象进行了分析,并提出了解决的工艺措施,通过对16块面积为0.5-1m^2工具钢－碳钢复合板的生产,取得了焊合率大于98％且无裂纹的良好结果。     

Precision removal of ITO layer using plate-form tool design

An ITO layer is produced using semiconductor techniques, although the defect rate during production is easily seen. Current work presents a new modus of electrochemical machining using a ‘design recycle’ system offering faster performance in removing the color filter surface’s ITO layer. Higher electrical current is not required when an effective feeding electrode is used to reduce the response area. Through establishing an ultra-precise recycling process to remove the thin film microstructure, this helps the semiconductor optoelectronic industry to reduce both production costs and pollution. The design features of the removal processes for a thin film and the tool design of plate-form electrode are of major interest. In the current experiment, the author utilizes a 5th Generation TFT-LCD. The design of tool electrodes is used with continuous and pulsed direct current in the electrochemical machining experiment. High rotational speed of the tool electrodes and high flow velocity of the electrolyte elevates the discharge mobility and improves the removal effect. Pulsed direct current can improve the effect of dregs discharge and is advantageous to associate with the fast feed rate of the workpiece. A color filter with a fast feed rate is combined with enough electric power to provide highly effective removal. A smaller end radius and a thin plate-form positive-electrode provide a larger discharge space and better removal effect. A precision recycling process is presented using an effective plate-form positive-electrode in electrochemical machining. It only needs a short period of time to remove the ITO layer easily and cleanly.     

利用扫描电镜分析砍创性骨外伤的研究

在大型显微镜下,对锐器（单刃刀）和钝器（短柄斧）形成的骨外伤的微观形态进行了分析研究．结果表明：通过特征识别骨外伤的砍切痕迹,往往误差较大,某些肉眼看不见的三维特征通过微观分析可以清晰地识别．着重强调扫描电镜（SEM）在骨外伤鉴定中,具有重要的使用价值．     

在组织中实践基于模型的系统工程

 基于模型的系统工程（MBSE）要解决复杂系统工程的问题,需要通过信息、计算和软件来架设传统系统与各领域工程（嵌入式、安全、结构等）之间的桥梁。综合产品团队使MBSE的有效方式可以有效降低实践风险,同时MBSE工具链和集成开发环境的成熟度也是制约实践效果的重要影响因素。全面数字化趋势引领的第4次工业革命中,MBSE向数据主线/数字工程等演进的趋势日趋显著。面向未来,必须认识到MBSE和产品数据管理/产品生命周期管理集成,以及在数字工程和数字主线大背景下理解和再造MBSE的必要性。     

液中放电沉积技术研究进展

液中放电沉积是一种新型的表面改性技术,起源于电火花加工技术,可在金属表面制备出具有高硬度、高耐磨性以及高结合力等优良性能的沉积层。此外,该技术不污染环境,有望替代部分常用但具有污染性的表面改性技术。液中放电沉积技术的核心内容为沉积层形成机制、工具电极材料以及介电流体成分。简单介绍了液中放电沉积技术的特点,重点阐述了沉积层的形成机制以及缺陷优化工艺,并从工具电极材料、介电流体成分和实际生产应用三个方面总结了液中放电沉积技术的国内外研究进展,展望了该技术的发展方向。