数控机床使用中的安全问题

以FANUC系统为例，针对编程时工件坐标系和基准点的设定、书写小数点、调整和取消刀具长度偏置、刀具号与刀具补偿号的核心核对和设定、轮廓铣削时存在的隐患，进行了详细的分析，并提出了相应的防范措施。     

HSK工具系统夹紧系统的研究

HSK工具系统在高速、精密加工中得到广泛的应用,但在实际的研究与使用中存在一些误区。解决这些问题对正确认识与使用HSK工具系统具有重要的理论意义和实际应用价值。本文系统地分析了HSK工具系统的夹紧问题,给出了综合夹紧力的具体计算公式,利用HSK工具系统刚度模型,讨论了夹紧力对系统刚度的影响,并确定出系统许用载荷与夹紧力的理论公式。     

采用经济型数控机床加工车轮

针对车辆制造厂家需要小批量、技术要求高的车轮的实际情况，提出了在经济型数控机床上加工车轮的设想，设计了新的、合理的加工工艺流程及专用工装夹具和刀具，并编制NC加工控制程序，加工出了符合图纸技术要求的合格车轮。     

基于人工神经网络的刀具状态监测系统

在自动化制造业生产中,刀具状态的监测具有十分重要的意义。在充分考虑对刀具状态密切相关的敏感特征参数的基础上,利用人工神经网络模型实现了刀具状态的监测。试验表明,该系统的错报率为6.3%,可有效地应用到工程实际中。最后,对系统的误差进行分析并提出了改进的方向。     

基于三角网格曲面模型的刀位轨迹计算方法

离散三角网格模型在CAD/CAM中应用很广,但针对该模型的刀位轨迹自动生成算法并不多见。在正确重建网格模型的拓扑关系基础上,给出了新的曲面几何特性分析方法,并提出了具有特色的精确的刀位轨迹计算方法,克服了直接由网格模型求交计算刀位方式存在的精度问题。测试结果显示,该方法简捷、可靠,能够达到实用化要求,并显著提高了刀位计算精度和加工效果。     

CONCEPT OF MODEL BASED TAMPERING FOR IMPROVING PROCESS PERFORMANCE: AN ILLUSTRATIVE APPLICATION TO TURNING PROCESS

This paper presents the concept of a methodology called Model Based Tampering (MBT), that considers the non-linear and stochastic nature of process dynamics, to compensate, in real-time, the effects of process degradation on the performance. The uniqueness of this concept emerges from the ability to combine and utilize the structures of the existing models to fit tractable and robust real-time control models in the form of low-dimensional nonlinear stochastic differential equations (n-SDEs). As an illustrative application of MBT, the minimization of diameter variation due to tool degradation in the turning process is considered. Through a series of simulation runs, the use of MBT was found to reduce diameter variation by 97%. The methodology is applicable to a wide range of manufacturing processes.     

一种新型的无机械手自动换刀装置

设计了一种液压式无机械手的自动换刀装置 ,刀库装有 9把刀 ,依靠 9个相同的连杆机构进行换刀 ,用于小型的加工中心 ,具有换刀时间短 ,换刀误差小的优点     

平面任意区域加工的刀具路径生成技术

对平面任意区域填充加工技术进行了研究。给出了基于射线的岛屿关系自动判断 ,提出了一种区域加工单元自动分割算法 ,研究了平面任意区域行切削填充加工刀具路径生成原理和软件关键模块的实现技术。该算法已成功地应用在自主开发的雕刻CAD/CAM系统中 ,通过加工实践 ,能够取得较好加工效果     

Device assessment of the electrical activity of threading dislocations in strained Ge epitaxial layers

It is shown that the high density of threading dislocations (TDs) and, more specifically, the high density of point defects associated with it and present in our strained Ge epitaxial layers on a Si_0.2Ge_0.8 relaxed buffer layer degrades the mobility and the leakage current of pMOSFETs and p⁺n junctions fabricated therein. Annealing in the range 550–650 °C prior to gate stack deposition improves the device performance, although there is no marked change in the TD density. From this, it is concluded that the annealing may reduce the density of point defects grown in during the epitaxial deposition.     

Fabrication of strained Si channel PMOSFET on thin relaxed Si1−xGex virtual substrate

A novel MBE-grown method using low-temperature Si technology is introduced into the fabrication of strained Si channel PMOSFETs. The thickness of relaxed Si_1−xGe_x epitaxy layer on bulk silicon is reduced to approximate 400 nm (x=0.2). The Ge fraction and relaxation of Si_1−xGe_x film are confirmed by DCXRD (double crystal X-ray diffraction) and the DC characteristics of strined Si channel PMOSFET measured by HP 4155B indicate that hole mobility μ_p has an maximum enhancement of 25% compared to similarly processed bulk Si PMOSFET.