Numeripath CNC-800M系统编程技巧探讨

基于Numeripath CNC-800M系统的特性和被加工机件的结构特点，探讨了使用该系统编程的一些工艺处理方法和技巧。     

On the influence of gamma prime upon machining of advanced nickel based superalloy

Whilst gamma prime (γ′) phase is the strengthening phase in Ni-based superalloys its influence on machining has been seldom investigated. This paper reports for the first time on the effect of γ′ upon machining of Ni-based superalloys when cutting with parameters yielding different cutting temperature intervals which lead to strengthening/softening effects on the workpiece (sub)surface. In-depth XRD, SEM/FIB, EBSD analysis and unique micro-pillar testing in the workpiece superficial layers indicated that with the increase of γ′ fraction the grain plastic deformation significantly decreased, while specific cutting energy can switch from low to high values influenced by the real cutting temperature.     

薄壁零件的数控车削加工工艺研究

薄壁零件的加工变形问题一直是机械制造技术中迫切需要解决的技术难题.从影响零件加工变形的因素出发,以具体产品为例,对薄壁零件的车削加工工艺进行研究,给出了解决车削薄壁零件加工问题的方法,效果较好.     

高速加工中心自动换刀装置的研究

针对我国目前弧面分度凸轮自动换刀装置设计制造水平不足的现状,设计一套结构简单、加工方便的自动换刀完成自动换刀,并详述了换刀的实现过程。新的自动换刀装置精度高、运行平稳、价格合理,能够取代弧面分度凸轮机构。     

A novel approach to fixture layout optimization on maximizing dynamic machinability

In the aerospace industry, the reasonable layout of fixture can efficiently suppresses machining vibration of thin-walled aerospace structure during machining. Based on the analysis of typical structural components encountered in the aerospace industry, a general frame-structure workpiece with fixture constraints can be equivalent as Mindlin plates with simultaneous elastic edges and internal supports. On basis of the equivalent models, the powerful pb-2 Ritz method defined by the product of a two-dimensional polynomial and basic functions can be introduced to be taken as trial functions. Substituting displacement functions into energy functional and minimizing total energy by differentiation leads to eigenfrequency equations of the workpiece–fixture system. Consequently, a novel nonlinear programming problem based on the frequency sensitivity can be built to optimize the layout of fixture supports to maximize the fundamental nature frequency of the workpiece–fixture system. The feasibility of the proposed approach is validated by a machining case.     

Accuracy improvement of wire-EDM by real-time wire tension control

In this paper, a closed-loop wire tension control system for a wire-EDM machine is presented to improve the machining accuracy. Dynamic models of the wire feed control apparatus and wire tension control apparatus are derived to analyze and design the control system. PI controller and one-step-ahead adaptive controller are employed to investigate the dynamic performance of the closed-loop wire tension control system. In order to reduce the vibration of wire tension during wire feeding, dynamic absorbers are added to the idle rollers of wire transportation mechanism. Experimental results not only demonstrate that the developed control system with dynamic absorbers can obtain fast transient response and small steady-state error than an open-loop control system, they also indicate that the geometrical contour error of corner cutting is reduced with approximately 50% and the vertical straightness of a workpiece can be improved significantly.     

SKD11铣削刀具寿命试验研究及工艺参数优化

为提高SKD11模具钢铣削刀具的寿命,对SKD11模具钢进行了刀具寿命铣削试验,基于极差方法分析了各工艺参数对刀具寿命的影响规律。基于刀具寿命铣削试验,利用多元线性回归方法,推导并求解出了SKD11模具钢铣削刀具磨损的数学模型。利用最优化设计方法和MATLAB优化工具箱,以加工效率和刀具磨损为目标函数,针对实际的铣削问题优选了工艺参数。优化的工艺参数能兼顾刀具寿命和加工效率,为加工企业降低综合生产成本提供了重要的理论依据和案例参考。     

非轴对称非球面平行磨削误差补偿技术研究

针对非轴对称非球面的成形加工法柔性不足及球形砂轮加工法对工具和机械的要求太高的缺点,提出采用普通圆弧金刚石砂轮加工的平行磨削法。对于新方法加工中存在的加工误差问题,提出在非轴对称非球面加工中使用带倾角圆弧修整器及对主轴半径和副轴半径误差采用离线补偿的加工技术。通过理论分析和试验表明此方法可达到提高非轴对称非球面的加工精度的效果。     

石墨电极的高速加工

石墨电极具有电极消耗小、加工速度快、耐高温、加工精度高等优点，逐渐取代铜电极成为电加工电极的主流。石墨的硬度低、脆性大，采用高速加工方式可提高表面质量和精度，减小石墨电极的后续加工，降低刀具成本。文章着重介绍了目前国外在石墨电极高速加工技术方面研究的最新进展，提出了石墨电极高速加工的策略和加工参数优化选择原则。     

蜗形凸轮加工机理研究及廓面误差分析

深入地研究和分析了蜗形凸轮廓面加工机理，应用空间啮合原理及旋转变换张量法，建立了蜗形凸轮数控加工刀具误差对凸轮轮廓法向误差影响的通用计算方法，对提高蜗形凸轮的加工精度、改进其加工方法奠定坚实的理论基础。