提高薄壁孔的加工精度

1存在问题我厂生产的调速器盖是495Q柴油发动机柱塞喷油泵总成的一只薄壁零件(如图1所示).它采用ZL401材料经模具压铸而成.在机械加工过程中,图1中的2—φ13(?)技术要求高,加工铝铸件壁薄变形量较大.长期以来,因加工中诸多原因使孔的加工精度达不到图纸要求,装配后有渗油现象.这就直接影响到整台喷油泵总成的技术指标.     

浅谈提高薄壁零件加工精度的工艺方法

薄壁零件刚性差、强度弱,在切削加工中极易变形,影响着零件的加工精度,一直是金属切削加工中的棘手问题。通过对零件的装夹,切削用量的选择、刀具的几何角度及切削液应用等方面的分拆和探讨,为提高薄壁零件的加工精度,提出了一些建议,可供实际应用时参考。     

提高薄壁零件加工精度的探讨

针对薄壁零件刚性差,制造过程中容易产生变形,加工精度不高等问题,分析了影响薄壁零件加工精度的因素,对提高套筒类薄壁零件加工精度的具体方法进行探讨.     

薄壁零件加工方法研究

薄壁零件是数控车床中较难加工的零件,加工薄壁零件主要解决变形和精度等问题。本文针对影响加工薄壁零件的主要因素,从薄壁零件的变形情况、薄壁零件的夹具设计、刀具几何角度刃磨等方面展开简述,分析了避免薄壁零件变形的方法以及提高薄壁零件加工精度的措施。     

提高薄壁件内孔加工精度的方法

<正>1问题分析由于薄壁件结构形状复杂,相对刚度较低,故加工工艺性差。本文根据企业加工实际情况(被加工零件如图1所示),提出一种解决薄壁件内孔车削加工变形的方法,从而提高了薄壁件内孔的加工精度。     

薄壁套的加工工艺研究

对薄壁套零件的加工难点进行了简单说明,提出了引起加工变形的主要原因有两点：一个是受夹具夹紧力作用产生的弹性变形;另外一个是受刀具切削热应力作用产生的塑性变形。结合典型的薄壁套零件的加工过程,详细阐述了有效解决该薄壁套零件在加工过程中产生加工变形的工艺方法。     

薄壁零件的车削加工精度概述

结合薄壁零件的特点,分析了实际加工过程中出现的问题及其影响加工精度的因素;重点分析了受力变形、受热变形和振动变形对加工精度的影响;提出了保证薄壁零件加工精度,即提高薄壁零件的刚度、设计合理夹具、减少切削热影响以及采用合理切削用量减小切削力的相关措施.     

薄壁件加工工艺

在实际生产中,在产品上往往会出现一些薄壁特征。而零件的薄壁特征加工是比较麻烦的,原因在于薄壁特征的尺寸特点,极容易导致在加工中变形,很难保证零件的加工质量。因此如何制定加工工艺来提高薄壁部分的加工精度显得尤为重要。     

浅析影响薄壁零件加工精度的因素及其工艺措施

薄壁零件有其自身独特的特点,给车削加工带来了很大的困难。分析了薄壁零件的特点,提出了影响薄壁零件加工精度的几点因素,并对其工艺措施进行了简单探讨。     

防止薄壁套筒加工变形的加工工艺

套筒外形如图1所示,材料为2A12。该零件为典型的薄壁件,尺寸及形位精度要求较高,在加工时由于工艺方法不当或装夹变形等因素,很难保证零件的加工精度。我们通过多次试验,摸索出一套针对该零件的加工工艺方法,通过制定合理的加工工艺流程,并配以简单的专用工装和测量方法,     

平面正交光栅仪测量加工中心位置精度

介绍一种测量加工中心位置精度的仪器——平面正交光栅。简述其结构、工作原理、安装、测量以及特点等。     

零件结构形式对铣削加工变形的影响研究

在弹塑性理论的基础上,建立了三维铣削仿真加工变形场的有限元分析模型,利用"单元生死"技术仿真了加工过程中材料的去除.研究了零件结构不同,加工过程中毛坯初始残余应力的释放对加工变形的影响,通过仿真数据与试验数据相比较,结果表明,只要建立正确的三维有限元分析模型,完全可以实现对零件加工变形规律的预测;工件毛坯残余应力在铣削加工过程中对称释放有利用减小零件加工后变形.     

虚拟加工过程薄壁工件铣削变形模型研究

在薄壁工件的切削加工中,工件的受力变形是影响加工过程的一个主要因素,文中针对薄壁工件侧面的立铣加工,建立了不同复杂度的切削过程模型,以仿真工件薄壁在加工中受到切削力发生的变形,虚拟实现受到工件变形影响下的切削过程。通过仿真创成的工件表面形貌与实际切成的工件表面的比较,对文中各模型进行了验证。     

The evaluation of process capability for a machining center

The machining center methodology is widely applied to production systems within the fast-developing processing industry. The automated machining center can simultaneously perform certain processes, such as milling, drilling, boring, and reaming, on the same machine at the same time, and manufactures limited quantities of multiple-type products. These products usually have numerically important quality characteristics with high accuracy. However, a machining center is unable to measure process capability on its own. Thus, we reflect the process capability of a machining center by measuring the quality characteristics of its processing products. In this paper, we propose the three integrated process capability indices (PCIs) C _p^mc, C _a^mc, and C _pm^mc to evaluate the integrated process precision, accuracy, and actual capability respectively. Furthermore, we develop a process capability monitoring figure (PCMF), which not only displays the status of the process precision and accuracy by the color management method [1], but it also forecasts the integrated process capability of the next productive time (batch) through the analysis of time series. Using the PCMF, engineers will be assisted with tasks such as monitoring the process quality, deciding the period of the borer’s replacement, and designing the process parameters.     

Development of a new precision internal machining process using an alternating magnetic field

Imparting compressive residual stress to a surface improves the fatigue structural integrity of components, which is particularly important for components used in such critical applications as high-pressure gas or liquid piping systems. This paper proposes a new precision internal machining process that controls the surface integrity of internal surface of these components. This process utilizes an alternating magnetic field to control the force and dynamic motion of the tools needed for machining. An experimental set-up was developed to test the processing principle. This study characterizes the in-process tool behavior—that is, the relationships between the magnetic field, the tool properties, and the tool behavior—and reveals the properties of the tools required to achieve the desired results: magnetic anisotropy and a specific geometric restriction. The surface roughness, hardness, and residual stress measurements following machining experiments demonstrate the effects of the tool behavior on the machining characteristics. This paper also proposes methods to obtain desired surface characteristics.     

The configuration of a machining centre and its influence on accuracy

The aim of the paper is to provide an experimental method for revealing systematic defects in a machining centre. The problem is first analysed by comparing results from two different machining operations carried out on the same unit. The machining unit as a whole is then studied in order to obtain maximum precision on each axis, and to determine the influence of machine layout on accuracy. Finally, the best possible layout is chosen in terms of optimum precision.     

基于三维零件模型的工艺路线设计方法研究

针对基于三维CAD的计算机辅助工艺设计(Computer Aided Process Planning,CAPP)的发展需求,提出了一种基于三维零件模型的工艺路线设计方法。从零件三维模型中提取加工特征,建立以加工特征为核心的工艺信息模型,有利于与上游CAD以及下游CAM的集成和信息共享。在工艺信息模型基础上建立以加工元为基元的工艺决策模型,通过聚类和排序约束实现工序/工步的确定和排序,实现工艺决策过程的算法化。通过飞机双面大框零件实例说明了该方法是简单有效的。     

新型薄壁筒加工工艺技术的研究

通过对薄壁筒零件工艺特点的分析,进行了工艺方案的比较,介绍了该零件的加工工艺及相关控制措施,提供了解决该类零件加工问题的方法。     

A study on the characteristics of a wafer-polishing process according to machining conditions

The polishing process for silicon wafers plays a key role in the fabrication of semiconductors, since a globally planar, mirrorlike wafer surface is achieved in the process. The surface roughness of the wafer depends on the surface properties of the carrier head unit, together with other machining conditions, such as working speed, type of polishing pad, temperature, and down force. In this paper, the results of several experiments are used to study silicon wafer surfaces. The experiments were designed to observe the down force and temperature when a wafer carrier head unit with wafer was pressed down onto a polishing pad. A load cell was employed to detect the applied pressure against the polishing pad, and the working temperature was measured with an infrared sensor. Wafer surface roughness was investigated according to several parameters and experimental data.     

新型切削加工机器人常用表面加工方法研究

在分析了传统切削加工机器人刚性差、精度低的基础上,研制成功了一种新型切削加工机器人。该切削加工机器人不仅具有机器人一样灵活的柔性,而且具有金属切削机床一样的刚性,特别适合于空间自由曲面的加工与测量等。在坐标变换理论的基础上,提出了切削加工机器人关联矩阵加工理论。并且根据这一理论,给出端铣刀立铣加工平面的计算方法。通过ADAMS进行仿真,验证了所开发的切削加工机器人的可靠性以及关联矩阵加工理论的正确性,为控制和数控编程提供依据。