机械图中表面粗糙度的自动标注

按照国家标准《机械制图》的规定,零件图上应标注表面粗糙度代(符)号,它是零件的技术要求之一。本文设计了标注表面粗糙度的二个子程序,每个子程序均能标注图样上常用的三种粗糙度符号,其中一个子程序用术标注表面为0°、90°、180°和270°的粗糙度代号;另一个子程序用来标注倾斜表面的粗糙度代号。在绘制零件图时,根据需要调用子程序来实现计算机自动标注表面粗糙度代号。     

AutoCAD 2000中用AutoLISP语言实现表面粗糙度代号的标注

本文介绍了一种利用AutoLISP语言来实现表面粗糙度代号标注的基本原理、具体方法。采用这种方法，可以有效提高机械图样的绘图效率。     

AutoCAD环境下机械制图表面粗糙度的标注方法

在机械制图中,零件图上的表面粗糙度标注是必不可少的.AutoCAD被广泛应用于机械制图的图形绘制,但是AutoCAD没有专门标注表面粗糙度的功能,论文针对该软件在表面粗糙度标注方面的不足,充分利用属性块的特性,把表面粗糙度Ra的数值定义为2个可变属性块,利用插入块的方法标注表面粗糙度.这样就能够大大提高绘制零件图的效率,并且符合国家标准规定.     

机械零件表面粗糙度自动标注的实现

阐述了标注表面粗糙度代号的各种方法,介绍了利用AutoLISP语言为AutoCAD增加表面粗糙度标注命令的程序实现过程和命令加载方法.通过运行此命令,能够在所选实体的指定位置自动生成符合国标规定的表面粗糙度代号.     

也谈表面粗糙度符号的标注

读《机械工业标准化》1996年第6期孔晓玲的文章：“《表面粗糙度符号、代号及其注法》新旧标准的区别与研讨”（以下简称原文），很受启发。经与GB／T131—93条文对照，发现有点问题，提出来洪大家研讨。原文在论及表面粗糙度符号长边转角加小圆的标注时说：“此符号可标在图的右上角（见图巴也可直接标注在图上（见图7），这一符号的应用可以避免误解，特别是标注在图上，带有小圆和不带小圆符号的理解是完全不同的”。GB／T131－93的4．3只规定“当零件所有表面具有相同的表面粗糙度要求时一其符号、代号可在图样的右上用统一标注。见…     

GB/T 131-2006修改解析(1)

国家标准GB／T131-2006《产品几何技术规范（GPS）技术产品文件中表面结构的表示法》是在GB／T131-1993《机械制图表面粗糙度符号、代号及其注法》的基础上,等同采用ISO1302：2002《产品几何技术规范（GPS）技术产品文件中表面结构的表示法》而制定的,该标准只适用于对表面结构有要求时的标注方法。 该标准是新一代GPS系列标准中的通用标准,它影响粗糙度、波纹度和形状轮廓等相关标准。该标准的修订,在表面结构技术领域建立了一个更加完整、明确和先进的图样标注体系,从设计的图样表达上,已不再是只给出参数值要求,同时也给出检验时的规范要求,因为在产品图样中科学准确地标注出轮廓、图形、支承率曲线等参数要求,对提高设计质量十分重要。因此GB／T131-2006体现了设计规范、功能要求和检验评定方法的有机统一,图样标注清晰且科学严谨。本刊将连续登载,敬请关注。     

利用AutoLISP实现AutoCAD中表面粗糙度的准确标注

阐述了各种情况下准确标注表面粗糙度代号所需的关键角度ＡＮＧ的确定方法,介绍了利用ＡｕｔｏＬＩＳＰ语言为ＡｕｔｏＣＡＤ增加表面粗糙度标注命令的程序实现过程和信念加载方法。通过运行此命令,能够在所选实体的指定位置自动生成符合国家标准规定的表面粗糙度代号。     

在AutoCAD中标注表面粗糙度的简易方法

在AutoCAD中，充分利用属性块的特性，把表面粗糙度Ra的数值定义为2个可变属性块，利用插入方法标注表面粗糙度。这样就能够大大提高绘制零件图的效率。     

表面粗糙度过渡不能削足适履

新国标《表面粗糙度》系取代原国标《表面光洁度》,两者之间主要区别,除标注代号不同外,在参数的种类上,光洁度只有R_a和R_x两种,而粗糙度有R_a、R_x、R_y、S、S_m和t_p六种,在参数的数值上,光洁度只有一个系列,而粗糙度有第一和第二两个系列,其中第一系列为优先值。将图样上原来标注的光洁度过渡为粗糙度,     

新旧标准表面结构标注方法对比及实现

着重介绍了表面结构标准的表示方法以及在图样中的标注方法,对比分析了新旧标准表面结构代号标注方法之间的差异,并且对新旧标准代号在AutoCAD中标注方法的实现提供了一种简单实用的方法,对新标准的宣贯和实施具有一定的参考价值。     

AutoCAD中表面粗糙度快速标注命令的实现

利用AutoLISP语言二次开发了表面粗糙度标注的命令，弥补了AutoCAD的不足，可方便地进行符合国家标准的表面粗糙度的标注，也说明了运用AutoLISP语言进行二次开发的方法和技巧。     

AutoCAD表面粗糙度自动标注的ARX二次开发

介绍一个在AutoCAD2000的环境下，表面粗糙度自动标注的ARX应用程序。对其编程要求、编程原理及编程中的若干问题和解决方法进行了讨论。给出了标注实例。     

工件表面粗糙度检测装置的智能化改造

表面粗糙度是一个评定工件表面质量的重要公差指标。基于VB技术设计检测系统,利用MATLAB数字图像处理技术,对表面粗糙度进行计算,并基于光切法的表面粗糙度智能自动化检测技术进行改造与研究。     

Influence of surface roughness effects on the performance of non-recessed hybrid journal bearings

The effect of journal and bearing surface roughness on the performance of a capillary compensated hole-entry hybrid journal bearing system has been theoretically studied. The analysis considers the average Reynold’s equation for the solution of lubricant flow field in the clearance space of a rough surface journal bearing system. The finite element method and Galarkin’s technique has been used to derive the system equation for the lubricant flow field. The non-dimensional parameters Λ (surface roughness parameter) and γ (surface pattern parameter) have been defined to represent the magnitude of height distribution of surface irregularities and their orientation, respectively. The influence of surface roughness on the bearing performance has been studied for the transverse, isotropic and longitudinal surface patterns. The bearing performance characteristics have been computed for both symmetric and asymmetric capillary compensated hole-entry journal bearing configurations for the various values of surface roughness parameter (Λ), surface pattern parameter (γ) and restrictor design parameter ( ). The computed results indicate that the inclusion of surface roughness effects in the analysis affects the performance of a bearing quite significantly vis-à-vis smooth surface bearing. The study indicates that for generation of accurate bearing characteristic data, the inclusion of surface roughness effects in the analysis is essential.     

Effects of thickness and surface roughness on mechanical properties of aluminum sheets

The effect of thickness on the mechanical properties of Al 6K21-T4 sheet specimens under uniaxial tension was investigated. In order to reduce the thickness of the specimens without changing the microstructure and grain size, chemical etching was carried out, resulting in Al sheets ranging from 0.40 mm to 1.58 mm in thickness. Additionally, the effect of surface roughness was determined by finite element (FE) calculations performed using FE code MARC 2007. Tensile specimens of varying surface roughness were modeled and simulated. An analysis of the combined effects of the thickness and surface roughness revealed that the yield and tensile strengths decreased when the number of grains over the thickness was decreased. The ductility also decreased when reducing the thickness. An FE simulation showed that both the surface roughness and thickness affected the flow-curve shape. Moreover, the effect of the surface roughness tended to increase when decreasing the sheet thickness of specimens having the same roughness.     

Modeling and prediction for 3D surface topography in finish turning with conventional and wiper inserts

Wiper insert have the characteristics of achieving an excellent surface finish and improving the productivity in turning processes. Wiper insert can provide twice feed rate while maintaining the comparable surface roughness compared to that provided by the conventional insert. In the present study, surface topographies in finish turning with conventional and wiper inserts are investigated. The key element of this work is that the cutting edge path equation in the cutting tool coordinate system is transformed into the machine tool and workpiece coordinate system by the use of spatial coordinate transformation. Following that a surface topography simulation algorithm based on the cutting edge path equation and cutting parameters is put forward. The output of this work is that both the simulated surface topography and surface roughness profile are good agreement with the experimental results. Both the simulated and the actual machined surface results show that better surface topography is obtained in finish turning with the wiper insert than that with conventional insert. Burnishing effect of the wiper insert leads to half decrease of the Ra and Rz. The actual surface profiles are no longer regular wave shapes due to ploughing effect and side flow existing in the cutting zone. In addition, a surface roughness map has also been developed to optimize the selection of wiper radius and feed rate to satisfy the requirement of surface finishing with higher productivity. From the viewpoint of cutting tool design, the wiper radius with five times larger than tool nose radius can fully come into its role. This provides a novel insight into the design of wiper insert over conventional techniques. Above all, the proposed model gives a better prediction of surface roughness in finish turning process compared to the previous empirical and regression roughness models. The prediction of surface roughness in finish turning with wiper insert is also realized.     

多线砂轮复合自动修磨装置的设计与精度检验

多线砂轮复合自动修磨装置采用CNC数控系统,利用两个独立金刚石滚轮休整器,实现单支和多支砂轮的高精度修磨,极大地降低了人工操作带来的加工误差,提高了产品加工精度和效率。通过表面粗糙度检测数据可知,具有多线砂轮复合自动修磨装置的数控丝锥螺纹磨床完全符合加工精度要求。同时,采用多元回归方程建立基于砂轮修整参数的表面粗糙度预测模型,并设计单因素试验,得到砂轮修整参数与表面粗糙度之间的关系。由显著性分析结果得出,径向修整进给量是影响表面粗糙度的主要因素。     

Construction of a surface roughness prediction model for high speed machining

In manufacturing environment prediction of surface roughness is very important for product quality and production time. For this purpose, the finite element method and neural network is coupled to construct a surface roughness prediction model for high-speed machining. A finite element method based code is utilized to simulate the high-speed machining in which the cutting tool is incrementally advanced forward step by step during the cutting processes under various conditions of tool geometries (rake angle, edge radius) and cutting parameters (yielding strength, cutting speed, feed rate). The influences of the above cutting conditions on surface roughness variations are thus investigated. Moreover, the abductive neural networks are applied to synthesize the data sets obtained from the numerical calculations. Consequently, a quantitative prediction model is established for the relationship between the cutting variables and surface roughness in the process of high-speed machining. The surface roughness obtained from the calculations is compared with the experimental results conducted in the laboratory and with other research studies. Their agreements are quite well and the accuracy of the developed methodology may be verified accordingly. The simulation results also show that feed rate is the most important cutting variable dominating the surface roughness state.     

表面粗糙度测量仪的微机改造

介绍了利用微机对表面粗糙度测量仪的改进设计 ,重点说明了系统的原理及软、硬件设计。