典型零件CAPP综合开发系统研究

介绍了一种基于数据库的典型零件CAPP综合开发系统(SD—CAPP)。该系统的主要特点是：在总体布局及局部结构中系统体现综合式开发策略，采用特征编码技术进行零件信息特征描述，运用面向对象的可操作模板式工艺决策方法实现工艺决策，数据库采用开放式结构，自动生成与输出工艺文件。该系统在实用性和先进性方面有较大突破。     

采用概率法解算装配尺寸链

采用概率法解算装配尺寸链（１５７５１３）穆棱林业局运输公司黄冈山（１６４１３３）沾河林业局孙淑梅任何机械产品都是出许多零件和部件组成的，零件的精度，特别是关键零件的加工精度，对装配精度有很大的影响。在成批产品装配中，为了有效地控制零件的加工误差，保证...     

基于UGNX的起重机锻造单钩参数化设计

依托UGNX系统建立锻造单钩的三维数字化模型,建立吊钩的主体尺寸之间及与截面尺寸之间的参数化关系,在此过程中通过UGNX的结构仿真模块中所带结构分析解算程序NX.Nastran和自带第三方解算程序Ansys对吊钩截面进行有限元分析优化,确保参数化设计的同时满足强度的要求。利用其加工模块对锻造单钩的锻模编制数控加工刀路,实现计算机数字化模拟加工,检查参数化设计后的吊钩制造工艺性是否合理,从而全面验证参数化设计的合理性及优越性。     

尺寸链CAD系统的研究

本文介绍了一种能够计算径向、轴向和装配等多种尺寸链的计算机软件系统．提出了调整系数的概念，实现了自动初定和校核公差．并提出了多种公差分配的方法．采用本系统计算尺寸链，具有操作方便、输入灵活、公差分配和调整合理、计算项目多、速度快等特点，适于在工厂进行推广应用．     

滚动轴承计算机辅助工艺过程设计

滚动轴承有表示其结构特点的代号，工艺过程又较规范，故系统采用以检索法为主，局部采用专家系统的混合式工艺过程生成方法。本文叙述了系统的结构和工作原理，零件信息的输入方法，零件信息数据库、工艺过程数据库和工艺知识库的组织和管理，以及工艺过程设计方法。系统可用打印机同时输出零件的工艺文件和工序图。     

CAPP设计中误差模型的建立

提出了一个在CAPP设计中用于合理制定各工序公差的误差模型。该模型以误差统计和误差传递思想为基础,根据各工序的工艺能力及中间工序加工误差对最终工序加工误差影响的大小来合理制定各工序公差。     

去毛刺的新方法—振动光饰加工

在金属和非金属零件的制造过程中,都会不同程度产生一些毛刺,必须去掉。现在,去毛刺的方法很多,有物理方法,也有化学方法。其中,较多采用的是回转滚筒加工法。它的加工过程是:将零件、磨料和添加剂等按一定比例装入滚筒后,驱动滚筒,使其按一定的速度回转。利用磨料和添加剂与零件之间产生的摩擦、碰撞,去掉零件上的毛刺。通常,滚筒内工     

木工机械企业CAPP系统的实施

根据木工机械企业的特点，提出了木工机械企业CAPP系统的实施目标，实施准备，软件选择及实施步骤。     

现代环保企业生产中的问题分析及对策

在对某环保企业产品定义和整个流程清晰定位并对未来发展趋势评估后,提出了引进PDM系统,使其与企业其他相关应用相互契合,如与CAD/CAM/CAPP以及ERP的集成,不仅能够实现对产品的生产和工序进行科学有效管理,同时还可以使企业在集成化和自动化过程中获得生产利益。     

基于计算机视觉的雾滴尺寸检测系统的研究设计

雾滴的尺寸参数是评价植保机械性能的最主要质量指标。将计算机视觉技术和灰色系统理论应用于雾滴尺寸参数的检测中,建立了雾滴尺寸参数自动检测和优化系统。     

渐开线圆柱齿轮CAPP系统设计

现代化工业对产品的功能结构及更新换代周期提出了越来越高的要求.因而只有采用先进的产品设计手段和方法,不断提高对产品的创新,才能满足社会发展的要求.通过对CAPP技术的研究,根据渐开线圆柱齿轮设计的基本理论,开发了齿轮CAPP系统,同时也一并介绍了系统的总体架构以及主要模块的设计方法.     

回转车铣头加工回转体径向平面的浅析

车铣是指利用车削和铣削的复合运动共同完成回转体切削加工的切削方法。利用此技术,采用回转车铣头即二轴加转动的联动车铣头加工回转体的径向平面要比采用三轴联动车铣头加工同样平面在结构上要简单很多。     

Pattern of secondary thickening in a Quercus cerris root system

We investigated changes in the pattern of secondary thickening along first-order lateral roots of Quercus cerris L. (turkey oak), a dominant species in the mixed forests of the Mediterranean basin. The eccentricity of radial growth was analyzed relative to the gravimetric center of the root, a measure that is unaffected by year-to-year variation in growth ring width. In cross sections collected at the taproot-lateral root junction, radial growth was greatest on the upper side of the root. However, at a distance of 10 cm from the taproot-lateral root junction, radial growth was greatest on the lower side of the root. With increasing distance from the taproot-lateral root junction, the direction of the vector of radial growth eccentricity changed in an anti-clockwise direction as viewed from the distal face of the root cross section. These findings applied to all lateral roots of the studied root system, irrespective of root size, depth of origin and axial growth direction. Ring analysis indicated that most first-order lateral roots grew to a length of 1 m in the first year.     

Vibrational properties of wetwood of todomatsu (<Emphasis Type="Italic">Abies sachalinensis</Emphasis>) at high temperature

The object of this study was to understand precisely the drying characteristics of wetwood of todomatsu (Abies sachalinensis Mast.). For this purpose, the vibrational properties of wetwood of todomatsu at high temperature were compared with those of normal parts that had lower green moisture content than the wetwood. Specimens were cut respectively from the wetwood and normal parts, and matched in the radial direction. The specimens and the measuring systems were placed in an electric drying oven and free-free vibration tests were conducted in the oven under absolutely dry conditions. The wetwood and the normal parts were tested separately. The temperature was raised from room temperature to 200°C and then lowered to 50°C in steps of 25°C. The specific Young’s modulus decreased with an increase in temperature during the heating process while it increased with the decreasing temperature during the cooling process. There was no significant difference in the specific Young’s modulus between the wetwood and the normal part at all tested temperatures. The loss tangent took a minimum value at about 100°C in both the heating and cooling processes. There was no significant difference in the loss tangent between the wetwood and the normal part. Thus, the elastic and viscoelastic behaviors of the wetwood appear to be similar to those of the normal part in the temperature range of an actual kiln-drying process.     

Microscopic tensile tests in the transverse plane of earlywood and latewood parts of spruce

This paper presents a method which makes it possible to measure elastic properties of a small group of tracheids in the transverse plane. The method is based on tensile tests under microscope that are performed with the assistance of an image analysis system. The calculation of the strain field is based on a global comparison of the grey levels between each deformed image and the initial image. All tests were carried out within one annual ring of spruce: • radial and tangential Young's modulus and Poisson's ratio can be measured in earlywood with a good accuracy, • radial Young's modulus and Poisson's ratio of tracheids in latewood can be estimated with good confidence, • two tests of very thin samples allowed the evaluation of the tangential elastic modulus in latewood. The small size of the sample together with the local measurement of the strain field permitted us to perform several measurements along one single annual ring. Consequently, it was possible to reveal a good relationship between the mechanical properties and the local density determined by microdensitometry. Received 27 October 1997     

Examination of within-tree variations and the heights representing whole-tree values of derived wood properties for quasi-non-destructive breeding of Eucalyptus camaldulensis and Eucalyptus globulus as quality pulpwood

Within-tree variations of derived wood properties of Runkel ratio, Luces shape factor, slenderness ratio, and solids factor were examined for Eucalyptus camaldulensis and Eucalyptus globulus trees and the tendency difference in the within-tree variations between individuals and between species, in both radial and axial directions by statistical data analysis. These properties are important for quality breeding of pulpwood. In both species, within-tree variations were generally observed as higher values in the upper and outer parts compared with other parts of the trunk for Runkel ratio and Luces shape factor. In E. camaldulensis, within-tree variations were observed as higher values in the upper and outer parts compared with other parts of the trunk for slenderness ratio and solids factor. In E. globulus, within-tree variations were observed as higher values in the outer parts compared with other parts for slenderness ratio and solids factor. However, significant difference of tendency was observed in radial variation between individuals of E. globulus for Runkel ratio and in both radial and axial variations between species for solids factor. Furthermore, within-tree variations of derived wood properties were analyzed to determine a sampling height in the trunk which can be used to represent whole-tree values. Representative heights of derived wood properties from two trees were found to be 2.8m in E. camaldulensis (except for Runkel ratio and Luces shape factor) and 1.8m in E. globules (except for Runkel ratio), regardless of differences in tree height (growth rate) and in tendency of within-tree variation of derived wood properties.     

版纳省藤与盈江省藤藤材特性的解剖研究

对特产于云南省的2个藤种盈江省藤和版纳省藤的纤维、导管、维管束和薄壁细胞的形态大小进行显微观测分析.结果表明:藤茎横向(内、中、外部)差异较大,纵向(上、中、下部)呈规律性变化.纤维长度、维管束分布密度、纤维胞壁厚度等自藤皮向藤芯减小,藤皮与藤芯的维管束分布密度差异较大;纤维宽度、导管分子长度与宽度和维管束大小等自藤皮向藤芯增大.与版纳省藤相比较,盈江省藤的纤维壁厚及纤维、导管和维管束尺寸等较大,维管束分布密度均匀,而且在藤茎横向的内外差异较小,变化梯度平缓,材质较版纳省藤的好,是特产于云南的优秀棕榈藤种.版纳省藤和盈江省藤在纤维、导管、维管束、薄壁细胞及表皮细胞等各解剖因子上均有差异,从解剖角度而言,2藤种应为南巴省藤的不同变种,解剖学证据支持《中国植物志》及《云南植物》上对2藤种的处理.     

Relationships of climate and cell features in stems and roots of black spruce and balsam fir

? The anatomical differences of mature black spruces and balsam firs were examined at stem and root level in order to characterize their wood properties at cellular level and link these differences to climate.

? Anatomical variability of these species was evaluated in relation to climate data gathered from 2001 to 2004 during the cell enlargement (CE) and wall thickening and lignification (WTL) phases. Lumen area, single cell wall thickness and total tracheid radial diameter were analyzed and regrouped into earlywood and latewood.

? Results from a principal component analysis (PCA) indicated that both first eigenvectors account for 82% and 90% of total variance for CE and WTL respectively. These component factors revealed that precipitation, humidity and number of days with precipitation significantly influence the lumen area (p = 0.0168) and radial cell diameter (p = 0.0222) in earlywood. Significant differences were registered between species and tree parts (stem and root) for the lumen area, radial cell diameter and cell wall thickness in both earlywood and latewood.

? In our study, black spruce exhibited smaller tracheid size in both stem and roots compared to balsam fir. Furthermore, the lower amount of tracheids produced during the growing season and higher proportion of latewood ensure a higher wood density of black spruce. The influence of temperature on earlywood formation is significant, whereas no influence was observed on latewood.

     

实木定制柜门的标准化设计

实木定制家具市场正在逐步扩大,柔性生产能满足市场的个性需求,标准化设计是实现柔性生产的前提,也是实现自动化、工业化、智能化生产的关键。以M企业的93款实木定制柜门设计生产现状入手,在分析现有问题(产品体系复杂导致零件难以互换、设计和生产信息传递存在壁垒)的基础上提出了构建标准化的设计平台。平台步骤包括健全柜门产品信息数据(5项资料的输入构成完善的前段数据来源)、搭建软件设计和拆单环境(制定数据库和柜门的拆分准则满足参数化设计需求)、加强柜门数据的处理速度与资料输出完整度(软件内部尺寸结构约束和图表制作与输出)。并阐述了平台搭建流程中所需的关键技术,针对企业在售柜门样式分析零件榫槽结构特征(边料、芯板、线条的连接方式)和尺寸(宽度和厚度)分布情况进行整合归纳,选取4项分类属性利用多属性交叉聚类算法划分产品零件族(尺寸为层次聚类,工艺为模糊聚类,榫槽为形状分类,弯曲程度为弯曲半径),以“标识码+分类特征码+尺寸码”的编码方式制定柜门产品信息码和零件加工信息码,在分析零件尺寸结构关系之上利用编程技术构建最小单元零件模型库,创建共享端口实现信息的交互与贯通。本研究系统地阐述了实木柜门标准化设计的关键流程,旨在为实木定制柜门的标准化设计奠定前端基础,从而促进实木家具的数字化升级。