胀形模应力分析及结构改进

在摩托车油箱类大型制件的胀形模生产中．由于材料拉伸变形较大,容易导致零件开裂、起皱等问题．通过对零件在拉仲胀形过程的应力分析,确定零件在成形中产生内皱等故障的原因．并对模具结构进行改进,用聚氨醣橡胶代替原钢制凸模,很好地解决了零件出现的缺陷．在生产中已获得了成功并投入使用．     

聚氨酯橡胶筛板

聚氨酯橡胶筛板山西省化工研究所合成材料厂开发成功的不阻塞型聚氨酯橡胶筛板先后通过山西省和中国统配煤矿总公司的技术鉴定，已被煤炭部列为新技术推广项目。这种橡胶筛板包括方筛板、弛张筛板和条缝筛板三大系列２０多个品种。它充分利用聚氨酯优良的耐磨性、高强度、...     

筛网工艺规程和压形模设计

根据实际生产经验获得理想的工艺路线,达到节约时间、提高劳动生产率的目的。设计了筛网压形模,以R3半圆孔定位,依次冲压各排异型孔成形,以提高工效,保证质量,并保证零件的中批量生产,提高劳动效率。     

我国模具发展展望

有关人士认为，未来我国的模具发展将呈现新的市场需求、逐年递增趋势。 模具日趋大型化。这是由于用模具成形的零件日渐大型化和高生产效率要求而发展的“一模多腔”所造成的。 模具的精度将越来越高。１０年前，精密模具的精度一般为５微米，现在已达到２至３微米，不久１微米精度的模具将上市。这要求超精加工。 多功能复合模具将进一步发展。新型多功能复合模具除了冲压成形零件外，还担负叠压、攻丝、铆接和锁紧等组装任务，对钢材的性能要求也越来越高。 热流道模具在塑料模具中的比重将逐渐提高。由于采用热流道技术的模具可提高制件…     

聚氨酯注模成型技术在家具生产中的应用

利用聚氨酯(PU)注模成型技术,可高效生产性能优良、造型美观、成本低廉的仿木材料,近几年被广泛应用于中国家具行业。本文从PU原材料选用及配比,模具设计及制作,注模工艺条件控制,以及PU生产工艺流程等方面,系统阐述PU注模成型的关键技术。     

PMDI在人造板行业中的应用

PMDI,中文名多亚甲基多苯基异氰酸酯,是广泛应用于聚氨酯行业的重要原材料之一.聚氨酯用途广泛,是人们生活中不可缺少的有机材料,可以代替塑料、橡胶、尼龙等多种材料,在医用材料、人造骨骼、食品包装、家居家电、建筑建材等都得到了广泛的应用.     

革新两则

一、偏心钻模在集材50拖拉机修理时,大平轴头插入板弹簧后的位置调整用偏心垫实现。该零件多由修理厂自己制造。我厂原来用划线钻削偏心孔,生产效率低,还保证不了质量。为解决这项生产问题,我们制造了偏心钻模,该钻模用在35毫米的立式或摇     

用形位公差统一典型零件公差

用形位公差来统一典型零件公差，将简化典型零件的加工、检测工艺和程序，促进生产效率的大幅度提高，并充分体现形位公差标准的本质特征和作用。     

动态信息

动态信息▲“都江”牌ＭＸ７２１６型双轴木工仿形铣床投放市场该新产品是采用靠模仿形加工原理，融机械传动和电气、气动为一体，仿形铣削和砂光同步作业，具有生产效率高，加工制件精度高和操作简捷等特点。该机床作为仿形木工机械的配套系列产品，主要用于仿古家具，仿...     

严寒地区窗下口渗漏质量通病的分析与研究

在外墙窗下口保温层部位,局部模浇硬泡聚氨酯的方法来解决窗下口渗漏的质量通病。硬泡聚氨酯可以替代常规保温材料,良好的防水性能可以简化外墙窗下口防水构造,模浇硬泡聚氨酯粘接强度高、尺寸稳定性好。能够有效提高窗下口防水效果,大大降低窗下口渗漏问题的产生。     

新型桥梁弹性伸缩缝

本文针对桥梁伸缩缝中存在的破损修复。提出了一种新型无缝桥梁弹性伸缩缝用于旧桥伸缩缝的改造，通过和板式橡胶伸缩缝、型钢缝的对比，证明该新型桥梁伸缩缝具有维修方便、行车平稳舒适、经济效益好等优点。     

微米木纤维模压制品握钉力计算理论

分析微米木纤维模压制品握钉力计算的重要性,提出其握钉力力学分析的基本假设,建立其握钉力计算的力学模型,推导螺纹牙受力的分布函数.应用本文提出的理论,可以根据微米木纤维模压制品的刚度和螺纹的几何参数定量计算螺纹牙受力分布,进而计算其握钉力,为微米木纤维模压制品握钉力计算提供重要理论依据.     

对中小型电机转子冲片模具制造工艺的改进

介绍了二种经济可行的中小型电机转子冲片模具制造工艺的改进方法.一种是用新凸工艺方法来固定凸模,即采用慢走丝线切割来加工模和固定板,以提高配合面的粗糙度;另一种方法是采用酸蚀凹模空刀,提高模具制造效率,降低成本,缩短了制造工期,这两种方法具有明显的经济效益和社会效益,可供同行借鉴.     

栗果霉烂机理及防治

为探讨栗果贮藏、运输期间的霉烂机理，通过大量调查研究，提出了影响栗果霉烂的主要原因及防治方法，为提高栗果的质量和保鲜度提供科学的理论依据。     

竹制品纳米复合涂层的抑菌防霉效果

以纳米TiO₂及纳米ZnO为原料制备了复合涂层,测试分析了竹制品复合涂层的抑菌和防霉效果。结果显示,复合涂层有较强的抑菌防霉效果,其中10%纳米ZnO的抑菌效果最强,纳米TiO₂和纳米ZnO混合物的防霉效果最强。试验证实,纳米TiO₂及纳米ZnO的复配处方有抑菌防霉作用,有望应用于竹制产品的表面抑菌及防霉。     

Adoption of rubber-integrated farm-livelihood systems: contrasting empirical evidence from the Indian context

This paper examines the influence of important socio-economic, institutional/policy level factors in determining the adoption/non-adoption of rubber-integrated farming systems in traditional and non-traditional rubber-growing regions in India. The empirical analysis is based on a survey of rubber growers in the traditional rubber regions of Kerala (south India) and the non-traditional rubber regions of Assam, Meghalaya, and Tripura (north east India). In sharp contrast to Kerala, where smallholder responses toward adoption of rubber-integrated farming systems have been lukewarm, the emerging rubber economies (most of which are tribal communities) of north east (NE) India have shown interest in adopting rubber as an integrated farming system along with pre-existing land-use livelihood activities. The study clearly demonstrates contrasting empirical evidence of adoption of rubber-integrated farm-livelihood systems in the rubber-growing regions in Kerala and the NE states in India. The contrasting scenarios of adoption of rubber-integrated farming systems are mostly explained by region-specific factors dominated by socio-economic, institutional variables, and policy-level constraints, as also revealed by multivariate analysis. By and large, the findings of the study have significant bearing on the socio-economic outcomes and the existing institutional development paradigm underlying the rubber-development programmes introduced in India since independence. The study shows that the existing institutional arrangements and policies, which evolved historically to facilitate rubber area expansion in the traditional regions (including Kerala), have been highly instrumental in perpetuating rubber farming as a monoculture system. However, such an institutional mechanism proves to be highly redundant in the context of the NE states which are otherwise diverse in terms of integrated farm-livelihood systems and shifting cultivation.     

结合实际工作谈建筑信息模型（BIM）的意义及推广

论述了建筑信息模型（BIM）的概念,并结合实际工作说明了建筑信息模型（BIM）技术对建筑师、工程师日常工作的意义,提出了推广BIM的一些建议。     

Ecoeffective production of timber

Abstract

Development in surface mould growth on painted/unpainted wooden claddings and acting climatic factors were investigated over a period of 3 years. Eight wood substrates, including modified, preservative-treated and untreated wood, were tested in combination with three types of paint: (1) water-borne alkyd modified acrylic paint without fungicide; (2) solvent-borne alkyd paint without fungicide; and (3) ICP (internal comparison product). One set of samples was exposed unpainted. The samples were tested according to a modified version of EN 927-3. A logistic regression model was fitted to the data. The degree of mould growth varied with exposure time, coating typology, wood substrate, temperature and relative humidity. Exposure time and coating typology contributed most to the model. After 3 years of outdoor exposure unpainted panels and panels coated with solvent-borne paint without fungicide had more mould growth than panels coated with ICP and water-borne paint without fungicide. Unpainted oil/copper–organic preservative-treated claddings had higher resistance to mould growth than other unpainted wood substrates. Coated untreated pine and coated acetylated pine were more susceptible to mould growth than other coated wooden substrates.