薄壁缸筒加工工艺

油缸是液压系统重要的执行元件之一,其缸体为典型的精密薄壁零件,加工时常会碰到排屑困难、圆度、锥度超差的问题。笔者对产生问题的原因进行了详细分析,并提出了解决办法。1　排屑　　一般油缸采用粗镗、浮镗、滚压工艺加工。排屑困难主要发生在粗镗中。粗镗用单刃镗刀,当工件较长时,如果刀具参数或切削用量选择不当,产生排屑困难,使加工不能顺利进行。这时,首先应检查切屑流向。当采用正刃倾角(λs>0)切削时,切屑流向待加工面,随着走刀的继续,切屑必将在镗刀附近堆积,造成排屑困难。这种情况,则必须改变刃倾角,使之成为负刃倾角(λs<0)。…     

大直径薄壁缸筒的加工

我厂有个图1所示的零件,由厚度35mm的35钢板热卷成形,在温度降至150℃左右时及时进行了焊接,并及时对毛坯进行了600～650℃的消除应力退火。针对工件大且薄的特点,为了装夹方便,在下部断续焊接了一个圆盘,见图2。在车削时,采用压板压住圆盘的装夹方法,使工件径向不再受力,以避免装夹变     

薄壁超长液压缸筒的加工

伸缩臂式工程起重机和高空作业车的伸缩液压缸商已越来越趋向于薄壁和超长,内径与壁厚比D／δ＝10～16．5,长度与内径比L／D＝40～70,有关资料提出D／δ≥16为薄壁,L／D≥20为超长。这类缸筒由于本身壁薄、超长,导致刚性差、加工精度要求高、内径加工难度大等问题。为此,对其加工需要进行深入的研究。1缸筒的技术要来图1为某伸缩缸简零件图,技术要求为：材料：45钢,内径精度：H9,圆度：0．025mm,缸简内表面粗糙度：Ra0．4μm,D／δ＝16．25,L／D＝57.壁厚均匀度要求：最大壁厚与最小壁厚差不大于2mm。其余表面粗糙度为兄12…     

第三篇 铝合金薄壁筒的加工

用通用装备加工薄壁圆筒是机械加工中的难点之一，虽然粒粒已有介绍薄壁零件的相应加工方法，但由于薄壁零件的材料不同，结构不同，要求的精度不同以及企业的工艺资源不同，对零件的采取工艺保证各有异同。     

硬铝合金薄壁锥筒的加工

薄壁零件加工误差的控制历来是机械加工中的一个难题。特别是大型超薄锥筒零件的加工,若加工精度较高、零件材料较软,其公差就更难保证;必须采取一定的工艺措施才能满足加工要求。本文针对我们在生产中遇到的问题及解决方法进行论述。 1.零件的结构分析 图1为硬铝合金薄壁锥筒零件的简图。该零件外形尺寸较大,锥筒有8°的锥度,总长达1000mm,最大直径为96600mm,其壁厚最小为3mm,内锥面结构复     

一种薄壁筒的加工工艺

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 ,介绍该零件的加工工艺及相关控制措施 ,提供解决该类零件加工问题的方法     

薄壁缸筒加工工艺分析

对薄壁缸筒加工中排屑困难、以及易产生圆度、锥度误差的情况进行了分析,并提出了解决方法。     

深孔薄壁筒加工工艺设计

就深孔薄壁筒类零件特点和加工难点进行论述,针对难点进行了具体的工艺分析和研究,并制定了相应的工艺方案,给出了具体的操作步骤,为类似零件的加工提供了可借鉴的理论依据。     

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。     

超薄壁不锈钢回转盘的加工

薄壁不锈钢回转盘常规的切削加工方法易产生变形，采用左右两刀同时加工能达到零件精度要求。     

组合薄壁杆件截面特性自动计算及软件开发

讨论了组合薄壁件截面特性(惯性矩、变曲中心等)自动计算原理，采用精确积分法推导出闭口和开口薄壁件截面特性的计算公式，利用Visual Basic，开发出组合薄壁件截面特性计算软件。计算实例表明，理论计算结果和自动计算结果一致，且能适应复杂的组合薄壁件情况，计算快捷有效。     

Spring back phenomenon exhibited in the process of hollow cylinder upsetting

Spring back of the end surfaces of the billet and the elastic deflection of the dies in the process of hollow cylinder upsetting between elastic platens is investigated using a thermo-elastic-plastic coupling model. The finite-element method and the finite-difference method are adopted to simulate the forming process, and the unloading process is performed on the elements of the workpiece in response to the spring back phenomenon accounted for in this study. Therefore, the effect of die elasticity on the variation of the inner surface profile of the hollow cylinder, predictions of forging load, and the distributions of temperature and strain components may be examined. The surface asperity of the billet and the forging load obtained by simulation agree quite well with the results of the upsetting experiment.     

高压钢筒变形规律研究

针对高压钢筒的结构特点和受载特点,提出了在钢筒外缠绕钢丝的技术原理和设计方法。采用把模型从中间截断方法,建立两端面约束、右端面约束和中截面约束3种情况下的有限元模型。分析比较了3种模型的变形规律,从而获得高压钢筒的变形规律和变形数据,为钢筒的安全设计提供了重要的依据。     

不锈钢薄壁件精密加工工艺分析

通过对不锈钢筒形薄壁件结构工艺性和影响加工变形的因素及其原理进行分析,提出了减小加工变形的技术途径,实践证明合理的装夹方式、工艺参数等措施较好地解决了此类零件的精密加工工艺问题。     

双相不锈钢00Cr22Ni5Mo3N缸套制造工艺

介绍特种发动机的双相不锈钢00Cr22N i5Mo3N缸套的制造工艺分析研究,解决缸套制造的三个工艺难点:确定缸套离子氮化后的内孔最大变形量mδax;最大变形量mδax给磨削加工带来的影响;缸套外圆、内孔同轴度/圆柱度及表面粗糙度的控制。     

不锈钢薄壁套类零件的加工

不锈钢具有韧性大、热强度高、导热系数低、加工硬化严重、切削热多、散热困难等特性,从而造成刀尖处切削温度高、容易产生积屑瘤,加剧刀具磨损、影响零件表面质量;薄壁套类零件刚性差、强度低、易变形,机械加工困难。通过对零件材质的切削性能及影响零件变形因素的分析,在工艺上采用粗精分开,并针对零件结构设计夹具;此外,合理选择刀具材料、几何参数、切削用量以及切削液等,从而使零件精度和外观都有明显提高。     

20钢液压缸镗滚技术

液压缸内表面要求较高的尺寸精度、形状精度以及适宜的表现粗糙度。当用20钢制作液压缸时,受其材料性能所限,用一般的加工工艺难以达到上述要求。文章介绍了在改装的车床上基于实验研究的镗滚技术。     

Online monitoring of wire breaks in prestressed concrete cylinder pipe utilising fibre Bragg grating sensors

With steel prestressing wires tensioned around core, Prestressed Concrete Cylinder Pipe (PCCP) is a high-strength composite pipe designed for large-diameter water propagation and distribution. However, some PCCPs may fail after a certain time of service due to corrosion and deterioration. Real-time health monitoring of wire breaks is essential to assess the condition and avoid catastrophic failures of PCCPs. In this paper, a novel approach based on Fibre Bragg Grating (FBG) sensing technology, is presented to monitor and locate wire breaks in PCCP lines. FBG vibration sensors are utilised to capture the signals of wire break activities in the pipeline and obtain their locations. The online monitoring system and localization principle of wire break activities are described. Preliminary experiments were carried out on PCCPs with an inner diameter of 2 m, which were filled with pressurized water. Experimental results indicate that the wire break activity can be detected and located effectively by FBG sensors. The detection error of wire break locations is analysed. With unique features, the proposed non-destructive method is expected to be used for the online monitoring of wire break activities in long term for the condition assessment and performance prediction of PCCP lines.     

Ultrastructural effect of self-ligating bracket materials on stainless steel and superelastic NiTi wire surfaces

Frictional interactions between wires and brackets reduce the efficacy in orthodontic treatments. Self‐ligating brackets (SLBs) are now more often used due to lower frictional forces when compared with conventional‐ligating brackets. In this study, scanning electron microscopy and atomic force microscopy were used to examine the microstructural effects of stainless steel and ceramic SLBs on the surface roughness of stainless steel and superelastic NiTi wires both after in vivo clinical orthodontic treatment as well as in in vitro three‐point bending experiments. A combination of two wires—0.019 in. × 0.025 in. stainless steel wires and 0.016 in. superelastic NiTi wires—and two SLBs—both passive‐type stainless steel SLBs and active‐type ceramic SLBs—was applied for 4 months (bicuspid‐extraction) in an in vivo setting and for 1 month in an in vitro setting (200 g loads). After the SLB treatments, all wires exhibited severe scratches secondary to frictional interactions with the brackets. When used with the stainless steel SLBs (Damon 3MX®), the surfaces of 0.019 in. × 0.025 in. stainless steel (P < 0.0001) and 0.016 in. superelastic NiTi wires (P < 0.05) were significantly smoother than when used with the ceramic SLBs (Clippy‐C®). Such results suggest that orthodontic treatments with stainless steel SLBs are more effective than with ceramic SLBs. Microsc. Res. Tech. 75:1076–1083, 2012. © 2012 Wiley Periodicals, Inc.