小型热固性塑料压模侧抽芯机构设计

介绍了外刷座塑件模具设计,分析了塑件成型过程采用的抽芯机构的优缺点,实践证明,模具的抽芯结构操作简便易行,制造成本低,对类似有侧抽芯要求的模具有一定的参考价值。     

汽车后视镜基座精密注射模设计

根据汽车后视镜基座的结构特点和成型要求,采用液压侧向抽芯机构、单点开放式热流道系统,设计了1副精密注射模。详细总结了该模具的成型零件、侧向抽芯机构、浇注系统、温度控制系统、导向定位系统、脱模系统和排气系统设计经验和要点。该模具结构先进合理,生产效率高,成型的塑件精度高。     

轿车后视镜外罩注射模设计

介绍了轿车后视镜外罩的成型工艺及注射模结构 ,为解决塑件的内侧抽芯和型芯的复位 ,模具采用了有双斜面的斜滑块结构 ,内抽型芯分解成7块、分次内抽芯。模具结构紧凑、内抽型芯可自动复位 ,提高了生产效率。     

壳体注射模设计

分析了壳体塑件存在内凹槽、外凹槽的结构特点,注射模的结构设计针对不同部位的凹槽采用不同的抽芯机构,采用成型滑块内侧抽芯机构成型塑件在定模部分的内凹槽,采用斜推杆抽芯机构成型塑件在动模部分内凹槽,采用斜导板滑块抽芯机构成型塑件外形凹槽,模具结构紧凑,各抽芯机构有效组合,运动平稳顺畅。经实际生产验证该模具结构合理,成型的塑件质量良好。     

控制电器基座注射模设计

介绍了一款控制电器基座的结构特点及成型工艺难点,完成了注射模成型结构设计,采用延时抽芯结构,解决了推杆与型芯之间的干涉问题,模具结构合理,生产的塑件达到要求。     

挖掘机发动机进气罩注射模设计

针对塑件形状复杂的特点,设计了1副热流道四板注射模成型,模具采用1模2腔布局,单腔使用单点热喷嘴浇注,模具分两次打开。模具还设计了2种抽芯机构和1种推板推出机构实现塑件脱模,液压缸二次抽芯机构用于成型塑件横向内壁的抽芯脱模,哈夫滑块机构用于塑件外壁的脱模,推板推出机构将塑件从竖向型芯镶件上推出。     

结合侧向抽芯和柔性抽芯的注射模设计

根据四通管塑件的结构特点,设计了带侧向抽芯和柔性抽芯的模具结构。侧向抽芯采用液压机构完成直线抽芯,柔性抽芯机构完成曲线抽芯。液压机构抽芯通过控制液压缸的活塞开合动作顺序,避免了侧向抽芯脱模时型芯镶件之间的动作干涉问题。设计的模具抽芯机构在实际应用中运动平稳,抽芯、复位准确,成型的塑件满足使用要求。     

轿车后视镜注射模设计

分析了轿车后视镜结构与成型工艺,详细介绍了模具的结构、抽芯机构、成型零件、温度控制与排气系统的设计,特别是对模具四面内抽芯机构进行了详细的说明。经生产验证,该模具工作可靠,生产效率高。     

侧滑块和滑块侧抽芯注塑模设计

针对单侧分布有侧孔、表面有浅槽和薄壁复杂塑件难成型的问题,进行了该塑件的注塑模设计研究.通过对塑件的结构和成型工艺性分析,利用侧滑块带动滑块作纵向、横向滑动,设计了侧滑块和滑块侧抽芯的注塑模具结构,实现了模具结构中的侧向分型.结果表明:该套模具结构紧凑,侧抽芯机构的运动平稳可靠.     

电子表壳注射模

分析了电子表壳塑件结构特点,介绍了该塑件注射模浇注系统、多方向组合抽芯机构及可换镶嵌式成型部件设计,实践证明该模具结构能满足产品成型需求。     

Wrought cobalt- base superalloys

Wrought cobalt-base superalloys are used extensively in gas turbine engines because of their excellent high-temperature creep and fatigue strengths and resistance to hot corrosion attack. In addition, the unique character of the oxide scales that form on some of the alloys provides outstanding resistance to high-temperature sliding wear. This article provides a review of the evolutionary development of wrought cobalt-base alloys in terms of alloy design and physical metallurgy. The topics include solid-so-lution strengthening, carbide precipitation characteristics, and attempts to introduce age hardening. The use of PHACOMP to enhance thermal stability characteristics and the incorporation of rare-earth ele-ments to improve oxidation resistance is also reviewed and discussed. The further development of cobalt-base superalloys has been severely hampered by past political events, which have accentuated the strategic vulnerability of cobalt as a base or as an alloying element. Consequently, alternative alloys have been developed that use little or no cobalt. One such alternative, Haynes® 230^TMalloy, is discussed briefly.     

Development of base materials for welding

Abstract

The various aspects of weldability, seen as a material property, are introduced. These are illustrated by considering examples, in particular the recent advances in structural C–Mn and microalloyed steels. Important issues for the further development of the weldability of these materials are outlined. In concluding, the growing importance of mathematical modelling as a tool for the design of new weldable materials is emphasised.     

基座注射模设计

通过对基座的工艺分析,介绍了带嵌件的塑件注射模设计要点和模具主要零件的制造。模具1出16件,采用镶拼组合结构,嵌件设计为带料形式,提高了生产效率。     

Oxidation kinetics of iron-carbon base alloys

The oxidation kinetics of iron-carbon base alloys in the eutectoid and eutectic range was studied at 760°C for durations up to 1000 min. Special attention was paid to the effect of graphite morphology and carbon content. In order to differentiate the oxidation of carbon from the oxidation of the metallic matrix, two simultaneous but separate thermogravimetric methods were employed. The metallic oxidation rate law for the 0.8% alloy is parabolic, whereas that for the eutectic alloys is linear. The lowest total weight gain was obtained in the 0.8% C alloy.     

Electrodeposition in micromolds with a microscreen base

Electrodeposition in sacrificial micromolds with a microscreen base and thermoplastic sidewalls is one of the main techniques for rapid fabrication of high aspect ratio metallic microstructures. These micromolds with an integral microscreen base are fabricated through an injection molding process by forcing a softened thermoplastic through a metal microscreen into a master template with microfeatures corresponding to those desired in the micromold. During this injection molding process, the holes of the microscreen are filled by the thermoplastic and form insulating segments on the micromold base. Further, the micromold consists of microcavities with insulating sidewalls. During the electrodeposition process into the microcavities, the deposit originates from the conductive parts of the microscreen base and grows along the insulating walls conforming to the micromold geometry. In this work, computational models for the governing transport and electrochemical phenomena are used to simulate the shape evolution of the electrodeposition front and the spatial current density profile with time. The effects of the applied voltage and microscreen geometry (the size and number of the insulating parts on the micromold base) are systematically studied for their influence on the nonuniformity of the current density and deposit surface profile. Conditions that lead to desirable process and part quality are derived from the studies.     

Transient oxidation of multiphase Ni-Cr base alloys

Four commercially available Ni-Cr-based alloys used with porcelain enamels were studied. Major alloying elements were Al, Be, Si, B, Nb, and Mo. All alloys were multiphase. During heat treatments simulating enameling conditions, phase changes occurred in most alloys and were detected using hardness testing, differential thermal analysis (DTA), and microscopy. Oxidation of these alloys at 1000°Cfor 10 min produced an oxide layer consisting principally of chromium oxide, but the oxide morphology varied with each alloy depending on the alloy microstructure. Controlling alloy microstructure while keeping the overall composition unchanged may be a means of preventing wrinkled poorly adherent scales from forming.