共查询到19条相似文献,搜索用时 203 毫秒
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针对微塑性成形工艺的特点,选择压电陶瓷作微驱动器,研制出微塑性成形专用设备,实现了在较小位移内获得较大输出载荷.使用研制的设备开展微型零件成形工艺研究.对微型齿轮件的成形质量进行分析表明,微型齿轮齿面光滑,表面质量好;在横截面上流线与齿轮轮廓一致,利于提高成形件的综合机械性能.使用3003铝合金箔板研究了微型杯的拉深成形工艺,分析了工艺参数对微拉深成形的影响规律,成功的拉深出最小外径为1mm的微型杯件.以上结果表明,微塑性成形技术能够批量地成形出高质量的微型零件. 相似文献
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目的 研究GH4698微型涡轮盘热塑性成形工艺。方法 采用有限元软件Deform-3D对镍基高温合金微型涡轮盘模锻过程进行数值模拟分析,研究坯料不同高径比、不同模锻温度下涡轮盘成形的最大载荷值、等效应力、等效应变、速度场的变化规律。结果 微型涡轮盘模锻过程载荷最大值随模锻温度升高而降低,温度和高径比对涡轮盘的凸台、直榫等部位的等效应力、等效应变影响有明显的差异。在涡轮盘路径1上,随着温度的升高,等效应力逐渐降低,变形更加均匀;随着高径比的增加,变形不均匀程度增大,高径比为1时等效应力的极大值最小;温度和高径比对速度场的影响较小。结论 温度和高径比对GH4698微型涡轮盘锻造变形行为有显著的影响,选择合适的模锻工艺参数可以有效降低成形载荷,并获得使用性能较好的微型涡轮盘。 相似文献
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目的研究采用浮动凹模工艺温精密成形圆柱斜齿轮时,不同凹模运动速度下齿轮力能参数和各种场量变化规律。方法结合浮动凹模原理和圆柱斜齿轮结构特点,利用Defrom-3D软件建立变形-传热耦合有限元模型,模拟圆柱斜齿轮采用浮动凹模温精密成形过程,分析不同凹模运动速度下的变形规律。结果通过模拟分析,得到了凹模运动速度不同时的温成形斜齿轮成形载荷特点、坯料流动速度场分布、等效应力-应变分布、温度场分布等规律。结论采用浮动凹模工艺成形圆柱斜齿轮,可以减小成形力,当凹模运动速度大于凸模下行速度时,齿轮成形性更好。 相似文献
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目的 提高现有微成形工艺的可成形性,解决薄板易破裂等缺陷,探究薄板软模微拉深成形工艺的工艺参数对成形性的影响,致力于制造具有更大拉深比的微型杯件。方法 采用退火后的纯钛薄板作为原始板材,设计了薄板的软模微拉深成形模具进行实验。实验中探讨了工艺参数和材料参数对微型杯件极限拉伸比的影响。工艺参数包括压边力、橡胶性能和润滑方式,材料参数主要是晶粒尺寸。结果 通过控制压边力能够避免微拉深工艺中的缺陷。压边力过低会导致法兰区域起皱,压边力过高会导致上圆角部位破裂。采用刚度系数为72N/mm的压边弹簧能够有效避免起皱和破裂。选用硬度为65HA的聚氨酯橡胶能够成形出极限拉深比最大(为2.64)的纯钛微型杯件。软模微拉深工艺必须采用有效的润滑方式来提高板材的流动行为。采用蓖麻油润滑能够有效避免微型杯件的破裂缺陷。板材的晶粒尺寸对极限拉深比的影响是最强烈的。晶粒尺寸为8.4μm的纯钛薄板能够制造出极限拉深比为2.64的微型杯件,而随着晶粒尺寸的增大,微型杯件的极限拉深比显著下降。结论 通过软模微拉深工艺并且采用合适的工艺参数成功制备了极限拉深比为2.64的微型杯件,与现有工艺相比,所获得的微型杯件的极限... 相似文献
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基于数值模拟的极限凸翻边研究 总被引:9,自引:1,他引:9
为了提高薄板冲压成形零件的疲劳寿命,将半手工操作的落锤压制(冲压)方法改为高压橡皮成形(静压)方法而进行的工艺研究试验;同时,为高压橡皮半模成形确定最合适的工艺过程设计(CAPP)进行计算机仿真.运用自行开发的静-动力有限元软件分析橡皮成形凸模圆角半径和板料厚度对凸翻边成形极限的影响,并建立预测橡皮成形凸翻边成败的t极限翻边高度Hmax、凸模圆角半径r凸、板料厚度t的关系曲面.根据所得数值模拟的极限凸翻边高度Hmax模与7.7万吨橡皮囊液压机的试验结果Hmax实的对比,吻合很好;数值模拟将凸翻边起皱-压贴的真实过程描述得很清楚,而理论计算结果与物理实验结果有一定的差值. 相似文献
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目的探究液室压力和拉深速度以及温度场分布规律对成形性能的影响。方法在通用有限元软件MSC.Marc中建立5A06铝镁合金温热介质充液成形有限元模拟的专用平台,对典型零件温热介质充液成形进行有限元模拟。结果在液室压力为5 MPa、拉深速度为5 mm/s的情况下成形效果最好,最佳温度场分布为凹模与板料温度250℃、凸模温度20℃、压边圈温度300℃,在此条件下,凸模直径为100 mm时极限拉深深度可达到161.4 mm。结论液室压力和拉深速度以及温度场的分布对成形性能有着显著影响。 相似文献
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目的掌握硬铝合金在温热条件下的成形性能变化规律。方法采用结合半球凸模胀形和椭圆液压胀形的复合试验法进行了FLD试验,用最小二乘法拟合试验数据,建立了成形极限预测模型。结果试样均在凸模顶端或附近发生破裂,在室温下网格保持较小的圆形,在210℃和300℃下网格被不同程度的拉长和变大,温度对铝合金2A16的成形性能影响很大,随温度升高,成形极限曲线上移。结论复合胀形试验法具有较高的可靠性与准确性;铝合金2A16在高温下成形性能更好;预测模型较好地表述了极限应变值与温度的关系,根据模型可快速得出FLD。 相似文献
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目的 减小铝合金交叉筋壁板激光热诱导锥面成形过程中的边缘效应。方法 利用有限元分析方法,通过对扫描线温度、应力应变分布的分析,得到边缘效应产生的原因;研究激光功率、扫描速度、扫描次数对边缘效应的影响,选择合适参数,采用激光热诱导成形系统,对5A06铝合金交叉筋壁板进行锥面成形试验,并用扫描仪检测成形精度。结果 边缘效应随着扫描速度的减小、激光的功率变大而减小,与单次扫描相比,两次扫描能有效减小边缘效应。试验证明,扫描速度对边缘效应的影响最大,将扫描速度保持在30 mm/s以下,调整激光功率和扫描速度控制能量密度,在保证弯曲角度的同时,也能较好抑制边缘效应。 相似文献
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As one of the indispensable actuating components in micro-systems, the shafted microgear is in great production demand. Microforming is a manufacturing process to produce microgears to meet the needs. Due to the small geometrical size, there are uncertain process performance and product quality issues in this production process. In this study, the shafted microgears were fabricated in two different scaling factors with four grain sizes using a progressively extrusion-blanking method. To explore the unknown of the process, grain-based modeling was proposed and employed to simulate the entire forming process. The results show that when the grains are large, the anisotropy of single grains has an obvious size effect on the forming behavior and process performance; and the produced geometries and surface quality are worsened; and the deformation load is decreased. Five deformation zones were identified in the microstructures with different hardness and distributions of stress and strain. The simulation by using the proposed model successfully predicted the formation of zones and revealed the inhomogeneous deformation in the forming process. The undesirable geometries of microgears including material unfilling, burr and inclination were observed on the shaft and teeth of gear, and the inclination size is increased obviously with grain size. To avoid the formation of inclination and material unfilling, the punch was redesigned, and a die insert was added to constraint the bottom surface of the gear teeth. The new products had then the better forming quality. The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00414-0 相似文献
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目的采用新型复合大塑性变形技术正挤压-等径角挤压工艺(FE-ECAP),研究5052铝合金在室温条件下的变形行为。方法基于有限元分析软件DEFORM-3D,在FE-ECAP工艺下对5052铝合金进行有限元模拟,研究变形过程中挤压载荷、等效应变、金属流动速度等场量的分布规律。结果 5052铝合金在FE-ECAP变形过程中,挤压载荷曲线呈双峰形态分布,在挤压模口附近达到第一次峰值,第二次出现在转角处,挤压载荷值为347 k N,同时也是整个挤压过程的最大值;经过FE-ECAP变形后,等效应变大量累积,使得主要变形区达到了高度均匀的变形状态;坯料外转角处金属的流动速度值大于内转角处的流动速度值。结论根据以上结果分析,在FE-ECAP工艺下,为使变形坯料性能优越,应尽量提高坯料变形的均匀性。 相似文献
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Reza Bagheriasl Kamyar Ghavam Michael J. Worswick 《International Journal of Material Forming》2014,7(2):139-154
A combined experimental and numerical study of the effects of die and punch temperature on the formability of a modified AA3003 aluminum alloy sheet for a case study sample is presented. Here, the non-isothermal deep drawing of a cup-like feature in a thin gauge aluminum automotive component is considered. An experimental forming setup that incorporates both heated dies and a cooled punch has been developed. A parametric study of the effects of die temperature, punch temperature, and blank holder force on the formability of the part is conducted. Numerical simulations of the warm forming process are performed using a coupled thermo-mechanical finite element model. The temperature-dependant material model combines the Bergstrom hardening rule with Barlat’s YLD2000 yield function and was implemented in LS-DYNA as a user-defined material model. Selected experimental cases were modelled numerically and compared to experiments. The FEA model was validated against experimental results by comparing measured and predicted punch force versus displacement as well as trends in the formability as a function of die temperature. 相似文献
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Key Problems in Microforming Processes of Microparts 总被引:2,自引:0,他引:2
Chunju WANG Debin SHAN Bin GUO Jian ZHOU Lining SUN 《材料科学技术学报》2007,23(2):283-288
From the viewpoint of production engineering, microforming is considered as an effective process to fabricate various microparts. Several key problems in microforming processes were investigated. A new microforming apparatus with a high stiffness piezoelectric actuator as the punch driver was developed to produce microparts.To improve the forming abilities and locate the billets, a floating microdie was designed. The size effects of the billets and die cavities on the microforming abilities were studied with upsetting and coining tests, respectively.And the isothermal microforming process of microgears was performed with the developed microforming apparatus. Several analysis methods were used to evaluate the forming quality of the microparts. 相似文献
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Hong-Yang Zhao Dong-Ying Ju Takeshi Asakami Lin Hu 《Materials and Manufacturing Processes》2001,16(5):643-654
Experimental studies on the twin roll casting process in order to produce thin aluminum alloy strips are presented in this paper. A new twin roll caster was developed as an effective experimental tool. The caster is equipped with a complete casting system incorporating a control and measuring system using multiple sensors and various actuators. The data acquisition system of the caster can measure various process parameters including meniscus, casting speed, and temperature as well as roll gap and pressure. With this system, aluminum alloy thin strips were manufactured and the process parameters such as strip temperature, casting velocity, and pressing force of roll were investigated. Furthermore, the crystallizability, microstructure, and mechanical properties of the strip are evaluated by X-ray diffractometer, scanning electron microscope, and tensile test. The results revealed the ability of the twin roll caster to produce directly the thin strip of aluminum alloy with improved mechanical strength. 相似文献
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The reflection and refraction of light at a dielectric interface gives rise to forces due to changes in the photon momentum. At the microscopic level, these forces are sufficient to trap and rotate microscopic objects. Such forces may have a profound impact in the emergent area of microfluidics, where there is the desire to process minimal amounts of analyte. This places stringent criteria on the ability to pump, move and mix small volumes of fluid, which will require the use of micro-components and their controlled actuation. We demonstrate the modelling, fabrication and rotation of microgears based on the principle of form birefringence. Using a geometric anisotropy (a one-dimensional photonic crystal etched into the microgear), we can fabricate microgears of known birefringence, which may be readily rotated by manipulating the input polarization in a standard optical trap. This methodology offers a new and powerful mechanism for generating a wide range of microfabricated machines, such as micropumps, that may be driven by purely optical control. 相似文献