发动机罩超深冲压成形

发动机罩零件,深411.8mm,属于超深拉伸零件,拉伸超深及造型骤变使得成形非常复杂。运用Autoform成形模拟软件,分析机罩拉伸成形过程,预判风险,优化成形工艺,最后调试拉伸模状态,得到符合制件质量要求的零件。     

TC4钛合金双曲度复杂航空零件热成形工艺研究

选取TC4钛合金双曲度复杂航空零件作为研究对象,采用热成形工艺进行成形.设计了3种成形模具工艺方案,分别为无拉伸梗、整体拉伸梗和局部拉伸梗.采用有限元仿真技术对3种成形工艺方案进行模拟,得到零件成形过程中的厚度变化情况,并预测可能产生的成形缺陷,对零件成形质量进行了评估,确认了拉伸梗在成形过程中的作用.通过3种成形工艺...     

汽车散热器主片拉伸成形工艺及模具

通过对汽车散热器主片零件进行拉伸成形的工艺分析 ,阐述了该零件拉伸成形的难点 ,采取了有效的工艺措施 ,设计了一次拉伸成形的模具 ,提高了产品质量和生产效率。     

板材柔性拉伸成形研究进展与展望

传统横向拉伸成形和纵向拉伸成形过程中,均存在夹持机构运动与过渡区板材变形不协调现象,进而诱发板材与模具不贴合、变形不均匀、起皱甚至拉裂问题。为降低零件制造成本、提高板材贴模度和零件成形精度,开展板材柔性拉伸成形研究极具学术研究价值和工程应用前景。综述了板材柔性拉伸成形模具柔性化和加载机构柔性化的研究进展,重点阐述了多辊下压式和多夹钳式柔性拉伸成形原理、装备构成及成形特点,分析了过渡区长度、板材加载路径等主要工艺参数对零件成形质量的影响,简述了力/位移加载分布式柔性拉伸成形方法,最后展望了板材柔性拉伸成形的发展方向。     

复杂鼓包蒙皮成形技术分析与优化

针对曲率复杂、工艺性差、加工难度大的复杂鼓包蒙皮,以某型飞机机轮舱腹板鼓包蒙皮为例,对零件的结构特点及成形难点进行分析。采用理论分析及有限元仿真分析技术,研究了落锤成形、拉伸+落锤成形、拉伸成形3种成形技术对应的模具型面设计、加工特点、加工工艺路线和优缺点,得出拉伸成形可取代落锤成形并提高零件的成形质量、节约工装、缩短生产周期。通过返修模具局部型面的方法解决了现场零件拉伸成形试验过程中产生的局部区域死皱及不贴模等缺陷,得出通过模具设计及工艺参数改进等方法可解决复杂鼓包蒙皮拉伸成形过程中的缺陷,为同类复杂鼓包零件的成形提供了解决思路。     

变流漏斗拉伸成形模具设计

分析变流漏斗成形工艺,设计了零件成形模具,实现了深尺寸大直径零件的拉伸成形模具设计,合理分布工序、保证了零件的尺寸及精度。     

异形零件的拉伸成形工艺及模具

异形零件的拉伸成形工艺及模具广东中山市燃气具工业集团公司模具厂（广东中山５２８４０３）卢小鹏在板金成形零件中，一般将既不象圆筒形也不似矩形的拉伸零件称为异形零件。由于异形零件在拉伸时材料变形复杂，不能进行较准确的工艺计算，常常缺乏可供参考的技术资料，...     

7075-O铝合金板料的摩擦搅拌渐进成形：成形零件性能的实验研究

本文中,用不同的主轴转速来成形两种典型零件,研究了摩擦搅拌渐进成形零件的综合性能：成形性,表面质量,拉伸性能,显微硬度和壁厚分布。试验结果表明,板料的成形性随着转速增加而呈现增强趋势;接触面的表面粗糙度在水平和竖直方向表现出不同的变化趋势;非接触面的表面质量几乎不受转速影响;相比原板料,成形零件的拉伸性能和显微硬度明显增强,但转转速超过3000 rpm后,硬度值开始逐步下降;在高转速下成形零件的壁厚分布略微优于低转速下的成形零件。总体上,除了力学性能,高转速下成形零件的综合性能比低转速下的成形零件好。     

皮带轮成形工艺及模具设计

分析了皮带轮的成形工艺 ,介绍了成形该零件的拉伸模、反拉伸模、整形模以及精整模结构     

航天用铝合金蒙皮拉形工艺研究

采用FET-1000T横向蒙皮拉伸成形机设备对2A14铝合金进行了蒙皮拉形工艺的研究。研究结果表明:对于单曲率蒙皮零件的成形,主要采用先预拉伸再弯曲成形后补拉伸的拉形工艺,预拉伸主要是保证成形前坯料的平直,补拉伸是为了减少零件弯曲成形后的回弹;经过预拉伸处理的蒙皮,母线直线度在0.9~1.2 mm之间,厚度在8.03~8.10 mm之间,其成形后的母线直线度大致呈现中间低两边高的现象,而厚度分布则呈现中间厚两边薄的趋势;适当的增加约0.6%的补拉伸量,既可以提高蒙皮的型面贴合度,又可以保证蒙皮的力学性能,从而达到蒙皮零件成形/成性的协同控制。     

摩擦板挤齿模的设计改进

针对原摩擦板挤齿模结构和生产效率方面存在的问题 ,对挤齿成形过程进行了初步分析 ,提出了一种改进方案 ,并介绍了模具试模调整方法及主要零件制造工艺     

大学校长与国家教育权力系统的关系诠释

作为国家实现其管理能力的实施机构体系 ,国家教育权力系统宏观地调控大学校长的办学行为 ;作为肩负着提升人类物质生活质量和精神生活质量双重使命的大学领导者 ,学术自由和大学自治是大学校长必须坚守的价值取向。树立系统观念 ,明确教育理念 ,把握合理的紧张尺度 ,培养良好的素质修养 ,保持不断改革创新的精神是当今我国大学校长应对自身矛盾处境的良策。     

A study on the machining characteristics in the external plunge grinding using the current signal of the spindle motor

This paper describes the machining characteristics of external plunge grinding. The study investigates the process using the current signals of a spindle motor through a hall sensor. Grinding experiments were conducted under various grinding conditions such as wheel speeds, workpiece speeds and infeed rates with a conventional vitrified bonded wheel. Analyzing the current signal of the spindle motor, a relationship between current signals and the metal removal rate in terms of the infeed rate is induced. It was also shown that a hall sensor has similar capabilities in evaluation of grinding behavior compared to the AE signals, which are useful for monitoring the grinding process.     

冰箱门胆吸塑模抽芯机构设计

在充分分析斜滑块抽芯机构运动及受力状态的基础上 ,介绍了一种利用脱模力抽芯的非气动抽芯机构设计方法。采用该方法设计的吸塑模结构紧凑 ,抽芯可靠 ,生产效率高     

Improvement of the deformation capacity o the column-to-beam joint by the reinforce welding method around the scallop bottom

Improvement of deformation capacity for a column-to-beam joint is an important theme for improving the earthquake-resistance performance of building structures. One of the causes of decreasing deformation capacity is the existence of stress concentration against the beam flange by the scallop (access hole). The non-scallop method is generally recommended to improve this problem, but it has a large disadvantage in that it is not able to apply to the on-site joint process. The reinforce welding method around the scallop bottom has been developed to be able to apply to an on-site joint and obtain better performance than the non-scallop method. The improved mechanism is a combination of: (1) decreasing the stress concentration; (2) increasing effective thickness; and (3) increasing total length of the breaking line. The deformation capacity by the reinforce welding method around the scallop bottom is a maximum 3.2 times that for the conventional scallop method in the reverse repeating bend test using an actual structure with a beam flange of 19 mm thickness and 490 N mm^?2 class steel. This improving effect is better than the non-scallop method.     

Analysis of the hydrodynamic state of the two-phase model of the solidifying weld metal

A robotic laser welding cell for stainless steel components, which includes a Cartesian robot, is described. The solution allows a drastic reduction in production times along with increased final quality compared to traditional welding technology, thus representing a particularly significant example of the advantages of the flexibility of a robot and the quality of the laser.     

Stability limits of milling considering the flexibility of the workpiece and the machine

High speed machining of low rigidity structures is a widely used process in the aeronautical industry. Along the machining of this type of structures, the so-called monolithic components, large quantities of material are removed using high removal rate conditions, with the risk of the instability of the process. Very thin walls will also be milled, with the possibility of lateral vibration of them in some cutting conditions and at some stages of machining. Chatter is an undesirable phenomenon in all machining processes, causing a reduction in productivity, low quality of the finished workpieces, and a reduction of the machine-spindle's working life.

In this study, a method for obtaining the instability or stability lobes, applicable when both the machine structure and the machined workpiece have similar dynamic behaviours, is presented. Thus, a 3-dimensional lobe diagram has been developed based on the relative movement of both systems, to cover all the intermediate stages of the machining of the walls. This diagram is different and more exact than the one that arises out of the mere superposition of the machine and the workpiece lobe diagrams. A previous step of rejecting resonance modes that are not involved in the milling at the bottom zones of the thin walls must be previously performed.

Finally, the proposed method has been validated, by machining a series of thin walls, applying cutting conditions contrasted with the limits previously obtained in the three-dimensional lobe diagram.     

贮油罐支架成形工艺及模具

通过对贮油罐支架的成形工艺分析 ,给出了合理的制造公差 ,确定了合理的工艺方案 ,使模具调试工作得以顺利进行     

径向冲孔模设计

对盒体零件的冲孔工艺方案进行了分析,介绍了各种冲孔工艺方案的优缺点,从而确定了利用凸轮机构,实现了该零件的径向冲孔。介绍了该模具结构及工作过程,给出了零件的工艺计算方法,提出了模具的设计方法,为解决同类零件的冲孔提供了参考。     

用科学发展观统领创新型大学建设

创新型大学是一种建立在创新基础上的大学组织形式,其核心理念和核心竞争力是创新。建设创新型大学是应对知识经济挑战和建设创新型国家的需要,是加快研究型大学自身发展的必然选择。必须用科学发展观统领创新型大学建设,大力推进教育创新、科技创新和管理创新。