非球面塑料透镜钢制模具型腔的加工工艺研究

介绍一种应用ＣＡＤ／ＣＡＭ技术，加工钢制非球面塑料透镜型腔的工艺。它涉及到非球面钢制型腔的工艺型腔设计、数控成型、精修抛光、测量等一系列技术。已制造了多种非球面型腔，正应用于照相机取景器、摄影镜头、望远镜、小型变焦镜头等产品。其中Ｔ９０２照相机摄影镜头已成批生产，精度达到设计和使用的要求。     

塑料光学元件制造

由于光学塑料具有许多杰出的优点 ,因而在照相机、光盘、投影镜头、眼镜等方面获得了日益广泛的应用。塑料光学元件的关键制造技术是模具设计和制造、选择合适的注塑设备、最佳的工艺参数等。为了制作以光盘物镜为代表的高精度非球面塑料透镜 ,就应采用注射压缩工艺抑制变形的成形技术 ,辅之以考虑变形而补偿模具的成形技术。     

非球面塑料透镜的设计及制造工艺研究

非球面的高效加工技术是近20年来国际上各发达国家十分重视开发的技术。迄今，国外的主要加工工艺分三类：第一、采用光学塑料一次注塑成型非球面透镜；第二、在光学球面玻璃基体上“复合”一层高分子材料，构成所谓“复合非球面透镜”；第三、采用光学玻璃用热压法一次成型非球面透镜。该项目在国内首次成功地探索采用光学塑料一次注塑成型非球面透镜的相关技术。其关键技术是：第一、采用CAD技术，设计含非球面塑料透镜的光学系统；第二、采用CAM技术，加工铜制或钢制的型芯的非球面，特别是钢制型芯的非球面最终还需采用精密光学研磨…     

不用胶卷的照相机

日本索尼公司把光学和电子学揉合在一起,创造了一种新型的照相机。这种照相机外表看起来与单镜头反射式照相机一样,但是它不用胶卷而用磁带。摄影时,照相机用传统方法将景物摄入镜头,景物影像通过镜头时,被转变为电子讯号,记录于磁带上。每个磁盘如手掌般大小,可以记录50张照片的电子讯号。这种记录于照相机上的照片可以通过放映机还原于电视屏幕上,亦可以通过专用设备印制成彩色照片。这种不用胶卷的照相机每秒可拍摄10张     

Ф420mm高次非球面透镜的加工与检测

介绍了Ф420mm熔石英高次非球面透镜的加工与检测方法。对现有数控加工工艺进行了优化,通过分工序加工方式,依次采用机器人研磨、抛光和离子束修形技术完成了透镜的加工。进行非球面透镜检测时,考虑透镜的凹面为球面,利用球面波干涉仪对其面形进行了直接检测,剔除干涉仪标准镜镜头参考面误差后,透镜凹面的精度达到0.011λ-RMS;针对透镜的凸面为高次非球面,采用基于背后反射自准法的零位补偿技术对其进行面形检测,其精度达到0.013λ-RMS。最后,采用一块高精度标准球面镜对加工后透镜的透射波前进行了自消球差检测,得到其波前误差为0.013λ-RMS。试验结果表明,非球面透镜各项技术指标均满足设计要求。所述工艺方法亦适用于更大口径的非球面透镜及其他类型非球面光学元件的高精度加工.     

应用多个非球面优化鱼眼镜头的方法

对于鱼眼镜头一类光学系统,其超大视场的物点对于光学系统的成像,是符合平面对称光学系统的成像规律的。应用LU发展的平面对称光学系统的波像差理论,研究如何在鱼眼镜头光学系统中应用非球面对成像系统进行优化设计。首先,通过计算各个光学面的非球面系数对超大视场光学系统波像差的影响,找到受非球面系数变化影响最大的几个光学面;然后,以这几个面的非球面系数为变量,以光学系统调制传递函数作为评价函数,应用自适应归一化实数编码遗传算法,优化设计鱼眼镜头光学系统;最后,通过实例验证了所提出方法的有效性。所提出的方法可以有效地确定一个或多个最佳非球面的位置,对优化设计鱼眼镜头系统具有指导意义。     

摄影镜头的光学薄膜膜系设计

摄影镜头的光学薄膜是减反膜 ,但摄影镜头的接受载体是彩色感光胶卷。所以摄影镜头的减反膜不仅应达到减反效果 ,还必须满足彩色胶卷的感光要求。从工作经验出发 ,阐述设计摄影镜头光学薄膜膜系的方法、重点 ,以及膜系设计的工艺性问题     

非球面曲面光学零件超精密加工装备与技术

"Nanosys-300非球面曲面超精密复合加工系统"是 "九五"重点预研课题-"非球面曲面的超精密加工与测量技术"的主要研究成果.重点对非球面曲面光学零件超精密加工机床,非球面曲面光学零件超精密加工工艺,非球面曲面光学零件超精密测量技术进行了研究.其主要技术成果有:非球面超精密复合加工系统综合设计和制造技术,高速超精密空气静压主轴系统,超精密闭式液体静压导轨系统,高速超精密空气静压磨头电主轴系统,开放式高性能数控系统集成技术等.系统的精度检测和工艺实验表明其研究水平进入了国际先进行列.     

离轴非球面反射镜设计与超精密加工技术

离轴非球面反射镜的设计与加工涉及到零件非球面设计,工艺路线的安排,工装夹具设计,以及超精密加工设备的使用、检测等多方面技术,加工难度大,在国内属于先进的加工技术。通过进行工艺攻关,应用Pro/E软件进行零件三维曲面设计,优化了夹具设计,在减轻夹具质量的同时,保证了其具备足够的刚度、强度,从而减少了切削时的振动影响。在加工过程中,通过调整加工参数,保证了曲面的表面粗糙度和面形要求。运用三坐标测量装置对零件进行了精密测量,验证了零件的尺寸精度符合设计要求。该技术的使用对加工同类型非球面离轴反射镜具有很好的借鉴和推广作用。     

主动式PSD自动对焦光学系统设计

在照相机主动式PSD自动对焦系统中，发射透镜与接收棱镜要求口径大、球差小，价格低、体积小，保证PSD上光斑小而且边缘清晰。本文认为，非球面单片透镜适合该系统。本文导出了非球面透镜的设计方法和计算实例，并给出了AF光学系统总体设计实例。     

用三次样条函数拟合模具型腔廓线

用样条函数拟合曲线具有型值点个数不受限制,保证曲线光滑,便于模具型腔曲线分析等优点。因此,这里采用三次样条函数拟合曲线构造模具型腔廓线,其型值点由已有模具型腔测得。然后分析构造出模具型腔廓线的成形规律,使型腔表面缺损处可获得精确的修正。     

冷冲压凹模的失效分析与电火花局部强化

分析了冷冲压凹模工作时内孔边缘易发生早期疲劳断裂的原因 ,采用电火花强化工艺对凹模内孔刃口处进行局部强化 ,解决了凹模早期疲劳失效问题。     

加工半圆柱型腔的一种新方法

针对传统方法加工半圆柱型腔时刀杆与型腔端部发生干涉的问题,进行了加工机构的创新设计:应用相对运动理论,通过刀具旋转和工件往复运动的合成,准确地实现了半圆柱型腔的铣削加工。     

加工半圆柱型腔的一种新方法

针对传统机械加工半圆柱型腔时,常常发生的刀杆与型腔端部干涉的问题,进行了机构创新设计。应用相对运动理论,采用刀具旋转和工件做相应的往复运动的合成运动,可以准确地实现半圆柱型腔的加工。     

A system for design of multicavity die casting dies from part product model

Design of a die casting die is a nontrivial task, which depends upon a number of influencing factors related to material, part geometry, manufacturing resources, cost, delivery time, etc. Complexity of this die design activity further increases in case of a multicavity die. Currently available die design systems lack in the level of automation and do not explicitly address multicavity die design. Present work is an attempt to develop a system, which facilitates computer-aided design of a multicavity die casting die. The objective of the proposed system is to automate the process of deciding number of cavities, design of cavity layout and die–base, and core and cavity creation for a multicavity die casting die. The proposed system, which we named Auto_Die_Caster, works as an add-on application to solid modeling software SolidWorks. The proposed system is divided into four modules, namely data initialization, cavity design, cavity layout and die–base design, and core–cavity design. Use of commercial software like SolidWorks as a platform both for part design and generation of die design eliminates loss of data which makes the proposed system quite useful in the industrial scenario. To demonstrate the capabilities of Auto_Die_Caster, it was tried for a number of die casting parts and the results are presented. Proposed system is a step forward to design manufacturing integration for die casting process.     

Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.     

新型减速齿轮塑性成形工艺研究

针对大模数拖拉机减速齿轮冷挤压时存在变形抗力大、齿腔充填困难、模具寿命低等技术难题,提出了在凹模齿腔深处设置分流型腔法,并结合浮动凹模技术,制订了挤压新工艺,试验结果显示,该工艺不仅能很好地提高充填性能,而且能降低载荷50%,提高了模具寿命。     

Design and Verification of an Auxiliary System for High Vacuum Die Casting

Vacuum die casting is the optimal method to produce high quality aluminum alloy components.At present,there are still very few systematic studies on vacuum die casting theory and equipment design.On the basis of the existing theories of the vacuum die casting pumping and venting systems,a simplified model is established in this research.The model has an aggregate unit consisted of "vacuum pump + buffer tank" and a cylindrical container(including the shot sleeve,cavity and exhaust channel).The theoretical analysis is carried out between the cavity pressure and the pumping time under different volume models.An auxiliary system for high vacuum die casting is designed based on the above analysis.This system is composed of a vacuum control machine and a new vacuum stop valve.The machine has a human-computer control mode with "programmable logic controller(PLC) + touch screen" and a real-time monitoring function of vacuum degree for buffer tank and die cavity.The vacuum stop valve with the "compressed gas + piston rod + labyrinth groove" structure can realize the function of whole-process vacuum venting.The new system shows great advantages on vacuuming the cavity with a much faster speed by making tests on an existing die casting mold and a 250 t die casting machine.A die cavity pressure less than 10 kPa can be reached within 0.8 s in the experiment and the porosity of castings can be greatly decreased.The systematic studies on vacuum die casting theory and equipment have a great guiding significance for high vacuum die casting,and can also be applied to other high vacuum forming in related theoretical and practical research.     

面向大型压铸模型腔壁厚的模糊优化设计

运用多目标模糊优化设计的原理,结合大型压铸模的工作条件,建立了逼近实际工况的型腔壁厚数学模型。采用最优水平截集法求解,并用复合形法进行优化。并给出了这种设计方法应用于潜望镜镜身铸件压铸模的工程实例。     

正交试验设计在TA2筒形件拉深成形过程中的应用

研究了TA2筒形件的拉深成形过程,对无压边圈情况下拉深成形的5个因素(凹模入口圆角、凸凹模间隙、模具与板坯之间润滑系数、凸模圆角、坯料直径)进行了有限元数值模拟及其正交试验,提出了采用成形后板坯最大厚度与最小厚度之差Δt的概念来作为描述零件成形结果的评价标准,且论证了采用该评价标准的合理性。对试验结果进行了直观分析和方差分析,得出了各因素对拉深成形过程的影响次序及显著性。