大型工件成形快速应变测量技术

针对目前大型工件在成形过程中应变测量的实际问题,提出了一种快速视觉测量方案,在采用近景工业摄影测量与坐标网格相结合的基础上,进行基于公共点的三维测量数据拼接可以高效地实现大型工件成形后表面全场应变的快速测量,通过对某汽车顶盖冲压零件表面应变的测量,验证了该方法的可行性和有效性。     

多点技术在飞机板类部件制造中的应用

多点技术是一种机电一体化的柔性制造技术,其核心是高度由计算机控制的基本体单元。多个基本体单元紧密排列在一起,构成型面可变的多点模具,用于板类零件成形。由于多点模具型面可由计算机任意调整,可代替传统模具用于不同形状的飞机板类部件的对压成形、蒙皮拉形等。基本体单元按照一定距离排列在一起,构成多点柔性工装,不仅可用于飞机大型板类零件成形后的测量、切割等操作的支撑与定位,还可用于飞机部件的柔性装配过程。应用多点技术,可以实现飞机板类部件生产过程的数字化。     

螺杆泵转子齿形的三座标检测原理和应用

螺杆泵转子的型面是成形螺旋面,它的型线精度直接影响齿间的泄漏和泵的效率,迫切需要提高它精度。但是由于它的形状复杂,精度高,这类零件的精度检测一直是个技术关键。本文提出了在三座标测量机上利用等距曲面原理,高精度地检测螺杆泵转子端面齿形和利用测量数据决定工具截形的新方法。一、检测原理和方法所用检测仪器为日本三丰F604型三座标测量机,被测转子横放在测量机的工作台上,     

汽车前隔板拉延工艺的数值模拟优化

以某车型的前隔板为研究对象,通过三维软件设计零件拉延成形工序的工艺补充面和压料面,借助有限元软件优化拉延成形工艺参数。经初步有限元分析得出零件存在拉裂缺陷,通过分析产生拉裂缺陷原因,采用点追踪法优化坯料形状,并再次进行数值模拟,得到合格的零件。采用优化的数值模拟结果来加工模具型面,实际调试模具时选用优化的坯料和成形参数,得到的实际拉延成形零件无起皱和破裂等缺陷,检测成形零件可能拉裂处的最大减薄率为0.221。实验结果表明CAE技术能够准确地预测成形缺陷,优化模具设计,缩短模具开发周期,降低成本。     

基于数值模拟技术的轿车盖板成形模具型面设计

本文以轿车盖板为研究对象，根据覆盖件成形特点，对该零件的成形工艺补充面、压料面和拉延筋进行分析，设计出了拉延模具型面。并运用有限元技术对其成形过程进行数值模拟，根据模拟结果对拉延型面进行调整、修改，最终得到合理的模具型面用于模具的加工制造，并对同类零件的设计起到一定的指导作用。     

基于起皱分析的钛合金异形盒件缺陷控制研究

针对钛合金异形盒零件成形起皱问题开展研究，对零件热成形过程中失稳起皱的原理进行分析，结合鼓动产生前后接触压力矢量分布情况得到成形过程中材料流动趋势以及褶皱产生的原因。通过监测零件成形过程中受压侧褶皱折弯角度及零件最大应变情况，发现在合模间隙为6 mm时零件发生失稳变形。对该状态下零件型面进行光顺，设计出零件2道次成形的过渡工装型面，并对工装排布与毛料结构进行优化，最后进行试验验证，成形后的零件贴模间隙为0～0.15 mm。结果表明，改进后的工艺方法将零件变形进行分解，使材料变化均匀，过渡型面消除了成形过程中的褶皱问题，实现了零件的精确成形。     

一种带有回弹补偿的钛合金钣金热成形工艺

钛合金零件热成形后的型面回弹是钛合金钣金成形工艺中亟待解决的重要问题。文章针对典型的钛合金弯曲类零件,采用数值解析法与几何修正法确定零件回弹前的型面尺寸,并在此基础上设计带有回弹补偿的热成形模具。结合工艺试验确认并优化了相关热成形工艺参数,有效控制了钛合金零件热成形过程的外形精度,实现了零件的精确成形。     

点焊拼接板的概率化成形极限图及其应用

成形极限图是评定金属薄板成形性能最为简单和直观的方法,是解决板冲压问题的一个非常有效的工具.本文根据点焊拼接板的特点提出了概率化成形极限图P-FLD,并采用MSC.Dytran有限元分析软件对点焊拼接板的胀形及拉深过程进行模拟研究,得到了点焊拼接板成形时的应变分布.将点焊拼接板的P-FLD和有限元模拟的零件应变分布点结合起来,得到零件应变极限图,从而为初步选材和确定冲压零件的安全裕度提供了参考.     

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。     

飞机蒙皮零件数控精确拉形技术应用研究

以某大型客机蒙皮零件为例,设计了基于数字化工艺设计与有限元仿真的数控精确拉伸成形技术方案。基于毛料面内变形状态分析设计了多工步拉形加载轨迹,通过"虚拟拉形"有限元模拟比较了多种纵拉和横拉方案及相应工艺参数下的成形质量。有限元模拟结果表明,该零件采用横拉方案效果优于纵拉方案,并根据有限元模拟结果优化了空间加载轨迹参数。根据设备求解生成数控代码,在Cyril Bath L2x350数控拉伸机上直接进行了自动化拉伸成形试验,获得了合格的零件,并比较验证了有限元分析和测量数据结果,验证了设计的飞机蒙皮零件数控精确拉形技术方案的可行性和准确性。     

Acoustic emission technique for online monitoring during cold forging of steel components: a promising approach for online crack detection in metal forming processes

The acoustic emission technique is a very promising non-destructive and online capable approach for the detection of damage events in metal forming processes. The feasibility of using this testing method for online monitoring of cold forging processes of the case hardening steel 1.7321 (20MoCr4) was experimentally proven. In this paper, exemplary upsetting tests under varying test conditions were continuously monitored to analyze the relationship between cracking and resulting AE as well as to determine ideal AE measuring parameters. Finally, the critical forming stage of an industrial cold forging process for manufacturing of drive bevel gears is examined by applying acoustic emission technique. Cracking and tool wear were detected by analyzing the distribution of the AE parameters energy, hits and amplitude over the forming process.     

电磁成形技术在粉末成形中的应用

介绍了电磁成形技术、粉末挤压成形方法以及电磁成形技术在粉末成形中的应用.用电磁成形技术压制粉末材料是获得高密度、高性能粉末冶金制品的一种有效方法,是低成本制造高密度陶瓷零件的新途径.     

Powder solders for hard soldering of aluminium and its alloys

In this paper, the possibilities for forming non-circular pulleys using laser cutting techniques and cutting techniques using water jets with abrasive materials are described. Research on laser cutting with use of gases for formation of carbon steel and acid-resistant steel pulleys is also discussed. The advantages of water jet cutting of non-circular pulleys are shown, and the methodology for measuring machined pulleys with a coordinate measuring technique is also presented. Use of computer-aided design systems with a range of software enabling automation of CNC contour saw control and optimization processes for formed elements spacing are all also discussed.     

数值模拟技术在锻造成形中的应用

锻造成形过程是一个非常复杂的弹塑性大变形过程,有限元法是用于锻造成形过程模拟中一种有效的数值计算方法。本文介绍了数值模拟技术在金属锻造成形中应用的基本理论、模拟中的关键技术,阐述了锻造成形数值模拟技术的现状及发展趋势。     

管材塑性拟合成形数控系统的设计

回弹是影响管材成形精度的重要因素。在分析管材单点成形原理的基础上,对管材塑性成形控制技术进行研究,提出基于单点成形技术的拟合渐进成形方法,并建立管材拟合成形坐标系,设计基于多轴控制技术的管材成形数控系统。该系统通过非接触式测量成形前后的距离差,将其转换为实际塑性成形角度,实时检测单点成形时回弹量,在下次加工时进行补偿和修正,实现管材拟合渐进成形的闭环控制。试验表明,该系统可以有效地测量回弹,保证管材成形加工的重复精度和适应性。     

Cognitive clamping geometries for monitoring elastic deformation in forming machines and processes

In the context of inline monitoring and controlling of forming processes, the distribution of acting forces on tool and forming machine causing elastic deformation of the clamping surfaces provides fundamental information on the resulting part quality whereas the inline detection is still challenging. This paper presents a novel method using the T-slot geometry as a cognitive area for inline analyzing of the elastic deformation of the tool-clamping surfaces. Using a newly developed sensor device, the elastic deformation state of the T-slot geometry under process forces is detected by strain measuring of a deformation body mounted inside the T-slot. The functionality principle of the sensor device and measuring method for process monitoring are demonstrated by simulation and experiments, demonstrating the potential for process control.     

Longitudinal forces in railway track and tamping machine shifting sets

Following American and British experience some attempts have recently been made in Poland to determine the axial forces in a rail by using the constrained transverse displacement technique. The method is based on vertical dislocation of a rail section separated from the rail-track up to a certain height with the registration of force used for this purpose. An original testing apparatus has been made to measure the forces and displacements. Taking advantage of experimental investigations it was possible to point out that horizontal displacements of the rail are indispensable. Hence, further investigation tasks were concentrated on constrained horizontal dislocations of the entire track grate.Using a specially prepared apparatus it was possible to measure the axial forces within the tamping machine shifting set and the transverse track displacements with various tensile forces in the rails (in the range of 0–500 kN). It was indicated that the tamper is a machine that can be employed for the determination of axial forces in rails using the constrained transverse dislocation technique. The method provides a capability of precise control of the displacement values. It is also possible to utilize measuring force and displacement testers and to create an operator's station. However, the problem is complex, which is indicated by the pulse mode of the horizontal force characterized by a much variable time characteristic.     

齿轮精密锻造技术的发展

研究和试验了圆柱直齿轮、圆柱斜齿轮和同步齿轮等 3种汽车用齿轮。制造工艺采用温锻加冷处理 ,用有限元模拟来分析锻造过程和设计模具 ,从而保证齿轮的精度。经过 3年的研究 ,已掌握其基本技术 ,下一步将进行工厂现场试验     

Predicting plastic deformation and work hardening during V-band formation

V-band clamps are manufactured using a cold roll forming process consisting of six passes which plastically deform an initially flat strip by bending to produce the band's V-section. In this paper a new method of validating numerically predicted plastic deformation in a cold formed metal strip is presented. Tensile testing of samples of the band's material was used to obtain a direct link between plastic strain and work hardness of this particular material. Using this correlation, the equivalent plastic strain (PEEQ) values predicted by finite element simulations were converted into hardness values. These values were compared to experimental work, in which samples of each pass of the roll forming process were taken to determine the work hardness in the cross section of the V-band using a micro-hardness machine. The error in strain predicted by the numerical method and hardness obtained by testing was found to be between 0.4% and 16.9%. This error was mainly due to uncertainty in material properties and the accuracy of the measurement technique. Compared to the more classical approach of measuring strain distribution with strain gauges, this method is more precise and accurate, as it is able to pick up even small changes in strain distribution.     

平板件电磁成形技术的研究进展

在简述了平板件电磁成形原理的基础上,从以下4个方面综述了此技术的国内外研究进展:成形线圈设计方面,列举了平板线圈,匀压力线圈,并列线圈以及工艺校形线圈的使用;磁场力计算方面,讲述了解析法和有限元法的应用;试验研究方面,阐述了电磁成形板材成形性能研究、电磁辅助成形研究的进展;数值模拟方面,叙述了各种数值模拟方法以及有限元软件的应用。最后,指出了平板件电磁成形技术推广过程中所需攻克的技术难题。