【作者】 李鹏；

【导师】 罗怡；

【作者基本信息】 大连理工大学 ， 机械工程（专业学位）， 2016， 硕士

【摘要】 零件装配是微小惯性器件生产制造过程中的重要环节,直接影响器件的性能。装配的可靠性是实现微小零件装配系统设备应用的保证。随着零件的微小化,表面力对零件拾取与释放的影响增加,尤其是在释放过程中,吸附头与零件之间的表面力导致的位置误差会影响装配精度,因此微小惯性器件装配中零件的可靠拾取与释放是装配成功与否的关键。本文需要装配的微小惯性器件由七个零件组成,其中三个为薄片类零件,最小质量为0.4g,零件的拾取方式采用真空吸附。为了减小装配时粘附力对零件装配精度带来的影响,分别对范德华力、静电力和毛细作用力三种粘附力进行了分析,研究了不同力的产生机理与影响因素,为减弱粘附力提供了一定的理论参考。设计并搭建了微力测量装置用于测量装配作业时吸附头和零件接触表面间的粘附力,针对上述三个零件,分别研究了不同的分离速度、加载的装配力和时间、吸附头材料及环境湿度等参数对粘附力的影响规律。测量实验结果表明：分离速度、加载装配力时间对橡胶吸附头和硅、镀金材料零件间的粘附力影响较大,粘附力随着参数值的增加显著增大,而对吸附头和氮化铝材料零件间的粘附力影响微弱；在加载的20-80mN装配力范围内变化时,橡胶吸附头和三种材料零件间的粘附力基本保持稳定；聚四氟乙烯(PTFE)材料吸附头能显著减小和三种材料零件间的粘附力；环境湿度对橡胶吸附头和三种材料零件间的粘附力影响显著,粘附力都随着湿度的增加而显著增大,但当湿度超过60%时,硅材料零件和橡胶吸附头间的粘附力大小基本稳定。综上,以吸附方式拾取微小零件时作业环境的湿度应尽量小,吸附头采用PTFE材料,分离速度和装配力加载时间应在合适的范围内选择较小的值有利于减小粘附力以提高装配的精度。上述研究工作为微小薄片类零件的可靠释放与高精度装配提供了技术手段和实验依据。针对已有装配系统流程单一,不灵活的缺点,本文对其进行优化,研究制定了可从不同的零件开始装配的装配流程,在Microsoft Visual C++平台上开发了精密装配系统的控制软件程序,系统可选择从任意零件开始完成后续整个组件的装配任务。装配实验结果表明,优化后的装配软件提高了系统装配效率和灵活性。更多还原

【Abstract】 Parts assembly is the important session of the manufacturing process of miniature inertial devices, which directly affects the performance of the devices. Assembly with reliability ensures the application of miniature parts assembly system device. With the miniaturization of parts, surface force has an increasing impact on parts pick-up and release, especially in the release process, the position errors due to the surface force between the adsorption head and part will affect the assembly accuracy, thus reliable pick-up and release of parts is the key to the success of miniature inertial devices assembly.The miniature inertial devices which need to be assembled in this paper consist of seven parts, and three of them are sheet-type parts and minimum quality of these parts is 0.4g, we use vacuum adsorption to pick up these three parts. In order to reduce the effects of adhesion force on the precision of part-assembly, We analyze the van der Waals force, electrostatic force, and capillary forces respectively:the three kinds of adhesion force. And we study the generating mechanism of various forces and influence factors, providing theoretical guidance for reducing adhesion force to some extent.We design and build a device to measure the adhesion force in contact surface between the adsorption head and part during the assembly operations, in response to above-mentioned three parts, we reveal the effects of different separation speed, the load assembly force and time, different adsorption head material and ambient humidity on adhesion. The measurement results show that the separation speed and the load assembly force time have major effects on the adhesion force between the rubber adsorption head and silicon, gilt material parts respectively. In both case the adhesion force increases significantly as the value of the two parameters increase. However, the two parameters have weak effect on the adhesion force between the adsorption head and aluminum material part. When the load assembled force range within 20-80mN, the adhesion force between the rubber adsorption head and three kinds of material parts remain stable. Also, adsorption head of polytetrafluoroethylene (PTFE) material can significantly reduce the adhesion forces on the three parts. Ambient humidity affect the adhesion of the surface between the rubber adsorption head and parts of three materials significantly. The adhesion increase as humidity significantly increases, but when the humidity is higher than 60%, the adhesion force between the rubber adsorption head and silicon material part becomes stable.Through experimental results, we know that when picking up miniature parts, we should execute in a low humidity environment, use adsorption head with PTFE material and select a smaller value within a suitable separation speed and load assembly force time tend to reduce adhesion force and improve the precision of the system assembly.The assembly process of the systems now is pure, and the system is inflexible. Aiming at these, this paper optimizes the assembly process based on current one and developed an assembly process with different parts. Also, we develop a control software program for precision assembly system on the Microsoft Visual C++ platform. The system can choose from any part to start the subsequent assembling task of the entire assembly. Fitting experimental results shows that the optimized assembly software can effectively improve the efficiency and flexibility of the system assembly.更多还原