Research And Development On (Key Technologies Of) Miniaturized High Accuracy Milling Machine

Because of the global increasingly need for microminiaturization product in diverse fields, civil market and national defense, people become more and more interested in the issues involve in the design, development and manufacturing of micro component .Micro milling technology plays an important role in complicated 3D micro parts manufacturing. However, at present, most of 3D micro parts made of metal materials are manufactured with conventional ultra-precision machines, which have high cost, low efficiency, large energy expenditure, low spindle rotational speed. Moreover, micro machine not only be good at improving, space utilization ratio and reducing, cost, but also excellent in capturing high speed manufacturing as well as high precision motion control due to less inertia.During the research we divided the milling machine into three principal parts: Spindling system, Micro-positioning system and controlling system. This paper focuses on the positioning part, has developed a piezoelectric inchworm macro-positioning system. The system makes full use of the inverse piezoelectricity effect of PZT ceramic to gain displacement. At the same time, the precision and the actuating property should be ensured because the PZT ceramic has superior characteristics just like small volume, high motion resolution, big output force and so on. But the maximum displacement of the PZT actuator is only 50μm, for many parts, it is hard to meet the machining requirements. Therefore, we decide to use the Inchworm Driving Scheme which imitates the crawling approach of inchworm according to the bionic principle in order to achieve longer machining feed.In this paper, in order not to affect the driven precision of the PZT actuators, we used the flexible hinge mechanism which can offer several advantages over classical joints, such as compact structure, no friction losses and no assembly. The flexible hinge positioning stage we have made would hardly have an impact on accuracy during the transmission process. And we also designed a lever amplifying frame with flexible hinge that will augment the step size of the positioning system. Finally, we verified the designed system through several experiments.