Study on Measurement of Tool and Workpiece Positions by Ultrasonic

近年来，要求高的加工精度。但在加工过程中很难保持高精度。机床的热变形是造成加工误差的原因之一。然而，如果工具和工件之间的距离可以在加工过程中测量，将减少加工误差，并可以获得高程度的精度，本研究进行了建立超声波的工具和工件的尺寸和工具和工件之间的距离的在线测量的应用。为了证明所提出的基于脉冲回波技术的方法的合理性，使用喷嘴进行了一些基本的实验，其中超声换能器被保持在喷嘴中。在该方法中，切削液从喷嘴喷出并用作超声波传播的介质。实验结果表明：1.在磨削表面（Ra 0.2 - 0.28 μ m）时，台阶尺寸可测量到<plus-minus>0.7 μ m以内;在铣削表面（Ra 4.4 μ m）时，台阶尺寸可测量到3.72 μ m以内;<plus-minus>该方法可测量刀具尺寸和刀具与工件之间的距离; 3.可测量斜面和曲面之间的距离; 4.可测量刀具与工件之间的距离; 5.可测量刀具与工件之间的距离4.可以使用双探针技术以及单探针技术。

In recent years, a high machining accuracy has been demanded. But it is too difficult to keep the high accuracy during machining. One of the causes for machining error is the thermal deformation of machine tools. However, if a distance between tools and workpieces can be measured during machining, a machining error will be decreased and a high degree accuracy can be obtained.This research was carried out to establish an on-line application of ultrasonics to the measurement of dimensions of tools and workpieces, and a distance between tools and workpieces. Some fundamental experiments were made using a nozzle in which an ultrasonic transducer is held in order to justify the proposed method based upon the pulse echo technique. In this method, a cutting fluid is spouted from a nozzle and used as a medium through which ultrasonics is propagated. Especially, the velocity of cutting fluid is measured at the same time.In this study, the following results were obtained.1.In the case of a grinding surface (Ra0.2-0.28mum) , the size of a step can be measured within <plus-minus> 0.7mum, and in the case of a milling surface(Ra4.4mum), the size of a step can be measured within <plus-minus> 3.72.Dimensions of tools and a distance between tools and workpieces can be measured with this method.3.A distance from an inclined surface and a curved surface can be measured.4.The double probe technique can be used as well as the single probe technique.