Development Of Piezoelectric Dynamometer Applied In Optical Glass Processing

Optical glass materials have been widely used in various fields such as optics,aerospace,medical equipment,etc.With the in-depth study in these fields,high requirements are placed on the processing precision of these optical-materials parts.However,if the precision need to be improved,the contradiction between the difficult to processing and high requirement of precision must be solved first.At present,cutting tools with diamond abrasive grains are mainly used in optical glass processing with ultrasonic vibration or other ways as auxiliary method.When studying the relationship among tools,material and machining precision,electron microscopy is mainly used to observe the surface quality and cutting force measurement has the advantage of reflect the entire processing.And cutting force has become an indispensable means to study cutting tools and processing.In this paper,a novel piezoelectric cutting force dynamometer is designed and developed to measure the change of cutting force in optical glass processing.By analyzing the difficulties in measuring cutting force,sensors are arranged vertically in dynamometer has been designed.In this way,the advantage of the force-to-electric conversion coefficient in piezoelectric shear effect is twice that of piezoelectric tension effect’s coefficient can be used to improve the axial sensitivity,and this form can satisfy the high precision measurement of small force.The prototype of piezoelectric dynamometer with variable arrangements is designed.The loading experiments of lozenge arrangement and rectangular arrangement are carried out by means of control variables.After comparing the different data,the scheme of rectangular arrangement is selected.Based on rectangular arrangement,a combined structure is designed and applied.Supporting structure has been optimized via Workbench software.The output of every single sensor in dynamometer under a unidirectional force are analyzed.For solving the error problem in output when vertical arranging form has been adopted,a successive adjusting method has been proposed.It has decreased the overall output error.And the assembly of dynamometer has been accomplished.The different index such as sensitivity,linearity,repeatability and crosstalk has been acquired according to static and dynamic calibration experiments in dynamometer.The consistency of the output in dynamometer has been verified via different point loading experiments.At last,the natural frequency of dynamometer is obtained by dynamic knocking experiments.Various experiments show that the dynamometer has good performance.An on-site calibration device is designed based on the requirements of testing environment.Both on-site calibration experiments and cutting force testing experiments are proceeded.Results show that,the dynamometer perform well and can detect variable force changes of four different cutting tools under several parameters,which can verify the practicability of dynamometer.