Research On Modeling And Compensation Of The Position Independent Geometric Errors In Five-axis Denture Machining Center

In the field of denture processing,traditional denture manufacturing methods require high technical skills and complicated manufacturing processes are being phased out.High-efficiency and high-precision digital denture processing methods are rapidly becoming popular.At present,domestic digital denture processing equipment has occupied the low-end market and a small part of the mid-end market in related fields by virtue of cost advantage.The high-end digital denture processing equipment market monopolized by foreign countries has become a breakthrough for domestic related enterprises.Independent research and development of high-end digital denture processing equipment,improve processing efficiency and processing accuracy,reduce equipment costs,is of great significance to meet the needs of domestic patients.In this context,the CIMS Research Institute of Hefei University of Technology developed a five-axis denture machining center and conducted an in-depth study on the geometric errors measurement and compensation of the five-axis denture machining center.Based on this,the main research contents of this paper are oRGNA as follows:(1)Structural design of the five-axis denture machining center.The main structural types of denture processing equipment commonly available on the market are collected and analyzed.The structural design work of a five-axis denture machining center are completed.And a model of a five-axis denture machining center are created using 3D modeling software.The physical prototype was made.(2)Kinematic modeling of a five-axis denture machining center.In this paper,the motion relationship and kinematic chain structure between the five axes of the five-axis denture machining center are analyzed,and the ideal forward kinematics and the ideal inverse kinematics of the five-axis denture machining center was established by using the screw theory.(3)Errors analysis and detection of the five-axis denture machining center.The working environment of the five-axis denture machining center and the characteristics of each component are analyzed to find out the errors items that have a great influence on the machining accuracy.Based on the consideration of the structural characteristics of the machining center and the shape characteristics of the machined workpiece,the measurement scheme corresponding to the errors term was designed,and the errors data was measured on the prototype of the five-axis denture machining center.According to the measured errors term,combined with the inverse kinematic solution of the five-axis denture machining center,the inverse kinematics of the five-axis denture machining center is obtained.(4)Design of compensation method for five-axis denture machining center and preparation of compensation software.Based on the understanding of the whole process of CNC machining,an offline compensation method is designed.The method compensates the geometric errors of the five-axis denture machining center by modifying the G code,and compensates the software by Matlab.(5)Perform simulation verification and processing test verification on the compensation effect of the compensation software.Using Vericut software to simulate the machining process,the machining simulation results before and after compensation are obtained and compared to verify the compensation effect.The five-axis denture machining center prototype was used for actual machining,and the compensation effect was comprehensively evaluated by appropriate detection methods.Combined with the feedback from users after the new five-axis denture machining center is introduced to the market,it shows that the five-axis denture machining center developed in this paper basically solves the structural problems of the first generation products,and the compensation method proposed in this paper has been improved to some extent.Machining accuracy of the five-axis denture machining center.The five-axis denture machining center developed in this paper has been successfully applied to dental prosthetic restoration in dental clinics with good response.The equipment participated in the "22nd China International Dental Equipment Exhibition" held at the Shanghai World Expo Exhibition and Convention Center from October 31,2018 to November 3,2018,and received extensive attention.