Research On Precision Measurement And Charaterization Of Geometric Error Of Complex And Small Parts

Complex micro-miniature parts generally refer to parts with a size of 0.1 mm to 10 mm,a feature size of 0.01 mm to 1 mm,and complex features.Various disciplines continue to develop towards high precision,and sophisticated,complex and tiny parts are playing an increasingly important role in various fields.No matter what processing technology is used,to obtain qualified complex and tiny precision parts,advanced measuring devices and methods are required.Because the structure and shape of complex and small parts are different and complex,the existing three-coordinate measuring device is difficult to meet its high-precision and high-efficiency shape and position error measurement requirements.In response to the above problems,the research goal of this paper is to develop a multi-coordinate measurement and characterization evaluation technology for geometric errors of small-sized parts.The main content is to apply a five-degree-of-freedom precision measurement platform to the two complex small parts to be tested given in the paper to complete the research on the method of measuring trajectory planning of complex small parts and realize the measurement trajectory planning of these two kinds of complex small parts.Study the characterization and evaluation method of shape and position error of complex small parts,develop graphical evaluation and characterization software for shape and position error of complex small parts,and realize the automation of the characterization of shape and position errors.First of all,according to the characteristics of complex small parts,a suitable measurement scheme is determined.And by studying the calculation method of the line spacing of multi-axis machining trajectories,the determination method of the measurement line spacing is determined.Compared with the existing measurement data acquisition step size method,the measurement data step acquisition method suitable for this paper is determined.The planning of the probe axis vector space pose is completed,and the maximum allowable radius of the probe is determined based on the curvature interference detection method.The planning of the measurement trajectory style is completed.Based on the homogeneous coordinate transformation method,the postprocessing algorithm of the measurement trajectory point file is established.And designed the measurement trajectory planning process.Secondly,the measurement data point collection technology was researched and the data collection plan was determined.The method of surface fitting reconstruction is determined.Based on homogeneous coordinate transformation,an inverse algorithm for actual measurement points is established.And the commonly used geometric shape and position error evaluation and characterization algorithm was implemented by math software engineering,and the shape and position error evaluation and characterization software was developed.Finally,analyze the parameters of the ultra-precision five-axis machine tool developed by our laboratory,and builds a five-degree-of-freedom precision measurement platform and measurement environment based on the ultra-precision machine tool.With the help of math software and Powermill software,based on the aforementioned measurement trajectory method,the planning of the measurement trajectory of the complex small parts to be tested in this paper was verified,and the integrity and engineering practicability of the above measurement trajectory planning method were verified.The factors of error measurement accuracy were analyzed,and the effects of factors such as probe radius,probe shaft vector declination,probe thermal deformation,and probe rigidity on the measurement accuracy were analyzed,and corresponding solutions were given.