| With the development of technical products towards high performance,high precision and integration,micro/nano-structured surfaces are playing more and more important roles in aerospace,electronic manufacturing,biomedical fields,to mention a few.As the new manufacturing processes tender to be of complexity,it proposes new challenges for high precision measurement which is an effective way to guarantee the micro/nano-manufacturing quality.As the new features emerge for modern micro/nano-manufacturing especially for ultra-precision diamond-machining technique,the surface forms of fabricated micro/nano-structures are experiencing the transfer from one dimensional structure to three dimensional(3D)one with multi-scale and complex characteristics.Nevertheless,1)The current high precision measurement systems are not capable of measuring all diverses of micro/nano-structures,and it is even more difficult for them to realize large-area,long range,high precision,and rapid measurement simultaneously.More importantly,some difficult-to-measure micro/nano-structures greatly challenge their measuring capabilities;2)Most existing systems are much too sophisticated and extremely environment-dependent,which makes it hard to adapt to manufacturing sites with compact space and diverse circumstances.As a result,they are generally used for off-line measurement,which means that the workpiece needs to be disassembled from the machine.Due to the re-positioning error,the subsequent manufacturing process is interrupted;3)The current in-situ measurement methodologies are basically limited to the line profile measurement,thus it is challenging to achieve entire surface imaging for complex 3D micro/nano-structures;4)Due to the existence of numerous uncertainty factors in manufacturing enviroments,further research is essentially needed to work on how to authentically reflect the real machined surface and realize the surface quanlity control.Aimed at meeting the requirements of high manufacturing precision and quality control,this thesis addresses the problems from developing large-area rapid measurement technique,system integration,in-situ measurement for 3D micro/nano-structures by introducing spatial spiral scanning and its application on diamond-machining process.With systematic key technologies and proprietary intellectual property rights,the in-situ instrument equipment is built on the ultra-precision diamond turning machine,successfully realizing the in-situ measurement of complex micro/nano-structures and feedback to the machining process for high surface form control.This thesis is divided into the following six chapters:Chapter 1 introduces the background of micro-manufacturing technologies,and describes the tendency of structural complexity of micro-components and the significance of high precision measurement in manufacturing fields.Different measuring instruments for micro/nano-structures are outlined and compared.Then,the current state-of-the-art measurement and in-situ measurement techniques for difficult-to-measure micro/nano-structures at home and abroad are described.Finally,the research contents and significance of this thesis are proposed.In Chapter 2,for the large-area scanning with high performances and for realizing the micro/nano-positioning of measuring head on the machine,a novel piezo-actuated two-degree-of-freedom micro/nano-positioning stage is designed,modeled and tested.It avoids series of problems for precision motor-driven stage such as high cost,backlash,low dynamic response and assembling errors,etc.Evolved from the design concept of micro-gripper,the proposed stage consists of multi-amplification mechanisms and Z-shaped flexure hinge based mechanism is employed to achieve the flexural amplification and decoupled guidance of orthogonal motions.The decoupling feature makes it possible to implement the raster-scanning mode during sample measurements as well as micropositioning of the probe.In Chapter 3,a new measuring head based on tunneling effect is presented.To tackle the problems in high speed and precision measurement of deep trench micro/nano-structures,a symmetric modulation method is proposed and demonstrated.By introducing the flexible measuring head into the fly cutting process,a preliminary in-situ measurement is conducted.Based on the in-situ measured results and compensation of depth-of-cut,the micro-prism array is successfully fabricated,which confirms the advantages of in-situ measurement in quality control.In Chapter 4,based on ultra-precision single-point diamond machining process,a novel in-situ measuring technique and auto-centering method of high aspect ratio probe are presented.In order to extend the three-dimensional measuring capability,a spatial spiral scanning based tip tracking strategy that can keep tracking the curved substrate of complex 3D micro/nano-structures is developed,and implemented for accurate in-situ characterization of the manufacturing errors of the 3D micro/nano-structures,which is a challenging task for traditional off-line measuring instruments.In Chapter 5,for high precision and reliable measurement of micro/nano-structured surfaces,a form characterization and uncertainty evaluation model based on Monte Carlo algorithm is established and validated,by taking into consideration the major error sources occurring in both manufacturing and measuring processes.Finally,the in-situ measuring system is combined with fast tool servo machining process,and the manufacturing mode including machining,measurement feedback,and error compensation is accomplished.The main research work,novelties and key technologies are summarized in Chapter 6.The potential future research on in-situ measurement for manufacturing micro/nano-structured components is outlined. |
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