Ultra-precision Technology Research Articles

Recent Development for Ultra-Precision Macro–Micro Dual-Drive System: A Review

Macro–micro dual-drive technology uses a micro-drive system to compensate for motion errors of a macro-drive system, solving the contradiction between large travel and high-precision motion. Additionally, it has a wide range of applications in the ultra-precision field. Therefore, it is necessary to analyze and research the ultra-precision macro–micro dual-drive system. Firstly, this paper analyzes the history of ultra-precision technology development and summarizes the research status of ultra-precision technology processing and application. Secondly, the micro-drive mechanism design and macro–micro-drive mode of macro–micro dual-drive technology, which can solve the contradiction of large stroke and high precision, are reviewed, and the application of macro–micro dual-drive technology in an ultra-precision system is summarized. Finally, the challenges and development trends of the ultra-precision macro–micro dual-drive system are analyzed. The research in this paper will play an important role in promoting the development of the ultra-precision system and macro–micro dual-drive technology.

Special Issue on Advanced Abrasive Processing Technologies

Abrasive processing technologies support both the creation of new products and progressive production processes as finishing processing in various industries, such as the automotive, telecommunications, semiconductor, healthcare, energy, and aerospace industries. In this era of major changes, known as the Fourth Industrial Revolution, advanced abrasive processing technologies that produce cutting-edge devices, machinery, and equipment for a smart society are needed. The subjects related to abrasive processing are extremely diverse, including function generation processing and ICT fusion processing, in addition to the continuing basic subjects, including high-efficiency processing, difficult-to-cut material processing, ultra/high-precision processing, etc. The field of abrasive processing has recently been expanding from removal processing to additional types of processing, such as additive manufacturing. As a result, its importance is increasing as a technology indispensable for advanced industries such as healthcare and the production of power semiconductors, cutting-edge semiconductors, etc. On the other hand, new abrasive processing technologies, such as grinding wheel surface property analysis and highly efficient surface finishing methods, have developed along with the advancement of the elemental technologies that support abrasive processing using the latest measurement methods and ultra-precision technology. Furthermore, new research, such as work on energy-assisted or reaction-assisted grinding, has been conducted through the fusion of the materials science and physical chemistry fields. This special issue contains seven papers that cover the following topics. - Abrasive jet processing - Analysis of the surface profile of a grinding wheel - Drilling of glass with a diamond tool - Reaction-assisted grinding - Barrel finishing - High-speed polishing We deeply appreciate the authors for their careful work and thank the reviewers for their incisive efforts in producing this special issue. We hope that it will help readers understand the latest research on abrasive processing, encouraging and providing hints for further research on abrasive processing technologies.

Study on Static Characteristics of Aerostatic Bearing Based on Porous SiC Ceramic Membranes.

The porous aerostatic bearing is a new supporting structure that is widely used in precision and ultraprecision engineering and the aerospace and other fields. The aerostatic bearing has a good bearing capacity and static stiffness. In this work, the numerical and experimental research on the static characteristics of an aerostatic bearing based on a porous SiC ceramic membrane is presented. The porous ceramic membrane prepared by reactive sintering, with a porosity of 25.8% and a pore size of 20.55 μm, was used as the restrictor to fabricate the aerostatic bearing. It was found that the ceramics have good permeability, and the permeability coefficient reached 2.78 × 10−13 m2 using permeability-test experiments. The effects of the gas-supply pressure and permeability coefficient on the static characteristics of the aerostatic bearing based on porous ceramics were analyzed using Fluent simulation calculation. When the gas-supply pressure was 0.5 MPa and the gas-film thickness was 6 μm, the static stiffness of the aerostatic bearing reached a maximum of 20.9 N/μm, while the bearing capacity was 632.5 N. The numerical results of the static characteristics of the aerostatic bearing are highly consistent with the experimental results, which verifies the accuracy of the Fluent simulation, and provides convenience for studying the static characteristics of aerostatic bearings.

Measurement of Sub-Surface Microstructures Based on a Developed Ultrasonic Atomic Force Microscopy

Accurate and non-destructive technology for detection of subsurface defect has become a key requirement with the emergence of various ultra-precision machining technologies and the application of ultra-precision components. The combination of acoustic technique for sub-surface detection and atomic force microscopy (AFM) for measurement with high resolution is a potential method for studying the subsurface structure of workpiece. For this purpose, contact-resonance AFM (CR-AFM) is a typical technique. In this paper, a CR-AFM system with a different principle from commercially available instruments is set up and used for the detection of sub-surface Si samples with grating structures and covered by different thickness of highly oriented pyrolytic graphite (HOPG). The influence of subsurface burial depth on the detection capability is studied by simulations and experiments. The thickest HOPG film allowing for sub-surface measurement by the proposed method is verified to be about 30 μm, which is much larger than the feature size of the subsurface microstructure. The manuscript introduces the difference between this subsurface topography measurement principle and the commercially available AFM measurement principle, and analyzes its advantages and disadvantages. The experimental results demonstrates that the technique has the capability to reveal sub-surface microstructures with relatively large buried depth and is potential for engineering application in ultra-precision technologies.

47 Plant Phenomics and Artificial Intelligence to Glean Information from Plant Sensing Technologies

Abstract One of the grand challenges of our generation is to get ready to feed 9 billion people by 2050 with sustainable use of environmental resources. However, our current agricultural system is not prepared for it. We are facing unprecedented challenges in adopting sustainable management practices, increasing production, and coping with pest and climate stressors that threaten yield; while running a profitable farm operation. In this talk, I will discuss our vision of a new cyber-plant-agricultural system that leads to an ultra-precision technology to monitor and manage plants or small plots at an individual level. To realize this grand vision, machine learning (ML) will play a large role. However, several key aspects of ML such as robustness, interpretability and data requirement need to be studied in the context of agriculture for successful deployment. In addition, high-throughput and effective plant phenotyping systems need to assimilate heterogeneous, multi-modal data for decision-making and should be suitable for distributed implementation for enhanced scalability. I will discuss a few success stories from our recent work to discuss these aspects of ML in plant agriculture that is relevant and potentially beneficial for the animal agriculture community.

Uncertainty analysis of two-dimensional self-calibration with hybrid position using the GUM and MCM methods

Two-dimensional (2D) self-calibration is more suitable for ultra-precision engineering than conventional calibration, as it does not require higher-precision device calibration. A grid plate is translated or rotated in various positions on a stage, and the translation and rotation can be combined into a hybrid position. Using 2D self-calibration, the stage and plate errors are separated from the overall measurement errors obtained by measuring the grid plate on the stage. During this process, random noise propagates to the separated stage errors through the self-calibration model, causing propagation of the uncertainty of the errors. Accordingly, in this study, least squares-based 2D self-calibration was investigated. An overdetermined linear equation system was established based on the relationships among the variables for self-calibration. The Guide to the Expression of Uncertainty in Measurement was used to calculate the uncertainty propagation ratio after obtaining the least squares solutions for the self-calibration model, and the uncertainty was further analyzed using the Monte Carlo method. The uncertainty propagation ratios were less than 1, indicating that the self-calibration model had a favourable noise-suppression ability. The robustness of this self-calibration approach was mathematically determined. The effects of various position schemes (with and without a hybrid position) on the uncertainty propagation ratio were examined to support the design optimisation of the self-calibration program. The experiments revealed that the use of hybrid position schemes was advantageous over not using such schemes, although the self-calibration performance was comparable under both types of schemes.

A Study on Focused Ion Beam (FIB) Milling Machining and Fabrication Technology of Nano-Scale Diamond Tool for Machining Fine-Patterns in a Free-Form Surfaces.

Recently, the technology of the industry has been increasing for diffractive optical elements, holograms, optical components, and next-generation display components. The advanced high value-added industry is designing fine patterns on ultra-precision optical components and applying them to various industries. In the case of the ultra-fine pattern, a contact-type machining technique is required because it requires a precise pattern in nano-scale units. In this paper, the fabrication technology of ultra-precision diamond which is essential in the ultra-precision processing technology was suggested. The material used in the experiment was a single-crystal diamond tool (SCD), and the equipment for machining the SCD used a focused ion beam (FEI COMPANY, system Nova 600) equipment. The back fire method was applied without metal coating in order to carry out the process study and the focused beam of 30 keV Ga+ ions were carried out processing for various fabrication of diamond cutting tools. As a result of applying the backfire method through the process experiment, the cutting edge width of the ultra-precision diamond tool was verified 275 nm.

Nanostructured grinding wheels for ultra-precision engineering applications

Manufacturers face challenges when dealing with abrasives that lose roundness, wear excessively, and suffer from pitting of the surface of the grinding wheel that needs rectification using dressing techniques. Nanostructured abrasive grits manufactured by hybrid fusion processes and by sintering/extrusion/printing processes are found to reduce pitting quite significantly. The phenomenon of wheel collapse is increasing and cycle times developed during the grinding of aerospace alloys are much smaller compared to using conventional materials. This paper reviews the phenomenon of wheel collapse induced by pitting and takes a critical look at the production and analysis of hybrid fused and printed/sintered abrasives. A mathematical analysis is carried out of the diffusion of primary and secondary phases due to mechanical and ultrasonic agitation with the aim of producing abrasive grits with improved strength and retention. Current developments in extruded, printed, and sintered grits for use in precision grinding applications are critically reviewed. The paper concludes by explaining how such abrasives are used in practice by industrial manufacturers of high-precision products.

Ultra-Precise Deposition Technology for High-Resolution Flat Panel Displays

Ultra-Precise Deposition Technology for High-Resolution Flat Panel Displays

Towards the establishment of ultra-precision processing technology and bonding technology for hard-to-machine semiconductor substrates for advanced 3D structural devices

Towards the establishment of ultra-precision processing technology and bonding technology for hard-to-machine semiconductor substrates for advanced 3D structural devices

Towards the establishment of ultra-precision processing technology and bonding technology for hard-to-machine semiconductor substrates for advanced 3D structural devices

Towards the establishment of ultra-precision processing technology and bonding technology for hard-to-machine semiconductor substrates for advanced 3D structural devices

Design and experimental investigation of a novel compliant positioning stage with low-frequency vibration isolation capability

Nowadays, those compliant positioning stages with the advantages of compact structure, micro-displacement output precision and negligible friction have been widely used in ultra-precision engineering. As a novel scheme, a z-directional positioning stage is proposed and discussed detailedly in this article. First, the conceptual scheme is clarified and structure optimization is conducted for obtaining a better performance. Attributed to the combination of the lever-principle amplifier and bridge-principle amplifier, a large amplification ratio could be ensured. Following that, the ideal displacement amplification ratio model is constructed based on the kinematics method for rapid evaluation of the displacement output performance. Meanwhile, the dynamic model is established through Lagrange’s equation on the basis of Pseudo Rigid Body Model (PRBM) method. The corresponding numerical simulations prove the effectiveness of the built theoretical model. Finally, an engineering prototype is processed and experimental tests are carried out to validate the capability of the positioning stage. The test results demonstrate that the designed stage could achieve the required performance and possess a high positioning accuracy, which meanwhile shows a special capability of low-frequency vibration isolation.

Demonstration of an Ultraprecise Optical Bench for the Taiji Space Gravitational Wave Detection Pathfinder Mission

For the Taiji space gravitational wave detection and its pathfinder mission, ultraprecise technology for optical assembly must be adopted to satisfy the high measurement sensitivities required. In this paper, we construct and evaluate an optical bench to assess its precision in optical assembly and bonding. We opted for hydroxide-catalysis bonding technology and designed a corresponding adjustment scheme to achieve an ultraprecise assembly for the optical bench. After alignment, the angular deviation between the interference beam and its ideal position in the global coordinate system is no more than 45 μrad, and positional deviation is less than 10 μm. The final experimental results indicate that the measurement precision of the evaluated board is 6 pm/√Hz, which meets the specifications required for the Taiji pathfinder.

A new methodology for developing flexure-hinged displacement amplifiers with micro-vibration suppression for a giant magnetostrictive micro drive system

Flexure-hinged displacement amplifiers play an important part in ultra-precision engineering due to their advantages of no friction, no backlash, compactness, high resolution and so on. In fact, the flexure-hinged displacement amplifier is initially proposed for addressing the travel shortcoming of piezoelectric or magnetostrictive actuators. However, some new challenges such as micro-vibration isolation and long service life, etc., arouse attentions especially when working in the harsh environment. Therefore, a new methodology for designing amplifier which could handle such issues is proposed and discussed in this paper. The focus of this study is on the design, theory analysis, and optimization of amplifiers, not only with the purpose of providing a larger displacement output, but also achieving micro-vibration isolation in desired frequency band. First, a generalized model for flexure hinges, the largest principal tensile stress and fatigue safety factor are formulated mathematically under combined tension and bending loads. Then the applied loads acting on each flexure hinge is calculated according to pseudo-rigid-body model. The equivalent dynamic model is established by Lagrange method. Whereafter, the procedure of the methodology is summarized and a different optimization strategy is implemented. Finally, a prototype is fabricated and tested. The experiments and simulation results confirm that the amplifier can achieve the desired amplification ratio and passive vibration isolation, which validate the effectiveness of this methodology.

Review of self-referenced measurement algorithms: Bridging lateral shearing interferometry and multi-probe error separation

With the development of new materials and ultra-precision processing technology, the sizes of measured objects increase, and the requirements for machining accuracy and surface quality become more exacting. The traditional measurement method based on reference datum is inadequate for measuring a high-precision object when the quality of the reference datum is approximately within the same order as that of the object. Self-referenced measurement techniques provide an effective means when the direct reference-based method cannot satisfy the required measurement or calibration accuracy. This paper discusses the reconstruction algorithms for self-referenced measurement and connects lateral shearing interferometry and multi-probe error separation. In lateral shearing interferometry, the reconstruction algorithms are generally categorized into modal or zonal methods. The multi-probe error separation techniques for straightness measurement are broadly divided into two-point and three-point methods. The common features of the lateral shearing interferometry method and the multi-probe error separation method are identified. We conclude that the reconstruction principle in lateral shearing interferometry is similar to the two-point method in error separation on the condition that no yaw error exists. This similarity may provide a basis or inspiration for the development of both classes of methods.

Optimal design and experimental performances of an integrated linear actuator with large displacement and high resolution

These linear actuators with large displacement, high resolution and compact structure have played an important role in ultra-precision engineering and still attracted a lot of attentions for various applications. Thus, a new integrated linear actuator with above capacities, based on the principle of coarse-fine composite, is proposed and discussed in this paper. Owing to the integration of a new electromagnetic rotor drive (ERD) and a smart giant magnetostrictive drive (GMD), a larger displacement can be initially achieved and maintained by the driving of the ERD, whereafter a smaller displacement can be adjusted and refined by the GMD. The mechanism structure and working principle are presented and described detailedly. As the key part, mechanical analysis and dynamic modeling of the ERD are carried out and established, and structure optimization is also conducted for obtaining a better working environment. A prototype was manufactured and its main performance was tested through a series of experiments. The results confirm that with a compact size of \(\phi43 \times 95\, {\text{mm}}\, (L)\) the maximum output displacement is 503 μm, and the movement resolution is up to 70 nm, proving the feasibility of precise positioning in ultra-precision engineering.

Active Hybrid Control Algorithm with Sky-Hook Damping and Lead-Lag Phase Compensation for Multi-DOFs Ultra-Low Frequency Active Vibration Isolation System

With the improvement of performance in the ultra-precision manufacturing engineering, the requirements for vibration isolation have become more stringent. In order to obtain a wider effective bandwidth and a higher performance of a multi-DOFs active vibration isolation system (AVIS), active hybrid control (AHC) technology is applied in this paper. AHC technology comprises a feedback active control (FBAC) technology and a feedforward active control (FFAC) technology. Absolute velocity feedback is employed to establish a sky-hook damping technology in FBAC technology. Velocity feedforward of base platform is adopted to build a lead-lag phase compensation (LLPC) technology in FFAC technology. Further, a coordinate vector conversion from unit level to system level is mentioned to describe the dynamic characteristic of the six DOFs AVIS applied in the ultra-precision field. And with the assistance of the transformed coordinate vector, the dynamic model of system level is built. Based on the establishment of the dynamic model and the research of AHC, an experimental platform which constitutes three vibration isolators and a real-time active control system is set up. The experimental results indicate that the amplitude of the resonant peak is further reduced significantly, compared to the general feedback control. And simultaneously active effective bandwidth is extended. AHC technology with sky-hook damping algorithm and LLPC control algorithm is verified to be more effective.

Fabrication of Micro V-Grooves in Ultra-Precision Grinding

Ultra-precision grinding is an effective method to machine the optical micro v-groove, which is one of microstructures applied to the fiber-optics connectors, displays and other photonics devices. The ultra-precision grinding technology directly obtains high surface quality for brittle materials when the grinding process is under the ductile mode. This paper introduces general aspects of ultra-precision grinding technology in the fabrication of the micro v-grooves structures and introduces the essential features of ultra-precision grinding. The process of the manufacturing of the optical micro v-grooves components is presented in this paper. It contains the prediction models of surface roughness and form accuracy in the ultra-precision grinding and the optimization model under the consideration of the influences of grinding parameters,grinder factors and the material properties on the surface quality and machining efficiency. This study therefore contributes to providing a further understanding on the mechanisms of material removal and surface generation in ultra-precision girnding.

Research Precision CNC Machine Error Analysis Hot Weights

The level of industrial strength is a measure of an important indicator of a country's pillar industry level is machinery manufacturing, in modern times, the rapid development of manufacturing technology, precision and ultra-precision manufacturing technology has become an important part of modern machinery processing and manufacturing,which CNC machine tools due to its own characteristics and soon became an important part of industrial manufacture. CNC machine tool manufacturing and processing machinery as an important tool, it is an important factor affecting the accuracy of indicators work-piece machining accuracy. Therefore, improving the accuracy of CNC machine tool research has been of great concern. This paper studies CNC machine thermal geometrical analysis accuracy error rights.

Process Experiment Research and Equipment Development of ELID Lapping

In this paper, according to the principle and the existing technology of ELID grinding, we use the existing lapping machine of Wenzhou Runsheng ceramic water valves factory as the experiment platform to develop an ELID lapping process system. Then utilizing ELID ultra-precision lapping technology to process alumina ceramic seals obtained a good effect. The roughness of processing samples reached about 15nm which was demanded by the enterprise, the efficiency increased 60% and the cost reduced 50%. On this basis, we designed an ELID lapping prototype. It laid a solid theoretical and practical basis for the production of ELID lapping machine in the future.