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Invited presentations

Size effects in multi-scaled materials processing and manufacturing


Prof. Mingwang Fu


The Hong Kong Polytech University


Biography:

Prof Mingwang Fu (MW Fu) is a Professor in The Hong Kong Polytechnic University with his research interests in advanced materials processing, Finite Element simulation, damage and fracture, micro-mechanics, plasticity of materials, multi-scaled and smart manufacturing, and size effects (SE) and SE affected process behaviors, performances, product quality and their scattering in multi-scaled manufacturing and materials processing. Prof. Fu is sitting in the Editorial Board of 18 journals including Int. J. of Plasticity, Int. J. Mech. Sci., Mater & Design, Int. J. of Damage Mechanics, Int. J. of Adv. Manuf. Tech., Associate Editor of Int. J. Mach. Tools Manuf., and editor of Elsevier’s Encyclopedia of Materials-Metals and Alloys. He has published 210 SCI papers and 6 English monographs published by top-notched publishers, and one edited Elsevier’s encyclopedia volume.


Abstract:

Size effect (SE) exists in many concerned domains due to the value change of size effect factors. Size effect factors are defined as the influencing parameters of the materials, structures or systems to be concerned whose value change would lead to different SE manifestations. In multi-scaled materials processing and manufacturing, including macro-, meso- and micro-scaled ones studied in this paper, SEs occur in these size scales and would induce different process behaviors, phenomena, and performances in different scales. The SEs can further result in the scatters of process behaviors, phenomena, and the quality and property of the fabricated different scaled parts and components. By using multi-scaled machining and deformation-based manufacturing as the case study processes of materials processing and manufacturing, the above-mentioned SEs and their induced manifestations are reviewed and analyzed. The current research status and the future focuses are articulated and discussed. Some critical issues to be addressed and unknowns to be understood are highlighted. The talk aims at presenting a panorama of SEs, their impacts and bottleneck issues in multi-scaled materials processing and manufacturing for making multi-scaled parts and components and how to address them to ensure the efficient realization of multi-scaled materials processing and manufacturing.




High Pressure Abrasive Water Jet Machining Technology for Engine Blisk Surface




  Prof. Hang Gao


  Dalian University of Technology






Biography: 


Doctor of Engineering, Professor of Dalian University of Technology, member of the international society of abrasive processing technology, and standing committee member of China production society. Mainly engaged in precision and ultra precision abrasive processing technology, high efficiency and low damage processing technology for difficult-to-cut materials and advanced composite materials. Prizes won include the first prize of national technological invention in 2017, the innovation team award of national scientific and technological progress award in 2019, the first prize of provincial and ministerial scientific and technological invention. More than 200 academic papers have been published and more than 20 authorized invention patents have been approved.



Abstract:


High pressure abrasive waterjet (AWJ) has been widely applied in cutting or sawing one or two-dimensional geometric structure parts as an efficient and economical cutting process. However, it is almost impossible for cutting parts requiring three-dimensional geometric surfaces. In addition, some challenges or problems such as larger machining allowance, serious cutting tool wear, lower machining efficiency and higher cost are faced in machining some difficult-to-cut materials parts such as aero-engine blisks and compressor impellers made by titanium alloy with traditional milling process. If the AWJ technology can be used to cutting three-dimensional complex surface, the above problems could be solved. This report introduces some attempts to cut three-dimensional complex surface with AWJ process. A new method of the AWJ cutting trajectory planning with the collaborative control of multi-geometric parameters (the multi-axis cutting speed and standoff distance) and multi-physical quantities (abrasive flow and water pressure) is presented, which can well solve the overcutting of small R radius structure in condition of strong geometric interference and realize three-dimensional cutting. A large sample of titanium alloy aero-engine blisk has been successfully cut, which also shows important engineering value in expanding application range of AWJ technology.



Superfinishing processes for additively manufactured components





  Prof. Joel Rech


   University of Lyon





Biography:



Joel Rech is Professor at the ENISE (University of Lyon). He leads a research group working on the characterization an, d modelling of physical phenomena at the tool/workmaterial interface in cutting and superfinishing operations. He made remarkable breakthroughs in numerical modeling of surface integrit, y induced by cutting and polishing processes (residual stresses, roughness, microstructure) and in modeling of tribological phenomena (friction, wear, etc.) of cutting tools. He has published more than 250 papers that have been cited over 5500 times. He is member of the CIRP and takes part in the editorial committee of 5 international journals.


Abstract:


Additive manufacturing processes are increasingly gaining importance among mechanical industries. This new field of 3D metal printers covers a wide range of processes using various raw materials (powders, wires, compounds etc.) and different sources of energy (laser, electron beam etc.). It can be stated, however, that the surface roughness of the surfaces generated by additive manufacturing differs considerably from the current state of the art produced by machining and superfinishing processes. This keynote aims at summarizing current developments in superfinishing processes which can be applied to improve surface roughness for various applications depending on the shape of the surface and its stiffness.



Stress Rheological Polishing Technology and it’s Applications



   Prof. Julong Yuan


   Zhejiang University of Technology




Biography:


Julong Yuan, Professor of Zhejiang University of Technology, State Council expert for special allowance, Young and Middle-aged Expert with outstanding contributions in Zhejiang province. Graduated from Harbin Institute of Technology and received the Bachelor's Degree, Master's Degree and Doctor's Degree from 1979 to 1989. He has been engaged in research and teaching work about precision and ultra-precision machining technology for many years, and published over 300 academic papers, authorized more than 60 invention patents. He has won two second prizes of national science and technology progress award and six first prizes of provincial and ministerial science and technology award.


Abstract:


Stress rheological polishing (SRP) is an efficient ultra-precision machining method that achieve surface polishing by using the shear rheological properties of the non-Newtonian polishing fluid. Based on the shear thickening effect, the SRP slurry can flexibly control the free abrasive particles and move relative to the workpiece surface to achieve material removal. By controlling the flow field of the SRP slurry and the shear stress field of the polished surface, complex surfaces can be polished flexibly and efficiently. The lecture mainly introduces the characteristics of SRP technology and its application in curved surface polishing. The high-performance SRP slurry with the shear-thickening rheological behaviors has been prepared. Based on the Preston formula, fluid dynamics and shear thickening mechanism, the material removal rate (MRR) model is established and a comprehensive surface roughness model is established to predict the average surface roughness. The experimental and theoretical tests of SRP process are conducted to investigate the influences of polishing velocity, abrasive concentration and grain size on MRR and surface roughness. SRP is an innovative, high-efficiency and ultra-precision polishing technology with extensive application prospect, and has been successfully applied in polishing of Si3N4 ceramics cylindrical workpiece, aluminum alloy middle frame of mobile phone, quartz hemispheric resonator, bearing ring raceway, aspheric lens and passivation of cutting edge.



Generation of functional optical microstructures by ultraprecision-machining


Dr. Oltmann Riemer


University of Bremen


Biography:


Oltmann Riemer is a mechanical engineer and he graduated from the Technical University Braunschweig. Since 1993 he is working as a research engineer and teaching assistant at the Laboratory for Precision Machining LFM at the University of Bremen (since 2018 Leibniz Institute for Materials Engineering, Bremen). He received his Dr.-Ing. degree from Bremen University in 2001. The focus of his research work is in the area of ultra-precision and micro-machining processes, i.e. specifically diamond turning and milling processes, cutting mechanics, micro machining technologies, and characterization of the surface integrity.


Abstract:


Today high tech and consumer products frequently include highly precise components with functional optical microstructures for key purposes. For mass production of glass or polymer optics dedicated replication processes are usually applied and therefor particular precision molds are required. High-precision ultraprecision-machining processes like diamond turning and milling processes are established manufacturing technologies to deliver those kind of optical and mechanical high precision components and optical microstructures. Depending on the process kinematics applied various base geometries can be generated from plano and spherical to freeform surfaces and microstructures can be superimposed onto these surfaces.

This presentation will introduce the relevant machining processes from the field of ultra-precision manufacturing. These processes and their application ranging from standard processes up to taylor-made novel machining methods will be discussed with respect to flexibility, geometrical spectrum of achievable forms and structures, surface finish, structure fidelity and figure accuracy.



Fundamental concept of deep learning and its applications in Intelligent Manufacturing





   Prof. Libo Zhou


   National Ibaraki University





Biography:

Prof. Libo Zhou received his MS and PhD degrees from the Tohoku University in Japan in 1988 and 1991.  Currently, he is the head of Department of Mechanical System in School of Science and Engineering, National Ibaraki University, oversee research activities of traditional and non-traditional manufacturing processes.  His research interests cover ultra-precision machining and evaluation, recently are extended to applications of A.I in manufacturing.


Abstract:


5G and IoT technologies make it possible to acquire the time-series data from various sensors in a modern manufacturing system.  Having such enormous volume of data, it becomes easier for us to apply deep learning technique for monitoring, detection, control and etc.  This talk will present the fundamental concept of modern Deep Learning from a classic viewpoint of Design of Experiment (DOE) or Taguchi Method.  An analysis on cutting process is made to demonstrate the high potential of Artificial Neural Network (ANN) by comparing against Linear/Non-linear regression models.  For anomaly detection, however, getting sufficient anomaly data for training of machine-learning model is difficult because most systems are optimized to run at their best conditions.  This talk will propose two kinds of anomaly detection models: AE+LOF and LSTM+AE.  Both models are trained by normal data only, and output the deviation from normal data when an anomaly data comes in.



Nanoscale removal mechanisms in the ductile grinding of brittle solids

 

 

  

  Prof. Han Huang


  The University of Queensland

 

 

 

 

 


Biography:

Han Huang is Professor of Manufacturing at University of Queensland, Australia. He has been leading a group of researchers working on advanced manufacturing technologies in the past two decades. He obtained his Bachelor and Master’s Degrees at Huazhong University of Science and Technology in China and PhD at University of Western Australia. He also worked in Singapore Institute of Manufacturing Technology developing robotic grinding and polishing technologies for aerospace industries, for which he received the prestigious Singapore National Technology Award. Prof Huang has published over 300 journal articles and received a number of research accolades including Australian Future Fellow, Australian Research Fellow and Queensland International Fellow. He now serves as an Associate Editor of International Journal of Mechanical Science, and has editorial roles in several international journals including International Journal of Machine Tools & Manufacture.

 

Abstract:


Brittle solid materials for structural and functional applications must be shaped to a high degree of precision with little or no subsurface damage by use of abrasive machining.  A comprehensive understanding of the removal mechanism involved in the abrasive machining of a brittle solid can help develop the efficient shaping process for the solid, which can substantially shorten the manufacturing time and hence reduce the cost.  This talk outlines the underlying science of the ductile removal of advanced brittle materials, particularly single crystals, in ultraprecision grinding.  Engineering aspects of ductile grinding will be reviewed.  Attention will be given to the fundamental role of removal events from individual and cumulative grit-workpiece contacts, using nanoscratch mechanics as the basis for analysis.  The critical influence of diversity in material microstructures in determining local deformation mechanisms and subsequent material removal will be highlighted.




Adaptive robot belt grinding technology and equipment of high-performance surface for blisk





  Prof. Yun Huang



   Chongqing University





Biography:


Huang Yun, the second-level professor of the College of Mechanical and Vehicle Engineering of Chongqing University, the doctoral supervisor, director of the Chongqing Engineering Research Center for Material Surface Precision Machining and Complete Equipment,the representative of the 12th National People's Congress, deputy director of the National Magnesium Alloy Materials Engineering Center, Director of the GBB Belt Grinder Standards Committee. He has long been engaged in high-efficiency and precision belt grinding technology and grinding machine design and manufacturing research work. Among them, CNC precision belt grinding equipment has made outstanding contributions to the precision machining of domestic aviation development blades and was selected as one of the "China's Top 100 Industrial Mother Machines" by the Ministry of Industry and Information Technology. The books"Principles and Application of Abrasive Belt Grinding" and "Modern Belt Grinding Technology and Engineering Application" have filled the gaps in domestic abrasive belt grinding technology and theory.


Abstract:


The surface integrity of blisk has a huge impact on its fatigue life. However, it is difficult to ensure its surface integrity due to its complex profile, difficult-to-machine material, and narrow blade spacing. Industrial robots have the advantages of good flexibility, easy scheduling, strong versatility, and low cost. They are increasingly used in the grinding of complex curved surfaces. what’s more, abrasive belt, fiber wheel and other coated abrasives are effective ways to improve the integrity of the blade surface, so the research on the high-performance surface robot grinding technology and equipment for the blisk is proposed. The following contents are Included: grinding tool matching method for the structural characteristics of the blisk surface; formation mechanism for surface integrity; optimization method for dynamic characteristics of robot grinding and automatic grinding programming technology.



Material removal mechanism and machined surface integrity of ductile metals in high speed machining process




    Prof. Zhanqiang Liu


    Shandong University






Biography:


Dr. Zhanqiang Liu is a Professor at Shandong University. He received his B.S. and M.S. degrees from Shandong University in China and Ph.D. degree from City University of Hong Kong. He leads a group working on the high performance machining process of difficult-to-machine materials. His research interests include high speed machining, and structure-process-property-performance relationships in machining processes. Prof. Liu has published more than 300 peer-reviewed journal papers with over 5000 citations. He is a member of the American Society of Mechanical Engineers (ASME) and executive director of Chinese Metal Cutting Tool Association. He has received several significant awards from National Natural Science Foundation and Ministry of Education of China owing to his remarkable achievements.

 
Abstract:


The research and application of high speed metal cutting (HSMC) is aimed at achieving higher productivity and improved surface quality. The advancements in HSMC are introduced with a focus on the material removal mechanism and machined surface integrity, and understanding the material removal mechanism is a foundation to ensure the machined surface quality. Through comparing with conventional machining, the advantages of HSMC are elaborated from the aspects of high material removal rate, good finished surface quality, low cutting force, and low cutting temperature. Meanwhile, the shortcomings of HSMC are presented from the aspects of high tool wear rate and tensile residual stress on finished surface. The variation of material dynamic properties at high cutting speeds is the underlying mechanism responsible for the transition of chip morphology and material removal mechanism.

The thorough understanding on pros and cons of HSMC can help to effectively utilize its advantages and circumvent its shortcomings. Furthermore, the challenges for advancing and future research directions of HSMC are highlighted. Particularly, to reveal the relationships among inherent attributes of workpiece materials, processing parameters during HSMC, and evolution of machined surface properties will be a potential breakthrough direction.



Ultra-precision Manufacturing Technology for Repairing the Surface Micro-Defects on High-Power Laser Optical Elements



   Prof. Mingjun Chen


    Harbin Institute of Technology




Biography:


Prof. Chen Mingjun is currently a professor at Harbin Institute of Technology and mainly focuses on the ultra-precision machining and nano/micro manufacturing technology. He is the director of “The Ultra-Precision and Micro-Nano Manufacturing Innovation Research Team”, which is one of the “Heilongjiang Touyan Innovation Team Program” teams. He has been elected as the Changjiang Distinguished Professor and the leading scientist of the “Ten Thousand Talent Program”. Prof. Chen directed more than 40 scientific research grants, including the National Key Research and Development Program, National High Technology Research and Development Program (“863”) of China, and has published more than 100 SCI academic papers.


Abstract:


The surface micro-defects on the large-aperture optics (e.g., KDP crystal and fused silica) have been regarded as the bottleneck issue, limiting the promotion of laser power output of laser-driven Inertial confinement fusion (ICF) facilities. In order to recycle these expensive optical components, a new ultra-precision manufacturing technology is developed for repairing these micro-defects. Firstly, two types of specific precision detection and repair equipments are designed to achieve the laser pretreatment, rapid detection and precision repairing of the surface micro-defects on KDP crystal and fused silica optics. A rapid detection method is then developed for detecting the surface micro-defects on the large-aperture optical elements, which includes the initial positioning stage using a large field of view camera and the precise positioning stage using a small field of view magnification microscopy system. Besides, for achieving the automatic tool setting with high accuracy and efficiency in the repairing process, an automatic alignment technology is proposed based on the automatic ranging of the micro-cutter’s reflection and the occurrence of the micro chips. Finally, two types of repairing strategies, i.e., micro-milling for KDP optics and CO2 laser ablation for silica optics, are developed for the precision repairing of the surface micro-defects. This work can achieve high repairing surface quality (Ra<30nm) and efficiency for the recycling of lager-aperture optical elements and hence contribute to the improvement of the power output of ICF facilities.  



Towards digital passport of manufacturing processes & product



   Dr. Jun Qian