Jiong Zhang

City University of Hong Kong | CityU · Department of Mechanical Engineering

Metal cutting is a crucial process in modern manufacturing. Enhancing the machinability of metals can significantly improve their production efficiency and surface integrity. Coating surface-active media (SAM) on the free surface of the metals before cutting is an easy method to improve machinability, which usually pertains to the category of the r...

Determining appropriate process parameters in large-scale laser powder bed fusion (LPBF) additive manufacturing pose formidable challenges that necessitate advanced approaches to minimize trial-and-error during experimentation. This work proposed a data-driven approach based on stacking ensemble learning to predict the mechanical properties of Ti6A...

Microfluidic chips have shown their potential for applications in fields such as chemistry and biology, and 3D printing is increasingly utilized as the fabrication method for microfluidic chips. To address key issues such as the long printing time for conventional 3D printing of a single chip and the demand for rapid response in individualized micr...

Surface roughness is one of the determining factors for evaluating the quality of machined parts. However, the inevitable time-varying and uncertain characteristics in the actual machining process brings challenges to the construction of virtual metrology model. To address the problems of time-consuming training and low prediction accuracy in conve...

Surface roughness is an essential technical indicator for the surface quality of machined parts and significantly affects the service performance of the products. Accurate prediction of the surface roughness in the machining process can play an important role in reducing costs and increasing efficiency. However, data-based methods often require a l...

Functionally-graded lattice structure (FGLS) has fascinating properties such as lightweight, tunable stiffness, minimized stress concentration, and excellent energy absorption. The advent of 3D printing has provided feasible and reliable manufacturing solutions for FGLS, which has been boosting wider applications of FGLS. In this paper, 3D-printed...

Additive manufacturing (AM) enables the rapid fabrication of complex metallic components via a layer-by-layer method. Support structures are essential to ensure the successful printing of overhang features, and they have to be removed after printing. However, the usage of a support structure increases the material waste, printing time, and cost for...

Surface roughness is the most important indicators for product quality. Many uncertain factors affect the surface roughness of the workpiece in the machining processes. Fuzzy broad learning system (FBLS) has shown considerable advantages in nonlinear and uncertain modeling. Thus it is a promising candidate for predicting surface roughness in machin...

Support removal is one of the thorny issues faced by laser powder bed fusion (LPBF). In particular, the efficient and safe removal of support structures from the thin-walled parts and obtaining high-quality surfaces still remains a challenge owing to their sensitivity to machining. An in-depth understanding of the material response behavior of LPBF...

Ceramic membranes are being increasingly adopted in water and wastewater treatment owing to their performance and long-term benefits. In addition to the attempts to reduce the fabrication cost, rationalizing the microstructure of ceramic membranes also draws increasing attention. In this work, titania (TiO2) nanoparticle suspensions with and withou...

The threat of cascading damage to downstream components caused by the light modulation intensification of laser repaired morphology on the surface of fused silica optics cannot be ignored in high-power laser systems. This paper uses the angular spectrum diffraction theory based on the analysis of repaired surface morphology of CO2 laser rapid ablat...

Inspired by the physical nature and functionality of morphable surfaces, this paper develops the polishing tools with such surface characteristics. The surface textures of morphable polishing tools can be tuned and adapted according to the stage and requirements of the targeted surface finish and material removal rate. To investigate the performanc...

{Share Link: https://authors.elsevier.com/a/1ebJP5R78j5M9Q} Internal surfaces generated by additive manufacturing (AM) are finding their wide applications in aerospace, automobile, and medical industries. Nevertheless, the poor surface quality resulting from the intrinsic melting and solidification process of laser powder bed fusion (L-PBF) is sti...

The intrinsic heat-affected zone (HAZ) during the microsecond pulsed laser processing significantly affect the surface quality of the fused silica optics. This study employed both three-dimensional numerical simulations and experiments to analyze the heat accumulation effect, morphology evolution mechanism, and the HAZ distribution during CO2 laser...

TiAl intermetallic alloys have attracted considerable attention in aerospace applications over the last few decades owing to their low density and superior mechanical properties at high temperatures. However, these alloys are also known as difficult-to-machine materials that hinder efficient manufacturing. This study presents a systematic investiga...

Material removal rate (MRR) modeling is crucial for process and quality control in abrasive finishing processes. In this paper, a novel broad echo state learning system (BESLS) is developed to predict MRR in the magnetically driven internal finishing process based on the force signal. This BESLS model employs reservoirs with echo state properties t...

In computer-controlled optical surfacing (CCOS) techniques, the tool influence function (TIF) is generally assumed to be time-invariant; thus, two-dimensional convolution can be employed to compute the dwell time. However, the material removal rate is time-variant in some CCOS processes. This time-variant material removal rate makes it difficult to...

In selective laser melting (SLM), support structures play a critical role in successful printing. Despite its necessity, the removal of support structures after printing becomes a challenging task which is usually time-consuming and labour-intensive. Mechanical post-processing can be employed to facilitate the automatic removal of support structure...

Purpose This study aims to further the understanding of support structures and the likely impacts on maraging steel MS1 parts fabricated by selective laser melting (SLM) at 45°, 60° and 75° building angles. Design/methodology/approach Two groups of samples, one group with support structures and the other group without support structures, were desi...

In this paper, the study on damage evolution of sapphire induced in scratching process using acoustic emission (AE) technology was carried out. Single-grit scratches with ramp scratch depth were conducted on C-plane of sapphire with AE signal monitoring. Groove microstructure after scratching shows that the damage evolution process is mainly determ...

This paper develops a tool path optimization method for robot surface machining by sampling-based motion planning algorithms. In the surface machining process, the tool-tip position needs to strictly follow the tool path curve and the posture of the tool axis should be limited in a certain range. But the industrial robot has at least six degrees of...

Support structures are needed due to the complexities of induced structural, thermal and process factors in the Selective Laser Melting (SLM). To date, little systematic study is found to unveil the support removability by a post-machining process. This paper presents an experimental study of removing 316L stainless steel cone and block supports by...

A time-optimal motion planning method for robotic machining of sculptured surfaces is reported in this paper. Compared with the general time-optimal robot motion planning, a surface machining process provides extra constraints such as tool-tip kinematic limits and complexity of the curved tool path that also need to be taken into account. In the pr...

Surface finish greatly affects the friction, wear, corrosion, heat transfer and lubrication properties of internal surfaces which find wide applications in medical, automobile, aerospace and mould and die industries. However, improving the internal surface finish is extremely challenging due to the restricted tool accessibility of conventional manu...

As one of the most important additive manufacturing (AM) techniques, selective laser melting (SLM) shows great potential in directly producing functional tooling and complex structural parts through layer-by-layer fabrication. However, some critical issues such as poor surface finish, insufficient dimensional accuracy and inadequate fatigue life ne...

Harvesting water from high humidity conditions is an attractive strategy towards strengthening water security due to its cost-effective and zero-energy mechanism. To facilitate this process, bio-inspired microstructures with heightened water accumulating ability are typically affixed onto atmospheric water harvesters. However, due to this surface m...

Optical materials, such as calcium fluoride single crystals, are widely used across various industries for their light transmission capabilities. These materials possess excellent mechanical, physical, and chemical resistant properties but also tend to be very brittle, which poses a challenge to the microcutting of complex freeform shapes with opti...

The rapid development of additive manufacturing technology provides a more flexible and efficient manufacturing solution for the high value-added parts with a complex topology. However, the poor surface finish poses a major obstacle for the wide application of the additively manufactured components when their functionality and tolerance are benchma...

Additive manufacturing (AM) technology has been evolving rapidly over the past few decades. Even though it is a more flexible and efficient manufacturing process for complex topology, there are many concerns regarding the fabricated parts. One of these concerns is the poor surface finish. Visible pattern and texture of the printed layers and unmolt...

This paper presents a novel magnetically driven polishing tool for internal surface finishing. Differing from the existing magnetic abrasive finishing or magnetic field assisted finishing (MAF) methods; this new technique performs material removal inside a tube using a spherical magnet with abrasives driven by external bar magnets. This configurati...

Selective laser melting (SLM), as one of the additive manufacturing (AM) processes, is widely applied to directly fabricate functional structures and complex geometries by selectively melting layers of powder. However, the surface finish of the parts fabricated by this process could not readily meet the requirements of various applications. Therefo...

V-groove structure is the key composing feature of many optical products such as gratings and optical fibre connectors. The quality of the V-groove structure depends on multiple factors of manufacturing routines, process parameters, material properties, etc. among which the machinability of the workpiece materials plays a crucial role in achieving...

This study demonstrated how to quickly and effectively print two-dimensional (2D) and three-dimensional (3D) microfluidic chips with a low-cost 3D sugar printer. The sugar printer was modified from a desktop 3D printer by redesigning the extruder, so the melting sugar could be extruded with pneumatic driving. Sacrificial sugar lines were first prin...

本发明公开了一种基于糖模的溶模铸造方法，包括：（1）根据不同的制造糖模方法，配制相应的糖料；（2）将配制好的糖料利用三维打印机，制造糖模；（3）将需要的糖模组合修整，形成整体的糖模组；（4）在糖模组的外表面涂上耐火材料和粘结剂，制造型壳；（5）向型壳内注入水，溶化糖模，回收融化的糖液重复利用至步骤（1）；（6）将型壳焙烧；（7）在型壳中浇入金属熔液；（8）待金属熔液冷却后，脱壳得到产品。本发明采用糖料代替现有技术的蜡料，对缓解石油危机，节约石油资源具有较大的作用，且糖具有易溶于水，原料来源广泛，资源充足，价格低廉，可方便的从植物中提取，对环境无污染等优点。