Kai Zhang

Bio: Kai Zhang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Metal powder & Rapid prototyping. The author has an hindex of 3, co-authored 4 publications receiving 172 citations. Previous affiliations of Kai Zhang include Shenyang Institute of Automation.

Research on the processing experiments of laser metal deposition shaping

Abstract: Laser additive direct deposition of metals is a new rapid manufacturing technology, which combines with computer-aided design (CAD), laser cladding and rapid prototyping. The advanced technology can build fully dense metal components directly from CAD files with neither mould nor tool. Based on the theory of this technology, a promising rapid manufacturing system called “Laser Metal Deposition Shaping (LMDS)” has been constructed and developed successfully by Chinese Academy of Sciences, Shenyang Institute of Automation. Through the LMDS system, comprehensive experiments are carried out with nickel-based superalloy to systematically investigate the influences of the processing parameters on forming characteristics. By adjusting to the optimal processing parameters, fully dense and near-net-shaped metallic parts can be directly obtained through melting coaxially fed powder with a laser. Moreover, the microstructure and mechanical properties of as-formed samples are tested and analyzed synthetically. As a result, significant processing flexibility with the LMDS system over conventional processing capabilities is recognized, with potentially lower production cost, higher quality components, and shorter lead-time.

Characteristics of laser aided direct metal powder deposition process for nickel-based superalloy

Abstract: Laser additive direct deposition of metals is a new rapid manufacturing technology, which combines with computer aided design, laser cladding and rapid prototyping. The advanced technology can build fully-dense metal components directly from CAD files without a mould or tool. With this technology, a promising rapid manufacturing system called "Laser Metal Deposition Shaping (LMDS)" is being constructed and developed. Through the LMDS technology, fully-dense and near-net shaped metallic parts can be directly obtained through melting coaxially fed powder with a laser. In addition, the microstructure and mechanical properties of the as-formed samples were tested and analyzed synthetically. The results showed significant processing flexibility with the LMDS system over conventional processing capabilities was recognized, with potentially lower production cost, higher quality components, and shorter lead time.

Intelligent Metal Powder Laser Forming System

Abstract: Metal Power Laser Forming (MPLF) is a high precision and complicated process. The quality of the formed parts is affected by many parameters and may vary significantly during the laser forming process. In order to guarantee the stabilities of the process, a state-of-the-art intelligent MPLF system was developed in this paper. The intelligent system includes CNC system, energy supply and control system, powder delivering and control system, and realtime feedback control system. The established state-of-the-art apparatus and several metal parts formed by the MPLF system are presented in this paper.

One-Pot Preparation of Silica Fibers from Rice Straw for Efficiency Removal of Heavy Metal Ions

Abstract: Silica fibers were prepared from the agricultural waste-rice straw via a slow calcination process. A possible formation mechanism of the obtained silica fiber was explained. The phytoliths/vascular composite fibers of rice straw work as the structural directing templates for the formation of silica fibers under the slow calcination process. Owing to the potassium silicate active site, the separable silica fiber showed great capability in removal of Cu2+, Ni2+, Cd2+ and Pb2+ from aqueous solution with efficiency higher than 99%. Additionally, over 90% of equilibrium adsorption capacity can be reached within 10 minutes, showing the easily accessible paths and active sites for ion transportation and adsorption in the as-prepared fiber. These results of this work are beneficial for scientists pursuing new synthetic route for valuable and widely applicable silica fiber materials from the agricultural waste, also helping to solve disposal of the agricultural waste and pollution problems.

Additive manufacturing: technology, applications and research needs

Abstract: Additive manufacturing (AM) technology has been researched and developed for more than 20 years. Rather than removing materials, AM processes make three-dimensional parts directly from CAD models by adding materials layer by layer, offering the beneficial ability to build parts with geometric and material complexities that could not be produced by subtractive manufacturing processes. Through intensive research over the past two decades, significant progress has been made in the development and commercialization of new and innovative AM processes, as well as numerous practical applications in aerospace, automotive, biomedical, energy and other fields. This paper reviews the main processes, materials and applications of the current AM technology and presents future research needs for this technology.

An overview of Direct Laser Deposition for additive manufacturing; Part I: Transport phenomena, modeling and diagnostics

Abstract: Laser-based additive manufacturing (LBAM) processes can be utilized to generate functional parts (or prototypes) from the ground-up via layer-wise cladding – providing an opportunity to generate complex-shaped, functionally graded or custom-tailored parts that can be utilized for a variety of engineering applications. Directed Energy Deposition (DED), utilizes a concentrated heat source, which may be a laser or electron beam, with in situ delivery of powder- or wire-shaped material for subsequent melting to accomplish layer-by-layer part fabrication or single-to-multi layer cladding/repair. Direct Laser Deposition (DLD), a form of DED, has been investigated heavily in the last several years as it provides the potential to (i) rapidly prototype metallic parts, (ii) produce complex and customized parts, (iii) clad/repair precious metallic components and (iv) manufacture/repair in remote or logistically weak locations. DLD and Powder Bed Fusion-Laser (PBF-L) are two common LBAM processes for additive metal part fabrication and are currently demonstrating their ability to revolutionize the manufacturing industry; breaking barriers imposed via traditional, ‘subtractive’ metalworking processes. This article provides an overview of the major advancements, challenges and physical attributes related to DLD, and is one of two Parts focused specifically on DLD. Part I (this article) focuses on describing the thermal/fluidic phenomena during the powder-fed DLD process, while Part II focuses on the mechanical properties and microstructure of parts manufactured via DLD. In this current article, a selection of recent research efforts – including methodology, models and experimental results – will be provided in order to educate the reader of the thermal/fluidic processes that occur during DLD, as well as providing important background information relevant to DLD as a whole. The thermal/fluid phenomena inherent to DLD directly influence the solidification heat transfer which thus impacts the part's microstructure and associated thermo-mechanical properties. A thorough understanding of the thermal/fluid aspects inherent to DLD is vital for optimizing the DLD process and ensuring consistent, high-quality parts.