Additive manufacturing of metallic components – Process, structure and properties

Additive manufacturing of metals

Additive manufacturing (AM), widely known as 3D printing, is a method of manufacturing that forms parts from powder, wire or sheets in a process that proceeds layer by layer. Many techniques (using many different names) have been developed to accomplish this via melting or solid-state joining. In this review, these techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid-state precipitation, mechanical properties and post-processing metallurgy. The various metal AM techniques are compared, with analysis of the strengths and limitations of each. Only a few alloys have been developed for commercial production, but recent efforts are presented as a path for the ongoing development of new materials for AM processes.

The metallurgy and processing science of metal additive manufacturing

Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following a...

/pdf/review-of-selective-laser-melting-materials-and-applications-2gpgz4zp60.pdf

Review of selective laser melting : materials and applications

https://dr.ntu.edu.sg/bitstream/10356/88603/1/Anisotropy%20and%20heterogeneity%20of%20microstructure%20and%20mechanical%20properties%20in%20metal%20additive%20manufacturing-%20A%20critical%20review.pdf

Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review

The microstructure and mechanical properties of deposited-IN718 by selective laser melting

Effects of processing parameters on tensile properties of selective laser melted 304 stainless steel

The utility model discloses a three-cylinder heatable selective laser melting rapid molding device, mainly comprising a laser, a scanning mirror, an F-Theta compound lens, a recovery cylinder, a molding cylinder, a powder feeding cylinder, a heating plate, a base plate leveling and powder laying device, a gas purification system and a control system. The base plate leveling, heating and powder laying device and the three cylinder bodies are arranged in a cavity. The gas purification system is connected with the cavity through pipes. The control system is electrically connected with the laser, the scanning mirror, the heating plate, a servo motor which drives pistols and lead screws, and the gas purification system. Through using the device, powder is laid layer by layer on the metal base plate for preheating and insulation, then the powder is melted layer by layer by the continuous fixed laser with assistance of elevation of the power feeding cylinder and the fall of the molding cylinder and the recovery cylinder, and metal parts with any shape can be rapidly machined. The utility model has the advantages that the deformation of parts is eliminated basically, the dimension accuracy and surface roughness of parts are favorable, and the density and mechanical performance thereof are high.

Selective laser melting rapid molding device for metal parts

Selective laser melting rapid forming device for directly manufacturing large-size parts

The utility model discloses selective laser melting rapid molding equipment for directly fabricating large-sized parts, which mainly comprises a laser array, an optical system array, a molding cylinder, a molding cylinder three-dimensional sectional heating thermal insulation structure, a molding cylinder weight balancing system, a substrate leveling device, double recovery cylinders, double powder storage tanks, double quantitative powder feeding and falling devices, a powder spreading device, a protective atmosphere hood, a gas purification system and a control system The adopted optical system array is constructed by a plurality of optical system units and mechanical mobile platforms, and the coverage area of the optical system can be randomly expanded or reduced The parts fabricated by adopting the selective laser melting rapid molding equipment for directly fabricating the large-sized parts are far greater than the parts fabricated by the domestic and overseas selective laser melting technology at present in dimension The molding efficiency is increased manifold without changing the molding precision or the complexity and the mechanical behaviors of the parts

Kai Guan

Papers

The microstructure and mechanical properties of deposited-IN718 by selective laser melting

Effects of processing parameters on tensile properties of selective laser melted 304 stainless steel

Selective laser melting rapid molding device for metal parts

Selective laser melting rapid forming device for directly manufacturing large-size parts

Selective laser melting rapid molding equipment for directly fabricating large-sized parts