Fabrication Of Metallic Components Research Articles

Design challenges in leveraging binder jetting technology to innovate the medical instrument field

AbstractDespite its significant advantages in terms of design freedom and the wide range of processable materials, the Binder Jetting technology has not yet received substantial attention in the healthcare field, especially concerning the fabrication of metal components. Hence, the paper investigates how this technology could be exploited to innovate the medical instrument field. Based on selected case studies, some preliminary design indications are derived on how to properly consider the various phases (i.e., printing, depowdering, and sintering) and related challenges of the Binder Jetting process.

Layer-level AISI 316L-18Ni (300) Maraging multi-material fabrication via Laser-Powder Bed Fusion

Overcoming most of the limitations of conventional subtractive techniques, Laser-Powder Bed Fusion (L-PBF) is a widely adopted technology that allows the fabrication of metallic components with complex geometries. Available machines can work with a large variety of materials; however, multi-material printing is limited to inter-layer fabrication, i.e., each layer is made out of a single material. In this work, we aim at expanding the multi-layer printing capabilities of L-PBF to intralayer manufacturing (i.e., two different materials in the same layer), overcoming the previous limitations. To investigate the effectiveness and validate the proposed method, two widely used steels are used as powders to manufacture bi-material specimens, i.e., the AISI 316L austenitic stainless steel and the 18Ni (300) Maraging steel. Based on metallurgical and mechanical testing evidence, the results show that the method is repeatable and capable of fabricating strong and tough intralayer interfaces. While weak interfaces between materials with rather different mechanical properties are common in multi-material printing techniques, our method allows us not only to produce bi-materials with stronger interfaces but also to reduce discontinuities to those normally found in additive manufactured components. These results are obtained without any modifications to the machine and with low-cost additional equipment, opening the way for easy and cost-effective implementation.

Laser metal deposition of self-lubricating alloys on selective laser melting maraging tools for the high temperature forming of aluminium

Selective laser melting (SLM) is an additive manufacturing technique that allows the layer-by-layer fabrication of metallic components with high dimensional tolerances, being also particularly suitable for implementing complex geometries such as cooling channels in hot forming tools. However, high temperature forming processes pose severe conditions that often require additional surface protection and functionality. The present work proposes to increase the lifetime and endurance of SLM tools using self-lubricating coatings deposited by laser metal deposition (LMD). To this end, 3D printed samples made of maraging steel prepared by SLM are functionalized with self-lubricating coatings applied by LMD. Two different metallic alloys are deposited, a nickel-based alloy containing metal sulphides and silver, and an iron-based alloy containing graphite. The resulting microstructure after the hybridization of both additive manufacturing techniques has been thoroughly analysed in terms of the microstructural changes. Afterwards, the functionalized 3D printed tools are investigated for prospective high temperature sheet metal forming of aluminium alloy AA6082 using a ring compression test rig at 300 °C, using a reference hot work tool steel as reference. The results show that the use of Ni-based self-lubricating coatings contributes to a more stable frictional behaviour, independently of the dilution of the externally added lubricant. These results serve as example for the enormous potential for the combination of laser metal deposition with selective laser melting for tool functionalization.

An experimental investigation on the combined effect of plastic deformation and grain size variation on the acoustic nonlinearity parameter.

The combined effect of grain size variation and plastic deformation on the acoustic nonlinearity parameter has been investigated in an austenitic stainless-steel material of grade 304. The nonlinear behavior of this parameter with grain growth has deviated to linear fit with deformation. This is due to the interaction of elastic waves with the strain-induced dislocation substructure in the grains. The normalized mean square strain of the deformed specimens has been estimated through angle dispersive x-ray diffraction studies using a synchrotron source, and this has been correlated with the change in the acoustic non-linearity parameter with deformation. The nonlinearity parameter is found to be very sensitive to the plastic deformation even in the presence of grain size variations. The results infer that the variations in the nonlinearity parameter can be used to have an estimate of the extent of localized deformations often occurring during the fabrication of metallic components.

Assessing the feasibility of fabrication and welding of nickel-alloyed ductile iron through the evaluation of tensile properties and mechanical characterization

Fabrication of metallic components using welding processes is of great importance in the engineering world. Alloying element added material is a necessary to fabricate industry-ready components, especially after the invention of fabrication methods using welding processes. In the present work, raw materials including iron scraps, sponge iron, and forged steel scraps are melted in a medium frequency furnace. Casting samples are cast produced as per the ASTM standards using nickel alloyed ductile iron and inspected for porosity and other defects. Tungsten inert gas welding is exercised to check for the suitability of produced alloy for the welding process. Mechanical characterization and tensile property of as-welded components were performed. Both cases were carefully examined and found with satisfactory results. Tungsten inert gas-welded samples were noticed without any weld defects; this opens the advantage to employ welding processes for the fabrication. This will certainly enhance the feasibility of welding process for various component fabrications.

An Extensive Review on Advance Forming Methods

Giving it a shape and making it a useful component defines the process of forming. Years of research have given new methods to this process. In various industries like automobile and aeronautics, the goal is to achieve complicated shapes with properties like high energy absorption, high rigidity at a lower cost. These aspects can be achieved by Advance Forming Methods (AFM), major work is being done on the hydroforming process as this process provide shapes that otherwise require a greater number of processes. The idea of flexible forming is something where the efforts are reduced along with a number of trials by introducing rubber pads into the sheet metal forming process and the complexity of tool design automatically reduces. Other than these processes, the process of rapid prototyping which is incorporated in the laser forming process is being used in the fabrication of metallic components. The areas of work which is being done are to reduce the number of failures by optimizing the process parameters to achieve better results at a low cost