Ancuţa Păcurar

Research on the Influence of the Orientation of Deposited Material on the Mechanical Properties of Samples Made from ABS M30 Material Using the 3D Printing Method

The majority of commercially available 3D printers utilize an additive manufacturing (AM) technique known as molten polymer deposition, whereby a solid thermoplastic filament is forced through a computer-driven extrusion nozzle. Even if it sounds simple at a first look, there are a series of factors that significantly influence the mechanical strength of parts manufactured by using the 3D printing method. The present work tries to investigate by using the finite element method and experimental research how the building orientation is influencing the mechanical strength of samples made from ABS M30 material using a Desktop 3D Printer machine that has been originally designed and produced at the Technical University of Cluj-Napoca (TUC-N).

Finite Element Analysis to Improve the Accuracy of ABS Plastic Parts Made by Desktop 3D Printing Method

The development of low-cost desktop versions of three-dimensional (3D) printers has made these devices widely accessible for rapid prototyping and small-scale manufacturing in home and office settings. Many desktop 3D printers rely fused deposition modeling process, that it is based on heated thermoplastic filiform material that it is extrused through a nozzle and deposited afterwards onto a heated building platform. The extruding accuracy in part fabrication is subject to transmission machinery and filament diameter on one hand and the technological parameters that are used in the manufacturing process (raster angle, tool path, slice thickness, build orientation, deposition speed, building temperature, etc.) on the other hand. The presented work try to investigate by using the finite element method, how the building temperature in close connection with the material characteristics is influencing the accuracy of a test part that has been designed in order to callibrate an Desktop 3D Printer machine that has been originally designed and produced at the Technical University of Cluj-Napoca (TUC-N).

Finite Element Analysis to Predict the Mechanical Behavior of Lattice Structures Made by Selective Laser Melting Technology

Within this article, there are presented a series of researches that are related to the field of customized medical implants made by Additive Manufacturing techniques, such as Selective Laser Melting (SLM) technology. Lattice structures are required in this case for a better osteointegration of the medical implant in the contact area of the bone. But the consequence of using such structures is important also by the mechanical resistance point of view. The shape and size of the cells that are connected within the lattice structure to be manufactured by SLM is critical in this case. There are also few limitations related to the possibilities and performances of the SLM equipment, as well. This is the reason why, several types of lattice structures were designed as having different geometric features, with the aim of analyzing by using finite element method, how the admissible stress and strain will be varied in these cases and what would be the optimum size and shape of the cells that confers the optimum mechanical behavior of lattice structures used within the SLM process of the customized medical implant manufactured from titanium-alloyed materials.

Estimating the Life-Cycle of the Medical Implants Made by SLM Titanium-Alloyed Materials Using the Finite Element Method

Within this article, there are presented a series of researches that were developed for the first time in Romania, in the field of customized medical implants made by using the Selective Laser Melting (SLM) technology. Finite Element Method (FEM) has been successfully used in order to analyze the fatigue and to determine the durability of a customized medical implant that has been selected for the made analysis. The material characteristics taken into consideration within the Finite Element Analysis (FEA) that has been performed were the ones of two types of dedicated metallic powders which are commercially available (TiAl6Nb7 and TiAl6V4 material) and suitable for the SLM 250 HL equipment from the SLM Solutions GmbH Company from Lubeck, Germany. The Finite Element Analysis made in the case of these two types of SLM titanium alloyed materials, proved that the modified characteristics, such as the yield strength and hardness of the material are significantly influencing the durability of the medical implants made by SLM technology.

New Manufacturing Technology for Variable Pitch and Variable Screw Profile Worms

One relatively new variant in gear transmissions is the rolling gear boxes. The rolling transmission wheels have variable pitch and variable screw profile surface section. In this paper it is presented the geometry of used helically surfaces and one new machining technology developed by our team. It is used the method of high machining, with high precision turning, which is a promising solution. The profile manufacturing can only be made on high precisions turning. The experimental researches were realized at the Direct-Line Ltd. in Budapest.

Finite Element Analysis to Improve the Accuracy of Parts Made by Stainless Steel 316L Material Using Selective Laser Melting Technology

One of the serious problems in the SLM process, using metallic powders is the thermal distortion of the model during forming. As a result of the locally concentrated energy input, the temperature gradient mechanism and the related processes lead to residual stresses and part deformations. Since the solidified part is cooled rapidly, the model tends to be deformed and cracked due to the thermal stresses. All these aspects were considered for a series of analyses that were made using the finite element method in order to determine the optimum process parameters (laser power, scanning speed, powder bed temperature) that are required in order to improve the accuracy of the metallic parts made by Stainless Steel 316L material using the Selective Laser Melting process.