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The aim of this paper is to present a study we already performed regarding the mechanical behaviour of different structures for infill patterns obtained by fused deposition modelling (FDM). This time, the authors used different infill factors (10%, 30% and 60%) and different printed pattern strategies (diamond, honeycomb, linear, wiggle), after which the structures obtained with the above parameters were evaluated from a mechanical point of view to identify the optimal variant, because the printing conditions play an important role, as they can particularly influence the properties of 3D printed structures that can be used, for example, as device (instrument) housing or functional tests. The experimental determinations were performed at the Laboratory of Ultra-precise Systems for Precision Mechanics from UPB to observe how printing strategies correlated with infill factors influence the mechanical characteristics of manufactured structures.

The paper presents a modern method of obtaining non-circular gearwheels from by means of additive technologies. Such a method is useful in case of wear or failure of a mechanical gear which has in its composition such non-circular metal gearwheels in the case of technical systems that must ensure continuous operation. With the help of the FDM technology (Fused Deposition Modeling) it will be created a model of the non-circular gearwheel that will constitute casting model for future gear, or they can even be used as functional gears if a suitable material and a precise execution technology with optimal printing conditions are considered.

The paper presents a comparative study of the technological process of obtaining casting moulds by means of additive technologies (fused deposition modelling and vat photopolymerisation) from a wide range of materials (thermoplastics and industrial photocurable resin). The obtained results of the researches in the study highlight the advantages and disadvantages of these methods for the realization of metallic and polymeric parts with unique character or very small series.

The paper presents and describes an electrochemical finishing process - anodic polishing, which substantially improves the quality of dental prostheses realized by selective laser melting, obtaining prosthetic restorations with distinguished mechanical properties. The authors developed a theoretical model of electrochemical polishing, which was validated by a numerical simulation, obtaining very close results between the two models. After this analysis, it is possible to choose the proper polishing regime and the appropriate process parameters in order to obtain predetermined finishes for dental prostheses realized by selective laser melting.

The main purpose of the authors is to develop an improved aeration system to be used in wastewater treatment that will reduce the energy consumption by 20% for conventional activated sludge wastewater treatment plants (WWTPs) and by 40% for Moving Bed Biofilm Reactor (MBBR) WWTPs. A new type of aeration system based on fine-bubble diffusers with high endurance and reliability made from corrosion resistant metals is developed. The paper presents the innovative aeration systems with holes smaller than O 1 mm. An ultrasound system is used to clean the diffusers for clogging prevention. Ultrasound systems are used in WWTPs, but in the treatment process and not as an additional solution for anticlogging.

The authors developed a study for behaviour of Geneva mechanism considering different materials and technologies. Generally, there are three basic types of Geneva motion mechanisms named external, internal and spherical. In this paper the authors considered external Geneva mechanism. The design and machining of a conventional Geneva mechanism are generally well known, but there are some particularities, if we consider 3D printing technologies. Conventional, Geneva mechanisms are used to low-speed applications, or to those in which noise and vibration are of no importance. Using PLA+Copper or ABS materials noise and vibrations are reduced considerably. Also, the entire mechanism has a reduced weight. There were considered different fill factors for 3D printed parts. The experimental setup allows fast changing of mechanism parts. This research aims the study of behaviour of 3D Printed machine elements like: springs, bearings, clutches gears, bellows, diaphragms, bushes, brakes, sliders, etc developed by authors.

The absence of teeth can lead to more complications at aesthetic, phonetic and even gastrointestinal level. Therefore, with the loss of a certain number of teeth as well as tooth extraction during treatment, immediate prosthetics is indicated. Global competition encourages manufacturers to develop certain technologies for the realization of prostheses, surgical templates, diagnostic and working models, where high productivity is required in the shortest possible time. For this purpose, so-called additive technologies of material are now successfully used. This paper presents the study and realization of dental prosthetic models by FDM (Fused Deposition Modelling) using two different materials that can serve as a prototype for future prostheses or even as temporary prosthetic restorations.

The authors developed a research for studying the behaviour of 3D printed machine elements such as: clutches, springs, bellows, screws, nuts, gears, differential and planetary mechanisms. There are different applications where metallic springs cannot be used: corrosive, explosive, magnetic field, electromagnetic radiation, nuclear techniques and other applications or environments that require light spring masses.