Experience of implementation in educational process modern technologies of FDM 3D printing

Fused Deposition Modeling is an additive manufacturing technology where a temperature-controlled head extrudes a thermoplastic material onto a build platform in a predetermined path. Standard, advanced thermoplastics and composites are used for printing. Among the areas of application for FDM printing, the main ones are rapid prototyping, as well as small-scale and batch production. The purpose of the work is the implementation of FDM 3D printing technology in the educational process of students in specialty 141 "Electroenergy, electrotechnics and electromechanics". The features of the technology of additive manufacturing of electrical apparatuses parts by the method of FDM printing have been investigated. Parts of four standard sizes were printed using ABS + and PLA plastics, namely, current transformer carcasses in the amount of 110 pieces and sensor bodies in the amount of 100 pieces. For printing, an FDM 3D printer was used built on the XZ Head Y Bed kinematic scheme with an open working chamber. The analysis of defects in finished products was carried out, which showed that the main defects are deviations of the actual dimensions and geometric shape of the finished products. Ways to prevent the occurrence of these defects are considered, namely, correcting the size of the model at the stage of preparing the model for printing, minimizing the filling density of the model, using brims in models, setting the optimal temperature of the working platform and simultaneously printing several products. The results of the study o features of the technology of additive manufacturing of electrical apparatuses parts by the method of FDM printing made it possible to develop a set of laboratory works for students of the specialty 141 "Electroenergy, electrotechnics and electromechanics".

Analysis of the behaviour of 3D samples printed by FFF/FDM technologies under bending stress with a focus on infill

The focus of this paper is to explore the possibilities of optimizing 3D printed elements produced by FFF/FDM technology based on bending tests according to ČSN EN ISO 178 (64 0607) with variations in the settings of the printing itself. The principle of FFF/FDM is the printing of a continuous fiber made of thermoplastic material, which is applied by machine to the previously printed fiber. There are many combinations of possible print settings, and one of them is the geometry of the inner density with variable density. Their resulting maximum values of the achieved load were then compared with the weight (amount of material used) and printing time. The result is a comparison to achieve economical printing with the greatest possible load capacity.

Development of a Novel Hybrid Thermoplastic Material and Holistic Assessment of Its Application Potential

Τhe development of a novel hybrid thermoplastic prepreg material enabling the fabrication of next-generation recyclable composite aerostructures produced by affordable, automated technologies is presented in the present work. The new hybrid material is produced using automated equipment designed and developed for this reason. A preliminary assessment of the application of the new material is made to obtain material properties related to its processability as well as to its strength. A typical aeronautical flat skin panel has been identified and produced using an autoclave-based process in order to assess the potential of the new material for producing aircraft structural parts. Moreover, a newly developed holistic index is implemented to enable a more holistic comparison of the suitability of the materials used for the panel production. The aspects considered for the material comparison are the quality, the environmental footprint, and the cost. The results of the study pointed out that the hybrid thermoplastic material that has been developed represents a viable manufacturing option from an industrial point of view and that its implementation in structural component manufacturing leads to clear cost and environmental advantages.

3D Printing Optimization for Environmental Sustainability: Experimenting with Materials of Protective Face Shield Frames

The motivation for research on 3D printing of protective face shields was the urgent societal demand for healthcare in the fight against the spread of COVID19 pandemic. Research is based on a literature review that shows that objects produced by additive technologies do not always have consistent quality suitable for the given purpose of use. Besides, they have different effects on the environment and leave different footprints. The overall goal of the research was to find out the most suitable thermoplastic material for printing shield frames in terms of mechanical properties, geometric accuracy, weight, printing time, filament price, and environmental sustainability. Fused deposition modeling (FDM) technology was used for 3D printing, and three different filaments were investigated: polylactic acid (PLA), polyethylene terephthalate (PETG), and polyhydroxyalkanoate (PHA). The weighted sum method for multi-objective optimization was used. Finally, PHA material was chosen, mainly due to its environmental sustainability, as it has the most negligible impact on the environment.

Cutting force, Vibration, and Temperature in Drilling on a Thermoplastic Material of PEEK

Polyetheretherketone (PEEK) is one of the semi-crystalline thermoplastic polymers with excellent machinability and chemical stability applied to precise structural plates and electronic components. This study installed multiple sensors to analyze the machining characteristics in the PEEK drilling. According to the time domain signals, the effects of spindle speed and feed rate on the machining characteristics of cutting force and vibration were investigated. In addition, an infrared thermography was installed to record the temperature variation within the drilling area. The experimental hole was 2-mm diameter with a 4.5-mm depth. Experimental results showed that the effect of the feed rate on thrust force is greater than the spindle speed; drilling by a low-level spindle speed with a low-level feed rate can obtain the smallest cutting force and acceleration amplitude in the spindle axis; the temperature within the drilling area is inverse to the feed rate and a high-level feed rate is helpful for forming regular curl chips. When adequate airflow was applied during the drilling operation, the hole’s shrinkage ratio and roundness can be decreased. The data presented in this paper provide valuable references for realizing the drilling of the thermoplastic—PEEK.

Properties of Orthodontic Clear Aligner Materials - A Review

BACKGROUND Clear aligners are orthodontic devices that are transparent, a plastic used to correct malaligned teeth. Here patient wears a series of customized clear, removable aligners that gradually move the teeth to the desired position. The clear aligner system is a modern adaptation of the systems described since the middle of the 20th century, therefore there were different devices and philosophies that have led to its creation and the system has evolved a lot over the decades. Clear aligner therapy has been a part of the orthodontic practice for years, but, popularity was increased since the introduction of Invisalign appliances (Align Technology) in 1998. There are almost 27 different clear aligner products currently on offer for orthodontic treatment. Nowadays, more people prefer clear aligner treatment because it is aesthetically superior to brackets and lingual orthodontics. The superiority of clear aligners lies in their aesthetics. The optical properties of the clear aligner material play a major role in aesthetics. The rising demand among adult patients for “invisible” orthodontic treatment has led to an exponential growth in the clear aligner market. Indeed, these aligners have a low aesthetic impact, as well as being able to effectively and progressively guide the teeth into their programmed positions. They are also removable and therefore do not hamper oral hygiene maintenance, in turn reducing the risk of white spots, caries, gingivitis and periodontal disease. All the materials do not possess the same chemical composition. The properties change before and after wear. In this article, we bring out the different materials used for the manufacture of clear aligners and their various properties. KEY WORDS Clear Aligners, Optical Properties, Thermoplastic Material, Mechanical Properties

Interdisciplinary system approach and concept of experimental and analytical method of material selection and design planning in order to improve effectiveness of periodontitis treatment

Objective. One of the most important tasks of dentistry at the present stage is creation of structures, which ensure a unity of dental system form and function and bring it closer to its original natural state. This approach permits to expand significantly the range of orthopedic treatment tasks and implement medical and technical requirements for materials, structures of dentures and splinting devices. Materials and methods. The article reflects the results of an experimental study to determine the Poisson's ratio of the Dental D thermoplastic material used as a structural material for the manufacture of a new therapeutic and preventive dental splint as well as a biomechanical analysis of changes in the displacement amplitude of the teeth included in the splint. Results. As a result, an accurate quantitative assessment of the developed method of tooth immobilization in mild periodontitis is given taking into account the behavior of the bone tissue of the lower jaw, hard tissues of the teeth and periodontium as well as in case when the dentition is affected by the chewing load. Conclusions. The analysis of the obtained data allowed us to form practical recommendations for use of the developed design at the stages of orthopedic treatment of patients with the initial stage of periodontal pathology in order to reduce functional overload of dentition and maintain mobility of teeth at physiological level.

Design of Shape Memory Thermoplastic Material Systems for FDM-Type Additive Manufacturing

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.