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Electrospinning of Polymer Fibres Using Recycled PET

Abstract

The effective recycling of polymer materials remains unresolved to this day, and this has had a devastating effect on the environment. This study examines an alternative method to PET recycling that is the generation of polymer fibers and fiber mats for filtration applications. The electrospinning instrumentation used in this study had to be designed and built in order to carry out the research. We have managed to produce PET fibers with 200-600 nm diameter, and free-standing fiber mats that could potentially be used in filtration applications.

Open access
Examination of Laser Microwelded Joints of Additively Manufactured Individual Implants

Abstract

Digital product processing and the utilization of novel, tissue-friendly materials allow the use of fixed dentures for patients. Its basis is a titanium plate fixed to the cortical bone surface at given screw positions. A digital dental cast is created from the existing bone surface, and modelling and necessary statistical analyses are carried out in a virtual environment. Safety of the welded joint is evaluated with mechanical methods. When designing the fixing points, an idealized denture is used that was previously designed for the patient. The number and position of pillar elements used for screw fixation of the denture are determined by the complex geometry of the denture itself, and the location, direction, and articulating position of existing teeth. The additively manufactured implant and the machined pillar sleeves are joined with laser-welding at given nesting positions. Homogeneity of the metallic material structure at the welded joint zone of the product is examined with micro-CT. Due to this implementation method, surgical time decreases together with complication rates and post-operative problems.

Open access
Examination of Layer Thicknesses of a Model Produced by Fused Filament Extrusion

Abstract

Nowadays additive manufacturing continues to gain more and more space in industrial technology. In particular, FDM (fused deposition modelling) machines have become easily available to the public. Quality of parts is impacted by several factors. In this study we investigate layer thicknesses of a prototype manufactured from PLA, and we pay special attention to the thickness of sequentially deposited layers.

Open access
Investigation of Imperfections Formed at the Ultrasonic Welding of Copper Sheets

Abstract

Ultrasonic welding is a very useful and simple welding process. It is suitable for establishing a joint between thin sheets and dissimilar metals with short preparation and finish work time [1]. Some welding defects were detected due to less than optimal ultrasonic welding parameters. These defects were ruptures, surface colour change and unacceptable deformations. This article aims to identify these failures and their causes.

Open access
Machinability of Ni-based Superalloys by Indexable End Mills

Abstract

The subject of this research is the machining of Ni-based super alloys using indexable end mills. The cutting ability of these materials is known to be difficult, even challenging with modern tools, so our goal is to create an efficient technology recommendation on an experimental basis. To this end, we have developed an experimental design from which results are used to determine the optimal technological parameters. This research took place at John Von Neumann University, Department of Vehicle Technology of GAMF Faculty.

Open access
Mechanical and Microstructural Features of Ceramic Hollow Spheres

Abstract

In this study two different types of hollow sphere were examined by mechanical, geometrical and microstructural measurements, and the fracture force, geometrical properties and chemical composition were determined. The diameter of the „01 globocer” type specimens was 2.37 mm on average, while the value for the „03 globocer” type specimens was 6.88 mm, both were smaller than the nominal diameter. The average deviation from the circularity of the 01 globocer specimens was 8 %, the value for the 03 globocer specimens was 6 %, while the average wall porosity was 53±3 % and 56±3 % respectively. The surface of the hollow spheres was uneven, which has an impact on the contact surfaces during pressure tests, which affects the fracture force values. The average value of the fracture force of 01 globocer spheres was 42 N, and of 03 globocer hollow spheres was 288 N. The diameter had a bigger impact on the fracture force values of the type 01 specimens than in the case of 03.

Open access
The Relationship between Materials Science and the Fourth Industrial Revolution

Abstract

There has been a spectacular and extremely fast development in all areas of materials science. This development is driven by science and technology, yet a time gap may be observed between the progress of technology that drives the fourth industrial revolution, and its acceptance in society. Our task is to learn how a balance may be achieved between rapid technological development and societal acceptance.

Open access
Research on Technical Ceramics and their Industrial Application: Preparation Techniques and Properties of Transparent AlON Ceramics

Abstract

Aluminium oxynitride (AlON) has a unique thermal and chemical stability that makes it the perfect candidate for a wide range of applications. This article provides a brief description and comparison of the most common AlON preparation methods along with their advantages and disadvantages. Although there has been extensive research on the material, especially more recently because of increased commercial interest, extensive systematic powder synthesis and processing studies have not been carried out to determine alternate, more cost efficient routes to fully dense transparent bodies. Further optimization of reaction sintering and transient liquid phase sintering could be important processing routes.

Open access
The Role of Focus Position in Single Pulse Laser Drilling of Highly Reflecting Materials

Abstract

The laser processing of materials which are highly reflective at laser wavelengths is problematic. We have to take into account that only a small part of the energy is absorbed, the main part being reflected. In this article we examine the laser processing of highly reflective copper and silver at 1070 nm wavelength. In laser drilling of printed circuit boards it is necessary to drill copper layer as well. In highly reflecting materials we can drill smaller holes because of the low energy efficiency. Naturally in single pulse laser drilling the focus position plays a key role: at the focal spot of the laser beam smaller diameter holes are produced, further from the focal spot, higher diameter holes are produced.

Open access