Design of an Experimental Injection Moulding Tool for Testing Microstructured Cavity Surfaces

This research is based on the impact assessment of the active element of injection moulding tools. The quality of the tool surface has a significant effect on the filling and cooling efficiency. Our goal is to create a uniform structure on the cavity’s surface that results in a high degree of orientation during the injection moulding process. A special experimental tool is needed for the research. Our design was based on the results of previous experimental research and preliminary criteria. The design was based on the size and position tolerances of the A side of the tool. As the previous study has shown, there are three main points to consider when designing an experimental moulding tool. These are the applied manufacturing technology, Design for Assembly, and the expansion of the measurement possibilities by using different sensors. The small beam size of the femtosecond laser also allows the machining of microscopic-sized details, a technology used to structure the cavity surface. The success of this was analyzed by microscopic examination.

Producing a Dissimilar Joint of Copper to Austenitic Stainless Steel by Ultrasonic Welding

There are several possibilities for establishing a cohesion joint between dissimilar metals. In the case of thin sheets, the ultrasonic welding process is suitable. This process can establish a cohesion joint rapidly, with a low heat input between the thin sheets. The authors have tried to determine the optimal ultrasonic welding parameters for copper and austenite stainless steel joining by using an experimental method of joining. Suitable results were obtained by welding tests due dissimilarities in the chemical, physical and mechanical properties of the copper and stainless steel. A standard size sheet thickness and test sample was used for the welding by different parameters. The parameters were refined based on the theoretical and practical knowledge during the experiments. The experimental welding was made by a Branson L20 type welder machine. The joint made by the different parameters was inspected by shearing-tensile tests (maximal force level).

Development of Graphite- and Graphene Reinforced Styrene-Butadiene Rubber

The environmental impact of rubber waste can be reduced by extending the lifetime of rubber products. It can be achieved by developing graphene/rubber nanocomposites with good abrasion resistance. In this paper, we investigated how rubber mixing technologies influence the mechanical properties of rubber. We added various amounts (0, 1, 5 and 10 phr) of graphite and graphene to rubber mixtures using a two-roll mill, an internal mixer, a single- and a twin-screw extruder. We performed tensile, tear strength and Shore A hardness tests on the vulcanisates and analysed their fracture surfaces with a scanning electron microscope. Our results show that graphene had a better reinforcing effect than graphite. Rubber mixing via extrusion may contribute to more severe polymer degradation, though their reproducibility is better than that achieved on a two-roll mill or in an internal mixer.

Characteristics of the Levels of Mechanisation in Arc Welding

Improvement of quality, reduction of the subjective possibilities of faults may be facilitated with the help of the technically rational and economically justifiable mechanisation of productive serial production as well as the use of the wide range of hardware and software IT possibilities. Mechanisation is usually understood as the mechanisation of technological operations that may otherwise be performed by manual operations (human movements and effort). Mechanisation is therefore the substitution, in whole or in part, of manual labour with the help of specialised equipment and the mechanical operation of the various movements. The present article examines the particular features of mechanisation in the field of outstandingly high significance in industrial applications, i.e. arc welding, assisting the forms of training applied in the specialty area.

Examination of Glass-Fibre Reinforced Composite Dental Fillings

In dentistry, the use of dental fillings is a routine procedure. The use of fillings is a cheap, simple and low-harm dental operation, however, the filling of deep cavities is a difficult task. During this research, three types of fillings were tested: composite fillings bonded directly to the cavity walls, fillings bonded to the cavity walls with a semi-direct method, and composite fillings bonded to the cavity lined with polyethylene fibres. In the course of our examinations, the gaps between the wall of the dental cavity and the dental filling were observed using scanning electron microscopy. The results of these measurements can be used to determine the quality of each type of filling procedure.

Manufacture of a Home-Made Spot Welding Machine from Household Electronic Waste

Nowadays, spot-welding technologies are being used on a very wide range of applications. Spot-welded joints can be found in many pieces of equipment, such as toasters, computers, telephone batteries, or even in various pre-manufactured car elements. Given the prevalence of the technology, there may be a legitimate need for a machine that can be used at home for simple spot-welding operations. Such a device could be produced more cost-effectively than those currently available on the market, while using household electronic waste. These could be produced for hobby purposes, thus creating an opportunity to recycle certain types of household electronic waste, thereby improving sustainability in an engineering approach.

Development of Pneumatic Deformability Test of Polylactic Acid Films

The aim of the present study is to develop a test method suitable for modelling thermoforming processes and which provides an index that accurately characterises the thermoformability of a film or sheet at a given temperature and pressure. For this purpose, the elevated temperature pneumatic deformability test was considered to be the most suitable. During the test, the film is blown until it tears, which takes only a few seconds. We recorded blowing during the test, and used the images to determine the ascent (k) of the specimens and approach the estimated surface of the deformed specimens with a sphere.

Manufacturing, Heat Treatment and Investigation of Foam-Filled Tubes

Composite metal foams are hybrid structures with the main advantages of high specific strength and mechanical energy absorption associated with low density. In the course of our research, we successfully manufactured functional metal foams of EN AC-44200 matrix filled with lightweight expanded clay aggregate particles (LECAPs) in EN AW-6060 alloy tubes with a diameter of 50 mm and a wall thickness of 5 mm. Manufacturing was performed by low-pressure infiltration directly into the aluminium tube. Six different types of samples were examined: metal matrix syntactic foam, in-situ metal foam, ex-situ metal foam, and their heat-treated pairs. In the compression tests, the heat treatment provided a visible improvement in the results of the ex-situ metal foams.

Design and Implementation of a Vacuum Forming Machine

The purpose of this work is to present the design of a laboratory scale vacuum forming machine, which can be used for the processing of thermoplastic sheets. The designed machine can process an A4 format plastic sheet. An important consideration in the design process was to follow a cost-effective approach. The vacuum forming instrument is made for educational purposes in the framework of a final project for the Polymer Technology Laboratory of the Department of Mechanical Engineering of the Sapientia EMTE University in Târgu Mureș. The structure and the operation of the machine is similar to that found in the industry. However, the cost of production is significantly lower. The main components of the machine include the frame, heater, vacuum pump and the clamping device.

Development of a Clamping Device for Tensile Testing of Intracranial Flow Diverter Stents

The main danger of a brain aneurysm (a sack-like bulge on the vessel wall) is that in the event of a rupture a severe hemorrhage can occur which may cause death. However, if doctors have tools at their disposal, such as numerical models and simulations for analyzing patient-specific blood vessels, they could use them to decide if a particular treatment is necessary and if so, when. For such models, the different mechanical characteristics of the flow control devices are the input data. Several of these mechanical properties of the devices, such as modulus of elasticity and tensile strength, are determined by tensile testing. In the course of our research, we have developed a clamping device suitable for uniaxial tensile testing of flow diverter stents.