Presented is an update of the recent literature on advances in difficult to machine materials such as nickel and titanium-based alloys, and composites used in aeroengine and aerostructure applications. The review covers ultrasonic vibration-assisted machining and the combination of this technique with minimum quantity lubrication and high-pressure cooling. Also discussed are low-frequency vibration-assisted aerospace alloy drilling and low- and high-frequency vibration-assisted drilling of stacks.
PL
Przedstawiono najnowsze osiągnięcia we wspomaganej drganiami obróbce materiałów trudnoobialnych, takich jak stopy niklu, stopy tytanu oraz kompozyty stosowane w silnikach i konstrukcjach lotniczych. Przegląd obejmuje obróbkę wspomaganą drganiami ultradźwiękowymi oraz połączenie tej techniki ze smarowaniem minimalnym i chłodzeniem pod wysokim ciśnieniem. Omówiono także wiercenie stopów lotniczych wspomagane drganiami o niskiej częstotliwości oraz wiercenie stosów wspomagane drganiami o niskiej i wysokiej częstotliwości.
The paper presents an update of the recent literature on advances in machining of difficult to machine materials such as nickel and titanium-based alloys, and composites used in aeroengine and aerostructure applications. The review covers the following issues: advances in high-performance cooling techniques as cryogenic machining, minimum quantity lubrication, the combination of MQL and cryogenic cooling, and high-pressure lubricoolant supply and hybrid cutting processes – vibration assisted machining (both low and high frequency), laser, plasma and EDM assisted machining. Examples of applications in industrial processes are also given.
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W artykule wskazano współczesne problemy obróbki skrawaniem materiałów stosowanych w przemyśle lotniczym, ze szczególnym uwzględnieniem stopów niklu i tytanu oraz kompozytów, które mają coraz lepsze właściwości użytkowe, ale niestety z reguły wiążą się z coraz gorszą skrawalnością, za którą musi nadążać rozwój materiałów ostrzy i metod obróbki.
EN
The article identifies problems of the machining of modern materials used in the aerospace industry, with particular reference to nickel and titanium alloys as well as composites. These materials have better and better performance properties, but unfortunately they are usually associated with worse machinability, which the development of blade materials and machining methods must keep up with. Innovative aerospace machining techniques have been described, including advanced cooling techniques (dry machining and minimum lubrication, high-pressure cooling and cryogenic cooling) and hybrid machining.
Aircraft are exposed to lightning strikes. Lightning strike protection (LSP) devices involve additional weight of the aircraft. Therefore, multifunctional materials that allows the conductivity of electrical current and, simultaneously, holds the mechanical properties required to withstand the typical conditions for an aerospace material are widely researched. A typical resin used in aviation is an insulator, so main research is done to reduce its resistance. On the other hand, the type of reinforcement can have a large influence on the electrical conductivity in the plane of reinforcement. The aim of the article is to evaluate the effect of the type and the basis weight of reinforcement on the electrical conductivity. For this purpose, with the use of a hydraulic press, different four-layer composites based on epoxy resin were produced. Each differing is in combination of carbon, glass layers and their basis weight (from 48 kg/m2 to 245 kg/m2 ). The measuring proceedings were carried by an RMS multi meter and, more accurate, by an LCR meter with 4 selectable test frequencies. The measurements were made both along the strand fibres and at a 45-degree angle. The results made it possible to determine which reinforcement of aircraft composites should be selected at the aircraft design level to provide increased electrical conductivity along the reinforcement fibres and thus influence one of the factors affecting the protection of the aircraft against the effects of lightning
The use of composite materials is continuously increasing in modern transport. This process is especially noticeable in aviation. The mass percentage of epoxy resin composites in contemporary aircraft constructions is usually higher than 50%, and these materials must meet increasingly demanding requirements. In these circumstances, in addition to mass and strength, it is necessary to predict other properties of the material, such as abrasion resistance. The article presents the analysis of the process of abrasion of carbon fibre reinforced polymers reinforced with various fillers. Straight carbon fibre mats were used for the tests. In addition, powders of pumice, alumina, silicon carbide, and glass microspheres at various concentrations in relation to the matrix were used as fillers. In order to investigate the influence of external factors on the abrasion process, each group of samples was subjected to abrasion under different external conditions: in an insulated environment, in the presence of water and loose abrasives: brown fused alumina (BFA) and white fused alumina (WFA). The measurements were carried out using a precision balance and an electron microscope. The results allow concluding on which kind of filler and in what concentration contributes to improvement of the abrasion resistance of the composite material the most. In addition, it was found that the conditions in which abrasion occurs have a very large impact on the course of this process.
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