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Relationship between surface roughness and chip morphology when turning hardened steel

Abidi Youcef

Production Engineering Archives

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2020

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Vol. 26, Iss. 3

92--98

EN

Hard machining is a process which has become highly recommended in manufacturing industry to replace grinding and perform production. The important technological parameters that determine this process are tool wear, machined surface roughness, cutting force and morphology of the removed chip. In this work, an attempt has been made to analyse the morphology and form of chip removed during turning of hardened steel AISI 1045 (40HRC) with mixed ceramic tool type CC650. Using a Taguchi plan L9, whose factors are cutting speed and feed rate with three levels for each. Macroscopic and microscopic results of chip morphology were correlated with these two cutting parameters additional to surface roughness. Sufficient experimental results were obtained using the mixed ceramic tool when turning of hardened steel AISI 1045 (40HRC) at high cutting speeds. Roughness of machined surface confirmed that it is influenced by feed rate. Chips show a sawtooth shape for all combinations of the experimental plan used. The chip form changed with cutting parameters variation and given an important indicator of suraface quality for industriel. Having the indicators on the surface quality from simple control of chip without stopping machining give an important advantage in order to maximize production and reduce costs.

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Effectiveness of Diamond Blades in the Turning of Aluminium Composites

Karolczak Paweł, Kołodziej Marek, Kowalski Maciej

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 4

262--272

EN

Owing to their excellent strength-to-weight ratio aluminium composite materials are very readily used in the construction of means of transport. The parts made of such materials must be characterized by high reliability and workmanship. Hence, machining is the predominant method of manufacturing parts from composites. The problem with the turning, milling and drilling of ceramic-reinforced composites is the abrasive action of the reinforcement, resulting in heavy wear of the blades and so in lower surface quality and dimensional-shape accuracy and higher manufacturing costs. A solution to this problem can involve the blades made of superhard materials or properly matched conditions of machining with sintered carbide blades. This paper presents the results of the turning tests carried out on an aluminium composite material reinforced with long ceramic fibres. An uncoated sintered carbide blade is compared with a diamond coated blade and a polycrystalline diamond blade. Post-turning surface roughness and machining forces were selected as the main indicators of cutting ability. The effect of the blades on the forming chips is shown and the higher resistance of the polycrystalline diamond blades to the abrasive action of the reinforcing fibres is confirmed by microscopic photographs. Besides the confirmation of the higher durability of the diamond blades, the conditions in which when using these blades one can achieve better machining effects than the ones achievable by the compared tools are defined. Moreover, it is shown that by properly matching the machining parameters and aiding machining with oil mist lubrication, it is possible to obtain excellent surface quality by means of carbide blades. The minimum quantity lubrication also increases the life of the blades.

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Analyses of calcium influence on the AlSi9CuMnNi alloy

Náprstková Nataša, Kraus Pavel, Cais Jaromír, Stančeková Dana, Miturska Izabela

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 3

32--38

EN

Treatment of metal alloys is one of the ways to affect the properties of the material. The article describes an experiment realized at FPTM UJEP when was experimentally studied the influence of alloys AlSi9CuMnNi calcium modification on some of its properties. The alloy was modified with various amounts of calcium and subsequently machining. Also hardness was measured in the resulting alloys. Machining was performed under certain cutting conditions. After machining the obtained chip was evaluated. Chip was evaluated for its shape, length and amount of chips per 100 g. Devices in FPTM laboratories were used to prepare experimental casts and to evaluate hardness and chips, like the melting furnace LAC K70/13, hardness tester Ernst AT 250X or microscope Olympus SZX 10. Experimental quantities of calcium was 0.05, 0.1 and 0.15 wt. %. Presented experiments are part of the extensive research undertaken at Faculty of Production Technologies and Management at Jan Evangelista Purkyně University in Ústí nad Labem.