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Achievements of sustainable manufacturing by machining

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Kopac J.

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tom Vol. 34, nr 2

180-187

EN

Purpose: Manufacturing industry is under increasing pressure of global competition, stricter environmental legislation and supply-chain demand for improved sustainability performance. The latter can be achieved through changes in products, processes and systems which are related to the sustainability issues. Sustainability in manufacturing is an appropriate approach; however it is still unified to a higher production rate and benefit. To encounter this problem academic, scientific, cultural and human organizations have to find the way, on a highest level of decision; maybe to rise the sustainability over production growth. This paper also presents some results from modelling and optimization of sustainable machining of Inconel 718. High temperature alloys, such as Nickel and Titanium alloys, pose significant difficulty in machining, due to their unique thermo-mechanical properties. Design/methodology/approach: In the paper are presented and evaluated two sustainable machining alternatives: cryogenic machining and high pressure assisted machining in comparison to conventional machining. The sustainability performance measures refer to environmental impact, energy consumption, safety, personal health, waste management and costs. The sustainability evaluation is supported with machining experiments on high-temperature Ni-alloy (Inconel 718). It is shown that tooling costs are presenting the major contribution to the overall production costs, when hard-to-machine materials are machined, what is contradictory with previous analysis. Findings: As a result, it is shown that sustainable machining alternatives offer economic, environmental and social performance improvement in comparison to conventional machining. The results of the experimental part show that appropriate cooling/lubrication application can provide improved overall machining performance while satisfying sustainable issues in terms of enhanced machined surface quality, tool-life, chip breakability, power consumption and increasing productivity. Research limitations/implications: The Faculty of Mechanical Engineering in Ljubljana, Slovenia is implementing two new cutting strategies for the machining of a special material – Inconel. The first one is cryogenic machining and the second is material cutting by assistance of high pressure jet cooling lubrication. Both machining strategy are in rang of sustainable manufacturing. The implications of processes like those are not only nature friendly, but also modern spirit for producers and users of products. Originality/value: Paper present the technical description of two modern machining processes, the comparison of them and benefit, advantages and disantvantages. Really new is the strategy and opinion of spirit, which can be included in product over sustainable manufacturing processes.

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The influence of cooling techniques on surface roughness and tool wear during cryogenic machining

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Wstawska I. , Ślimak K.

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tom Vol. 34, no. 2

51--59

EN

The main objective of this work is a comparision of different cooling techniques, namely cutting zone cooling, cutting tool cooling and workpiece cooling. The literature survey related to the analysis of surface texture (Ra) and tool wear (VBc) after applying different cooling techniques was also taken into account. The analysis revealed that the applied cooling technique has a significant influence on the values of parameters of surface’s roughness. Furthermore, in all cases observed, there was a positive influence of cryogenic machining on selected physical and technical aspects after turning and milling such materials as Inconel 718, titanium alloy Ti-6Al-4V, aluminium alloys and elastomers. This work can also be considered as a starting point for further research and the analysis of machinability during cryogenic machining.

PL

Celem niniejszego artykułu było porównanie metod obróbki kriogenicznej: chłodzenia strefy skrawania, chłodzenia przedmiotu obrabianego oraz chłodzenia narzędzia. Przedstawiono wpływ powyższych metod na chropowatość powierzchni obrobionej (Ra) oraz zużycie narzędzia (VBc). Porównanie wykazało istotny wpływ metody obróbki na chropowatość powierzchni obrobionej. Ponadto we wszystkich przypadkach zauważono pozytywny wpływ obróbki kriogenicznej na wybrane właściwości fizyczne po toczeniu i frezowaniu takich materiałów, jak: Inconel 718, stop tytanu Ti-6A1-4V, stopy aluminium, oraz materiały elastomerowe. Może to stanowić punkt wyjścia do dalszych badań skrawalności materiałów w niskiej temperaturze.

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Hybrydowe procesy skrawania wspomagane mediami technologicznymi

80%

Grzesik W.

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tom R. 91, nr 12

1050--1056

PL

Przedstawiono hybrydowe sposoby skrawania, wykorzystujące wspomaganie mediami technologicznymi (media-assisted machining – MAM). Omówiono zasady i możliwości technologiczne intensywnego chłodzenia CCS pod dużym ciśnieniem (high pressure cutting – HPC), minimalnego chłodzenia (minimum quantity cooling/lubrication – MQC/MQL), chłodzenia kriogenicznego (cryogenic machining – CM) oraz integracji tych oddziaływań w procesie skrawania w różnych zastosowaniach przemysłowych – zwłaszcza w przypadku kształtowania elementów z materiałów trudnoskrawalnych. Opisano sposoby zasilania mediami technologicznymi oraz rozwiązania narzędzi/systemów narzędziowych i wyposażenie obrabiarek hybrydowych CNC. Podano przykład optymalizacji obróbki MAM z uwzględnieniem chłodzenia kriogenicznego.

EN

A special group of hybrid assisted processes termed media-assisted processes which various liquid and gaseous media supplied to the cutting zone is highlighted. Special attention is paid on such cooling techniques as high-pressure machining (HPC), high-pressure jet assisted machining (HPJAM), minimum quantity cooling/lubrication (MQC/MQL) and a group of cryogenically cooled machining including such cryogenic media as CO2 snow and liquid nitrogen (LN2). Some important effects resulting from the various cooling strategies are outlined and compared. In particular, quantitative effects concerning chip breaking, thermal and tribological behavior of the cutting process as well as burr reduction, surface quality and subsurface layer are presented. The optimization procedure concerning both energy consumption and machining costs in terms of material removal rate (MRR) is presented.