Lubri-cooling and tribological behavior of vegetable oils during milling of AISI 1045 steel focusing on sustainable manufacturing

The focus of this study is the search for cutting fluids that are not toxic to humans or damaging toward the environment, with a view to sustainable manufacturing. The technical viability of the use of biodegradable natural vegetable oils as cutting fluids in the milling of AISI 1045 steel was evaluated applying the minimum quantity of lubricant (MQL) technique. The edible vegetable oils studied were cottonseed, babassu nut, canola, sunflower, corn and soybean. For comparison purposes, the commercial vegetable-based fluid LB 2000 (not edible) was considered, applying the same MQL technique, in addition to the dry condition as a benchmark. The fluids were firstly submitted to specific tests to quantify their lubri-cooling capacity as well as their physical and chemical properties. Based on the results obtained in each test the fluids were ranked. The two edible oils with the best results for cooling ability were cottonseed and canola and these were applied in tests to study the tool life during milling, using coated cemented carbide tools. After milling, the tools were analyzed by scanning electron microscopy to examine the wear mechanisms. Cottonseed and canola oils showed promising results, particularly considering that they are non-toxic towards humans and non-polluting in the environment. Adhesion or attrition (stick-slip phenomenon) was the dominant wear mechanism encountered, regardless of the oil tested. (C) 2017 Elsevier Ltd. All rights reserved.