Study and Comparison of Lubricity of Green and Commercial Cutting Fluid Using Tool-Chip Tribometer

Abstract

A lubricant is a substance introduced between surfaces in mutual contact to reduce friction, which ultimately reduces the heat generated when the surfaces move. Liquid lubricant, designed specifically for metalworking processes, such as turning, drilling, milling etc. is known as cutting fluids (CF). Cutting fluid is a blend or combination of oil, emulsifier and additives, mostly derived from chemicals or petroleum products. However, it has got many side effects as it is toxic and harmful to environment during its disposal. Hence, vegetable based cutting fluid or green cutting fluid (GCF) is being developed and gaining importance with time. Properties of these cutting fluids are dependent on the nature of the base-oil, nature of surfactants and the properties of water used to make the CF. These fluids act on the nascent surfaces generated during cutting to form a low friction boundary layer as they slide past the cutting tool. We propose a unique tool-chip tribometer (TCT) in which these boundary layers, formed by the action of lubricants on freshly cut surfaces, can be generated and their tribological properties alone studied in isolation. This equipment can be used to study the fundamental mechanisms of the lubrication using emulsions on nascent surfaces and can be used in optimizing the composition of such fluids. The scope of this work is to assess different cutting fluids in this tool-chip tribometer. The tribological performances of metal cutting on nascent surfaces are compared. Unlike in the conventional methods of assessing the lubricity of cutting fluids using cutting tests, here the friction has been evaluated separately from cutting forces.

Development and Testing of a Modular Lathe Tribometer Tool to Evaluate the Lubricity Aspect of Cutting Fluids on Freshly Cut Surfaces

“…The cutting fluid used in the machining operation significantly reduces the frictional forces. This results are in terms with the results from tool chip tribometer [10]. Figure 8 shows the coefficient of friction variation with speed and Table 4 Thus, the observations from the study provide a upshot for analysis, further study and improvement of green cutting fluid and lathe tribometer.…”

“…This could be attributed to the influence of tribofilm formed by different cutting fluids. GCF which has vegetable oil (coconut oil) as the base oil which has got better lubricity and wetting/lubricating properties than the other cutting fluids which has mineral oil as the base oil [10,11]. Further it will aid in reducing friction in cutting tool and work piece interface.…”

“…The cut track is generated by engaging a knifeedged tool against a rotating disc immersed in the pool, and a separate pin with ball attached to it slides on the cut surface so generated. The friction between this ball pin and the newly reacted layer is found [10]. Few drawbacks of tool chip tribometer is that, it needs special sample preparation (disc, pin etc) and setting time is around an hour for conducting one experiment, further cutting operation is performed with parting tool in submerged condition.…”

Evaluation of a comprehensive non-toxic, biodegradable and sustainable cutting fluid developed from coconut oil

“…The factor that increases the anticorrosion property is not only the type of the corrosion inhibitor used but also the combined effect of base oil, emulsifier and additives used for the formulation. 21,22 Whereas CCF 2, CCF3, CCF4 and CCF5 has shown noticeable corrosion, this was visible in the chips also (as corrosion products). The control (Deionized water) has shown the maximum corrosion.…”

“…As shown in figure, a cutting fluid should be possibly tested to determine the toxicity and biodegradability levels for a sustainable manufacturing process These results are in agreement with the observation and results from tribological test performed using tribometer, conducted to evaluate the generated friction during machining. 21 The efficiency of the emulsion in rendering a low friction layer on the surface will depend on the composition of the emulsion and on the speed, load and temperature characteristics in the tribological system. Current regulations in cutting fluid account for only machining performance but do not account for the ingredients selection and biodegradability screening, which is vital for determining the overall quality of a product and sustainability.…”