Minimum Quantity Solid Lubrication Research Articles

Effect of minimum quantity solid lubrication (MQSL) parameters on cutting force and temperature during turning of EN31 steel

Considering the trends in the contemporary manufacturing and machining industry, dimensional accuracy, tool wear and quality of surface finish is becoming increasingly important. Hard-to-cut materials imposes two major difficulties, generation of high cutting temperature at tool and workpiece interface which subsequently leads to the increase in cutting force of the tool which ultimately increases the tool wear. The implementation of a proper lubrication system critically improves the surroundings of contact area by controlling the frictional relation which would ensure change in the machining mechanics. Minimum quantity solid lubrication (MQSL) is the process of supplying solid lubricant (molybdenum disulfide and graphite) along with oil at minimum quantities. In the present study turning experiments were performed by varying MQSL parameters (nozzle distance, compressed air pressure, lubricant flow rate and concentration of solid in lubricant) to comprehend the MQSL performance on cutting force and cutting temperature in turning EN31 steel. For this, a portable and cost-effective high velocity MQSL set-up was developed. MQSL performance was compared with wet and dry turning results. The present work offers a comprehensive picture which helps in ultimate the effect of lubricant parameters of MQSL in turning of EN31 steel.

Performance of PVD and CVD coated cutting tool inserts in machining under MQL-MQSL environment

The current study evaluated the performance of coated tools during machining and addressed the applicability of minimum quantity lubrication (MQL) and minimum quantity solid lubrication (MQSL). Experimental investigations have been done to evaluate the machinability aspects such as flank wear and hence tool life, forms of tool wear and surface roughness in turning of AISI 52100 steel using dry, MQL and MQSL machining with physical vapour deposition (PVD) multilayer (TiAlN/TiN) and chemical vapour deposition (CVD) bilayer (TiCN/Al2O3) coated carbide inserts. Longer tool life is observed under MQL and MQSL cutting conditions, which can be due to enhanced lubrication and cooling effect. It can be seen that PVD coated carbide tool with MQL and MQSL performed effectively as compared to CVD tools for selected cutting environments. Based on the findings, the presented approach provides a more clear methodology to select the combination of the cutting tool and lubrication strategy.

Tribological studies of EN31 steel and Ti-6Al-4V alloy materials using pin-on-disc tribometer

Mechanical parts in modern machining systems are often subjected to friction and wear causing high heat generation at the contact zones leading to reduced lifecycle and increased power consumption of machinery. Coolants, despite controlling this high contact zone heat, are uneconomical due to their high cost. Various researchers across industries have been focusing towards replacing coolants by developing newer lubricants to obtain environmental and economic benefits. The current work presents an experimental investigation to evaluate tribological characteristics of bearing steel (EN 31) and Ti-6Al-4V alloy using MoS2 as solid lubricants. Friction and wear properties were measured on a pin-on-disc tribometer at different sliding conditions. Solid lubricant was effectively supplied to the pin-disc interface zone through a specially designed experimental set-up namely minimum quantity solid lubricant (MQSL). The obtained results are compared with the dry and wet environmental conditions. The results indicate a significant improvement in the tribological performance of steel and alloy materials under MQSL when compared with dry and wet environment conditions. The work presented here provides a good understanding of methods to cool/lubricate the sliding zones, reduce temperature at sliding interface to make the machining of difficult-to-cut materials more efficient and economic.

Investigations on machinability aspects of AISI 52100 with minimum quantity solid lubrication

Sustainability has been a major concern of today’s manufacturing industries. Various efforts have been made to improve the productivity and performance of machining. It is always aimed to reduce the heat generated during machining by various cooling and lubrication approaches. In the present work, efforts have been made to assess the effectiveness of minimum quantity lubrication and solid lubricants in machining. Experiments have been performed under MQL and MQSL environment with selected flow rate (300 ml/hr), 20 wt% of calcium fluoride (CaF2) and 10µm particle size of solid lubricant and results are compared with dry and flood cooling environment. The process performance is observed by measuring surface roughness produced, tool flank wear, the microhardness of machined workpiece, and forms of the chip produced. Results revealed the superiority of lubricant mixture applied in form of MQSL due to enhanced lubricating properties imparted by solid lubricant added with MQL.

Experimental investigation to study the performance of solid lubricant during turning EN31 steel and Ti-6Al-4V alloy

In the present day manufacturing industry, achieving machining accuracy, high production rate, and high material removal rate and increasing tool cutting life is becoming more vital and challenging task. Machining of hard materials is difficult to carry out because of high temperature generation between tool-workpiece interface which results in significant reduction in surface quality, tool life and high wear rates of the cutting tools are experienced. The use of proper lubrication in machining processes is critically important to modify the conditions of contact area by effective control over frictional interaction which should ensure change in tool-chip interface and machining mechanics. This paper present some preliminary results on experimental studies on EN31 and Ti-6Al-4V alloy materials on NC lathe machining using TiN coated cutting tool. MoS2 type of solid lubricants were used as lubricants. High velocity minimum quantity solid lubricant experimental setup is fabricated to supply graphite solid lubricant into tool-chip-workpiece interface. The present investigation concentrates in comparing the cutting force and surface roughness both in solid lubricant and dry conditions.

Experimental measurement and modelling of surface roughness in turning with CaF<SUB align="right">2 solid lubricant assisted minimum quantity lubrication

To improve the quality of a product, it is important to evaluate, both experimentally and analytically, the factors affecting the machining process. In this context, the proposed work focuses on the modelling and analysis of surface roughness measured in a turning process with wet and minimum quantity solid lubrication (MQSL) approaches. In the MQSL application, micron-sized calcium fluoride (CaF2) solid lubricant powder particles are mixed in Society of Automotive Engineers (SAE) 40 cutting oil and applied to a machining zone. It also provides a predictive model for the minimisation of the surface roughness in turning operations in wet and MQSL environments. The correlation between the cutting parameters and measured surface roughness in wet and solid lubricant assisted machining is determined. Results indicate that surface roughness is affected by feed, depth of cut followed by cutting speed. These outcomes can be used by the machining industry to use the best combination of parameters affecting surface roughness with the MQSL approach.

Experimental measurement and modelling of surface roughness in turning with CaF2 solid lubricant assisted minimum quantity lubrication

To improve the quality of a product, it is important to evaluate, both experimentally and analytically, the factors affecting the machining process. In this context, the proposed work focuses on the modelling and analysis of surface roughness measured in a turning process with wet and minimum quantity solid lubrication (MQSL) approaches. In the MQSL application, micron-sized calcium fluoride (CaF2) solid lubricant powder particles are mixed in Society of Automotive Engineers (SAE) 40 cutting oil and applied to a machining zone. It also provides a predictive model for the minimisation of the surface roughness in turning operations in wet and MQSL environments. The correlation between the cutting parameters and measured surface roughness in wet and solid lubricant assisted machining is determined. Results indicate that surface roughness is affected by feed, depth of cut followed by cutting speed. These outcomes can be used by the machining industry to use the best combination of parameters affecting surface roughness with the MQSL approach.

Electrostatic high-velocity solid lubricant machining system for performance improvement of turning Ti–6Al–4V alloy

In any machining operation, a major division of energy is converted into heat which creates detrimental effects on tool wear, tool life and surface quality of machined work material. Effective cooling/lubrication in the machining zone is essential to improve friction and temperatures by efficient heat dissipation which increases tool life and surface quality. But adverse health effects caused by use of flood cooling are drawing manufacturers’ attention to develop methods for controlling occupational exposure to cutting fluids. In demanding the improvement of productivity and product quality of machining, use of solid lubricant thin film was suggested as one of the necessary alternative machining techniques to apply lubricants effectively to the high-temperature zone. There is a general concern in the machining process in terms of applying lubricants effectively to the machining zone. Therefore, this research work contributes to the development of a novel approach to apply lubricants effectively to the rake face and flank face of the cutting tool without polluting the environment. Electrostatic high-velocity solid lubricant assisted machining is a novel technique used in the machining process with a very low flow rate (1–20 mL/h) to enhance the process performance of turning difficult-to-cut materials. The performance of electrostatic high-velocity solid lubricant technique is studied in comparison to minimum quantity solid lubricant, minimum quantity lubricant and dry and wet (flood cooling) to assess the performance considering surface roughness, cutting force and tool wear as performance indices. The experimental results revealed that electrostatic high-velocity solid lubricant with MoS2 solid lubricant at low volume and constant flow rate has observed high potential to apply lubricants effectively in the machining zone when compared with the considered environmental conditions. This work is expected to form a scientific basis toward developing electrostatic high-velocity solid lubricant technique for reducing the manufacturing impact in the machining of aerospace components such as Ti–6Al–4V alloy in terms of both machinability and environmental perspectives.

A Novel Technique to Achieve Sustainable Machining System

Turning is one of the most fundamental and indispensable processes of metal removal in industry. Increasing pollution-preventing initiatives globally and consumer focus on environmentally conscious products has put increased pressure on industries to minimize or eliminate the use of cutting fluids. The use of solid lubricant in machining operation is one of the most effective strategies in this direction to achieve sustainable machining system. In the present research work, the feasibility of a novel approach for developing a new generation of machining technique namely High Pressure Minimum Quantity Solid Lubricant experimental set-up has been envisaged with an aim to improve process performance and to eliminate the use of cutting fluids in machining operation. A detailed comparison has been made with wet, dry, MQL machining operation to assess the process performance on the basis of tool wear and surface finish. The results indicate that HP-MQSL mixture at a small and constant flow allows better penetration of the mixture into the tool-work and tool-chip interface, thus providing reduction on the tool wear and surface roughness more effectively than a wet, dry, and MQL machining at high speed conditions, thereby to achieve sustainable machining system.

Performance assessment of MQSL: Minimum quantity solid lubricant during turning of Inconel 718

Abundant application of cutting fluids may increase production cost and cause environmental and health damages, particularly when not properly managed. Thus, alternative measures are needed to overcome the difficulties of using cutting fluids. If sustainable and ecological manufacturing aspects are envisaged, any attempt to improve the machinability of such difficult-to-machine material is always welcome. In this direction, this research work aims to develop experimental set-up as a possible approach to fostering sustainability in metal cutting lubrication to supply solid lubricant at minimum quantity and also to study the effect of applying solid lubricant (molybdenum disulphide and graphite) mixed with oil, during turning of Inconel 718 using cemented carbide tools. The concentration of the solid lubricant in the fluid and the flow rate of the mixture were varied to analyse the main output parameters such as surface roughness, cutting forces and tool life. Experimental findings of this study show that minimum quantity solid lubricant consisting of molybdenum disulphide and oil mixture performed better, and therefore, it may be considered to be a cost-effective and environmental-friendly lubrication technique than flood coolant and sprayed oil with or without graphite to retard all types of damaging processes and to improve machinability characteristics of Inconel 718.