Multi-objective optimisation for minimum quantity lubrication assisted milling process based on hybrid response surface methodology and multi-objective genetic algorithm

© 2019 by SAGE Publications Ltd.Parametric modelling and optimisation play an important role in choosing the best or optimal cutting conditions and parameters during machining to achieve the desirable results. However, analysis of optimisation of minimum quantity lubrication–assisted milling process has not been addressed in detail. Minimum quantity lubrication method is very effective for cost reduction and promotes green machining. Hence, this article focuses on minimum quantity lubrication–assisted milling machining parameters on AISI 1045 material surface roughness and power consumption. A novel low-cost power measurement system is developed to measure the power consumption. A predictive mathematical model is developed for surface roughness and power consumption. The effects of minimum quantity lubrication and machining parameters are examined to determine the optimum conditions with minimum surface roughness and minimum power consumption. Empirical models are developed to predict surface roughness and power of machine tool effectively and accurately using response surface methodology and multi-objective optimisation genetic algorithm. Comparison of results obtained from response surface methodology and multi-objective optimisation genetic algorithm depict that both measured and predicted values have a close agreement. This model could be helpful to select the best combination of end-milling machining parameters to save power consumption and time, consequently, increasing both productivity and profitability.Peer reviewedFinal Published versio

EXPERIMENTAL ANALYSIS AND OPTIMIZATION OF THE CONTROLLABLE PARAMETERS IN TURNING OF EN AW-2011 ALLOY; DRY MACHINING AND ALTERNATIVE COOLING TECHNIQUES

The latest trends in machining research show that great efforts are being made to understand the impact of different cooling and lubrication techniques as well as cutting parameters on machining performances. This paper presents the investigation results of different cutting parameters and different cutting environments such as dry machining, minimum quantity lubrication (MQL) and minimum quantity lubrication with compressed cold air (MQL+CCA) on average surface roughness, cutting force and material removal rate. The experiments were designed based on three input parameters and three different cutting environments when turning of EN AW-2011 alloy. Taguchi-based grey relational analysis was used to identify the optimal process parameters by which minimum values of surface roughness, minimum value of cutting force and maximum value of material removal rate will be achieved. The results showed that minimum quantity lubrication in the stream of compressed cold air, in comparison to dry and minimum quantity lubrication machining, gives the best machining performances. Therefore, the use of MQL + CCA method, which reduces the amount of lubricant may represent in the described extent of turning operations an alternative to turning processes most often carried out by wet method that causes considerable costs for purchasing, maintaining and using cutting fluids

Impact of Palm Oil based Minimum Quantity of Lubrication on Machinability of Ti and its Alloy (Ti-6AI-4V)

This project investigates the usage of palm oil as a metal cutting fluid in minimum quantity lubrication assisted turning operations and its effect on surface roughness, tool wear and cutting temperature for Titanium alloy Ti-6Al-4V. Artificial Neural Network models were developed to determine the optimum cutting parameters considering the sustainability of palm oil in titanium alloy machining to improve future manufacturing costs and qualities

Effect of different cooling strategies on surface quality and power consumption in finishing end milling of stainless steel 316

In this paper, an experimental investigation into the machinability of AISI 316 alloy during finishing end milling operation under different cooling conditions and with varying process parameters is presented. Three environmental-friendly cooling strategies were utilized, namely, dry, minimal quantity lubrication (MQL) and MQL with nanoparticles (Al$_{2}$O$_{3}$),and the variable process parameters were cutting speed and feed rate. Power consumption and surface quality were utilized as the machining responses to characterize the process performance. Surface quality was examined by evaluating the final surface roughness and surface integrity of the machined surface. The results revealed a reduction in power consumption when MQL and MQL + Al$_{2}$O$_{3}$ strategies were applied compared to the dry case by averages of 4.7% and 8.6%, respectively. Besides, a considerable reduction in the surface roughness was noticed with average values of 40% and 44% for MQL and MQL + Al$_{2}$O$_{3}$ strategies, respectively, when compared to the dry condition. At the same time, the reduction in generated surface roughness obtained by using MQL + Al$_{2}$O$_{3}$condition was marginal (5.9%) compared with using MQL condition. Moreover, the results showed that the improvement obtained in the surface quality when using MQL and MQL + Al$_{2}$O$_{3}$ coolants increased at higher cutting speed and feed rate, and thus, higher productivity can be achieved without deteriorating final surface quality, compared to dry conditions. From scanning electron microscope (SEM) analysis, debris, furrows, plastic deformation irregular friction marks, and bores were found in the surface texture when machining under dry conditions. A slight smoother surface with a nano-polishing effect was found in the case of MQL + Al$_{2}$O$_{3}$ compared to the MQL and dry cooling strategies. This proves the effectiveness of lubricant with nanoparticles in reducing the friction and thermal damages on the machined surface as the friction marks were still observed when machining with MQL comparable with the case of MQL + Al$_{2}$O$_{3}$

A Review of Minimum Quantity Lubrication Technique with Nanofluids Application in Metal Cutting Operations

Minimum quantity lubrication (MQL) technique did not only serve as a better alternative to flood cooling during machining but enhance better surface finish, minimizes the cost, reduces the impact loads on the environment and health hazards on the operation personnel. However, the coolant or lubrication media used in MQL technique posed certain restrictions especially at very high cutting speeds where the lubricating oil tends to evaporates as it strikes the already heated cutting tool at elevated temperature. Desire to compensate for the shortcomings of the lubricating media in the MQL technique led to the introduction of nanoparticles in the cutting fluids for use in the MQL lubrication process. Nanoparticles have much higher and stronger temperature-dependent thermal conductivity and enhanced heat transfer coefficient at very low particle concentration, which are key parameters for their enhanced performance in many of the machining applications. Optimizing the nanoparticles concentration leads to efficiency in most of their application. Their ball bearing effect lubrication at the cutting zone through formation of film layer which reduces friction between the contact surfaces thereby reducing cutting force, temperature and tool wear. It has been reported in various studies that nanoparticles introduction in cutting fluids led to excellent machining performance in reduction of cutting forces, reduced tool wear, reduced cutting temperature and improved surface finish of the work piece thereby increasing productivity and reduction of hazards to the health of personnel and the environment better than the pure or conventional MQL process. Thus, the application of various nanoparticles and its performances in metal cutting operations with respect to the cutting forces, surface finish, tool wear and temperature at the cutting zone are evaluated and highlighted

Sustainable machining of molds for tile industry by minimum quantity lubrication

Nowadays, to reduce water pollution, soil contamination, and human health hazards, the environmental legislation is forcing manufacturing companies to avoid the use of metalworking fluids. Thus, the adoption of the dry machining and minimum quantity lubrication (MQL) techniques is becoming essential. However, small and medium companies are having difficulties and are skeptical about the adoption of these new techniques. In this study, a methodology is proposed to implement an MQL system for sustainable machining with a step-by-step procedure that facilitates its industrial application. The methodology is divided into three steps: i) MQL configuration to verify its effect on surface roughness, considering the effective flow rates and nozzle position; ii) process modeling based on the Box–Behnken design of experiments (DoE) to model surface roughness, power consumption, and tool life; and iii) process optimization for minimizing cost and environmental impact in terms of water usage and kg of CO2 equivalent. The methodology is applied in the manufacturing process of a component of a mold for the tile industry. Different alternatives are analyzed and the best alternative in both economic and environmental aspects is the use of the MQL system with optimal cutting parameters and an early tool change strategy that ensures part quality without subsequent grinding operations

Performance Evaluation of Minimum Quantity Lubrication (MQL) When Machining High-Performance Materials

The manufacturing sector is among the fastest-growing in today\u27s industrialized world. Manufacturers are concerned about increasing their competitiveness and profitability. Increasing the efficiency and sustainability of manufacturing processes is one way to improve productivity and improve profit margins. Learning about cutting conditions and how they affect machined surfaces and tool life can help improve productivity. Nowadays, the goal is not just to increase productivity but also to make processes more environmentally friendly and cleaner. This research aims to analyze the machinability of difficult-to-cut magnesium alloys through different cooling and lubrication strategies and their impact on the environment. This study conducted controlled machining tests with dry and vegetable oil mist cutting settings to measure surface roughness, tool contact length, chip morphology, and flank wear. The present study provides insight into the cutting performance of coated carbide tools. To improve the machinability of magnesium alloys, the study also investigated tool wear mechanisms, surface roughness, and primary and secondary components of machining, such as effective shear angle, compression ratio, and coefficient of friction. In this study, we found that minimum quantity lubrication (MQL) performed well under various speed ranges for coated tools. Cutting speed and feed rate correlated closely with tool wear, surface roughness, and other output response parameters. MQL-based systems offer great potential to improve the machinability of magnesium alloys, and they should be explored further

Impact of supercritical carbon dioxide cooling with Minimum Quantity Lubrication on tool wear and surface integrity in the milling of AISI 304L stainless steel

In this study, the effect of supercritical carbon dioxide cooling with Minimum Quantity Lubrication (scCO2+MQL) on tool wear and surface integrity of AISI 304 L austenitic stainless steel in milling was investigated. A series of machining experiments based on a Design of Experiments (DoE) was carried out at various combinations of cutting parameters to investigate the effect of cutting speed and feed rate on tool wear, near-surface residual stresses, surface roughness and microhardness. The results were compared with the experimental results obtained from milling with flood coolant. A significant improvement in tool life was observed in milling with the scCO2+MQL using multilayer coated tungsten carbide inserts. The tool life in terms of cutting time increased by ∼324%, in comparison to a baseline flood coolant. Further, a decrease in surface roughness value (Ra) by about 30%, from 1.09 µm for flood coolant to 0.78 µm after face milling with scCO2+MQL was seen. Additionally, the Ra value slightly increased after machining, for both cooling methods with the increase of cutting speed of ∼19%. The observed changes in Ra value were discussed in terms of a built-up-edge (BUE) formation. There were no apparent differences in surface microhardness between both cooling methods. However, the surface microhardness increased with feed rate after milling with both scCO2+MQL and flood coolant due to the increased strain hardening. Also, there was no significant difference in residual stresses after milling, neither with scCO2+MQL nor the flood coolant. The surface residual stress values obtained in the transverse and longitudinal directions were consistent with a predictive model with errors of around 3–8%

MQL assisted cleaner machining using PVD TiAlN coated carbide insert: Comparative assessment

311-325Minimum quantity lubrication (MQL) is an alternative over dry machining due to economic and ecological sustainability. In the current research, a comparative investigation has been carried out on machinability and surface integrity aspects of hardened AISI 4340 steel using PVD TiAlN coated carbide inserts during dry and MQL assisted hard turning. Under the dry condition, turned surface has been encountered tensile residual stress whereas compressive residual stress has been generated under MQL condition. Formation of a white layer on the chip has not been experienced under both conditions. Cutting speed predominantly influences tool wear and feed influences more on surface roughness. Dimensional deviation and auxiliary flank wear have been significantly reduced under MQL condition with 16.21% cost savings. An improvement in machinability characteristics and surface integrity under MQL cutting has been noticed compared to dry with favorable interaction and contribute towards cleaner machining process. This may be adopted in machining shop floor as a good replacement over dry machining