Prediction and optimization of machining parameters for minimizing power consumption and surface roughness in machining
Introduction
The 1980s have witnessed a fundamental change in the way governments and development agencies think about environment and development. The two are no longer regarded as mutually exclusive. It has been recognized that a healthy environment is essential for a healthy economy. Energy and materials are the two primary inputs required for the growth of any economy and these are obtained by exploiting the natural resources like fossil fuels and material ores. The industrial sector accounts for about one-half of the world's total energy consumption and the consumption of energy by this sector has almost doubled over the last 60 years (Fang et al., 2011). The consumption of critical raw materials (such as steel, aluminium, copper, nickel, zinc, wood, etc) for industrial use has increased worldwide. The rapid growth in manufacturing has created many economic, environmental and social problems from global warming to local waste disposal (Sangwan, 2011). There is a strong need, particularly, in emerging and developing economies to improve manufacturing performance so that there is less industrial pollution, and less material & energy consumption. Energy efficiency and product quality have become important benchmarks for assessing any industry. Machine tools have efficiency less than 30% (He et al., 2012) and more than 99% of the environmental impacts are due to the consumption of electrical energy used by the machine tools in discrete part machining processes like turning and milling (Li et al., 2011). Sustainability performance of machining processes can be achieved by reducing the power consumption (Camposeco-Negrete, 2013). If the energy consumption is reduced, the environmental impact generated from power production is diminished (Pusavec et al., 2010). However, sustainability performance may be reduced artificially by increasing the surface roughness as lower surface finish requires lesser power and resources to finish the machining. However, this may lead to more rejects, rework and time. Therefore, an optimum combination of power and surface finish is desired for sustainability performance of the machining process. A lot of research on the modelling and optimization of machining parameters for surface roughness, tool wear, forces, etc has been done during last 100 years after the well known formula relating tool life to cutting speed was given by Taylor (1907). However, a little research has been done to optimize the energy efficiency of machine tools. Moreover, in the past, metal cutting operations have been mainly optimized based on economical and technological considerations without the environmental dimension (Yan and Li, 2013). Reduction in power consumption will improve the environmental impact of machine tools and manufacturing processes.
Machine tools require power during machining, build-up to machining, post machining and in idling condition to drive motors and auxiliary equipments. However, the design of a machine tool is based on the peak power requirement during machining of material which is very high as compared to non-peak power requirement of the machine tool. This leads to higher inefficiency of energy in machine tools. The optimization of machining parameters for minimum power requirement is expected to lead to the application of lower rated motors, drives and auxiliary equipments and hence save power not only during machining but as well as during build-up to machining, post machining and idling condition. In addition to the machining parameters, the power requirement during machining also depends upon workpiece properties and cutting tool properties. In this study the work material is steel and cutting tool material is uncoated tungsten carbide. This combination is the most widely used combination in the industry and any reduction in power consumption is expected to lead to high saving of power in absolute numbers. No doubt, steel is one of the widely researched materials in machining for more than last half century, but there is a renewed interest in application of steel because of its sustainability – 100% recyclable and almost indefinite life cycle. AISI 1045 steel is one of the steel grades, widely used in different industries (construction, transport, automotive, power, etc.). In order to maximize sustainability performance, the materials that are both in abundant supply and have the potential for recycling/re-use with no significant environmental effect should be used (Pusavec et al., 2010). Energy requirement for steel recycling is less than one third of aluminium recycling.
There is a close interdependence among productivity, quality and power consumption of a machine tool. The surface roughness is widely used index of product quality in terms of various parameters such as aesthetics, corrosion resistance, subsequent processing advantages, tribological considerations, fatigue life improvement, precision fit of critical mating surfaces, etc. But the achievement of a predefined surface roughness below certain limit generally increases power consumption exponentially and decreases the productivity. The capability of a machine tool to produce a desired surface roughness with minimum power consumption depends on machining parameters, cutting phenomenon, workpiece properties, and cutting tool properties, etc. The first step towards reducing the power consumption and surface roughness in machining is to analyse the impact of machining parameters on power consumption and surface roughness. This paper aims at optimizing the power consumption and surface roughness simultaneously. Optimization of machining parameters through experimentation is a not only tedious but costly also, therefore, this paper presents a predictive mathematical model to optimize the power consumption and surface roughness simultaneously. The multi-objective predictive model has been developed using the grey relational analysis coupled with principal component analysis. The response surface methodology has been used to optimize the machining parameters to minimize the multi-objective function.
Section snippets
Literature review
Process models have often targeted the prediction of fundamental variables such as stresses, strains, strain rate, temperature, etc but to be useful for industry these variables must be correlated to performance measures and product quality (accuracy, dimensional tolerances, finish, etc) (Arrazola et al., 2013). Recent review papers on machining show that the most widely machining performances considered by the researchers are surface roughness followed by machining/production cost and material
Research methodology
The research carried out for this paper can be broadly divided into three phases – experimental planning; multi-objective predictive model formulation; and machining parameters optimization – followed by result confirmation using experimental studies as shown in Fig. 1.
In the first phase experimental plan was developed to select the machine tool, cutting tools, machining material, machining parameters and their levels, and performance characteristics (power consumption and surface roughness).
Selecting machining parameters and performance characteristics
The turning experiments were carried out in dry cutting conditions using a centre lathe, which has a maximum spindle speed of 2300 rpm and a spindle power of 5.5 kW. For increasing rigidity of the machining system, workpiece material was held between chuck and tailstock and the tool overhang was 20 mm. The choice of machining parameters was made by taking into account the capacity/limiting cutting conditions of the lathe, tool manufacturer's catalogue and the values taken by researchers in the
Calculating the grey relation co-efficient using GRA
The experimental results for the Ra and P are listed in Table 2. Preprocessing sequence (Table 3) was computed using Eq. (4) as both surface roughness and power consumption fit ‘the-smaller-the-better’ methodology. shows the value for reference sequence and for comparability sequence. The deviation sequence is computed using:
Therefore the value of deviation sequence for comparability
Analysis of variance
The relative importance among the machining parameters (v, f, d) for the multiple performance characteristics (Ra and P) needs to be investigated so that the optimal parameters can be decided effectively. The analysis of variance (ANOVA) has been applied to investigate the developed model and the effect of machining parameters on the multi-objective function. Table 7 shows ANOVA results for the linear [v, f, d,] quadratic [v 2, f 2, d2] and interactive [(v × f), (v × d), (f × d)] factors.
Confirmation experiments
The confirmation experiments were conducted on the optimal machining parameters (v = 127.63 m/min, f = 0.12 mm/rev and d = 0.50 mm) predicted using the developed model. The result of the confirmation runs for the power consumption and surface roughness are listed in Table 8. It can be observed that the optimal machining parameters predicted by the developed model will lead to lower power consumption and better surface roughness as shown in Table 8.
The influence of machining parameters on power consumption and surface roughness
Machine tools consume power to provide the relative movement to the cutting tool with respect to the workpiece and rotation of spindle. The three machining parameters, viz. cutting speed, feed and depth of cut determine the material removal rate. As the feed and depth of cut increases, the undeformed chip section increases and hence the force required to remove this area also increases which forces the machine tool to consume more power. The surface roughness also increases with increase in
Conclusions
This paper presents a multi-objective predictive model for the minimization of power consumption and surface roughness during the machining of AISI 1045 steel. It has been observed that the predictive model provides optimum machining parameters. The predictive model has been found statistically significant using ANOVA. The results of the proposed model provide an improvement of 6.59% reduction in power consumption and 2.65% improvement in surface roughness over the best experimental run. It has
References (34)
- et al.
Optimizing power consumption for CNC turned parts using response surface methodology and Taguchi’s technique—a comparative analysis
J. Mater. Process. Technol.
(2008) - et al.
Recent advances in modelling of metal machining processes
CIRP Ann. – Manuf. Technol.
(2013) Optimization of cutting parameters for minimizing power consumption and maximizing tool life during machining of Al alloy SiC particle composites
J. Clean. Prod.
(2013)- et al.
Mathematical modeling of surface roughness for evaluating the effects of cutting parameters and coating material
J. Mater. Process. Technol.
(2009) - et al.
Optimization of process parameters using a response surface method for minimizing power consumption in the milling of carbon steel
J. Clean. Prod.
(2014) Optimization of cutting parameters for minimizing energy consumption in turning of AISI 6061 T6 using Taguchi methodology and ANOVA
J. Clean. Prod.
(2013)- et al.
Evaluation of vegetable based cutting fluids with extreme pressure and cutting parameters in turning of AISI 304L by Taguchi method
J. Clean. Prod.
(2011) - et al.
Investigating the minimum quantity lubrication in grinding of Al2O3 engineering ceramic
J. Clean. Prod.
(2014) - et al.
A new approach to scheduling in manufacturing for power consumption and carbon footprint reduction
J. Manuf. Syst.
(2011) - et al.
Application of Taguchi method to selection of optimal lubrication and cutting conditions in face milling of AlMg 3
J. Clean. Prod.
(2011)
Optimization of cutting conditions for sustainable machining of PEEK-CF30 using TiN tools
J. Clean. Prod.
A modeling method of task-oriented energy consumption for machining manufacturing system
J. Clean. Prod.
Grey relational analysis coupled with principal component analysis for optimization design of the cutting parameters in high-speed end milling
J. Mater. Process. Technol.
Energy efficient process planning for CNC machining
CIRP J. Manuf. Sci. Technol.
Transitioning to sustainable production – part I: application on machining technologies
J. Clean. Prod.
Taguchi design and response surface methodology based analysis of machining parameters in CNC turning under MQL
J. Clean. Prod.
Optimization of turning operations with multiple performance characteristics using the Taguchi method and Grey relational analysis
J. Mater. Process. Technol.
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