Grinding Fluid Research Articles

Effects of a variety of cutting fluids administered using the minimum quantity lubrication method on the surface grinding process for nickel-based alloys

This paper presents the characteristics of nickel-based alloys, alongside their division into groups, and describes the features that make such materials difficult to grind. The possibilities of exerting a positive influence upon machining conditions, especially through the proper application of grinding fluids, are briefly presented. Both the precise methodologies for, and the results of, the experimental tests carried out on flat surfaces are also detailed. The aim of these tests was to determine the influence of the application of two types of grinding liquid (Ecocut Mikro Plus 82 and Biocut 3000) upon the grinding force values and surface roughness of the machined workpieces made from three nickel alloys (Nickel 201, INCONEL® alloy 600, and MONEL® alloy 400). An additional goal of the tests was to determine the influence of grinding wheel structure on the course and results of the machining process. The results indicate that the physical and chemical properties of Biocut 3000 enabled the most advantageous properties of the machined surface roughness, alongside a simultaneous increase in grinding power, when compared to the results when applying Ecocut Mikro Plus 82. The results showed an almost inversely proportional dependence upon the specific tangential grinding force F t′ and arithmetic mean deviation of the surface profile R a values, especially in cases of machining Nickel 201 and INCONEL® alloy 600. The original traverse grinding methodology used in the tests made it possible to assess the changes of the grinding conditions within the conventionally selected zones.

A biomimetic engineered grinding wheel inspired by phyllotaxis theory

In comparison with the conventional grinding wheels (GWs), GWs with defined grain distributions (or engineered GWs) have been widely explored and studied due to the stable grain-workpiece interactions. However, in most previous studies, grains were allocated at linearly-distributed positions without any theoretical models or foundations. To fill this gap, the GW with a phyllotactic grain distribution inspired by the phyllotaxis theory in biology is proposed in this paper. By analyzing the evenness of phyllotactic pattern in the peripheral direction and expanded view, the grain distribution parameters are theoretically designed and manufactured firstly. Then, the condition of grinding fluid in the grinding zone was observed and analyzed to verify the superiority of the grinding wheel with abrasive phyllotactic pattern by using the method of finite element modeling (FEM) contrastively. Finally, to evaluate the proposed practicality of the biomimetic engineered grinding wheel, some comparative grinding experiments of grinding surface roughness and wear were conducted. In conclusion, the advantages of biomimetic engineered grinding wheel inspired by phyllotaxis theory were demonstrated and approved.

Investigation of Grinding Fluid for Prevention of Chip Adhesion in Miniature Drilling of Glass Plate Using Electroplated Diamond Tool

In the hole drilling process, produced chip cannot be released from the inside hole which leads to broken glass plate due to the adhered chip on tool. Chip discharge method was announced by many researchers. However, the method using the tool-only with drilling command is rarely seen. In this laboratory, we have developed a tool in order to discharge chip. The developed tool is capable in preventing chip adhesion and producing high quality and efficient hole drilling process. The developed tool has several hundred times longer tool life than a conventional tool. However, the amount of adhered chips on cutting tool increase as the number of hole drilling process increases. The chip adhesion condition is different according to the kind of grinding fluid. Adhesion of chips on tool can be related to the properties of grinding fluid. Thus, in this study, the types of grinding fluid used during the hole drilling process were investigated to determine the state of chip adhesion. Three types of grinding fluid used are Emulsion, Soluble and Solution and all of them include surfactant which is considered to have an effect on prevention of chip adhesion. The main conclusions obtained in this study are as follows. Chip adhesion state was investigated after drilling process and it was found that instead of grinding fluid properties, surfactant also has significant effect on chip adhesion on tool by absorbing the adhered chip from the tool. The results showed that grinding fluid with long-chain surfactant has small amount of chip adhesion whereas grinding fluid with short-chain surfactant has large amount of chip adhesion. Therefore, it can be concluded that grinding fluid with long-chain surfactant is capable in preventing chip adhesion during hole drilling process.

Theory analysis of grinding fluid jet and its effect on surface roughness of workpiece

Theory analysis of grinding fluid jet and its effect on surface roughness of workpiece

Experimental evaluation of the lubrication performance of mixtures of castor oil with other vegetable oils in MQL grinding of nickel-based alloy

Vegetable oil is employed as base fluid in precision grinding because of its biodegradability and non-pollutant properties. Castor oil exhibits superior lubrication performance to other vegetable oils, but its high viscosity and poor flow limit its application in industrial production. In this study, castor oil was used as base oil and individually mixed with six other kinds of vegetable oils (i.e., soybean, maize, peanut, sunflower, palm, and rapeseed oils) at a ratio of 1:1 to change the rheological properties of the former. Each mixture was obtained as base oil for minimum quantity lubrication grinding. The high-temperature nickel-based alloy GH4169 was used as workpiece to evaluate the lubrication performance at the grinding wheel/workpiece interface. The mechanism of lubrication was also studied based on the molecular structure of vegetable oil. Specific grinding force, specific grinding energy, surface roughness, surface microtopography, and grinding debris were compared among the experimental and comparison groups (castor oil). The workpiece surface profile was analyzed using the correlation function and cross-correlation coefficient. Results indicated that the comprehensive lubricating performance of mixed oil was superior to that of castor oil, and soybean/castor oil exhibited the optimal performance. The specific tangential grinding force and specific normal grinding force were 0.664 and 1.886 N/mm, respectively, with 27.03% and 23.15% reduction, respectively, with respect to those of castor oil. The surface profile curves of the workpiece obtained from four kinds of working conditions (castor oil, castor/soybean oil, castor/maize oil, and castor/palm oil) were also analyzed. The amplitude of the surface profile curve in castor/soybean oil is larger and the correlation coefficient is higher (0.51) than those under other mixed oils; hence, the workpiece showed the optimal surface quality.

Effects of Grinding Fluid Excited by Ultrasonic Vibration

Ultrasonic excited fluid has been researched for machining of hard-to-grind materials. Ultrasonic vibration is applied to grinding fluid by an ultrasonic oscillating comb-shape effecter with integrated nozzle. Grinding fluid discharges from a nozzle placed between the comb’s feet and passes through the vacant space between comb teeth. By this setup, flowing grinding fluid can be continuously excited by ultrasonic vibration. Based on the principle of an ultrasonic washing machine, impulsive force caused by cavitation bubble will reduce the adhesion of chips on the cutting face of grain and chip pockets. Some effects of ultrasonic excited grinding fluid have been recorded such as reducing grinding heat in the case of grinding for Titanium alloy and decreasing in grinding force, improving surface roughness in the case of grinding for Aluminum and stainless alloy. However, the reason of better grinding performance is still unknown. Therefore, experiments conducted with different type of grinding fluids with and without ultrasonic vibration are needed. Pure Titanium, which considered a hard-to-cut material, is chosen as work material. Grinding forces and grinding heat during grinding will be measured and evaluated to clarify the mechanism of ultrasonic excited grinding fluid.

Optimization of process parameters in the high-speed milling of titanium alloy TB17 for surface integrity by the Taguchi-Grey relational analysis method

TB17 is an ultra-high-strength titanium alloy, a material typically difficult to machine. The surface quality and integrity of titanium alloy TB17 are poor after machining, which can seriously affect its service performance and restrict its fields of application. Therefore, the optimization of high-speed milling process parameters for the new ultra-high-strength titanium alloy TB17 was investigated based on multiple performance characteristics, including surface roughness, surface microhardness, and surface residual stress. The Taguchi method with grey relational analysis was utilized for the experiments. Additionally, analysis of variance was employed to evaluate the most influential factors for surface integrity in the high-speed milling of titanium alloy TB17. The results of the analysis using the Taguchi-Grey relational analysis method indicate that the preferred combination of high-speed milling process parameters are as follows: the cutting fluid condition of H-1 fine grinding fluid, using a milling speed of 100 m/min, a feed per tooth of 0.02 mm/z, an axial depth of cut of 1 mm, a radial depth of cut of l.5 mm, a rake angle of 18°, a clearance angle of 12°, and a helix angle of 60°. Moreover, the analysis of variance reveals that milling speed has the greatest effect on the surface integrity in the high-speed milling of the TB17 titanium alloy, and the contribution percentages for each factor are as follows: the cutting fluid condition (3.98%), milling speed (25.89%), feed per tooth (8.96%), axial depth of cut (1.29%), radial depth of cut (13.71%), rake angle (17.17%), clearance angle (6.62%), and helix angle (15.64%).

An in-situ infrared temperature-measurement method with back focusing on surface for creep-feed grinding

Abstract In creep-feed grinding research, it is vital to measure surface temperature of workpiece in order to optimize process parameters, prevent potential thermal damage, improve the surface integrity of workpiece and provide reference for modelling of grinding. Various measurement techniques for grinding temperature have been developed by using thermocouples and infrared radiation techniques. However, some inevitable problems still exist with slow response, strong noise interference and high sensibility to coolants. In order to obtain precise and reliable temperature of workpiece surface during grinding, an in-situ infrared technique is designed by focusing on the back surface of workpiece. With the help of a two-dimensional sliding table, the focus of infrared thermometer can be adjusted to the small hole in the workpiece to measure grinding temperature accurately. This method can avoid the high-frequency signal interruption of mechanical vibration and electrical noises, since the measurement is contactless and has signal shielding. The procedures to set up the measurement facility and measure grinding temperature are described in this paper. This paper also includes the analysis of measurement results of grinding temperature. Compared with other measurement techniques, this method is not affected by mechanical vibration and grinding fluids. By using infrared technology, this method can measure accurate grinding temperature with a fast response.

An experimental assessment on the performance of different lubrication techniques in grinding of Inconel 751

The application of emulsion for combined heat extraction and lubrication requires continuous monitoring of the quality of emulsion to sustain a desired grinding environment; this is applicable to other grinding fluids as well. Thus to sustain a controlled grinding environment, it is necessary to adopt an effectively lubricated wheel-work interface. The current study was undertaken to assess experimentally the ​ effects of different grinding environments such as dry, minimum quantity lubrication (MQL) and Cryo-MQL on performance, such as grinding force, temperature, surface roughness and chip morphology on Inconel 751, a higher heat resistance material posing thermal problems and wheel loading. The results show that grinding with the combination of both liquid nitrogen (LN2) and MQL lowers temperature, cutting forces, and surface roughness as compared with MQL and dry grinding. Specific cutting energy is widely used as an inverse measure of process efficiency in machining. It is found from the results that specific cutting energy of Cryo-MQL assisted grinding is 50–65% lower than conventional dry grinding. The grindability of Inconel 751 superalloy can be enhanced with Cryo-MQL condition.

A study on the viability of minimum quantity lubrication with water in grinding of ceramics using a hybrid-bonded diamond wheel

With the currently strict environmental law in present days, researchers and industries are seeking to reduce the amount of cutting fluid used in machining. Minimum quantity lubrication is a potential alternative to reduce environmental impacts and overall process costs. This technique can substantially reduce cutting fluids in grinding, as well as provide better performance in relation to conventional cutting fluid application (abundant fluid flow). The present work aims to test the viability of minimum quantity lubrication (with and without water) in grinding of advanced ceramics, when compared to conventional method (abundant fluid flow). Measured output variables were grinding power, surface roughness, roundness errors and wheel wear, as well as scanning electron micrographs. The results show that minimum quantity lubrication with water (1:1) was superior to conventional lubrication-cooling in terms of surface quality, also reducing wheel wear, when compared to the other methods tested.

Experimental study on grinding wheel radial wear in surface grinding of steel CrV12 using a zonal centrifugal coolant provision system

The tribology of the grinding process can be considered in the context of a tribosystem, in which the main structural elements (grinding wheel, workpiece, grinding fluid, and environment) are interrelated and interdependent. One of the most important factors influencing the contact conditions of these listed elements of the grinding process tribosystem are the proper selection of grinding fluids and anti-adhesive substances, as well as careful consideration of how they are applied. This article describes a new zonal centrifugal coolant provision system as well as the results of experimental studies conducted into its use. The aim of these experiments was to determine the impact of the system of grinding fluids provision on grinding wheel radial wear in the surface grinding process of steel CrV12. Reference methods within the described studies consisted of dry grinding and grinding using the flood method, among others. The obtained results of the experiment revealed that the use of a zonal centrifugal coolant provision system enabled the acquisition of a similar radial wear rate of the grinding wheel at 90% reduction of grinding fluids flow rate, compared with flooding method. It was also demonstrated that in the most favorable conditions, it is even possible to significantly reduce the intensity of the radial wheel wear, compared with the conventional method.

Surface characterization of diamond film tool grinding on the monocrystal sapphire under different liquid environments

Surface characterization of diamond film tool on the monocrystal sapphire under H2O, 3% ethylene glycol and 3% ethylenediamine was investigated. The typical components and chemical changes of the surface of diamond thick film were studied by means of Raman and XPS. Results showed that tribological properties of diamond film tool were associated with the liquid environment located the grinding. Diamond film tool under 3% ethylenediamine solution exhibited the minimum value of friction coefficient, while that under H2O exhibited maximum value of friction coefficient. As the ethylenediamine and ethylene glycol were added during the grinding process, the reaction between diamond film and the sapphire pieces occurred, and the chemical composition change of the surface was also studied. Under the same process parameters, a better surface quality of sapphire under the grinding fluid of ethylenediamine can be obtained.

Dry-dressing for ecological grinding

In order to comply with strict environmental regulations, a current challenge for industry is the need to reduce, or, where possible, completely eliminate the use of cooling and lubricant fluids. In the case of a high added-value technology such as grinding (typical in aerospace, biomedical, and other high-tech sectors) the damaging effects of fluids on the environment, humans, and the economy have been thoroughly described. Grinding is thus considered as an environmentally-unfriendly manufacturing process, and in recent years, an increasing amount of research has focused on the removing the use of fluids in the grinding process. However, none of these studies have tackled the problem of the unavoidable use of fluids in the auxiliary operation of wheel conditioning, known as dressing. Ecological and sustainable grinding technologies require advances in the removal of fluids in dressing. In this paper, a novel proposal for dry-dressing is presented. First, experimental work shows the need for effective cooling (as provided by grinding fluids) when dry-dressing is carried out. In this case, when using industrial steel tool-holders the temperature in the diamond tool can be over 973 K during dressing, leading to loss of mechanical properties and accelerated wear. It is proposed then to use copper in the tool holder instead of steel, so that the thermal conductivity can be largely improved. With this approach, temperatures in the diamond tool can be kept below 700 K (reduction of about 35%), increasing thus wear resistance. These findings have been confirmed by SEM observations and by measurements of dressing power consumption under different dressing conditions and wheel specifications. Thermal deformations in dry-dressing can be as much as 10 times higher than when cooling with conventional grinding fluids. It has been shown that thermally induced deformations can be kept below 2 μm by assisting the operation with a jet of cold air (253 K) obtained from a Vortex tube. This new approach of dry-dressing can be readily implemented at low cost in industrial grinding machines.

Investigation on Heat Transfer Performance of Heat Pipe Grinding Wheel in Dry Grinding

The use of fluid in grinding enhances heat exchange at the contact zone and reduces grinding temperature. However, the massive use of fluid can cause negative influences on environment and machining cost. In this paper, a novel method of reducing grinding temperature based on heat pipe technology is proposed. One new heat pipe grinding wheel and its heat transfer principle are briefly introduced. A heat transfer mathematical model is established to calculate equivalent thermal conductivity of heat pipe grinding wheel. Compared with the wheel without heat pipe, heat transfer effect of heat pipe grinding wheel is presented, and the influences of heat flux input, cooling condition, wheel speed, and liquid film thickness on heat transfer performance are investigated. Furthermore, dry grinding experiments with two different wheels are conducted to verify the cooling effectiveness on grinding temperature. The results show that thermal conductivity of the wheel with heat pipe can be greatly improved compared to the one without heat pipe; heat transfer performance of heat pipe grinding wheel can change with different grinding conditions; meanwhile, grinding temperatures can be significantly decreased by 50% in dry grinding compared with the wheel without heat pipe.

The effect of the grinding wheel modification on the state of the workpiece surface layer after internal cylindrical grinding of steel C45

Internal cylindrical grinding is one of the most difficult grinding processes due to the very long zone of contact between the grinding wheel and the workpiece surface. Such conditions limit delivery of the grinding fluid into the grinding zone, as well as impeding the removal of chips from it. As a result, during the internal cylindrical grinding process, difficult thermal conditions occur in the machining zone which finally could lead to grinding defects. One of the most efficient and cost-effective ways of improving the grinding stability and repeatability is modifying the grinding wheel structure. As such, modifications usually do not require interfering with the construction of the grinding machine or its equipment, they are universal and, possibly, widely applicable. This article presents a modified grinding wheel with helical grooves shaped on its active surface. Such modification was developed to reduce the thermal load of the workpiece surface and the occurrence of thermal defects. The effectiveness of the proposed grinding wheel modification was examined experimentally in the reciprocal circumferential internal cylindrical grinding process of 45C steel. The goal of the described tests was to determine the influence of the suggested grinding wheel modification on the condition of the workpiece surface layer (the surface roughness and residual stresses). The test results obtained indicated that application of the modified grinding wheel has a positive influence on the residual stresses in the workpiece surface layer, resulting in better delivery of the grinding fluid into the area of contact between the wheel and the machined material. Moreover, a decrease of the Ra parameter value by approximately 7–19%, as compared to the results of the process carried out with the (unmodified) reference grinding wheel was indicated.

Experimental investigation and modelling on air layer formation around a rotating grinding wheel

AbstractImpingement of grinding fluid deep into grinding zone is a challenge due to presence of air layer around the grinding wheel. This paper presents experimental observation on air boundary layer formed around a rotating grinding wheel, a rexine-cloth covered grinding wheel and a solid disc. The effect of porous and rough grinding wheel surface towards strengthening air boundary layer has been studied. Modelling has been done to estimate variation of air pressure within this boundary layer. Out of three different methods of extrapolation done, the most suitable one is suggested. Results obtained using three different wheels are compared. A scraper board is also employed to observe reduction of air pressure. Higher value of air pressure is noted in case of bare grinding wheel than that in other conditions. Use of scraper board along with rexine-covered wheel is found to reduce air pressure to a large extent such that it becomes close to air pressure noted around the solid wheel. It shows the beneficial...

Evaluation of Grinding Performance of Unsaturated Polyester Resin

Polyester resins are unsaturated resins formed by the reaction of dibasic organic acids and polyhydric alcohols. Polyester resins are being used in different mechanical and other industrial or household items. It also helps making Fibreglass Reinforced Plastics (FRP). Grinding of this unsaturated polyester resin is often needed, and hence, suitable process conditions are to be chosen to achieve desired grindability. In the present paper, grinding performance of unsaturated polyester resin with or without applying grinding fluid using an alumina wheel has been explored. Experimental observation shows fairly good grindability of this resin with alumina grinding wheel under wet condition and with less in feed in dry condition.

Determination of burn thresholds of precision gears in form grinding based on complex thermal modelling and Barkhausen noise measurements

Thermal damage control in high efficiency form grinding of precision gears is critical for obtaining the required gear surface integrity and ensuring the contact strength in service life. Complex thermal models have been developed to determine the variation of burn thresholds of power under different grinding parameters in form grinding mode of gears. The thermal models analyse in detail the variation of local contact geometry between the grinding wheel and gear surface, and the variation of heat partitioning to different thermal parts including the workpiece, wheel, grinding fluid and grinding chips. The burn thresholds of power in the form grinding of carbonised steel gears have been determined by relating the grinding temperature with the Barkhausen Noise and micro-hardness measurements for the ground surfaces. The models and the determined burn thresholds can be used for presetting the parameters and conditions of grinding process and monitoring the grinding process to avoid the occurrence of thermal damages to the gear surfaces.

Experimental study into the grinding force in surface grinding of steel CrV12 utilizing a zonal centrifugal coolant provision system

In order to efficiently remove heat from the machining zone, grinding fluids are used in the majority of grinding processes. Intensive cooling periods make it possible to efficiently influence the machining heat conditions, and through lubricating fluid components, limit the friction of active cutting vertices of unspecified geometry and a frequently negative rake angle. The obtained grinding results are considerably influenced by the amount of grinding fluid and the way it is delivered, which directly influences its effectiveness in reaching the zone of contact between the grinding wheel and the machined surface. The following article presents a new solution, as far as centrifugal grinding fluid delivery is concerned, through a special grinding wheel grip and the channels formed in it. Moreover, the system recommended here is also characterized by zonal grinding fluid delivery into the grinding wheel, which is aimed at additionally increasing the efficiency of grinding fluid delivery into the grinding zone. The results of tests evaluating the effect this system has upon grinding force values are presented. The reference methods employed in these tests were centrifugal grinding fluid delivery without zonal limitation, delivering grinding fluid using the flood method, as well as dry grinding. The results of the experiment showed that using the method recommended here enables the creation of conditions in the grinding zone similar to, or even more advantageous in certain conditions, than when delivering grinding fluid using the flood method. It also leads to a general reduction in grinding fluid expenditure by as much as 10 times.

Experimental evaluation of the lubrication properties of the wheel/workpiece interface in minimum quantity lubrication (MQL) grinding using different types of vegetable oils

Given the increasing attention to environmental and health problems caused by machining, the development of an environment-friendly grinding fluid has become an urgent task. As an environment-friendly grinding fluid, vegetable oil has gained considerable attention. In this study, seven typical vegetable oils (i.e., soybean, peanut, maize, rapeseed, palm, castor, and sunflower oil) were used as the minimum quantity lubrication (MQL) base oil to conduct an experimental evaluation of the friction properties of the grinding wheel/workpiece interface. With nickel-based alloy GH4169 as workpiece material, the flood grinding working condition and MQL grinding working condition (i.e., using the seven vegetable oils and paraffin oil) were selected. The evaluation of the lubrication property mainly referred to grinding force, friction coefficient, specific grinding energy, and grinding ratio (G-ratio), as well as surface morphology and surface roughness. Experimental results indicated that MQL grinding using vegetable oil achieved a lower friction coefficient, specific grinding energy, and grinding wheel wear than flood grinding. Among the grinding fluids, castor oil achieved the best lubrication property and the best surface quality of workpiece. Castor oil had a friction coefficient and specific grinding energy of 0.30 and 73.47 J/mm3, which decreased by 50.1% and 49.4%, respectively, compared with flood grinding. Moreover, various grinding fluids changed cutting forces through changes in their lubrication property and further changed G-ratio. However, lubrication property was one of factors that influenced the G-ratio. Maize oil had the highest G-ratio of 29.15. Peanut, sunflower, and soybean oil with more saturated fatty acids, castor oil with more castor acids, and palm oil with numerous palmitic acids were suitable as lubricating fluids.