Grinding Fluid Research Articles

Analysis of Chemical Oxygen Demand in Barrel Finishing Based on Reusing Water Resource of Grinding Fluid.

To explore the sustainable development of grinding fluid in barrel finishing, the idea of water resource reuse in grinding fluid has been proposed. The influence of the graphene oxide (GO) and the sodium dodecyl benzene sulfonate (SDBS) as main components in the grinding fluid on the chemical oxygen demand (COD) was analyzed. Repreparing new grinding fluids by utilizing the water resources in grinding fluid after finishing will not cause a sharp increase in COD value. GO which absorbs SDBS can be taken away from grinding fluid by physical separation. It will decrease the COD value of grinding fluid. However, SDBS exists in the form of colloids in the grinding fluid and cannot be removed through physical separation, which also affects the COD value. Based on water quality indicators (the COD, pH, total hardness, metal aluminum, anionic surfactants, and total dissolved solids), the water quality index (WQI) of the reusing grinding fluid after finishing by the physical separation is significantly reduced. It indicates that reusing water resources in grinding fluid is a feasible way to reuse grinding fluid.

Lubrication flow in grinding

In the machining process known as grinding, fluid is applied to regulate the temperature of the workpiece and reduce the risk of expensive thermal damage. The factors that influence the transport of this grinding fluid are not well understood; however, it is important to gain understanding in order to try to avoid the unnecessary cost incurred from its inefficient application. In this work, we use the method of matched asymptotic expansions to derive the multiscale system of equations that governs the flow. Under the lubrication approximation, we show that it is possible to calculate the flow rate through the grinding zone without having to solve for the flow far from the grinding zone. Additional empirically determined boundary conditions do not need to be imposed. With this lubrication model, we quantify the effect of experimental parameters on the flow field in the grinding zone and study how the flow regime responds to changes in these parameters.

Ultrasonic-Assisted Grinding of Microholes Using Ultrasmall-Diameter Cemented WC Tools

Although grinding is a widely employed method for hard and brittle materials, drilling microholes requires the use of an ultrasmall-diameter grinding wheel that is difficult to fabricate and breaks easily when grinding force is applied, resulting in a high tool cost. To solve this problem, cemented WC micropins were fabricated by electrical discharge machining, and microholes were drilled using them as micro-grinding tools with the assistance of ultrasonic oscillation. The micropin tools can be employed in grinding because the convex parts of the electrical discharge craters formed on their surfaces serve as cutting edges of abrasive grains in grinding wheels. To clarify the drilling conditions necessary for ultrasmall-diameter tools to drill holes with a diameter less than 5 µm, the relationships between drilling conditions and drilling characteristics were investigated. The drilling conditions included the tool rotation speed, tool feed speed, ultrasonic oscillation amplitude, and use of grinding fluid. The drilling characteristics included the hole diameter and grinding force evolution. The investigation showed that a high tool rotation speed prevented the increase in the grinding force because of the faster grinding speed. A low tool feed speed was favorable to lower grinding force. At a high tool feed speed, most likely, the tool was fed before the workpiece material was sufficiently removed, thereby exhibiting a large grinding force. The ultrasonic oscillation amplitude had no noticeable effect on the grinding force. The hole diameter was not affected by the tool rotation speed, tool feed speed, or ultrasonic oscillation amplitude. Although the use of grinding fluid reduced the grinding force, the hole diameter increased, probably because enhanced lubrication caused the tool to slip on the workpiece surface at the beginning of drilling, resulting in an increased rotational runout. Under the favorable conditions obtained, a hole of 3.2 µm in diameter was successfully drilled in crown glass.

Numerical Investigation Into Convective Heat Transfer Coefficient of the Grinding Fluid Used in a Deep Grinding Process

Numerical Investigation Into Convective Heat Transfer Coefficient of the Grinding Fluid Used in a Deep Grinding Process

Experimental analysis of chemical removal effect in RISA grinding of optical glass

In the large-aperture lens manufacturing, not only high surface quality but also high productivity is required. From this perspective, Reaction-Induced-Slurry-Assisted grinding (RISA grinding), in which cerium oxide slurry is supplied instead of using general grinding fluid, has been developed to achieve high surface quality at high removal rate. However, the surface profile error becomes large due to chemical removal effect of the cerium oxide slurry. Therefore, the purpose of this study is to experimentally investigate the influence of the chemical removal effect on the surface profile error using AE signals and servo current signals in RISA grinding. First, relation between dwell time and removal depth is analyzed by conducting a basic grinding test without the workpiece rotation. The result shows that the actual removal depth increases with increase of dwell time despite applying the constant depth of cut. Then, zero-cut RISA grinding test is conducted. It is found that the removal process proceeds even though zero-cut grinding, and its removal rate varies according to the wheel feed rate. Furthermore, the amount of cerium oxide abrasives adhered to the grinding wheel can be estimated from the AE signals and servo current signals.

Al<sub>2</sub>O<sub>3</sub> Nanofluids: An Experimental Study for MQL Grinding

In the course of grinding, conventional grinding fluid is frequently utilised, which leads to excessive consumption and negative environmental effects. MQL, or minimum quantity lubrication, is a possible replacement for traditional dry and fluid coolant application. It is well known that the MQL grinding process's effectiveness depends on the lubricating and cooling capabilities of fluid. A water-based Al2O3 nanofluid was used in this work to grind materials due to its outstanding convective heat transfer and thermal conductivity qualities. Hardened steel's grinding properties are examined and contrasted with those of MQL grinding done in wet, dry, and pure water. Al2O3 nanofluid MQL grinding using water dramatically lower the grinding temperatures, minimise grinding forces, and enhance the ground surface finish.

Analysis of Grinding Flow Field under Minimum Quantity Lubrication Condition

The flow field around the grinding wheel prevents grinding fluid from entering the grinding area, which deteriorates machining conditions and reduces the quality of the workpiece. MQL (Minimum Quantity Lubrication) grinding uses compressed gas to improve the ability of the grinding fluid to pass through the flow field of the grinding wheel so that a small amount of the grinding fluid can meet the cooling and lubrication requirements and reduce the cost of using grinding fluid. In this study, we investigated the flow field of grinding wheels under MQL conditions and obtain the rules that influence factors such as grinding fluid flow rate, grinding wheel linear speed and compressed gas pressure affect the flow rate of grinding fluid. The simulation method was used to simulate the flow field of the grinding wheel and the trajectory of the grinding fluid droplets. The simulation results show that these factors are important ones affecting the effective flow rate of grinding fluid. Meanwhile, the experimental results verify that these factors have the same influence pattern on the effective flow rate and grinding temperature.

Analysis of grinding fluid efficiency in double-sided grinding

Analysis of grinding fluid efficiency in double-sided grinding

Investigation of sustainability and performance of Ag-coated CuO cutting fluid in grinding of Inconel 738

Investigation of sustainability and performance of Ag-coated CuO cutting fluid in grinding of Inconel 738

Computational Fluid Dynamics of Useful Grinding Fluid Flow and Sensitivity Analysis of Grinding Parameters

In the grinding process, a high speed rotating grinding wheel develops a stiff air barrier around it. This air barrier restricts the flow of incoming grinding fluid through a nozzle jet into the grinding zone, and this leads to a considerable amount of grinding fluid being wasted. An insufficient amount of grinding fluid from the nozzle jet not reaching the grinding wheel-workpiece contact zone will result in many defects in the workpiece as well as in the grinding wheel. In this paper, a unique method of air scraper is modelled and simulated in order to impinge the grinding fluid maximum through a thick boundary layer around the periphery of the rotating grinding wheel and the effect of grinding parameters are analyzed and Ugff rate equation established using Box Behnken Design method.

Tribological Mechanism of Graphene and Ionic Liquid Mixed Fluid on Grinding Interface under Nanofluid Minimum Quantity Lubrication

Graphene has superhigh thermal conductivity up to 5000 W/(m·K), extremely thin thickness, superhigh mechanical strength and nano-lamellar structure with low interlayer shear strength, making it possess great potential in minimum quantity lubrication (MQL) grinding. Meanwhile, ionic liquids (ILs) have higher thermal conductivity and better thermal stability than vegetable oils, which are frequently used as MQL grinding fluids. And ILs have extremely low vapor pressure, thereby avoiding film boiling in grinding. These excellent properties make ILs also have immense potential in MQL grinding. However, the grinding performance of graphene and ionic liquid mixed fluid under nanofluid minimum quantity lubrication (NMQL), and its tribological mechanism on abrasive grain/workpiece grinding interface, are still unclear. This research firstly evaluates the grinding performance of graphene and ionic liquid mixed nanofluids (graphene/IL nanofluids) under NMQL experimentally. The evaluation shows that graphene/IL nanofluids can further strengthen both the cooling and lubricating performances compared with MQL grinding using ILs only. The specific grinding energy and grinding force ratio can be reduced by over 40% at grinding depth of 10 μm. Workpiece machined surface roughness can be decreased by over 10%, and grinding temperature can be lowered over 50 ℃ at grinding depth of 30 μm. Aiming at the unclear tribological mechanism of graphene/IL nanofluids, molecular dynamics simulations for abrasive grain/workpiece grinding interface are performed to explore the formation mechanism of physical adsorption film. The simulations show that the grinding interface is in a boundary lubrication state. IL molecules absorb in groove-like fractures on grain wear flat face to form boundary lubrication film, and graphene nanosheets can enter into the grinding interface to further decrease the contact area between abrasive grain and workpiece. Compared with MQL grinding, the average tangential grinding force of graphene/IL nanofluids can decrease up to 10.8%. The interlayer shear effect and low interlayer shear strength of graphene nanosheets are the principal causes of enhanced lubricating performance on the grinding interface. EDS and XPS analyses are further carried out to explore the formation mechanism of chemical reaction film. The analyses show that IL base fluid happens chemical reactions with workpiece material, producing FeF2, CrF3, and BN. The fresh machined surface of workpiece is oxidized by air, producing NiO, Cr2O3 and Fe2O3. The chemical reaction film is constituted by fluorides, nitrides and oxides together. The combined action of physical adsorption film and chemical reaction film make graphene/IL nanofluids obtain excellent grinding performance.

Synergistic Lubrication Mechanism of Nano-Fluid and Grinding Wheel Prepared by CNTs@T304 Nano-Capsules

Grinding fluid often struggles to enter the grinding area and overcoming this challenge has been a major focus of research in recent years. Therefore, CNTs@T304 nano-capsules are prepared by filling the cavities of CNTs with a lubricant of T304. CNTs@T304 nano-capsules were used as an additive in this paper to prepare resin grinding wheels and nanofluids, respectively. The resin wheels filled with nano-capsules were used for grinding under the lubrication of nanofluids, and T304 could then be released to the grinding area to play a self-lubricating role during grinding. First, CNTs@T304 nano-capsules were characterized, and the properties of the prepared grinding wheels and nanofluids were tested. Second, the effects of the filling of nano-capsules and grinding speed on the grinding force, grinding temperature, surface roughness, and grinding ratio were studied. Finally, the lubrication mechanism of the nano-capsules was revealed through surface analysis of the workpiece. The results suggested that nano-capsules had good thermal stability and the nanofluid prepared from them exhibited good dispersion stability and thermal conductivity. The grinding wheel was found to satisfy the service conditions when the filling content was less than 15%. Compared with a common wheel, the grinding force and grinding temperature were reduced by 24% and 28%, respectively, and the surface roughness of the workpiece and the grinding ratio were increased by 18% and by 21%, respectively, when grinding GCr15 steel with the nano-capsule wheel. Lubrication with nanofluids could further reduce the grinding force, grinding temperature, and surface roughness values. During grinding, the self-lubrication film formed by the T304 released from the nano-capsules in the wheel served first and foremost as a lubricant. The intervention of the nanofluid enhanced the heat-exchange effect and lubrication efficiency in the grinding zone.

Bearing Inner Ring Raceway Low-Temperature Aerosol Cooling Lubrication Grinding

A low-temperature aerosol cooling and lubrication grinding test bench was built to evaluate the cooling and lubrication performance of the low-temperature aerosol. The mechanism of grinding residual stresses in the inner ring raceway under the coupling effect of grinding force and grinding heat was studied, and the effects of the grinding process parameters and cooling and lubrication conditions on the distribution state of the grinding residual stresses in the surface layer of the inner ring raceway were revealed. The results showed that reducing the initial temperature of the grinding fluid could reduce the residual tensile stresses on the raceway surface. The results also showed that the low-temperature aerosol cooling lubrication method is conducive to the generation of the axial residual compressive stress of −500 MPa and tangential residual compressive stress of −300 MPa in the inner ring raceway surface layer of the bearing. Compared with the convective heat transfer coefficient, the effect of the initial temperature of the grinding fluid is smaller.

Temperature field responses to face gear grinding conditions based on a comprehensive force–thermal model

Previous works on the thermal modelling for face gear grinding usually used Hertzian contact theory and ignored the material removal mechanism. By contrast, a comprehensive force–thermal model was founded on the wheel–gear geometry and material mechanism for economical and efficient prediction of grinding temperature field in this work. In the process of grinding face gear, a force model was established on the basis of single-grain model under the action of grinding fluid. The temperature analytical model for face gear was derived considering the contribution of the cross-sectional area of the undeformed chip thickness to the heat flux. Moreover, energy partition ratio to workpiece was optimized by applied the idea of averaging to solving formulas. The temperature field responses to different grinding conditions were simulated and investigated. The aftereffect of grinding parameters on the temperature fields on the tooth surface and the reason for variations in the grinding temperature to different grinding positions of face gear was analysed. The experimental results with newly measurement method are highly consistent with the simulation results with the error of −6.10% to −13.69%, thereby validating the proposed model. This work provides theoretical support for obtaining a uniform grinding temperature during grinding face gear and to obtain a high tooth surface integrity.

Study on Characteristics of Two Phase Flow Field in Grinding Zone of Large Spiral Angle Groove Wheel

Aiming at the high specific removal energy and heat generation rate in grinding process, and the low heat transfer efficiency in grinding arc zone of ordinary grinding wheel, the problems of local high temperature and grinding burn are easy to occur. In this paper, the plane grinding of grooving wheel with large spiral Angle is taken as the research object, and the numerical analysis model of gas-liquid two-phase flow field in wedge zone and grinding arc zone is established. The enhancement mechanism of heat transfer performance in grinding arc of large spiral Angle groove wheel was investigated. The results show that the flow of grinding fluid into the grinding arc will be hindered by the airflow around the grinding wheel, resulting in backflow and side leakage. Compared with ordinary grinding wheels without grooves, the backflow and side drainage in grinding zone of big spiral Angle grooves grinding wheels are significantly reduced, and a large amount of grinding fluid is transported in the heat exchange channel. The spiral groove has a good conduction effect on the grinding fluid, and the grinding fluid is easier to enter the grinding zone, thus significantly improving the heat transfer performance of the grinding zone and effectively reducing the grinding temperature during the grinding process.

Effect of grinding conditions of gears made of 20MnCr5 steel after single-piece flow heat treatment on the condition of the surface layer of the tooth working surface

The paper investigated the effect of selected processing conditions during gear grinding on the value and distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment (TCT) conducted by a continuous single-piece flow method.The gears were carburised with LPC at 920C, then quenched in a 4D Quenching chamber at 7 bar and tempered at 190C for 3 hours. In the next step, the working surfaces of the gear teeth were ground by supplying grinding fluid (GF) to the grinding zone using the WET method and the MQL method with a minimum amount. Measurements were made on the distribution of microhardness and residual stress formed in the technological surface layer of gears after thermochemical treatment and after the grinding process.The results of the study showed the influence of workpiece speed vw and the method of delivery to the grinding zone GF on selected parameters describing the condition of the technological surface layer of the teeth of gears made of 20MnCr5 steel. The grinding process with a white aluminium oxide grinding wheel causes deterioration in the material's residual stress state. For each of the three analysed workpiece speeds vw, smaller changes in microhardness with respect to the microhardness of the material before grinding occur in the surface layer of samples ground with GF fed with the MQL method. Similarly, residual stress values are in the area of favourable compressive stresses.Environmental considerations and the need to comply with increasingly stringent environmental protection and worker safety regulations are pushing researchers and entrepreneurs to completely eliminate or reduce the consumption of grinding fluids in the grinding process. Based on the research and analysis carried out in this study, it was concluded that applying minimum GF by the MQL method could be an alternative to the conventional WET method.In sustainable manufacturing, it is extremely important to produce high-quality items while reducing the cost of manufacturing and taking care of the environment and workers' health. This includes the manufacture of gears, a basic component used in gear transmissions in the automotive industry, for example. The research has established that it is possible to use the MQL method, which reduces the amount of GF used when grinding the working surfaces of gear teeth, as an alternative to the conventional WET method.The conducted research was the first to determine the most favourable conditions, in terms of the obtained residual stresses and microhardness, for grinding the working surface of gear teeth using the MQL method.

An internal cooling grinding wheel: From design to application

The cooling and lubrication conditions during the grinding process significantly impact the nickel-based superalloy's final service performance. The existing jet cooling and heat pipe technology can solve the heat conduction problem in the grinding process of superalloy. Still, managing cooling, lubrication, and chip removal are difficult. This paper describes the design and fabrication of a novel central fluid-through internal cooling slotted grinding wheel with an ordered grain pattern to improve the grinding machinability of a nickel-based superalloy. The pressurized grinding fluid was ejected into the grinding zone via the pipe and tool holder from the lower-end face of the inner cooling wheel. The structure of the grinding wheel was optimized using computational fluid dynamics (CFD). The flow field in the grinding area achieved the highest overall flow rate, distribution homogeneity, and effective exit flow when the internal flow channel had four through-holes. The exit for the inner runner is located at the abrasive edge and diamond staggered pattern. Single-layer brazing was used to create cubic boron nitride (CBN) abrasive rings with various abrasive patterns. The internal cooling wheel matrix and various components were prepared according to the optimized grinding wheel geometry model. A grinding test bench was built to conduct an experimental study of grinding the nickel-based alloy GH4169. The results show that, under the same conditions, a diamond-shaped staggered pattern obtains lower grinding temperature, lower surface roughness, better surface morphology, and more significant residual compressive stress distribution than an abrasive cluster diagonal circular staggered pattern or disordered pattern. The average effective flow rate calculated by CFD is increased by 42.3% when compared to the disordered pattern. In the experiment, compared to the disordered arrangement, with the increase of grinding wheel’s rotating speed and coolant pressure, the average grinding temperature of abrasive grain with diamond-interleaved arrangement decreases by 58.2% and 51.7% respectively, and its surface hardening degree decreases by 11.1% and 11.7% respectively.

Parameter optimization and prediction of surface roughness in grinding using CNSL as a cutting fluid

Surface grinding is one of the versatile processes in manufacturing, performed to achieve a smooth finish and close tolerance. The process is associated with high temperatures which influence the workpiece surface integrity, surface finish, and dimensional delicacy because of complex thermal stresses and thermal deformation of the workpiece. The usage of a cutting fluid becomes inevitable to address these problems.Cashew nut shell oil is a non-edible vegetable oil that is eco-friendly and possesses some potential properties required for cutting fluid. In this study, cashew nut shell oil is tried as a cutting fluid and its performance is compared with the traditional synthetic cutting fluid in surface grinding of EN8 material. The cutting parameters with two levels considered are the type of cutting fluid, grinding wheel speed, grinding wheel grade, depth of cut, and workpiece speed with the surface roughness or finish as the output response. The design of experiments has been carried out using the factorial method to analyze the effects of factors on the response. Parameter optimization has been done to get the optimum cutting parameters for minimum surface roughness. A model for predicting surface roughness has been proposed and the optimum cutting parameters for minimum surface roughness have been obtained. Also, validation experiments have been performed at an optimal condition and selected three conditions to prove the proposed model’s accuracy and confirm the potentiality of the cashew nut shell oil as a cutting fluid. The results show that the performance of cashew nut shell oil as a cutting fluid is better as compared to the conventional synthetic cutting fluid in obtaining a better surface finish.

Influence of nano-minimum quantity lubrication with MoS2 and CuO nanoparticles on cutting forces and surface roughness during grinding of AISI D2 steel

Environmental side effects of machining lubricants are the main reasons for the progressive development of utilizing the minimum quantity lubrication (MQL) method instead of conventional methods. Owing to the high specific energy of cutting and generation of more heat in grinding, the MQL technique has a lower efficiency than conventional methods. However, by adding nanoparticles to the base oil, the lubrication efficiency in grinding can be enhanced. In this research, grinding of cold work tool steel AISI D2 was studied using a MQL technique by adding MoS2 and CuO nanoparticles to two types of vegetable-based oils: colza and soybean with different concentration percentages, and their effects were examined on the cutting forces (normal and tangential forces) and surface roughness. The results indicated that the values of normal force and tangential forces diminished by 19 and 35 % when using CuO nano powder in soybean base oil with a concentration of 4 % and MoS2 nano powder in soybean base oil with a concentration of 2 %, respectively. Furthermore, when using CuO nano powder in colza base oil and with a concentration of 2 %, the surface roughness had a significant reduction of 77 % in comparison with pure oil as a grinding fluid.

Enhancing useful flow of cutting fluid and thermal performance in surface grinding via segmented wheel

Cutting temperature is reported to be a serious concern while grinding aerospace materials such as titanium alloy Ti6Al4V, which is having very low thermal conductivity. Segmented wheels designed with active abrasive regions and passive non-cutting slots have been proposed as a potential solution for thermal management in the grinding zone. Reduced accumulation of heat due to intermittency in cutting and enhanced dissipation through passive slots could exhibit improved temperature control even at dry grinding conditions. As the number of segments increased, the grinding force was significantly reduced for Ti6Al4V. Under the wet cutting condition, the segmented wheel could facilitate a more effective flow of cutting fluid into the passive slots, which is referred to as useful flow. However, there was a trade-off set by the number of segments, where an eight-segmented wheel showed superior thermal performance in comparison with the 32-segmented wheel. The reasoning of the same in terms of useful flow patterns and boundary layer thickness has been attempted in this paper.