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

2016 ◽  
Vol 231 (6) ◽  
pp. 1162-1173 ◽  
Author(s):  
Ryszard Wójcik ◽  
Krzysztof Nadolny
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Thermal Conditions ◽  
Active Surface ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Workpiece Surface ◽  
Cylindrical Grinding ◽  
Grinding Fluid ◽  
Internal Cylindrical Grinding

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.

scholarly journals Experimental Studies on MoS2-Treated Grinding Wheel Active Surface Condition after High-Efficiency Internal Cylindrical Grinding Process of INCONEL® Alloy 718

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 255 ◽  
Author(s):  
Kapłonek ◽  
Nadolny ◽  
Sutowska ◽  
Mia ◽  
Pimenov ◽  
...  
Keyword(s):  
High Efficiency ◽  
Surface Condition ◽  
Experimental Studies ◽  
Active Surface ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Abrasive Tool ◽  
Alloy 718 ◽  
Cylindrical Grinding ◽  
Internal Cylindrical Grinding

This work demonstrates that molybdenum disulfide can be successfully used as an impregnating substance that is introduced in the abrasive tool structure for improving its cutting properties and favorably affecting the effects of the abrasive process. For the experimental studies, a set of MoS2-treated small-sized grinding wheels with a technical designation 1-35×10×10×109A5X60L10VE0 PI-50 before and after the reciprocating internal cylindrical grinding process of rings made from INCONEL® alloy 718 was prepared. The condition of grinding wheel active surface was analyzed using an advanced observation measurement system based on stylus/optical profilometry, as well as confocal and electron microscopy. The obtained results confirmed the correctness of introduction of the impregnating substance into the grinding wheel structure, and it was possible to obtain an abrasive tool with a given characteristic.

A New Analytical Model of Heat Flux Distribution to Compute Residual Stresses in the Case of External Cylindrical Grinding Process

2012 ◽  
Vol 445 ◽  
pp. 125-130 ◽  
Author(s):  
Haifa Sallem ◽  
Hédi Hamdi
Keyword(s):  
Heat Flux ◽  
Residual Stresses ◽  
Metal Cutting ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Near Surface ◽  
Workpiece Surface ◽  
Cylindrical Grinding ◽  
Cutting Processes ◽  
External Cylindrical Grinding

Grinding process is an energy intensive process in the sense that, it requires a larger amount of energy per unit of volume of material removal compared to other metal cutting processes. In this case, effects on the ground workpiece in terms of induced residual stresses and metallurgical changes due to heat generated play an important role on the lifetime of parts in their mechanism. In order to investigate effects on the workpiece during external cylindrical grinding process, a new analytical approach is firstly developed to model the action of the grinding wheel as a heat flux, which moves along the workpiece surface. The value and the shape of the heat flux entering the workpiece are directly identified. Based on the established model, numerical simulations are performed to predict temperature, cooling and its effects on residual stress distribution in the ground near surface.

scholarly journals Simulation Studies on Centrifugal MQL-CCA Method of Applying Coolant during Internal Cylindrical Grinding Process

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2506
Author(s):  
Seweryn Kieraś ◽  
Marek Jakubowski ◽  
Krzysztof Nadolny
Keyword(s):  
Coolant Flow ◽  
Grinding Wheel ◽  
Geometrical Parameters ◽  
Grinding Process ◽  
Simulation Studies ◽  
Cylindrical Grinding ◽  
Supply Line ◽  
Air Gun ◽  
Internal Cylindrical Grinding ◽  
Cooling And Lubrication

This paper describes simulation studies regarding the application of the centrifugal minimum quantity lubrication (MQL) method simultaneously with the delivery of a compressed cooled air (CCA) stream in the internal cylindrical grinding process. The idea of a new hybrid cooling and lubrication method connecting centrifugal (through a grinding wheel) lubrication by MQL with a CCA stream is described. The methodology of computational fluid dynamics (CFD) simulation studies, as well as the results of numerical simulations, are presented in detail. The aim of the simulations was to determine the most favourable geometrical and kinematic parameters of the system in the context of air-oil aerosol and CCA flow, as well as heat exchange. In the simulation, the variables were the grinding arbor geometrical parameters, the angle of CCA supply line outlets, and the grinding wheel and workpiece peripheral speed. As a result of the simulation studies, the most favourable geometrical parameters were designated, determining the orientation of the ends of the two CCA supply line outlets before and after the grinding zone, the number of openings in the drilled-out grinding arbor, and the influence of the grinding speed on the parameters of the coolant flow and temperature of objects in the grinding zone. In addition, the results of simulation tests made it possible to visualise the velocity vectors of the two-phase coolant flow in a complex system of air-oil aerosol delivery centrifugally through an open structure of a very fast rotating porous layer (grinding wheel), with an additional supply of CCA using an external cold air gun (CAG).

Investigation of Grinding Fluid Supply Parameters on Workpiece Surface Integrity

2014 ◽  
Vol 1017 ◽  
pp. 458-463
Author(s):  
Shi Chao Xiu ◽  
Xiu Ming Zhang ◽  
Ang Jiang ◽  
Xiao Liang Shi ◽  
Shu Jun Li ◽  
...  
Keyword(s):  
Surface Integrity ◽  
Flow Model ◽  
Fluid Distribution ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Two Phase ◽  
Workpiece Surface ◽  
Grinding Fluid ◽  
Parameters Selection ◽  
Fluid Supply

The grinding heat directly affected workpiece surface in the grinding process and it might produce some defects such as crack and burn. Meanwhile wear debris generated in the grinding process could easily embed grinding wheel blowhole and caused clogging and passivation. So it was particular important to avoid defects and improve the grinding workpiece surface integrity effectively. This paper established an incompressible turbulent fluid spray model based on the study of the existing airflow and the grinding fluid distribution in the grinding zone. Then according to different grinding fluid supply parameters established the two-phase gas liquid spray flow model by using CFD(computational fluid dynamics), simulated and calculated the model, compared the mass flow rate of the grinding fluid flow field with different spray distances, heights, speeds and spray angles in the grinding zone and determined the most reasonable spraying jet position. At the last, through researching on the workpiece surface integrity experiment, it provided an experimental basis to determine the most suitable spray jet position and verify the rationality of supply parameters selection.

The effect of active surface morphology of grinding wheel with zone-diversified structure on the form of chips in traverse internal cylindrical grinding of 100Cr6 steel

2016 ◽  
Vol 232 (6) ◽  
pp. 965-978 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Wojciech Kapłonek ◽  
Grzegorz Królczyk ◽  
Nicolae Ungureanu
Keyword(s):  
Surface Morphology ◽  
Active Surface ◽  
Experimental Investigations ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Electron Microscopic ◽  
Cylindrical Grinding ◽  
Scanning Electron Microscopic ◽  
Internal Cylindrical Grinding ◽  
Traverse Grinding

The article presents the results of experimental investigations to determine the effect of active surface morphology of grinding wheels with a zone-diversified structure on the form and size of chips generated during traverse internal cylindrical grinding of 100Cr6 steel. In the grinding process involving grinding wheels with a zone-diversified structure, chip formation phenomena differ in the rough and finish grinding zones of the tool. In order to expand one’s knowledge of this phenomena, the microtopography measurements of the grinding wheel active surface in the rough and finish grinding zones were made, as well as scanning electron microscopic observations of these areas after the dressing cut and following internal cylindrical traverse grinding. The conducted studies showed that chips in the rough grinding zone of the grinding wheel active surface are usually several hundred micrometers in length. In the finish grinding zone, however, mainly micro-chips were generated whose length does not exceed 100 µm (usually around 10 µm in length). In the rough grinding zone, shearing-type and flowing-type chips dominate with a few examples of spherical melted chips. Moreover, in the finish grinding zone, mainly slice-type and knife-type micro-chips were observed.

Potential for improving efficiency of the internal cylindrical grinding process by modification of the grinding wheel structure—Part I: Grinding wheels made of conventional abrasive grains

2016 ◽  
Vol 231 (4) ◽  
pp. 621-632 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Witold Habrat
Keyword(s):  
Sol Gel ◽  
Active Surface ◽  
Positive Influence ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Abrasive Grains ◽  
Wide Range ◽  
Internal Cylindrical Grinding ◽  
Different Diameters

This article offers an overview of 14 grinding wheel construction modifications used in the peripheral grinding of flat-shaped internal and external cylindrical surfaces, when grinding wheels made of conventional abrasive grains are used (Al2O3, sol-gel alumina, SiC, etc.). The text contains characteristics of grinding wheels with mixed grains, glass-crystalline bond, a centrifugal provision of the coolant into the grinding zone, aggregate grains, zones of different diameters, radial rough grinding zone, extended finish grinding segments, active surface macro- and micro-discontinuities, as well as multiporous, impregnated (self-lubricating), sandwich, sectional and segment grinding wheels. Each of the presented structural modifications was described by giving construction scheme, used abrasive grains, range of applications, advantages as well as disadvantages. Modifications of the grinding wheel construction allow for effective improvement of both the conditions and the results of the grinding process. A wide range of the known modifications allows for their proper selection depending on the required criteria of effective evaluation and taking into account the specific characteristics of conventional abrasive grains. As a result, it is possible to obtain positive influence on a number of technological factors of the grinding process. The described modifications of the grinding wheel structure can be also an inspiration and the basis for creating new solutions in this field.

scholarly journals Experimental Studies on the Centrifugal MQL-CCA Method of Applying Coolant during the Internal Cylindrical Grinding Process

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2383 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Seweryn Kieraś
Keyword(s):  
Hybrid Method ◽  
Experimental Studies ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Cylindrical Grinding ◽  
Minimum Quantity ◽  
Dry Grinding ◽  
Internal Cylindrical Grinding ◽  
Cooling And Lubrication

This paper presents the results of experimental research concerning the possibility of supporting the cooling function during internal cylindrical grinding using the minimum quantity lubrication (MQL) method by additional delivery of a compressed cooled air (CCL) stream. The article presents a description of a hybrid method of cooling and lubrication of the grinding zone integrating centrifugal (through a grinding wheel) lubrication with the minimum quantity of lubricant and cooling with a compressed cooled air stream generated by a cold air gun (CAG). The methodology and results of experimental studies are also presented in detail, with the aim of determining the influence of the application of the hybrid method of cooling and lubrication of the machining zone on the course and results of the internal cylindrical grinding process of 100Cr6 steel in comparison with other methods of cooling and lubrication, as well as compared with dry grinding. The research results obtained using the described hybrid method of cooling and lubrication of the grinding zone are related to the results obtained under the conditions of centrifugal MQL method, cooling with a stream of CCA, cooling and lubrication with a stream of oil-in-water emulsion delivered using the flood method, and dry grinding. The efficiency of the grinding process is evaluated (based on the average grinding power Pav, grinding wheel volumetric wear Vs, material removal Vw, and grinding ratio G), along with the thermal conditions of the process (based on the analysis of thermograms recorded by infrared thermal imaging method), the textures of machined surfaces (based on microtopography measured by contact profilometry), the state of residual stress in the surface layers of workpieces (determined by X-ray diffraction method), and the state of the grinding wheels’ active surfaces after grinding (based on microtopography measured by laser triangulation and images recorded with a digital measuring microscope). The obtained results of the analyses show that the application of the hybrid method allows for the longest wheel life among the five compared grinding methods, which is about 2.7 times the life of grinding wheels working under the flood cooling and centrifugal MQL methods, and as much as 8 times the life of grinding wheels working under the conditions of CCA only and dry grinding.

scholarly journals Modeling and experimental analysis of wheel-work interface in the cylindrical plunge grinding process

2014 ◽  
Vol 3 (4) ◽  
pp. 484
Author(s):  
Tarik Tawfeek
Keyword(s):  
Contact Stiffness ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Plunge Grinding ◽  
Workpiece Surface ◽  
Roundness Error ◽  
Cylindrical Grinding ◽  
Grinding Processes ◽  
Proposed Model ◽  
Grinding Machine

This paper presents a study of grinding wheel-workpiece interference in external cylindrical plunge grinding processes. This is to study the effect of workpiece surface memory on the workpiece roundness error after grinding. The study has been carried out theoretically on a model simulating cylindrical grinding process. The model takes contact stiffness, grinding wheel and workpiece wear into consideration. The proposed model was sued to predict the normal grinding forces in cylindrical grinding as a function of the previous height and number of waves of the initial profile.The new model has been validated by conducting experiments on a cylindrical grinding machine. Results indicate that the proposed model shows a good agreement with the experimental data obtained.The results of experiments indicate that the proposed modeling method is both feasible and reliable. The results showed that the theoretical model was effective studying the output of cylindrical grinding process. Normal grinding force, vibration level, and roundness error in cylindrical plunge grinding processes are dependent on the workpiece surface memory. Keywords: Plunge Grinding, Modeling, Roundness Error, Surface Memory.

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