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).

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 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.

scholarly journals Morphology of Near- and Semispherical Melted Chips after the Grinding Processes Using Sol-Gel Abrasives Based on SEM-Imaging and Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
W. Kapłonek ◽  
K. Nadolny ◽  
W. Habrat
Keyword(s):  
Sol Gel ◽  
Machining Process ◽  
Grinding Wheel ◽  
Geometrical Parameters ◽  
Grinding Process ◽  
Sintered Corundum ◽  
Internal Cylindrical Grinding ◽  
Sem Imaging ◽  
Titanium Grade ◽  
Process Observation

Selected issues related to SEM-imaging and image analysis of spherical melted chips formed during the grinding process are presented and discussed. The general characteristics of this specific group of machining products are given. Chip formation phenomena, as well as their overall morphology, are presented using selected examples of near- and semispherical melted chips occurring singly or concentrated in clusters on the grinding wheel surface after the machining process. Observation of the spherical melted chips and acquisition of their images were carried out for grinding wheel active surfaces with microcrystalline sintered corundum abrasive grains SG™after the internal cylindrical grinding process of a 100Cr6 steel and Titanium Grade 2® alloy by use of a scanning electron microscope, JEOL JSM-5500LV. Analysis of the obtained SEM micrographs was carried out by Image-Pro® Plus 5.0 software to determine the selected geometrical parameters describing the morphological features of the assessed chips.

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.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
High Speed ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Edge Contact ◽  
Cylindrical Grinding ◽  
Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

scholarly journals Internal Cylindrical Grinding Process of INCONEL® Alloy 600 Using Grinding Wheels with Sol–Gel Alumina and a Synthetic Organosilicon Polymer-Based Impregnate

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 115 ◽  
Author(s):  
Wojciech Kapłonek ◽  
Krzysztof Nadolny ◽  
Krzysztof Rokosz ◽  
Jocelyne Marciano ◽  
Mozammel Mia ◽  
...  
Keyword(s):  
Sol Gel ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Alloy 600 ◽  
Abrasive Tool ◽  
Grinding Wheels ◽  
Impregnation Process ◽  
Organosilicon Polymer ◽  
Internal Cylindrical Grinding ◽  
Abrasive Tools

The development of modern jet engines would not be possible without dynamically developed nickel–chromium-based superalloys, such as INCONEL® The effective abrasive machining of above materials brings with it many problems and challenges, such as intensive clogging of the grinding wheel active surface (GWAS). This extremely unfavorable effect causes a reduction in the cutting ability of the abrasive tool as well as increase to grinding forces and friction in the whole process. The authors of this work demonstrate that introduction of a synthetic organosilicon polymer-based impregnating substance to the GWAS can significantly improve the effects of carrying out the abrasive process of hard-to-cut materials. Experimental studies were carried out on a set of a silicon-treated small-sized sol–gel alumina 1-35×10×10-SG/F46G10VTO grinding wheels. The set contained abrasive tools after the internal cylindrical grinding process of INCONEL® alloy 600 rings and reference abrasive tools. The condition of the GWAS after the impregnation process was studied, including imaging and measurements of its microgeometry using confocal laser scanning microscopy (CLSM), microanalysis of its elemental distribution using energy dispersive X-ray fluorescence (EDXRF), and the influence of impregnation process on the grinding temperature using infrared thermography (IRT). 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 recommended characteristic. The main favorable features of treated grinding wheel concerning the reduction of adhesion between the GWAS and grinding process products (limitation of the clogging phenomenon) as well as reduction of friction in the grinding process, which has a positive effect on the thermal conditions in the grinding zone.

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

2016 ◽  
Vol 231 (4) ◽  
pp. 813-823 ◽  
Author(s):  
Krzysztof Nadolny ◽  
Witold Habrat
Keyword(s):  
Cubic Boron Nitride ◽  
Positive Influence ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Structural Modifications ◽  
Synthetic Diamonds ◽  
Wide Range ◽  
Internal Cylindrical Grinding ◽  
Different Diameters

This article offers an overview of 11 grinding wheel construction modifications used in the peripheral grinding of flat, shaped, internal, and external cylindrical surfaces, when grinding wheels made of superabrasive grains are used (natural and synthetic diamonds, as well as mono- and microcrystalline cubic boron nitride). The text contains characteristics of grinding wheels with: bubble corundum grains, glass-crystalline bond, conic chamfer, zones of different diameters, a centrifugal provision of the coolant into the grinding zone, aggregate grains, zone-diversified structure, as well as impregnated (self-lubricating), multiporous, segment and “intelligent” grinding wheels. Each of the presented structural modifications were 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 allow for their proper selection depending on the required criteria of effective evaluation and taking into account the specific characteristics of superabrasive 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.

Optimization and Application of Laser-Dressed cBN Grinding Wheels

2016 ◽  
Vol 1136 ◽  
pp. 90-96 ◽  
Author(s):  
Ali Zahedi ◽  
Bahman Azarhoushang ◽  
Javad Akbari
Keyword(s):  
Environmental Concerns ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Average Roughness ◽  
Cylindrical Grinding ◽  
Laser Dressing ◽  
Dressing Tool ◽  
Cbn Grinding Wheel ◽  
Spindle Power

Laser-dressing has been shown to be a promising method for overcoming some shortcomings of the conventional methods such as high wear of the dressing tool and its environmental concerns, high induced damage to the grinding wheel, low form flexibility and low speed. In this study, a resin bonded cBN grinding wheel has been dressed with a picosecond Yb:YAG laser. The efficiency of the laser-dressed grinding wheels has been compared with the conventionally dressed and sharpened grinding wheels through execution of cylindrical grinding tests on a steel workpiece (100Cr6). The conventional dressing and sharpening processes have been performed by using a vitrified SiC wheel and vitrified alumina blocks, respectively. By recording the spindle power values along with the surface topography measurements of the ground workpieces and the extraction of two roughness parameters (the average roughness Ra and the average roughness depth Rz), it is possible to provide an assessment of the cylindrical grinding process with different dressing conditions i.e. laser-dressing and conventional dressing. Accordingly, a strategy will be proposed to optimize the cylindrical grinding process with laser-dressed wheels regarding the forces and roughness values.

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