Flat Surface Grinding Research Articles

Improvement of steel alloys using indirect cooling grinding (I.C.G.)

Appropriate choice of machining conditions contributes directly to improved performance of the machining process. Cooling and lubricating the grinding surface in the machining process has been done using different methods, but each method has its own disadvantages. A new cooling system is proposed in this research to improve the surface roughness in flat-surface grinding. The workpiece is cooled using a mixture of water and antifreeze as a coolant, without directly contacting the cutting tool. The temperature of the workpiece surface remains fixed, and grinding of the workpiece is performed. This novel method has several benefits including no oxidation of workpiece and tool surfaces, no surface hardening from rapid cooling, no chip addition to the coolant, and extended grinding capabilities without replacement. The proposed methodology was tested on four steel alloys, including hot-worked and cold-worked steel, as well as two improved alloys. The tests involved changing various parameters such as the depth of cut, surface temperature, and coolant flow-rate, to analyze how they affected surface roughness. According to the results, the proposed method was remarkably efficient for low-chromium steel alloys. The best surface roughness was obtained using the indirect cooling system for the 1.1191 steel alloy (an improved steel alloy). In general, better results (lower roughness at higher cutting depth) were achieved at higher coolant flow-rates.

Effects of thermo-chemical treatment and grinding process of external cylindrical surfaces on residual stresses in 13CrMo4-5 steel

This paper presents a study aimed at determining the effect of the carburizing treatment process and the subsequent grinding process on the residual stresses occurring in ring-shaped specimens made of 13CrMo4-5 steel.During the tests, vacuum carburizing was used, achieving an effective case depth ECD = 0.5 mm. Subsequently, the cylindrical outer surfaces of the samples were ground by conventional plunge grinding and with innovative kinematics using a test stand based on a conventional flat-surface grinding machine. As part of the study, microhardness and residual stresses were measured before and after grinding. Measurements were carried out to a depth of 1 mm. The main component of the stand is an original special device that allows the cylindrical specimen to be clamped. Then the angle between its axis of rotation and the axis of rotation of the grinding wheel is set with respect to the plane of the grinding machine’s magnetic table. In the described tests, the axis of rotation of the cylindrical specimen was deviated from its original position by 15 and set at an angle of 75 to the axis of rotation of the grinding wheel. The specimens were ground with a grinding wheel of noble electro-corundum marked 38A60K8V. In both kinematic cases of the grinding process, a machining allowance of 0.01 mm was removed.Grinding using innovative kinematics did not cause any significant changes in the microhardness distribution, either for vacuum or conventional carburizing. In addition, residual stress measurements using the Dawidenkov-Sachs method showed that innovative grinding enables a more favourable distribution than those obtained after conventional plunge grinding.Further research will focus on, among others, selecting the angular settings of the workpiece axes relative to the grinding wheel axes depending on their dimensions. Grinding guidelines should include coverage ratio, infeed value, grinding time, and peripheral speeds. In addition, the plan for future research includes measuring the components of the grinding force and the geometric structure of the surface.Grinding process is a crucial stage of steel treatment in almost every industrial branch. 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.The proposed test stand, together with the authors’ device, makes it possible to conduct machining of the external surfaces of cylindrical workpieces on a flat surface grinder. In this case, the innovation of the grinding process consists of the non-parallel alignment of the cylindrical rotational axis of the specimen and the rotational axis of the grinding wheel with respect to the plane of the magnetic grinding table.

Force modeling for 2D freeform grinding with infinitesimal method

A universal method of grinding force modeling in arbitrary 2D freeform grinding is proposed, which is based on the infinitesimal approach. The main idea of this method is to discretize the freeform surface into a group of surfaces with very small widths along the profile of the surface cross section, which can be considered as flat surfaces inclined at different angles. The form grinding process can be considered as a series of inclined flat surface grinding, where the normal grinding force of each flat inclined surface is divided into portions along specific directions. The process of inclined flat surface grinding at certain angle is equivalently converted to flat surface grinding in terms of the same abrasive wheel peripheral velocity and workpiece velocity but different cutting depth and contacting curvature in inclined view plane. A mathematical model of grinding force in flat surface grinding (FSG) is established, where the sliding stage, plowing stage and chip formation stage are considered respectively with 9 coefficients which are determined with linear regression from the grinding experiments. The forces in form grinding are then obtained by summing the individual inclined surfaces grinding forces, which are verified via rail form grinding (RFG). The algorithm was validated by means of the grinding experiments with average relative percentage errors of 6.08% and 7.01% respectively on tangential grinding force and normal grinding force in FSG and average relative percentage errors of 8.47% and 10.37% respectively on longitudinal grinding force and vertical grinding force in RFG.

Relationship between Pressure and Output Parameters in Belt Grinding of Steels and Nickel Alloy.

Belt grinding of flat surfaces of typical parts made of steel and alloys, such as grooves, shoulders, ends, and long workpieces, is a good alternative to milling. Several factors can influence the belt grinding process of flat surfaces of metals, such as cutting speed and pressure. In this work, the importance of pressure in the belt grinding was investigated in terms of technological and experimental aspects. The grinding experiments were performed on structural alloy steel 30KhGSN2/30KhGSNA, structural carbon steel AISI 1045, corrosion-resistant and heat-resistant stainless steel AISI 321, and heat-resistant nickel alloy KHN77TYuR. The performance of the grinding belt was investigated in terms of surface roughness, material removal rate (MRR), grinding belt wear, performance index. Estimated indicators of the belt grinding process were developed: cutting ability; reduced cutting ability for belt grinding of steels and heat-resistant alloy. It was found that with an increase in pressure p, the surface roughness of the processed surface Ra decreased while the tool wear and MRR increased. With a decrease in plasticity and difficulty of machinability, the roughness, material removal rate, reduced cutting capacity (Performance index) , material removal decreased, and the tool wear increased. The obtained research results can be used by technologists when creating belt grinding operations for steels and alloys to ensure the required performance is met.

Design and Fabrication of a Multinomial Model for Machine Interference Problem

Machining has gotten crucial to the cutting-edge industry. It is utilized legitimately or in a roundabout way in the production of practically all the merchandise and ventures being determined everywhere in the world. This project is mainly carried out in Multi-Function Operating Machine for production industries. It is a multipurpose machine that can be used to perform various operations like drilling (screw fitting, boring, broaching), grinding and lathe operations (facing, step turning, knurling and cutting) of small workpieces very precisely. A lathe is one of the oldest and perhaps most important machine tools ever developed. Hole machining, constituting a considerable percentage of all machining operations, is accomplished, as a rule, be rotary and axial feed motions of the cutting tool or work. The boring cycle is a widely utilized machining activity by which however or daze openings are cut or begun in a workpiece. Penetrating is a machining activity wherein the opening is created or broadened by the utilization of an extraordinary cutting device, called a drill, normally having more than one forefront. Crushing is a machining activity where a multi-edged pivoting grating device called a granulating wheel eliminates abundant material from the workpiece. Granulating of level surfaces called surface crushing. Grinding of flat surfaces called surface grinding.

Modeling of Vibration Condition in Flat Surface Grinding Process

This article presents a new model of the flat surface grinding process vibration conditions. The study establishes a particular analysis and comparison between the influence of the normal and tangential components of grinding forces on the vibration conditions of the process. The bifurcation diagrams are used to examine the process vibration conditions for the depth of cut and the cutting speed as the bifurcation parameters. The workpiece is considered to be rigid and the grinding wheel is modeled as a nonlinear two-degrees-of-freedom mass-spring-damper oscillator. To verify the model, experiments are carried out to analyze in the frequency domain the normal and tangential dynamic grinding forces. The results of the process model simulation show that the vibration condition is more affected by the normal component than the tangential component of the grinding forces. The results of the tested experimental conditions indicate that the cutting speed of 30 m/s can permit grinding at the depth of cut up to 0.02 mm without sacrificing the process of vibration behavior.

Features of cutting force database formation for modeling of pendulum grinding of flat surfaces of tools made of R9M4K8 and X12 steels

The purpose of the article is to create a database on cutting forces P z , P y to enable the simulation of loads on the tools made of R9M4K8 and X12 steels and on machine-tool parts and components using computer programs. forces additionally allow to simulate thermal phenomena in the grinding zone, which being an adverse factor in abrasive processing reduce the performance of cutting tools and dies. The cutting forces are measured using the Kistler dynamometer system and the output of the obtained information is presented in the computer. Correction factors to the basic model taking into account the idle passes by the width of the processed surface are obtained. It is found out that the increase in the operational allowance when grinding with cubic boron nitride wheels is not accompanied by an increase in cutting forces, which is typical for traditional abrasive wheels (in particular for electrocorundum). The cutting forces at grinding of die steel X12 are greater than those at grinding high-speed steel R9M4K8: P y - by 1.2 times, P z - by 1.36 times. The results obtained will increase the efficiency of using CAE-systems (Computer-aided engineering systems) in mechanical engineering, particularly in grinding. It is confirmed that the increase in the grinding coefficient K gr =P z /P y reflects the improvement in the abrasive wheel operating conditions. In particular, it increases when the wheel comes out of contact with the workpiece from 0.32 to 0.46 at the reverse motion in the same zone from 0.46 to 0.64.

Kształtowanie właściwości warstwy wierzchniej podczas szlifowania

The article describes the grinding of flat surfaces combined with changes in the properties of the surface layer, in particular through its hardening. Issues related to the grindhardening technology are discussed. In addition, tests have been presented in which improved grinding properties of the workpiece through plastic deformation have been obtained after the grinding process.

Effect of Deep Cryogenic Treatment on Microstructure and Wear Resistance of LC3530 Fe-Based Laser Cladding Coating.

The effect of deep cryogenic treatment on microstructure and wear resistance of LC3530 Fe-based powder laser cladding coating was investigated in this paper. The cladding coating was subjected to deep cryogenic treatment for the different holding times of 3, 6, 9, 12, and 24 h, followed by tempering at room temperature. Microstructure of the cladding coating was observed by optical microscope (OM) and the microhardness was measured by the Vickers-hardness tester. The wear was tested by ball and flat surface grinding testing conducted on the material surface comprehensive performance tester. The wear scars were analyzed using a non-contact optical surface profiler and scanning electron microscope (SEM). The results showed the grain size of cladding coating after 12 h of deep cryogenic treatment was significantly reduced by 36.50% compared to the non-cryogenically treated cladding coating, and the microhardness value increased by approximately 34%. According to the wear coefficient calculated by the Archard model, the wear resistance improved about five times and the wear mechanism was micro-ploughing. The deep cryogenic treatment could enhance the wear resistance of the cladding coating by forming a wear resistant alloy compound and higher surface microhardness.

Wpływ parametrów szlifowania wgłębnego na nanotwardość i chropowatość powierzchni stali C45

The paper presents the results of investigations on the effect of the depth of concurrent grinding of flat surfaces on the roughness and nano-hardness of the surface layer of C45 steel with a ferritic-pearlitic structure and average grain size of 20 μm. A significant increase in the hardness of the surface layer of the workpiece was obtained for all grinding depths.

Force and energy considerations on the face grinding of flat surfaces

Face grinding is a process that is capable of meeting both the productivity and flexibility demands of industry, with acceptable manufacturing costs. Efficient grinding is the result of an optimisation process that considers detailed knowledge of the interaction between a grinding wheel and the material of the workpiece, but which should also consider energy aspects. The face grinding process of flat surfaces has been analysed in this work through an experimental campaign, in an attempt to relate the grinding parameters to the forces and energy. Thus, a grinding apparatus was instrumented with a force measuring device in order to monitor the grinding forces applied during the removal of the material. The applied power and energy were also evaluated. The experimental results are discussed in this paper, and are related to the analytical relationships that were found to develop for the specific face grinding operation. [Submitted 12 March 2017; Accepted 7 October 2017]

Force and energy considerations on the face grinding of flat surfaces

Face grinding is a process that is capable of meeting both the productivity and flexibility demands of industry, with acceptable manufacturing costs. Efficient grinding is the result of an optimisation process that considers detailed knowledge of the interaction between a grinding wheel and the material of the workpiece, but which should also consider energy aspects. The face grinding process of flat surfaces has been analysed in this work through an experimental campaign, in an attempt to relate the grinding parameters to the forces and energy. Thus, a grinding apparatus was instrumented with a force measuring device in order to monitor the grinding forces applied during the removal of the material. The applied power and energy were also evaluated. The experimental results are discussed in this paper, and are related to the analytical relationships that were found to develop for the specific face grinding operation. [Submitted 12 March 2017; Accepted 7 October 2017]

Temperature of Heating and Cooling of Massive, Thin, and Wedge-Shaped Plates from Hard-to-Machine Steels During Their Grinding

Grinding of flat parts occurs by solid abrasive particles due to the physicomechanical process of deformation and to the action of a process liquid at high temperatures in a zone small in volume and difficult for observation. The rate of heating and cooling depends on the change in the intensity of the heat flux and in the velocity and time of action of the heat source. A study has been made of the regularities of the influence of each of these parameters on the depth and character of structural transformations during the grinding of flat parts from hard-to-machine steels. A procedure to calculate temperature in grinding massive, thin, and wedge-shaped parts has been developed with account taken of the geometric and thermophysical parameters of the tool and the treated part, and also of cutting regimes. The procedure can be used as a constituent part in developing a system for automatic design of the technological process of grinding of flat surfaces. A relationship between the temperature in the grinding zone and the regimes of treatment has been established which makes it possible to control the quality of the surface layer of massive, thin, and wedge-shaped plates from hard-to-machine steels. The rational boundaries of shift of cutting regimes have been determined.

Comparative tests of the proper active grinding powers and maximum grinding temperatures, conducted on corrosion-resistant steel surfaces, using aluminium oxynitride and noble electrocorundum grinding wheels

This paper presents the results of comparative experimental tests of proper active powers and maximum temperatures, conducted on the circumference grinding of flat surfaces, made of grade 321 corrosion-resistant steel (1.4541), using modern aluminium oxynitride and noble electrocorundum vitrified-bonded grinding wheels. The tests were carried out in both up-cut and down-cut conditions. In both kinematic grinding aspects, the tested factors were determined by discrete increase of reductive grinding yield, applying increasing grinding-wheel in-feed to the workpiece and keeping the remaining grinding parameters at the constant level. The test results were later subjected to simplified statistical analysis, and an attempt was made at substantive test justification. It was demonstrated that, regardless of the assumed kinematic grinding aspects of steel grade 1.4541 (321), the values of all the comparatively tested values of aluminium oxynitride grinding wheels were, with increasing reductive grinding yield, lower than the corresponding values of the noble electrocorundum grinding wheels.

Design and Technology Support of the Grinding Process for Heavily-machined Steel Sheets

In the article the analytical dependence between grinding modes, thermal processes, coolant influence and surface finish is determined on the basis of complex study of rules by which thermal processes during grinding of thin plates of heavily-machined steels are developing. The new types of grinding tools with the intermittent working surface are designed allowing practice of extending technological possibilities of the faultless face grinding of flat surfaces. The requirements for stable obtaining of surface finishes Rа = 0,2 ÷ 0,4μm are specified.

Suppression of the inflection pattern in ultraprecision grinding through the minimization of the hydrodynamic force using a toothed wheel

Fluid coolant has been widely used for cooling, lubrication, and the removal of cutting chips in the grinding process; however, it can generate grinding marks due to the hydrodynamic force especially in case of a lack of the spindle stiffness. This leads to inflection patterns on the workpiece, with sub-micrometer level of waviness, which is quite critical in rotationally symmetric ultraprecision grinding. In this study, we propose the use of a toothed wheel which is remarkably efficient in suppressing the inflection pattern by minimizing the hydrodynamic pressure. A toothed wheel has a simple geometry with a peripheral surface similar to a saw. The teeth disturb the generation of the coolant flux layer and noticeably decrease the hydrodynamic force. Furthermore, the toothed wheel increases the net grinding force due to the tangential cutting edge.This study simulated the hydrodynamic pressure in the grinding process and validated the flat surface grinding results by varying the tooth geometry. A comparison showed that the hydrodynamic force was decreased by 20–35% and that the inflection pattern of the ground surface was markedly decreased in rotational symmetric grinding.

Model symulacyjny szlifowania wibracyjnego powierzchni płaskich

Model symulacyjny szlifowania wibracyjnego powierzchni płaskich

Study on Effects of Organic Matter Concentrationon Engineering Ceramics Grinding

The grinding liquid concentration has a great influence to its application and cost. Based on the tribological properties, viscosity, heat capacity, the research was conducted to find the performance of grinding fluid with difference concentration. Experimental results show that the grinding fluid can be chosen with low concentration in the process of cutting grinding. For the flat surface grinding and the cylindrical grinding, appropriate method is to give high grinding liquid concentration.

S1330104 平面ELID研削における送り速度が被加工物の反りに及ぼす影響([S133-01]先進砥粒加工技術(1))

S1330104 平面ELID研削における送り速度が被加工物の反りに及ぼす影響([S133-01]先進砥粒加工技術(1))

Influence of the abradant’s composition on the selected physical properties in the process of front grinding of surfaces with microcrystalline sintered corundum grinding wheels

This paper presents the results of experimental research on the influence of the composition of the abradants applied in the microcrystalline sintered corundum grinding wheels at the maximum temperature obtained in the grinding zone, maximum grinding power thrust component, grinding power feed component, active grinding power, and volumetric abradant wear. Tests were conducted in the conditions of front finishing grinding of flat surfaces of the objects made of corrosion-resistant steel, with austenitic structure. In our tests, we used a mini-grinder for flat surfaces, controlled by a CNC system, shank mounted grinding wheels made of mixed electrocorundum-cubitron abradant, a piezoelectric dynamometer, a thermal camera, a digital power analyzer, and a laser gauge. The test results were subjected to statistical and substantive analyses. It was found that, together with a proportional increase of the microcrystalline sintered corundum content in the grinding wheel’s material, the values of the indicated physical properties displayed a decreasing tendency that could be determined by the trend functions, in the form of second-degree polynomials, without interaction. It was further found that such changes in the abradant composition significantly influenced the changes of the values of selected physical properties, and the test results well-approximated by the test object functions, in the form of third-degree polynomials, without interaction. The test object functions were characterized by the occurrence of local extremes whose locations indicated that it was the most beneficial to operate grinding wheels with the abradant content belonging to the range of 7CB–9CB, in the assumed testing conditions.