Belt Finishing Process Research Articles

Modeling surface roughness profiles generated by the belt finishing process of a 27MnCr5 carburized steel

Belt finishing is a superfinishing process that enables to reach fine surface roughness. This paper proposes a numerical model, predicting belt finishing roughness profiles of a 27MnCr5 carburized steel. It utilizes belt topographies that are then numerically deformed thanks to a specific morphological filter. A method for determining the morphological filter parameters is proposed and depends on the size of the grains. Then, the deformed topography of the belt virtually scratches the workpiece at a given depth of indentation (computed by a rough contact model). The model predicts surface roughness profiles in the steady state regime. The paper shows a reasonable agreement between experimental and numerical results. The model captures the main trends: the higher the grain size the higher the roughness of the workpiece. Computational time needed for this model is a few minutes, making it a useable solution for the industry.

Surface Integrity induced by the Belt Finishing Process and Effects on the Fatigue Limit of a 27MnCr5 Carburized Steel

Among superfinishing processes, belt finishing is well known for its ability to induce compressive residual stresses and low surface roughness. Moreover, it is promoted by industry, as this process requires limited investments and is easy to handle. Combined with hard turning, precise dimensions and fine surface roughness of the parts can be ensured. Therefore, the combination of these processes could replace the grinding operation performed on automotive gear shafts for example. The article proposes to study the effects of the belt finishing operation on surface integrity of 27MnCr5 carburized steel shafts. Residual stresses and surface roughness are investigated for hard machined and belt finished samples. Afterwards, rotating bending fatigue tests are performed, and the fatigue limit of the belt-finished samples is compared with hard machined ones.

Investigation of belt-finishing effect on the residual stress field through repeated scratching on rough hard-turned surface

Belt-finishing process is renowned for its high capability to enhance surface integrity through scratching of the work-piece by means of multiple abrasive grains. In this work, the axial residual stress field induced by repeated scratch tests on an initial rough hard-turned surface is studied through numerical modeling. An analytical model is adopted to calculate the penetration depth and its evolution corresponding to the fixed indentation load and the number of scratching. The effect of the initial surface roughness, the loading conditions, the number of repeated scratching, and the coefficient of friction on the residual stress field, has been studied. The results show that whatever, the parameter's values, the affected layer doesn't exceed 11 μm. Moreover, the best compressive residual stress field is obtained for the highest loading conditions, the lowest initial surface roughness and friction coefficient. The numerical results are then used as qualitative evidence to describe the residual stress field evolution during a belt-finishing process, and to propose an optimum solution, ensuring the highest surface integrity during such a process.

Towards the prediction of surface roughness induced by the belt finishing process: influence of the workmaterial on the roughness reduction rate

Abstract The belt finishing process is of great interest for the automotive industry so as to obtain smooth surfaces, especially after hard tuning operations. It enables to reduce and homogenize the surface roughness. It also prevents any shifting of surface quality from tool wear in hard turning. Belt finishing induces its own surface topography which will be rather independent of the previous one. Its surface signature is correlated to the abrasive belt topography. However models able to predict the final roughness of a part are missing. This article proposes to investigate the roughness reduction during the transitory state of the belt finishing process. The study is performed for different workmaterials. The main objective being to propose a first simple approach to predict the final roughness as a function of the initial roughness, work material and time.

Investigating adhesion wear on belt and its effects on dry belt finishing

Adhesion wear on abrasive belt sometimes occurs as an abnormal abrasion way because of an improper selecting on working conditions during the belt finishing. In this paper, the forming process of the adhesion wear and its effects on the finished surface is investigated through a series of experiments. The results reveal that the applied pressure and the belt feed rate are supposed to be the two sensitive variables for forming the adhesion wear. A certain amount of accumulated chips is a trigger to cause adhesion wear initially, and then, the sufficient heat accumulation becomes the main factor for the following adhesion wear. Thus, shortening the finishing duration, decreasing applied pressure, rotating speed and introducing cooling/lubrication system are recommended to avoid adhesion wear. The belt finishing process with adhesion presents a potential to further decrease surface roughness by 30% maximum, improve bearing characteristics and obtain equivalently high compressive residual stresses; however, this merit has to go with the sacrifice of belt’s cutting ability.

Wear study of structured coated belts in advanced abrasive belt finishing

Abstract Advanced belt finishing process is remarkably simple and inexpensive. The principle of operation is simple: pressure-locked shoes platens circumferentially press an abrasive coated belt on a rotating workpiece. This abrasive machining process reduces significantly surface irregularities subsequently improving geometrical quality and increasing wear resistance and fatigue life. It is therefore extensively used in automotive industry to superfinish crankshaft journals. However, the major industrial issue about this manufacturing process is its efficiency and robustness. One of the most promising ways to solve this issue is to control the distribution and morphology of the abrasive grits. Recently a new generation of abrasive belts coated with structured and shaped agglomerate grits has been commercially available. These structured coated belts with mastered cutting edge orientations promise to be more efficient as they have a better wear resistance compared to the traditional coated abrasive belt. Therefore, this work aims to discuss these assumptions and to establish the link between three structured coated belts, the surface finishes and the physical mechanisms which govern their wear performances. In particular a parametric study, based on the cycle time and the rotation speed, is lead in order to analyze the potential of each structure in terms of surface roughness improvement, wear resistance and consumed energy. The experimental results have demonstrated that, depending on the abrasive structure considered and for a same number of revolutions, modifying the cycle time or the rotation speed can lead to different surface finishes and belt's wear.

Multiscale assessment of structured coated abrasive grits in belt finishing process

This paper outlines the link between grit morphology and surface roughness of belt-finished workpieces. It features a comparative analysis of a new generation of abrasive belts with diverse abrasive structures, and a multi-scale roughness characterization of abrasive belt wear on a variety of finished surfaces. The ultimate thickness of the mechanically deformed layer and surface profile projections depends, to a great extent, on the abrasive mechanisms of friction and wear employed in the finishing process. By modifying the physical mechanisms (cutting, plowing or sliding), it is possible to achieve a concomitant change in the rate of material removal and, consequently, to the specific surface roughness of the finished parts.Our research shows that the active roughness scale resulting from belt finishing is strongly dependent on the grit orientation and the binder distribution. The results are promising for increasing the efficiency of the abrasion processes and for improving the surface texturing of finished parts.

Three dimensional modelling of temperature distribution during belt finishing

This study focuses on the belt finishing process to understand the effect of the local geometry of each abrasive grain via the curvature radius and the attack angle on the local contact temperature. In order to reach this last parameter, a three–dimensional numerical model is established and presented in order to determine the temperature distribution at the interface abrasive papers/workpiece. The established model considers that the local geometry of each abrasive grain is conical with a hemispherical tip. The numerical results show that at a small depth of penetration, both sphere and cone have an influence on temperatures distribution. For larger depths, this distribution depends only on the conical geometry of the abrasive grains. It is also shown that the effect of the interaction of asperities on the temperature during belt finishing cannot be neglected, especially at higher load.

Energetic analysis of cutting mechanisms in belt finishing of hard materials

Belt finishing has been tested successfully as a complementary process to hard turning. This technology improves the surface texture and generates compressive residual stress. However, the mechanisms and characteristics of this new process have not yet been fully explained. This article provides a comprehensive characterization of cutting mechanisms generated by belt finishing. First, an analytical analysis based on cutting forces is developed. Then, the macroscopic specific energy is dissociated into a cutting specific energy responsible of shearing and ploughing mechanisms and a sliding specific energy due to adhesion. It has been demonstrated that cutting is more predominant than sliding in belt finishing process. The omnipresence of cutting demonstrates the effectiveness and the profitability of belt finishing operation.

Influence of abrasive grain geometry on friction coefficient and wear rate in belt finishing

We focus our study on belt finishing process using a 3D model with multi-asperity abrasive wear on real rough surfaces. The established model allows determining the effect of the local geometry of abrasive grain on the friction coefficient and wear rate. This study shows that the friction coefficient and wear rate increase with the local slopes of the roughness. With the increase of the macroscopic normal load, the wear rate increases rapidly. Such effect is related to the increase of the cutting force of each grain leading to the transition in dominant wear mode from ploughing to wedging and cutting.

The effect of lubrication conditions on belt finishing

The belt finishing process is a recent manufacturing technique in the field of superfinishing of hard material. Belt finishing leads to an homogenous surface with a very smooth surface roughness and good bearing curve parameters. In this way, belt finishing can complement effectively hard turning, whose disability is the shifting of the surface quality due to tool flank wear. In order to study the effect and the interaction of lubrications conditions on belt finishing after hard turning, an experimental study is proposed. The interaction between lubrications conditions and belt feed and the effect on roughness parameters has been investigated. It was shown that minimum quantity lubrication with low belt feed is the best way to have the optimal roughness characteristics. Under these conditions, the process is not a basic belt finishing operation but a combination of belt finishing and lapping due to the presence of a slurry made of free abrasive grains, microchips and oil, in the contact. Additionally, it has been revealed that dry belt finishing is not suitable because of the rapid destruction of abrasive grains.

On the residual stress field induced by a scratching round abrasive grain

Most of superfinishing processes are based on the action of abrasive grains scratching the surface of a workpiece. These processes are known to improve the surface texture but they also modify the surface integrity, and thus the durability of engineering parts. In this paper, the residual stress field induced by the scratch of a single round abrasive grain is investigated by means of an implicit finite element analysis. First, it is shown that the residual stress profile is always modified over a depth of two or three times the contact radius, whatever the mechanical and physical properties. Second, key-parameters having a high influence on the tensile and compressive zone have been identified. They are the contact severity, the friction coefficient and the workpiece hardness. Third, it appears that the residual stress profile is not really affected by the presence of initial homogeneous residual stress field in the material. These results are then used to explain the experimental residual stress fields induced by a belt finishing process and a honing process on a AISI52100 hardened steel. Finally the possibility to design appropriate abrasive tools to improve both surface texture and surface integrity of manufactured parts is discussed.

Correlation between surface topography and tribological mechanisms of the belt-finishing process using multiscale finishing process signature

In practice, two surfaces statically equivalent can be issued from two different manufacturing processes (grinding, belt finishing, honing, …) or obtained using different working process variables (abrasives grits size, contact pressure, …). The common tools and different norms used for industrial surface characterization (ISO 4288, ISO 12085, …) have the main limit of discriminating them through their process signatures. This Note introduces a multiscale decomposition method of the surface topography based on continuous wavelets transform. This approach allows the determination of the multi-scale transfer function of the morphological modification on the surface topography after a finishing process. This technique has been successfully applied to discriminate two surfaces obtained by the belt-finishing process. Moreover, it makes it possible to connect the surface topography modification to the physical and tribological mechanisms of the process (ploughing, cutting, …). To cite this article: S. Mezghani et al., C. R. Mecanique 336 (2008).

New criterion of grain size choice for optimal surface texture and tolerance in belt finishing production

The basics of the belt finishing process are not well understood yet because it is difficult to define the relationships between process variables and surface characteristics particularly from the point of view of surface roughness and tolerance. For this reason, the optimal working variables of the belt finishing process are not yet predictable. This work is devoted to track the effect of the abrasives grains size. The optimal abrasives grains size is firstly identified by comparing the initial and the finished surface topographic signature on a wide range of surface wavelengths. The analysis method is based on a multi-scale characterization using the continuous wavelets transform. It makes it possible to define a criterion as for the choices of the optimal abrasive grains size of the belt finishing process for a given workpiece surface.

The Effect of Belt Finishing Process Variables on the Topography of Finished Surfaces

The high performance of industrial applications requires increasingly technical functional surfaces, particularly from the point of view of topography and micro texture. Belt finishing is one of the finest machining processes widely used to improve surface texture and to increase wear resistance and fatigue life. It modifies the surface topography in a wide range of roughness and waviness scales, and consequently modifies the functionality of the surface in terms of the bearing area, local plasticity, and durability. In this paper, the topographic signature of the belt finishing process on a wide range of wavelengths of surface topography is analyzed to track the effect of each working parameter, and makes it possible then to understand the principal physical mechanisms activated during the super finishing operations (cutting, ploughing, and friction). To this aim, a multiscale decomposition of the surface topography before and after finishing by using a 2D continuous wavelet transform is introduced.

Mechanical modelling of micro-scale abrasion in superfinish belt grinding

In synchronized transmission, the shift lever force and corresponding shiftability are the most important design considerations. The present paper introduces an engineering attempt to rigorously model a synchronizing functional surface (cone surface of idler gear) according to its finish specifications. The virtual input surface is generated by an original fractal function, which reproduces the surface “signature” due to the wheel grinding process. To model the subsequent superfinishing operation by belt finishing process, which uses a soft-coated belt as a tool, an algorithm simulating the abrasive polishing conditions is especially developed and applied to rework the initial fractal surface. The basic idea of this model is that the higher the height of a peak of the profile, the lower its probability of resistance during an abrasion cycle. The belt finishing process is hence modeled by five parameters: two parameters that characterize the initial surface (fractal dimension and range amplitude) and three parameters describing the abrasion polishing process (probability of resistance, wear volume and the number of abrasion cycles). In order to ascertain that the component will be manufactured to the required specifications, the model's parameters have to be determined. For this goal, a functional model with an optimization scheme is created. This simulation provides the morphology of the initial surface and how to cope with the superfinishing process to obtain the functionality of the surface. An elevated initial roughness is required from which slow erosion is proceeded to erode peaks and conserve some valleys of the initial profile (lubricant tanks). Finally, it is shown that automotive designers impose morphological specifications obtained by the belt grinding process to prevent scuffing of the motor parts.

Modelling of the residual stresses induced by belt finishing on a AISI52100 hardened steel

New technological process consisting of hard turning followed by belt finishing, in place of the widely used method in industry, e.g., grinding, has lately been launched in the automotive industry. This is because, many transmissions parts, such as synchronizing gears, crankshafts and camshafts require superior surface integrity along with appropriate fatigue performance. This paper provides a modelling of part residual stresses produced after belt finishing in order to provide some explanations about the experimental results previously obtained. Indeed, it has been shown that the belt finishing process improves very significantly the surface integrity by the induction of strong compressive residual stresses in the external layer. The model has confirmed this trend. It has also revealed that, among the process parameters of the belt finishing technique, the lubrication appears as a key parameter to get compressive stresses, whereas the elementary force on each abrasive grains influence the depth of the affected layer.

Characterization and modelling of the residual stresses induced by belt finishing on a AISI52100 hardened steel

New technological process consisting of hard turning (HT) followed by abrasive machining, in place of the widely used method in industry, e.g., hard turning versus grinding, has lately been launched in the automotive industry. This is because, many transmissions parts, such as synchronizing gears, crankshafts and camshafts require superior surface finish along with appropriate fatigue performance. This paper provides a comprehensive characterization of part residual stresses produced in dry turning of a hardened AISI52100 bearing steel using PCBN tools, and also its modification after a special abrasive finishing operation, i.e. belt finishing. The residual stresses generated in hard turning or in ‘hard turning + belt finishing’ are investigated by two complementary ways: an experimental X-ray diffraction characterization after each step of the process, and a finite element model of the belt finishing operation in order to bring an understanding of the experimental results. Additionally the sensitivity of some parameters such as the lubrication and the indentation force during belt finishing are investigated. It has been shown that the belt finishing process improves very significantly the surface integrity by the induction of strong compressive residual stresses in the external layer and by a great improvement of the surface roughness. Among the process parameters of the belt finishing technique, the lubrication appears as a key parameter to get compressive stresses.

Influence of the belt-finishing process on the surface texture obtained by hard turning

The belt-finishing process is a recent manufacturing technique in industry, the mechanisms and characteristics of which have not yet been fully explained. This paper attempts to make a contribution to the understanding of the consequences of the process on the surface roughness of surfaces prepared by hard turning. Abrasive film wear and contact parameters between grains and surfaces are analysed. The effects and significant interactions of the most influential belt-finishing parameters on the surface roughness are then investigated. It was shown that the applied force and the hardness of the roller have a great influence on the surface roughness. Furthermore, the film feed rate influences considerably the wear of grains and, as a consequence, this parameter has an important impact on the material removal mode and on the surface roughness.

The effect of abrasive grain's wear and contact conditions on surface texture in belt finishing

The belt finishing process is a recent manufacturing technique in the field of superfinishing of hard material. Its mechanisms have not yet been fully explained. This paper attempts to make a contribution to the understanding of the wear mechanisms of the abrasive film and its influence on surface roughness. First, the contact conditions between abrasive film and the surface have been analysed and the abrasive film wear has been theoretically modelled. Effective contact duration between grains and machined surface on the one hand, and average contact pressure on the other hand have been introduced as key parameters. Then, the effects of the most influential belt finishing parameters and their interactions on the surface roughness and the material removal have been experimentally investigated. It was revealed the existence of an optimum surface roughness reachable independently of the force and of the roller's hardness. It has also been revealed the existence of an optimum belt finishing duration depending on the feed, the force and on the roller's hardness.