Roller Burnishing Process Research Articles

Influence of process and geometry parameters on the surface layer state after roller burnishing of IN718

Highly stressed components of modern aircraft engines, like fan and compressor blades, have to satisfy stringent requirements regarding durability and reliability. The induction of compressive residual stresses and strain hardening in the surface layer of these components has proven as a very promising method to significantly increase their fatigue resistance. The required surface layer properties can be achieved by the roller burnishing process, which is characterised by high and deeply reaching compressive residual stresses, high strain hardening and excellent surface quality. In order to achieve a defined state of the surface layer, the determination of optimal process parameters for a given task still requires an elaborate experimental set-up and subsequent time-consuming and cost-extensive measurements. The development of well funded process knowledge about the correlation of the process parameters, the processed geometry and the surface layer state is the subject of this article.

Study of roller burnishing process on En-8 specimens using design of experiments

Roller burnishing process is a superior cold forming finishing process. It is done on machine or ground surfaces for both external and internal surfaces. In this process, a smooth, hard object (under considerable pressure) rubs over the minute surface irregularities that are produced during machining or shearing. The hardened rolls of the tool press against the surface and deform the protrusions to a more nearly flat geometry. Since the surfaces are cold worked and in residual compression, they possess improved wear and fatigue resistance. The burnishing process is an attractive finishing technique which can increase the work-piece surface finish as well as micro-hardness in a single process, with reduction in tool set-up time which is difficult in conventional processes. The increase in the surface strength mainly serves to increase fatigue behaviour of work-piece under dynamic load. In this study surface roughness and micro-hardness are the main response variables and the process parameters under consideration are spindle speed, tool-feed, number of passes and lubricants. The material under consideration is En-8, which is commonly used industrial standard. Applying Taguchi’s design of experiments on the specimens, the aim is to find optimized values for enhancing the surface quality and hardness economically. The standard orthogonal array L-9 has been used. On experimental analysis, it is found that all the process parameters significantly affect the quality and in EN-8 the micro-hardness values are larger due to work-hardening effect. After the burnishing process no change in surface micro-structure was seen. Key words: Roller burnishing, surface finish, micro-hardness, Taguchi techniques, micro-structure, optimization.

Numerical analysis of embossing process of regular inequalities with triangular outline

AbstractThe paper presents the numerical analysis of plastic formation process of regular inequalities of surface with triangular outline. The physical and mathematical models of deformations (displacements and strains) and stress in the process were worked out. The process is considered as a geometrical and physical non–linear problem with unknown boundary conditions. The computer analyses were conducted with the use of Finite Elements Method (FEM). The solution of problem was conducted with use of updated Lagrangian description. In simulations material model of elasto/visco – plastic (E/VP) was used. The solution of variational equation of movement object was conducted applying the explicit method. The results of simulation are basis to projection of new technological operation – plastic formation of regular inequalities with triangular outlines as previous burnishing rolling process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The numerical analysis of burnishing rolling process with taking into account inaccuracy of surface preparation in previous treatment

AbstractIn the paper the numerical analysis of burnishing rolling process with taking into account inaccuracy of surface preparation in previous treatment are shown. The researches were realized in two stages, in the first one outline of asperities was prepared in turning process. The ranges of outline deviation (height and distance) of triangular asperity after turning are shown as the result. In the second one the numerical analysis of burnishing rolling with different outline deviation were made. The application in ANSYS was elaborated. To solve problem explicit method was used. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Experimental Study on the Sliding Friction and Wear Characteristics of Roller Burnished Polymers

Abstract The increasing utilization of polymers in sliding members has triggered much research on the enhancement of surface quality and tribological performance. In this regard, no work has considered the application of roller burnishing as a new surface treatment method for polymeric surfaces. The present work aims to investigate the influence of burnishing feed and roller contact width on the sliding friction and wear performance of acetal homopolymer and polyurethane. Dry and lubricated sliding conditions for both parallel and crossed burnished orientations were considered. The results revealed that low burnishing feed rate and smaller roller contact width led to a decrease in coefficient of friction for both polymers while improvement in the wear resistance was observed. Hence, it can be suggested that the roller burnishing process has high potential as a valuable polymer surface treatment technique.

The influence of roller burnishing process on hardness and roughness of cylindrical polymer surfaces

In the present study, the potential for using the roller burnishing process to improve surface roughness and hardness of thermoplastics (acetal homopolymer, POM-H) and thermosets (polyurethane, PU) is investigated. The effect of roller burnishing parameters such as burnishing force, speed, feed, and roller width contact is studied. The results showed that all burnishing parameters had a controlling effect on surface roughness and hardness of POM-H and PU, but with different degrees. The effect of the roller burnishing process was more pronounced on POM-H compared with PU. Depending on the burnishing parameters, the surface roughness of POM-H and PU was decreased by ∼(32–37) and (28–32) per cent, respectively. Meanwhile, the hardness was marginally increased, i.e. by ∼0.8 and 1 per cent for POM-H and PU, respectively.

Surface characteristics of Al-(SiC)<SUB align=right>p metal matrix composites by roller burnishing process

This paper describes burnishing process as an alternate super finishing process for aluminium reinforced metal matrix (Al-(SiC)p) composites. The advantage of the burnishing process is non-chip removals to attain surface finish whereas other finishing process depends on chip removal to attain the desired surface finish, which may cause further surface abrasion and geometric tolerance. The effect of various input parameters such as burnishing speed, lubricants and number of passes on the output parameters such as surface roughness and surface hardness is studied.

THE EFFECT OF DIAMOND PRESSING AND ROLLER BURNISHING OF UNHEAT TREATED CARBON STEEL SURFACES

Diamond pressing (DP) and roller burnishing (RB) processes are surface plastic deformation methods used to improve surface quality (microhardness and surface roughness). In the present work DP and RB tools with a special holder were used to study the effect of DP and RB on the surface texture of three different carbon steels (low, medium, and high) and to compare the both methods. The results show that the RB in the case of low carbon steel is better than the DP in terms of its effect on the microhardness and surface roughness, but in the case of the medium and high carbon steel the results depicts that the DP is better than RB in terms of its effect on the microhardness, but the RB is better than DP in terms of its effect on the surface roughness. As a result of this study it was found that DP and RB have a great effect on surface texture and RB was found to be better in surface roughness, but DP has better results in surface microhardness relative to ground surfaces. Also in this paper micrographs of the processed surfaces of low, medium and high carbon steel are given and it is shown that the depth of plastic deformed surfaces by diamond pressing was about (330, 345, 390) µm and by roller burnishing about (270, 245, 230) µm for the three steels, respectively.

Characteristics of Rb40 steel superficial layer under ball and roller burnishing

Both ball and roller burnishing processes are largely considered in industrial cases in order to ameliorate surface characteristics. Usually, roughness and hardness are sought to measure surface integrity. The aim of this study is to develop a device for mechanical plastic deformation of structural Rb40 steel using ball and roller burnishing and to investigate the evolution of associated roughness, hardness and wear resistance. It was found that roller burnishing provides optimal roughness results, particularly when initial surface quality is close to 3 μm whereas in terms of hardness, ball burnishing becomes interesting. Optimum roughness and hardness are obtained for a specific operating regime in which decisive parameters are the applied force as well as the number of passes. When considering roughness criterion, it is recommended to limit the number of passes to two while three passes are advised for a hardness basis. Rb40 steel superficial layers treated by either roller or ball burnishing behave as a grinded surface with an appreciable wear resistance.

Study of Roller Burnishing. Analysis of Roller Burnishing Force by the Upper-Bound Method.

The upper-Bound method is applied to the analysis of the roller burnishing process. In this analysis spherical velocity field with the stream function is used in roller burnishing. A minimization technique of the total dissipation energy rate involving arbitrary variables was presented under a given roller burnishing condition. The influences of burnishing conditions such as burnishing depth, feed speeds and bulges on the roller-burnishing load were discussed. Roller burnishing experiments were also conducted on internal surface of SUS 304 cylinder with various burnishing conditions. The experimental results were compared with the analytical ones. The burnishing force obtained by the upper-bound method agreed with the experimental data.

Finishing of Internal Surface of Stainless Steel Cylinders by a Roller Burnishing Tool. Study of Optimal Burnishing Condition.

Roller-burnishing is one of the post-machining methods employed to finish the machined surface. The increase of fatigue life, hardness and reliability of a machined surface are achieved easily by the method. This paper discusses with the affect of burnishing conditions on the pre-machined surface and the influence on subsequent roller-burnishing process. The finishing experiments was conducted on internal surface of small diametral cylinder of SUS 304 with various burnishing conditions. The experimental results are described and the optimal burnishing conditions are discussesed. The finishing surface roughness less than 0.5 μmRy could be obtained easily by the roller-burnishing method in optimal burnishing condition.

Seizing Effect in the Roller Burnishing Process

Micrographs of metal surface layers after the roller burnishing process show that while about 90% of surface 1ayer thickness is displaced forwards of a roller motion, a thin contact zone undergoes a backward displacement. This seizing effect is caused by a softening of the contact zone due to overheating of the material, during high speed rolling, or due to the plastic strain cumu- lation in the layer after multiple rolling repetition. The effect is responsible for a peeling and cracking of surface layers during the burnishing process. The plastic analysis of the process taking into account the above effect is presented in the paper. The proposed slip-line field and corresponding ve- locity field are modification of the simplified solution for the rolling of the rigid-plastic half-space given by Collins. PACS numbers: 68.10.Cr, 68.35.Gy