Burnishing Parameters Research Articles

Surface Finishing of Plastic Injection Mold Steel with Ball Burnishing and Spherical Polishing Processes on a Machining Center

This study investigates the possible ball burnishing and spherical polishing surface finish process of a freeform surface plastic injection mold on a machining center. The optimal plane polishing parameters were determined by utilizing the Taguchi’s orthogonal array method for plastic injection molding steel PDS5. Five polishing parameters, namely the speed of the polishing ball, abrasive material, feed, stepover distance and the depth of penetration were selected as the experimental factors of Taguchi’s Design of Experiment to determine the optimal plane polishing parameters, which have the dominant influence on surface roughness. The optimal plane polishing parameters have been determined after conducting the experiments of the Taguchi’s L18 orthogonal table. The optimal plane polishing parameters for the plastic injection mold steel PDS5 were the combination of the polishing speed 18,000 rpm, the abrasives of aluminum oxide (Al2O3) with grid no. 5000, the feed of 100 mm/min., stepover distance of 60μ m, and the depth of penetration of 240 μ m. The surface roughness Ra of the specimen can be improved from about 1.125μ m to 0.067μ m using the optimal ball burnishing parameters for plane burnishing. The surface roughness Ra of the burnished specimen can be further improved from about 0.067μ m to 0.023μ m using the optimal polishing parameters.

The effect of burnishing parameters on burnishing force and surface microhardness

According to the results obtained from the boundary condition study of the burnishing process, cylindrical polycrystalline diamond (PCD) tools have been designed and fabricated. We probe deeper in the burnishing process by comparing the mechanics of using cylindrical PCD tools to work on aluminium alloy and brass compared to turning. The empirical equations of three components of the burnishing force were established with the aid of a quartz force measuring system and statistical methods. The results obtained show that the distributions of force are different between burnishing and turning. Furthermore, the effect of the burnishing parameters on the burnishing force and the surface microhardness of the workpiece were examined with theoretical analysis. Here, it was concluded that the burnishing feed and depth are the most significant factors affecting the burnishing force and surface microhardness.

Automated surface finishing of plastic injection mold steel with spherical grinding and ball burnishing processes

This study investigates the possibilities of automated spherical grinding and ball burnishing surface finishing processes in a freeform surface plastic injection mold steel PDS5 on a CNC machining center. The design and manufacture of a grinding tool holder has been accomplished in this study. The optimal surface grinding parameters were determined using Taguchi’s orthogonal array method for plastic injection molding steel PDS5 on a machining center. The optimal surface grinding parameters for the plastic injection mold steel PDS5 were the combination of an abrasive material of PA Al2O3, a grinding speed of 18000 rpm, a grinding depth of 20 μm, and a feed of 50 mm/min. The surface roughness Ra of the specimen can be improved from about 1.60 μm to 0.35 μm by using the optimal parameters for surface grinding. Surface roughness Ra can be further improved from about 0.343 μm to 0.06 μm by using the ball burnishing process with the optimal burnishing parameters. Applying the optimal surface grinding and burnishing parameters sequentially to a fine-milled freeform surface mold insert, the surface roughness Ra of freeform surface region on the tested part can be improved from about 2.15 μm to 0.07 μm.

Finite Element Analysis of Effects of Ball Burnishing Parameters on Residual Stresses

A three-dimensional coupled thermal-mechanical model of ball burnishing process is developed using commercial explicit finite element code MSC. Marc. The workpiece is modeled as being elastic-plastic, while its flowstress is taken as a function of strain, strain-rate, and temperature. Temperature-dependent material properties are also considered in this analysis. The burnishing ball is considered as rigid and only heat transfer analysis is carried out for it. In the zone of the workpiece and tool contact, the Coulomb friction is taken into account. Effects of ball burnishing parameters (burnishing force, feed rate, speed, ball diameter and number of tool passes) on residual stresses are analyzed. The results show that burnishing force, ball diameter, number of passes and burnishing feed have the most significant effect on the residual stresses. However, burnishing speed seems to just produce little effect on those. Larger burnishing force, larger number of passes, smaller ball diameter and small feed rate seem to be more effective in increasing in the maximum compressive residual stress and the depth of the layer at the compressive stress state.

Effects of working parameters on surface finish in ball-burnishing of hardened steels

Burnishing is a chipless finishing method, which employs a rolling tool, pressed against the workpiece, in order to achieve plastic deformation of the surface layer. Recent developments made possible burnishing of heat-treated steel components up to 65 HRC. Features of burnishing include a good roughness (comparable to grinding), as well as improvement of mechanical characteristics of the surface (fatigue strength, corrosion resistance, and bearing ratio), due to implementation of compressive stresses into the surface layer. This paper will present influences of certain burnishing parameters upon roughness, for a hardened steel component (64 HRC).

Investigation of the burnishing process with PCD tool on non-ferrous metals

It is well known that the no-chip machining process, burnishing, can easily improve surface roughness, waviness and hardness. To get the practical useful parameters, the effects of various burnishing parameters (spindle speed, depth, feed, burnishing radius and lathe) on surface roughness and waviness of the non-ferrous components were studied experimentally with a theoretical analysis. The experiments were conducted with a simply designed cylindrical surfaced polycrystalline diamond tool developed by us. It was found that smaller parameters do not mean lower surface roughness or waviness and different optimum burnishing parameters can be got under different burnishing conditions.

Freeform surface finish of plastic injection mold by using ball-burnishing process

The objective of this study is to introduce the possible ball-burnishing surface finish process of a freeform surface plastic injection mold on a machining center. The design and manufacture of a burnishing tool was first accomplished in this study. The optimal plane ball-burnishing parameters were determined by utilizing the Taguchi’s orthogonal array method for plastic injection molding steel PDS5 on a machining center. Four burnishing parameters, namely the ball material, burnishing speed, burnishing force, and feed, were selected as the experimental factors of Taguchi’s design of experiment to determine the optimal burnishing parameters, which have the dominant influence on surface roughness. The optimal burnishing parameters were found out after conducting the experiments of the Taguchi’s L18 orthogonal table, analysis of variation (ANOVA), and the full factorial experiment. The optimal plane burnishing parameters for the plastic injection mold steel PDS5 were the combination of the tungsten carbide ball, the burnishing speed of 200mm/min, the burnishing force of 300N, and the feed of 40μm. The surface roughness Ra of the specimen could be improved from about 1 to 0.07μm by using the optimal burnishing parameters for plane burnishing. Applying the optimal burnishing parameters for plane burnishing to freeform surface plastic injection mold, the surface roughness Ra of freeform surface region on the tested plastic injection part could be improved from about 0.842 to 0.187μm, through a comparison between using the fine milled and using the ball-burnished mold cavity.

231 Some Investigations on the Burnishing of External Cylindrical Surfaces

Burnishing is a process of finishing a metal by compressing its surface layer by the application of a highly polished and hardened ball or roller. Burnishing being an application of the cold working process produces significant improvements in the functional properties of the burnished surface. This paper presents an experimental investigation concerning the effect of some burnishing parameters, namely speed, feed, applied force, and number of passes on surface finish, and micro-hardness of the surface layer for 70-30 cu-zn alloy during an external ball burnishing process. The analysis of the experimental data has been carried out using a response surface methodology. Two mathematical models correlating the process parameters and their interactions with some of the response parameters have been derived and discussed. The residual stress distribution, the maximum residual stress, and depth of the stressed region of solution treated and aged 7075 aluminium alloy workpieces that are orthogonally burnished are determined using a deflection etching technique.

Determination of Optimal Ball-Burnishing Parameters for Plastic Injection Moulding Steel

The objective of this study is to determine the optimal plane ball-burnishing parameters for plastic injection moulding steel PDS5 on a machining centre by utilising the Taguchi's orthogonal array method. The design and manufacture of a burnishing tool are described. Four burnishing parameters, namely the ball material, burnishing speed, burnishing force and feed, were selected as the experimental factors in Taguchi's design of experiments to determine the optimal burnishing parameters which have the dominant influence on surface roughness. The optimal burnishing parameters were found after carrying out the experiments specified by Taguchi's L 18 orthogonal table, by the analysis of variation, and by a full factorial experiment. The optimal plane burnishing parameters for the plastic injection moulding steel PDS5 were a combination of a tungsten carbide ball, a burnishing speed of 200 mm/min, a burnishing force of 300 N and a feed of 40 μm. The surface roughness R a of the specimen can be improved from about I μm to 0.07 μm by using the optimal burnishing parameters for plane burnishing.

Study on the aluminum alloy burnishing processing and the existence of the outstripping phenomenon

Here the authors use a no-chip finishing process — the burnishing process — to reduce the surface roughness. The effects of various parameters on the surface roughness of aluminum (Al) alloy burnished with a cylindrical surfaced polycrystalline diamond (PCD) tool were studied. Problems in selecting the optimum burnishing parameters and conditions were discussed. In the experiment, the outstripping phenomenon was found. Some conditions of the burnishing process in which the outstripping phenomenon occurred were determined.

Experimental techniques for studying the effects of milling roller-burnishing parameters on surface integrity

Roller-burnishing is used in place of other traditional methods to finish 6061-T6 aluminum alloy. How to select the burnishing parameters to improve surface integrity (reduce surface roughness, increase surface microhardness and produce compressive residual stress) is especially crucial. This paper presents an investigation of the effect of roller-burnishing upon surface roughness, surface microhardness and residual stress of 6061-T6 aluminum alloy. The residual stress distribution in the surface region that was burnished is determined using a deflection-etching technique. Mathematical models correlating three process parameters: burnishing speed, burnishing depth of penetration and number of passes, are established. A Group Method of Data Handling Technique, GMDH, is used. It is shown that low burnishing speeds and high depths of penetration produce much smoother surfaces, whereas a combination of high speed with high depth leads to rougher surfaces because of chatter. The optimum number of passes that produces a good surface finish was found to be 3 or 4. The maximum value of compressive residual stress decreases with an increase in burnishing speed. The maximum compressive residual stress increases with an increase in burnishing depth of penetration and/or number of passes.

An investigation into roller burnishing

Burnishing, a plastic deformation process, is becoming more popular as a finishing process: thus, how to select the burnishing parameters to reduce the surface roughness and to increase the surface microhardness is especially crucial. This paper reports the results of an experimental program to study the influence of different burnishing conditions on both surface microhardness and roughness: namely, burnishing speed, force, feed, and number of passes. Also, it reports the relationship between residual stress and both burnishing speed and force. The residual stress distribution in the surface region that is orthogonally burnished is determined using a deflection etching technique. Mathematical models are presented for predicting the surface microhardness and roughness of St-37 caused by roller burnishing under lubricated conditions. Variance analysis is conducted to determine the prominent parameters and the adequacy of the models. From an initial roughness of about R a 4.5 μm, the specimen could be finished to a roughness of 0.5 μm. It is shown that the spindle speed, burnishing force, burnishing feed and number of passes have the most significant effect on both surface microhardness and surface roughness and there are many interactions between these parameters. The maximum residual stress changes from tensile to compressive with an increase in burnishing force from 5 to 25 kgf. With a further increase in burnishing force from 25 to 45 kgf, the maximum residual stress increases in compression.

The effects of initial burnishing parameters on non-ferrous components

Most of the previous works published on burnishing process concentrated on the effects of load, feed, speed, and number of tool passes. In the present study the effects of additional parameters such as the initial surface roughness and hardness of the workpiece, the ball diameter of the burnishing tool and the use of different lubricants on this process were studied. Two non-ferrous workpiece materials, namely free machining brass and cast Al–Cu alloy, were used. The results show that most of the above-mentioned initial burnishing parameters have significant effects on the burnishing process.

Effect of various parameters on the surface roughness of an aluminium alloy burnished with a spherical surfaced polycrystalline diamond tool

The effect of various parameters on the surface roughness of an aluminium alloy burnished with a spherical surfaced polycrystalline diamond tool are studied experimentally with a theoretical analysis. Problems in selecting the optimum burnishing parameters and some burnishing mechanisms are discussed. With suitable parameters employed, the new no-chip finishing process developed can eliminate or reduce the cutting marks left on the workpiece surface by diamond cutting tools, with its surface roughness reduced to Ra=0.026 μm from the original 0.5 μm.

Surface Characteristics of Some Roller Burnished Non-ferrous Components

Burnishing as a cold working process can be used to decrease the roughness of surfaces, and to increase the surface hardness as a result of work hardening. In the present work, a roller type burnishing tool was used to study the influence of the main burnishing parameters on the surface roughness and hardness of commercial aluminum and brass. It was found that roller-burnishing can be used successfully to improve surface roughness and to increase surface hardness. Also, it was found that burnishing force and number of burnishing tool passes are the predominant parameters, for control of surface roughness and hardness of rolled-burnished components.

An investigation into the surface characteristics of burnished cast AlCu alloys

Burnishing is considered as a surface finishing process. In this process the metallic surface of the workpiece undergoes plastic deformation by the pressing action of a hard and highly polished rotating burnishing ball or roller. In the present work an attempt was made to study the effects of different burnishing parameters (force, speed and feed) on surface roughness and hardness of cast AlCu alloys. The experiments were conducted with a simply designed ball burnishing tool. The results obtained show that an improvement in surface characteristics can be achieved by the application of this process on cast AlCu workpieces.

Influence of burnishing process on surface roughness, hardness, and microstructure of some non-ferrous metals

Burnishing is a cold working process, which easily produces a smooth and work-hardened surface by plastic deformation of surface irregularities. In the present work, the influence of the main burnishing parameters (speed, feed, force, number of tool passes, and ball diameter) on the surface roughness and the hardness of two different non-ferrous metals were studied. Furthermore, subsurface hardness and microstructure under specific conditions were also studied. It was found that the burnishing forces and the number of tool passes are the most pronounced parameters, which have great effects on the workpiece's surface during the burnishing process. A simple, inexpensive and newly designed ball-burnishing tool, with interchangeable adapter for using different ball diameters, was used throughout the experimental work presented in this paper.

Ball burnishing of 316L stainless steel

The process of ball burnishing AISI 316L stainless steel was studied. Taguchi techniques for the statistical design of experiments were employed to establish the optimum parameters for achieving good surface finish (response) on flat specimens. An L16 (4 5) orthogonal array was chosen to study the effects of five burnishing parameters (control factors). The roughness of the pre-burnished surface was included as a noise factor. It was found that the type of ball material, the depth of penetration, the burnishing speed and the type of lubricant significantly affect, at a 99% level of confidence, the surface finish of the burnished specimens. Feed was significant at a 95% level of confidence. The minimum roughness could be achieved using ZrO 2 as the ball material, kerosene as lubricant, a depth of penetration of 20 μm, a feed of 110 μm and a burnishing speed of 300 mm/min. A confirmation test yielded an average surface finish of 1.017 μm ( R tm ), which fell within a 90% confidence interval constructed about the predicted optimum. Using this set of parameters, a 3D curved surface was similarly burnished. The curved surface was generated using the solid modeler CATIA running on an IBM 4381 P13 mainframe. Pre-burnishing milling and ball burnishing were performed in a single setting on a LeBlond Makino FNC40 vertical machining centre. Surface roughness values varying between 0.6 and 0.9 μm ( R tm ) were obtained for the curved surface.

Investigations on the surface roughness produced by ball burnishing

Burnishing, a plastic deformation process, can be used to finish surfaces. Experimental work was conducted on a vertical machining centre to establish the effects of various ball burnishing parameters: depth of penetration, feed, ball material, burnishing speed and lubricant, on the surface roughness of AISI 1045 specimens. The ball materials used were WC and SUJ2. It was found that all the parameters studied affect the surface finish to varying degrees. The surface roughness parameter R tm first decreases and then increases with increasing depth of penetration. The effects of feed and burnishing forces on the surface finish also showed similar trends. The effect of speed depends on the type of lubricant used. Grease is a better lubricant than cutting oil for the speed range of 450 mm min −1 to 1200 mm min −1. With appropriate selection of the process parameters, a pre-machined surface roughness of about 4 μm can be finished to approximately 0.7 μm.

Surface hardening by ball burnishing

The ball burnishing process is becoming more popular not only as a finishing process but also for improving the service properties of machine parts. Experimental work was carried out on a vertical machining centre to establish the effects of four ball burnishing parameters, depth of penetration, feed, ball material and lubricant, on the burnishing forces and the hardness of the AISI 1045 specimens. The variation of hardness below the burnished surface is also reported. A 68% increase in hardness can be obtained. The layer of maximum hardness lies beneath the burnished surface.