scholarly journals Towards the Determination of Machining Allowances and Surface Roughness of 3D-Printed Parts Subjected to Abrasive Flow Machining

2021 ◽  
Vol 5 (4) ◽  
pp. 111
Author(s):  
Mykhailo Samoilenko ◽  
Greg Lanik ◽  
Vladimir Brailovski
Keyword(s):  
Surface Roughness ◽  
Computer Aided Design ◽  
Material Removal ◽  
Orientation Dependence ◽  
Surface Finishing ◽  
Abrasive Medium ◽  
Abrasive Flow Machining ◽  
Planar Surfaces ◽  
Numerical Tool

Abrasive flow machining (AFM) is considered as one of the best-suited techniques for surface finishing of laser powder bed fused (LPBF) parts. In order to determine the AFM-related allowances to be applied during the design of LPBF parts, a numerical tool allowing to predict the material removal and the surface roughness of these parts as a function of the AFM conditions is developed. This numerical tool is based on the use of a simplified viscoelastic non-Newtonian medium flow model and calibrated using specially designed artifacts containing four planar surfaces with different surface roughnesses to account for the build orientation dependence of the surface finish of LPBF parts. The model calibration allows the determination of the abrasive medium-polished part slip coefficient, the fluid relaxation time and the abrading (Preston) coefficient, as well as of the surface roughness evolution as a function of the material removal. For model validation, LPBF parts printed from the same material as the calibration artifacts, but having a relatively complex tubular geometry, were polished using the same abrasive medium. The average discrepancy between the calculated and experimental material removal and surface roughness values did not exceed 25%, which is deemed acceptable for real-case applications. A practical application of the numerical tool developed was demonstrated using the predicted AFM allowances for the generation of a compensated computer-aided design (CAD) model of the part to be printed.

Development of the improved Preston equation for abrasive flow machining of aerofoil structures and components

2018 ◽  
Vol 233 (9) ◽  
pp. 1397-1404 ◽  
Author(s):  
Kai Cheng ◽  
Yizhi Shao ◽  
Mitul Jadva ◽  
Rodrigo Bodenhorst
Keyword(s):  
Surface Roughness ◽  
Material Removal ◽  
Machining Process ◽  
Dynamics Simulation ◽  
Abrasive Machining ◽  
Abrasive Particles ◽  
Abrasive Flow Machining ◽  
Flow Features ◽  
The Media ◽  
Experimental Trials

The paper presents an improved Preston equation, which aims to be part of the industrial application to abrasive flow machining. The equation will aid the engineers to optimise the process for desired surface roughness and edge tolerance characteristics on complex geometries in an intuitive and scientific manner. The methodology presented to derive the equation underpins the fundamental cutting mechanics of abrasive machining or polishing assuming all abrasive particles within the media are spherical as manufacturers defined. Further to derivation, full four factorial experimental trials and computational fluid dynamics simulation are implemented to generate the flow features of media on coupon to evaluate and validate the equation for its competency and accuracy on prediction of material removal. The modified Preston equation can significantly contribute to optimise the abrasive flow machining process, and will advantage the integrated machine design to predict better virtual surface roughness and material removal rates.

Model of surface roughness and material removal using abrasive flow machining of selective laser melted channels

2020 ◽  
Vol 26 (7) ◽  
pp. 1165-1176
Author(s):  
Julian Ferchow ◽  
Harry Baumgartner ◽  
Christoph Klahn ◽  
Mirko Meboldt
Keyword(s):  
Surface Roughness ◽  
Empirical Model ◽  
Material Removal ◽  
Maximum Deviation ◽  
Channel Diameter ◽  
Content Type ◽  
Abrasive Flow Machining ◽  
Fluid Behavior ◽  
Proposed Model ◽  
Power Law Index

Purpose Internal channels produced by selective laser melting (SLM) have rough surfaces that require post-processing. The purpose of this paper is to develop an empirical model for predicting the material removal and surface roughness (SR) of SLM-manufactured channels owing to abrasive flow machining (AFM). Design/methodology/approach A rheological model was developed to simulate the viscosity and power-law index of an AFM medium. To simulate the pressure distribution and velocity in the SLM channels, the fluid behavior and SR in the channels were simulated by using computational fluid dynamics. The results of this simulation were then applied to create an empirical model that can be used to predict the SR and material removal thickness. To verify this empirical model, it was applied to an actual part fabricated by SLM. The results were compared with the measurements of the SR and channel diameter subsequent to AFM. Findings The proposed model exhibits maximum deviation between the model and the measurement of −1.1% for the down-skin SR, −0.2% for the up-skin SR and −0.1% for material removal thickness. Practical implications The results of this study show that the proposed model can avoid expensive iterative tests to determine whether a given channel design leads to the desired SR after smoothing by AFM. Therefore, this model helps to design an AFM-ready channel geometry. Originality/value In this paper, a quantitatively validated AFM model was proposed for complex SLM channels with varying orientation angles.

Study on machining mechanism of high viscoelastic abrasive flow machining for surface finishing

2016 ◽  
Vol 231 (4) ◽  
pp. 608-617 ◽  
Author(s):  
Zhiguo Dong ◽  
Gang Ya ◽  
Jiancheng Liu
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Experimental Tests ◽  
Normal Pressure ◽  
Machining Process ◽  
Surface Finishing ◽  
Abrasive Flow Machining ◽  
Machining Mechanism ◽  
Flow Pressure

Abrasive flow machining is a pragmatic machining process used for part finishing. This article primarily focuses on the study of machining mechanism of high viscoelastic abrasive flow machining, with the aim to understand the relation among the abrasive media’s flow pressure, the material removal rate and the machining quality. The theoretical calculation models of the normal pressure on the inner surface of a circular tube and the wall sliding velocity are established based on rheology theory. The material removal rate of abrasive flow machining with a high viscoelastic abrasive media is derived. Numerical simulations with various machining conditions were conducted using the mathematical models proposed in this research and the obtained findings are discussed. The feasibility of these models introduced for high viscoelastic abrasive machining is also investigated and verified through actual experimental tests.

The Prediction of Material Removal and Surface Roughness of Workpiece during Abrasive Flow Machining

2013 ◽  
Vol 579-580 ◽  
pp. 70-75
Author(s):  
Guang Zhen Zheng ◽  
Ke Hua Zhang ◽  
Jin Fu Ding ◽  
Zeng Hao Fang ◽  
Li Bin He
Keyword(s):  
Surface Roughness ◽  
Theoretical Calculation ◽  
Axial Force ◽  
Material Removal ◽  
Radial Force ◽  
Abrasive Flow Machining ◽  
Pressure Transducers ◽  
Material Deformation ◽  
Removal Weight

In order to study the finishing mechanism of abrasive flow machining (AFM), the model of material removal and solving method of surface roughness during material deformation have developed based on axial force and radial force. However, the axial force and radial force have been respectively measured by two pressure transducers fixed in the fixture. Both the material removal weight and surface roughness of workpiece have been calculated and measured during AFM experiments. The conclusions arrived by the analysis about the results of theoretical calculation are in agreement with the experimental AFM in some extent.

Effect of Media Degradation on Finishing Characteristics in Abrasive Flow Machining

2016 ◽  
Vol 874 ◽  
pp. 127-132
Author(s):  
Takashi Sato ◽  
Edwin Soh ◽  
Yuuichiro Nakayama ◽  
Miki Shinagawa ◽  
Yasuhiko Fukuchi
Keyword(s):  
Surface Roughness ◽  
Flow Rate ◽  
Significant Influence ◽  
Material Removal ◽  
Complex Geometry ◽  
Process Conditions ◽  
Flow Volume ◽  
Abrasive Flow Machining ◽  
Minor Influence ◽  
Single Batch

Abrasive flow machining (AFM) is one of the most promising technologies for internal finishing and de-burring for features with complex geometry. This study investigates the effect of media degradation on finishing characteristics achieved using the AFM process. A total of 50 experiments, using Inconel 718 cylindrical coupons machined by Wire-Electron Discharge Machining (WEDM), were conducted employing the same process conditions while using a single batch of AFM media. Experimental results indicate that media degradation has minor influence on surface roughness, but more significant influence on material removal and media flow rate. Material removal decreases exponentially with increasing cumulative media flow volume despite media flow rate increasing. There is a linear correlation between material removal and media flow rate. As a result, material removal can be estimated from media flow rate which can be monitored easily.

Ion Beam Machining of Micromechanical Structures

1986 ◽  
Vol 76 ◽  
Author(s):  
S. T. Davies ◽  
D. K. Bowen
Keyword(s):  
Surface Roughness ◽  
High Precision ◽  
Material Removal ◽  
Ion Beam ◽  
Surface Finishing ◽  
Precision Engineering ◽  
Surface Evolution ◽  
Fine Surface ◽  
Micromechanical Structures ◽  
Argon Ion

ABSTRACTThe needs of high precision engineering currently call for dimensional tolerances of the order of 0.1μm and surface roughness of order 0.01μm, often in hard, brittle materials or materials of relatively poor machinability. The development of argon ion beam machining for milling, drilling and turning or lathing is reported as a means of satisfying these requirements. Highly controllable material removal is achieved for the fabrication of micromechanical structures, profiling of surfaces and fine surface finishing. Surface evolution at submicron precision is demonstrated, with particular reference to the production of both circular and non-circular sections in an “ion beam lathe”.

Precision Honing of Stainless Steel Valve Core

2011 ◽  
Vol 487 ◽  
pp. 438-442
Author(s):  
Zhi Gang Dong ◽  
C.W. Kang ◽  
L. Xu
Keyword(s):  
Experimental Study ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Topography ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Grit Size ◽  
Steel Cylinder

The paper reports an experimental study on the effect of honing parameters on the honing surface roughness, material removal rate and surface topography. A cylindrical honing machine was developed, on which the honing experiments for stainless steel cylinder parts were performed with different honing parameters including the abrasives and its grit size of honing stones, honing pressure and honing time. The results can provide helpful instruction to the determination of the honing process and parameters.

Effects of Helical Rod Profiles in Helical Abrasive Flow Machining (HLX-AFM) Process

2015 ◽  
Author(s):  
B. S. Brar ◽  
R. S. Walia ◽  
V. P. Singh ◽  
P. Singh
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Material Removal ◽  
Work Piece ◽  
Drill Bit ◽  
Twist Drill ◽  
Abrasive Flow Machining ◽  
Helical Twist ◽  
Percentage Improvement ◽  
Finishing Process

Abrasive flow machining (AFM) process is a fine finishing process employing abrasive laden self modulating putty for the finishing of mainly internal recesses. Though the AFM is suitable for the finishing of internal cavities, but the material removal is very low during this finishing process. Helical abrasive flow machining (HLX-AFM) has been recently developed to improve the machining efficiency of AFM process. This process employs a coaxially fixed helical twist drill-bit during the extrusion of the abrasive laden media through an internal cylindrical recess. The presence of a fixed drill-bit inside a cylindrical cavity of the work-piece results in considerable increase in material removal and improvement in surface finish. In the present investigation, the same HLX-AFM setup has been used and the effects of two more helical profile rods viz. a 3-start helical profile and a spline have been studied along with the helical twist drill-bit for improving the quality characteristics of material removal and percentage improvement in the surface roughness during the fine finishing of internal cylindrical surface of brass work-pieces. The experiments were planned according to L9 orthogonal array of Taguchi method and the optimal process parameters were selected. The employment of a rod with six splines and a 3-start helical profile results in improved finishing in comparison to the drill-bit profile, due to the presence of more number of flutes and grooves on the coaxially held stationary rods. The helical profile type has 3.75% contribution towards the percentage improvement in the surface roughness, but is not significant in affecting material removal. The presence of 3-start helical profile led to 61.40% improvement in surface roughness (from Ra - 1.3 μm to 0.5 μm) at optimal level with no effect on material removal, which means no extra machining is taking place. The parameter of abrasive-to-media concentration ratio (varying from 0.75 to 1.25) is the most contributing factor with 85.90% contribution toward suface finish improvement and 71.71% contribution towards material removal. The finishing performance of 3-start profile is 15% better than the standard helical drill-bit with no increase in the operating pressures. SEM micrographs corroborated the fact that 3-start profile led to more number of light abrasive cutting grooves and thus more surface finish. HLX-AFM with 3-start helical profile rods can be employed for the finishing, form corrections of internal cylindrical cavities of any size. Presence of the profile rod results in increase in the reduction ratio and thus more machining action. The developed process can also generate cross-hatch lay pattern on internal cylindrical surfaces.

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