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.

INVESTIGATION OF SINGLE-POINT DRESSING OVERLAP RATIO AND DIAMOND-ROLL DRESSING INTERFERENCE ANGLE ON SURFACE ROUGHNESS IN GRINDING

2010 ◽  
Vol 34 (2) ◽  
pp. 295-308 ◽  
Author(s):  
Akram Saad ◽  
Robert Bauer ◽  
Andrew Warkentin
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Empirical Model ◽  
Material Removal ◽  
Removal Rate ◽  
Single Point ◽  
Experimental Conditions ◽  
Workpiece Surface ◽  
Different Depths ◽  
Overlap Ratio

This paper investigates the effect of both single-point and diamond-roll dressing techniques on the workpiece surface roughness in grinding. Two empirical surface roughness models are studied – one that incorporates single-point dressing parameters, and another that incorporates diamond-roll dressing parameters. For the experimental conditions used in this research, the corresponding empirical model coefficients are found to have a linear relationship with the inverse of the overlap ratio for single-point dressing and the interference angle for diamond-roll dressing. The resulting workpiece surface roughness models are then experimentally validated for different depths of cut, workpiece speeds and dressing conditions. In addition, the models are used to derive a relationship between overlap ratio for single-point dressing, and interference angle for diamond-roll dressing such that both dressing techniques produce a similar surface finish for a given material removal rate.

Experimental investigations into abrasive flow machining (AFM) of 3D printed ABS and PLA parts

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nitin Dixit ◽  
Varun Sharma ◽  
Pradeep Kumar
Keyword(s):  
Surface Roughness ◽  
Biomedical Applications ◽  
Fused Deposition Modeling ◽  
Experimental Investigations ◽  
Future Research ◽  
Content Type ◽  
Abrasive Flow Machining ◽  
Fused Deposition ◽  
Cylindrical Parts ◽  
3D Printed

Purpose The surface roughness of additively manufactured parts is usually found to be high. This limits their use in industrial and biomedical applications. Therefore, these parts required post-processing to improve their surface quality. The purpose of this study is to finish three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) parts using abrasive flow machining (AFM). Design/methodology/approach A hydrogel-based abrasive media has been developed to finish 3D printed parts. The developed abrasive media has been characterized for its rheology and thermal stability using sweep tests, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The ABS and PLA cylindrical parts have been prepared using fused deposition modeling (FDM) and finished using AFM. The experiments were designed using Taguchi (L9 OA) method. The effect of process parameters such as extrusion pressure (EP), layer thickness (LT) and abrasive concentration (AC) was investigated on the amount of material removed (MR) and percentage improvement in surface roughness (%ΔRa). Findings The developed abrasive media was found to be effective for finishing FDM printed parts using AFM. The microscope images of unfinished and finished showed a significant improvement in surface topography of additively manufactures parts after AFM. The results reveal that AC is the most significant parameter during the finishing of ABS parts. However, EP and AC are the most significant parameters for MR and %ΔRa, respectively, during the finishing of PLA parts. Practical implications The FDM technology has applications in the biomedical, electronics, aeronautics and defense sectors. PLA has good biodegradable and biocompatible properties, so widely used in biomedical applications. The ventilator splitters fabricated using FDM have a profile similar to the shape used in the present study. Research limitations/implications The present study is focused on finishing FDM printed cylindrical parts using AFM. Future research may be done on the AFM of complex shapes and freeform surfaces printed using different additive manufacturing (AM) techniques. Originality/value An abrasive media consists of xanthan gum, locust bean gum and fumed silica has been developed and characterized. An experimental study has been performed by combining printing parameters of FDM and finishing parameters of AFM. A comparative analysis in MR and %ΔRa has been reported between 3D printed ABS and PLA parts.

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.

An empirical model of four processes for sharing organisational knowledge

2014 ◽  
Vol 38 (2) ◽  
pp. 305-320 ◽  
Author(s):  
August Tsai
Keyword(s):  
Business Process ◽  
Empirical Model ◽  
Process Model ◽  
Value Added ◽  
Technology Infrastructure ◽  
Knowledge Application ◽  
Content Type ◽  
Proposed Model ◽  
Organisational Knowledge

Purpose – This study aims to introduce an empirical model which incorporates newsgroups, knowledge forums, knowledge assets and knowledge application processes to share organisational knowledge. Therefore it seeks to illustrate an application for integrating knowledge management (KM) into the business process. Design/methodology/approach – The Taiwanese contingent of an international certification body – also a council member of the International Organisation for Standardisation (ISO) – was selected for a case study. A hybrid technology infrastructure was designed and employed to implement the proposed model. Based on knowledge value added validation, the proposed KM model provides a set of new operating systems for sharing knowledge within an organisation. Findings – Although many theories regarding implementation of KM in organisations have been proposed and studied, an application model for practical integration of various modern principles to share organisational knowledge is strategically important. Therefore a model that integrates principal KM applications into the business process, and the measurement of the resulting benefits, has been developed. Originality/value – Knowledge is a valuable asset for an individual in today's economy; nevertheless the acquisition of such an asset relies heavily on knowledge sharing within an organisation. The author has proposed an exclusive hybrid platform with an empirical process model to address innovative approaches and practical values of KM within an organisation.

Study on Precision Polishing of a Mini Roller Mold

2010 ◽  
Vol 126-128 ◽  
pp. 551-556
Author(s):  
Choung Lii Chao ◽  
Ying Ching Hsiao ◽  
Wen Chen Chou ◽  
Chia Wei Kuo ◽  
Wen Lang Lai ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Surface Finish ◽  
Empirical Model ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Condition ◽  
Microscopic Analysis ◽  
Semi Empirical ◽  
Better Than

This research aimed to design and develop a polishing system for precision polishing mini roller mold to nanometer surface finish. An experimental polishing system was built in the present study to polish nickel plated specimens with various polishing compounds. The polished specimens were subsequently examined by Alfa-step, OM and SEM for surface finish, morphology and microscopic analysis respectively. The obtained surface condition and material removal rate were correlated to the polishing parameters such as spindle speed, abrasive concentration, and abrasive grit size for the improvement of the polishing effect. Mini-rollers of 5mm in diameter, 50mm in length were successfully polished to a surface roughness better than 2nm Ra in several hours without damaging the roundness and cylindricalness using abrasive of 0.3μm, 10,000rpm polishing speed and 0.5mm gap distance between polisher and the specimen. A semi-empirical model of polishing was also developed in the study for predicting the materials removal rate.

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.

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.

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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