Viscoelastic medium modeling and surface roughness simulation of microholes finished by abrasive flow finishing process

2018 ◽  
Vol 100 (5-8) ◽  
pp. 1165-1182 ◽  
Author(s):  
Sachin Singh ◽  
Deepu Kumar ◽  
M. Ravi Sankar ◽  
V. K. Jain
Keyword(s):  
Surface Roughness ◽  
Viscoelastic Medium ◽  
Finishing Process ◽  
Abrasive Flow Finishing

Development of polymer abrasive medium for nanofinishing of microholes on surgical stainless steel using abrasive flow finishing process

2019 ◽  
Vol 234 (3) ◽  
pp. 355-370 ◽  
Author(s):  
Sachin Singh ◽  
M Ravi Sankar
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
High Surface ◽  
Machining Process ◽  
Abrasive Medium ◽  
Finishing Process ◽  
Drug Eluting ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

The finishing operation completes the manufacturing cycle of a component. Depending on the level of finish (micro and nano) required on the component surface, different finishing processes are employed. Several components employed in medical, automotive and chemical industries use different types of passages for the flow of fluid. The surface roughness of such passages decides the functionality of the component. Drug-eluting stents are one of the recent advancements in the medical industry. They possess microholes for release of the drugs to the point of cure. Microholes are mostly fabricated by thermal-based micromachining processes that generate metallurgically destroyed surface layers with high surface roughness. Later, these are polished using chemical or electrochemical polishing techniques, which chemically destroy the quality of the surface. These metallurgically and chemically modified (destroyed/changed) rough surfaces on the microhole wall can cause contamination of the drug. So in this article, microholes of diameter 850 ± 30 µm are fabricated in surgical stainless steel (SS 316L) workpieces using the electric discharge micromachining process. Machined microholes are finished by employing a non-traditional finishing process called the abrasive flow finishing process. Instead of using a commercially available expensive abrasive flow finishing medium, the economic medium is fabricated in-house, and its rheological study is carried out. Machining process produces microholes with a surface roughness of about 1.40 ± 0.10 µm. Later, by finishing of microholes with the abrasive flow finishing process, the surface roughness is reduced to 150 nm (percentage surface roughness improvement of about 88.53%). Therefore, the abrasive flow finishing process is a viable alternative to chemical-based polishing processes as it removes the recast layer and achieves nanosurface roughness.

Development and Rheological Characterisation of Abrasive Flow Finishing Medium for Finishing Macro to Micro Features

2020 ◽  
Vol 70 (2) ◽  
pp. 190-196
Author(s):  
Sachin Singh ◽  
M. Ravi Sankar
Keyword(s):  
Surface Roughness ◽  
Surface Finish ◽  
Recast Layer ◽  
Technological Advancement ◽  
Minimal Cost ◽  
Finishing Process ◽  
Fine Surface ◽  
Micro Features ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

Technological advancement demands the manufacturing of components with a fine surface finish at a minimal cost. This scenario acts as the driving force for the research communities to develop economic finishing processes. Abrasive flow finishing (AFF) is one of the advanced finishing processes employed for finishing, deburring, radiusing and recast layer removal from the workpiece surfaces. AFF process uses a finishing medium that acts as a deformable tool during the finishing process. It is the rheological properties of the medium that profoundly influences the end surface finish obtained on the workpiece after the AFF process. In the current work, an attempt is made to develop an economic AFF medium by using viscoelastic polymers i.e., soft styrene and soft silicone polymer. Detailed static and dynamic characterisation of the medium is carried out. Later, to study the finishing performance of the developed medium, AFF experiments are performed for the finishing of macro and micro feature components. The experimental study showed that the nano surface finish could be achieved by varying the viscosity of the developed medium. Developed medium achieved 89.06 per cent improvement in surface roughness during finishing of tubes (macro feature component), while 92.13 per cent and 88.11 per cent surface roughness improvement is achieved during finishing of microslots and microholes (micro feature component), respectively.

Experimental, Theoretical, and Simulation Comparative Study of Nano Surface Roughness Generated During Abrasive Flow Finishing Process

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Sachin Singh ◽  
Deepu Kumar ◽  
Mamilla Ravi Sankar
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Simulation Model ◽  
Abrasive Particle ◽  
Complex Surface ◽  
Abrasive Medium ◽  
Finishing Process ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

Abrasive flow finishing (AFF) is one of the advanced finishing processes used mainly for finishing of complex surface features. Nano finishing of aluminum alloys is difficult using conventional finishing processes because of its soft nature. So, in this work, aluminum alloys are finished using AFF process. Since the finishing is carried out using polymer rheological abrasive medium (medium), the finishing forces on aluminum alloy workpieces are too low compared to conventional finishing processes. Thus, this process generates nano surface roughness on aluminum alloy. By using the theoretical model, change in surface roughness (ΔRa) with respect to various AFF input parameters is studied. A new simulation model is proposed in this paper to predict the finishing forces and ΔRa during AFF process. Modeling of finishing forces generated during the AFF process is carried out using ansys polyflow. These forces are used as input in the simulation model to predict ΔRa. Medium rheology decides the magnitude of the generated finishing forces in AFF process. Therefore, to predict the forces accurately, rheological properties of the medium are measured experimentally and used as input during modeling. Further, to make the simulation more realistic, abrasive particle bluntness with respect to extrusion pressure and number of strokes is considered. Because of considering these realistic conditions, simulation and experimental results are in better agreement compared to theoretical results.

Investigation on Precision Finishing of Helical Gears Using Newly Developed Silicon Carbide Mixed Styrene Butadiene Media and Abrasive Flow Finishing Process

2021 ◽  
Vol 06 ◽  
Author(s):  
Irfan Ahmad Ansari ◽  
Dipti Sharma ◽  
Kamal K. Kar ◽  
Janakarajan Ramkumar
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Surface Finish ◽  
Helix Angle ◽  
Helical Gears ◽  
Good Surface ◽  
Finishing Process ◽  
Good Surface Finish ◽  
Styrene Butadiene ◽  
Abrasive Flow Finishing

The good surface finish of gears is one of the critical parameters which leads to its noise-free operation, efficient power transmission, and longer service life. However, most of the gear manufacturing processes do not produce a good surface finish. Therefore, gears need post-processing to finish their surface. Out of several methods of gear finishing like gear grinding, lapping, and honing, the abrasive flow finishing process offers more flexibility due to its self-deformable abrasive medium which can easily flow across complex internal or external geometry. The present study aims to improve the surface finish of helical gear by abrasive flow finishing (AFF) by experimentally identifying the optimum range of the potential input process parameters. An AFF set up was used for gear finishing by using a medium of styrene-butadiene and soft silicone polymer, Silicon carbide abrasive, and silicone oil as a blending agent. A special fixture was developed comprising of five parts namely spider, mandrel, upper, middle, and bottom cylinder with a circumferential hole, which allows the back and forth movement of AFF medium through the annular volume between fixture and gear. Further, an experimental investigation of process parameters like viscosity, effect of percentage of various components in medium, operating pressure, and helix angle of helical gears have been studied on percentage improvement of surface roughness (Ra) value of the gear. It is found that the concentration of abrasives in media and extrusion pressure were the two most significant parameters that have a maximum effect on the percentage reduction in surface roughness and finishing rate. Results show that the optimum combination of the extrusion pressure and abrasive weight percentage is 38 bar and 40 % that produces best results of around 76 and 69 % improvement in Ra for gear of helix angle 30 degree and 45 degree respectively.

Optimal parameters of abrasive flow finishing for hip joint implants

2021 ◽  
pp. 095440542199561
Author(s):  
Yahya Choopani ◽  
Mohsen Khajehzadeh ◽  
Mohammad Reza Razfar
Keyword(s):  
Surface Roughness ◽  
Standard Deviation ◽  
Femoral Head ◽  
Hip Joint ◽  
Spherical Shape ◽  
Shape Deviation ◽  
Head Surface ◽  
Joint Implants ◽  
Finishing Processes ◽  
Abrasive Flow Finishing

Total hip arthroplasty (THA) is one of the most well-known orthopedic surgeries in the world which involves the substitution of the natural hip joint by prostheses. In this process, the surface roughness of the femoral head plays a pivotal role in the performance of hip joint implants. In this regard, the nano-finishing of the femoral head of the hip joint implants to achieve a uniform surface roughness with the lowest standard deviation is a major challenge in the conventional and advanced finishing processes. In the present study, the inverse replica fixture technique was used for automatic finishing in the abrasive flow finishing (AFF) process. For this aim, an experimental setup of the AFF process was designed and fabricated. After the tests, experimental data were modeled and optimized to achieve the minimum surface roughness in the ASTM F138 (SS 316L) femoral head of the hip joint through the use of response surface methodology (RSM). The results confirmed uniform surface roughness up to the range of 0.0203 µm with a minimum standard deviation of 0.00224 for the femoral head. Moreover, the spherical shape deviation of the femoral head was achieved in the range of 7 µm. The RSM results showed a 99.71% improvement in the femoral head surface roughness (0.0007) µm under the optimized condition involving the extrusion pressure of 9.10 MPa, the number of finishing cycles of 95, and SiC abrasive mesh number of 1000.

Modeling of surface roughness in a novel magnetorheological gear profile finishing process

2020 ◽  
pp. 095440622097826
Author(s):  
Ravi Datt Yadav ◽  
Anant Kumar Singh ◽  
Kunal Arora
Keyword(s):  
Surface Roughness ◽  
Gear Tooth ◽  
Surface Characteristics ◽  
Spur Gear ◽  
Tooth Profile ◽  
Tooth Surface ◽  
Magnetic Flux Density ◽  
Element Analysis ◽  
Finishing Process ◽  
Gear Profile

Fine finishing of spur gears reduces the vibrations and noise and upsurges the service life of two mating gears. A new magnetorheological gear profile finishing (MRGPF) process is utilized for the fine finishing of spur gear teeth profile surfaces. In the present study, the development of a theoretical mathematical model for the prediction of change in surface roughness during the MRGPF process is done. The present MRGPF is a controllable process with the magnitude of the magnetic field, therefore, the effect of magnetic flux density (MFD) on the gear tooth profile has been analyzed using an analytical approach. Theoretically calculated MFD is validated experimentally and with the finite element analysis. To understand the finishing process mechanism, the different forces acting on the gear surface has been investigated. For the validation of the present roughness model, three sets of finishing cycle experimentations have been performed on the spur gear profile by the MRGPF process. The surface roughness of the spur gear tooth surface after experimentation was measured using Mitutoyo SJ-400 surftest and is equated with the values of theoretically calculated surface roughness. The results show the close agreement which ranges from −7.69% to 2.85% for the same number of finishing cycles. To study the surface characteristics of the finished spur gear tooth profile surface, scanning electron microscopy is used. The present developed theoretical model for surface roughness during the MRGPF process predicts the finishing performance with cycle time, improvement in the surface quality, and functional application of the gears.

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