Abrasive Flow Finishing Process Research Articles

Experimental investigation on deballing and surface finishing of selective laser melted 18Ni300 steel using polymer rheological abrasive medium

Additively manufactured metallic parts compete with casted and forged parts in physical and mechanical properties. However, the presence of various surface defects, such as balling and staircase effects, lack of fusion, surface undulations, etc., hinders the direct functional application of the as-built part and demands further post-processing. Abrasive flow finishing (AFF) is an extensively employed post-processing technique to finish additively manufactured parts. This process uses polymer rheological abrasive medium (abrasive medium) to finish internal and external surfaces. Even though significant research has been carried out on the surface finishing of selective laser melted metallic parts, the mechanism of material removal and surface finish improvement is not explored much. In the present work, the mechanism of deballing and surface finish improvement on selective laser melted 18Ni300 steel using the AFF process is studied. A newly developed polysaccharide-based abrasive media with monomodal and bimodal abrasive particle distribution are employed for finishing. At an extrusion pressure of 7.5 MPa, the influence of abrasive particle distribution and the number of finishing cycles on the amount of material removed and percentage change in surface roughness (% ΔRa) is observed. It was found that the abrasive medium with bimodal abrasive particle distribution resulted in more material removal and % ΔRa than monomodal. Surface roughness reduction of up to 93% was obtained using the abrasive medium with bimodal abrasive particle distribution. It was noticed that the loosely adhered powder particles were removed within the initial 15 cycles, and the balling effect was completely eliminated within 75 cycles. After 375 cycles, the as-built side surface was free from all other surface defects, such as micro-cracks, shallow pits, material ridges etc. Based on the obtained results, a suitable material removal mechanism in selective laser melting parts using the AFF process was proposed.

Sound intensity analysis of straight bevel gears finished by using AFF process

This article reports using the Abrasive flow finishing (AFF) process to finish straight bevel gears (SBG) to improve their microgeometry errors and surface characteristics. Microgeometry errors, surface roughness parameters, and dual flank roll testing parameters was compared for unfinished and the AFF finished SBG. An indigenously developed bevel gear test rig was used for the sound intensity measurement and experiments were conducted by varying speeds at four levels. Finishing of SBG by the AFF process reduced their microgeometry errors, surface roughness, and improved functional performance parameters, resulting in reduced sound power generation. This study proves the potential of the AFF process to improve gear quality and help to establish it as a cost-effective, productive, and sustainable non-traditional solution for high-quality gear finishing.

Development and performance evaluation of galactomannan polymer based abrasive medium to finish atomic diffusion additively manufactured pure copper using abrasive flow finishing

Abrasive flow finishing (AFF) is an advanced finishing process where the surface roughness of the component is gradually reduced by reciprocating an abrasive medium. A typical abrasive medium consists of base polymers, rheological additives, and abrasive particles. In most cases, the base polymer chains are based on siloxane, natural or synthetic elastomers, thermoplastic polymers, etc. The abrasive media developed with these polymer chains are expensive, and most of them are not biodegradable. In the recent past, hydrogel-based abrasive media gained significant attention as it results in a cost-effective, eco-friendly, and biodegradable abrasive medium. Since water is the main constituent in these media, this may cause corrosion of the component surfaces. Due to the high shear strain rates involved in the AFF process, the hydrogel-based media quickly lose moisture and becomes dry; thus, the life of the media reduces. In the present work, a long-lasting and noncorroding abrasive medium was indigenously developed for the AFF process. This medium constitutes galactomannan polymer, glycerol solution, cross-linker, and abrasive particles. The developed medium was absolutely free from expensive rheological modifiers. In addition to the rheological characterization, the developed medium was characterized using scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. The finishing performance of the developed media was assessed by finishing atomic diffusion additively manufactured (ADAM) pure copper curved samples. The effect of the number of finishing cycles, extrusion pressure, and abrasive mesh size was investigated on the amount of material removed and the percentage change in average surface roughness (Ra). A reduction of Ra up to 90% in the longitudinal direction and 75% in the transverse direction was obtained using the developed abrasive medium. Based on the obtained finishing results, the material removal mechanism from the ADAM surface was proposed.

A study on in-vitro behaviour of stainless steel 316L subjected to rotational magnetorheological abrasive flow finishing process

In Rotational Magnetorheological Abrasive Flow Finishing (R-MRAFF) process, Magnetic Field Intensity (MFI) is the primary factor for the formation of ferrous chains which is responsible for finishing. Changing the pole distance between magnets to achieve a difference in MFI values will alter the strength of the ferrous chains. In this study, three different MFI values such as 0.34, 0.36, and 0.40 Tesla were chosen for finishing on Stainless Steel 316L (SS 316L). Surface wettability, bio-corrosion, and hemocompatibility studies were conducted to investigate the in-vitro behavior of SS 316L. The wettability of the implants changed from hydrophobic (100.92°) to hydrophilic (83.452°) surface as the MFI value increased. Bio-corrosion studies revealed improved corrosion resistance for R-MRAFF process finished samples, with the corrosion rate reduced from 3.693 to 0.967 μm year−1. Hemocompatibility of SS 316L was improved with reduced platelet adhesion when compared to the pristine sample.

Using abrasive flow finishing process to reduce noise and vibrations of cylindrical and conical gears

This paper reports on reduction of noise and vibrations of cylindrical and conical gears through simultaneous reduction in their microgeometry errors, functional parameters, and surface roughness by finishing them with abrasive flow finishing (AFF) process. Previously identified optimum values of AFF medium viscosity and finishing time were used during AFF of the chosen gears. Noise and vibrations characteristics of the unfinished gears and the AFF finished gears were studied by varying motor speed and applied load at four levels each. An indigenously developed test rig was used for spur and straight bevel gears whereas drivetrain diagnostic simulator was used for helical gears. Indigenously developed dual flank roll tester was used to evaluate functional parameters of the unfinished and the best finished gears by AFF process. It was found that AFF process simultaneously reduced microgeometry errors, functional parameters, maximum and average values of surface roughness of spur, helical, and straight bevel gears. It reduced noise and vibration by 5.2 dBA and 5.3 m/s2 for spur gears, by 3.4 dBA and 7.5 m/s2 for helical gears, and by 4.6 dBA and 4 m/s2 for straight bevel gears. This study proves that AFF is an easy-to-operate and effective process for reducing noise and vibrations of cylindrical and conical gears through simultaneous reduction in their microgeometry errors, functional parameters, and surface roughness values. Outcome of this work will be helpful for various manufactures and users of different types of gears.

Simultaneous improvement of microgeometry and surface quality of spur and straight bevel gears by abrasive flow finishing process

This article reports on influence of extrusion pressure, abrasive particle size and volumetric concentration on simultaneous reduction of surface roughness and microgeometry errors of spur and straight bevel gear by abrasive flow finishing (AFF) process. A vertical configured experimental apparatus was developed for two-way AFF and developed fixtures for finishing gears. Experimental investigations were conducted to identify optimum parametric combination, using response surface methodology, based on Box–Behnken design approach. Results revealed that higher values of abrasive particle size and volumetric concentration yield more percentage decrease in surface roughness and microgeometry error. Roughness profile, bearing area curve, microhardness, surface morphology, and wear resistance of the gear having best quality finishing were studied. Surface morphology analysis of the flank regions of the best finished spur and straight bevel gears found them to be smooth and free from cracks and burrs. Reciprocating wear test results revealed higher wear resistance of the AFF finished gears as compared to the unfinished gears. AFF also enhanced microhardness of the finished gears, which would enhance their operating performance and service life. This study shows that AFF is a flexible, economical, productive, easy to operate, and sustainable nontraditional process for precision finishing of gear that can simultaneously improve microgeometry, surface finish, microhardness, surface morphology, wear resistance, and residual stresses of the finished gears. Gear manufacturers and users will be benefited by the outcome of this study. JEL codes: C00, C20

Optimal parameters of abrasive flow finishing for hip joint implants

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.

Multi-Response Optimization of Magnetic Abrasive Flow Finishing Process on Aluminum (6061-T6) Using Utility Concept Embedded Firefly’s Algorithm

Surface finish is the most desired properties of any sophisticated machinery parts for its proper functioning and long endurance. The surface finish must be in the order of micrometer to nanometer for most of the machinery parts. The nontraditional surface finish processes prepare these parts; in these processes, the uses of electromagnet play a vital role in the surface finishing mechanism. Magnetic abrasive flow finishing (MAFF) is such a hybrid process, which gives a combined effect of abrasive flow finishing (AFF) and magnetic abrasive finishing (MAF). In this method, a pair of electromagnets are attached to the AFF setup. By using electromagnet in the AFF process, it enhanced material removal and surface finishing. The main process parameters selected in the MAFF process were magnetic flux density, number of cycles, percentage abrasive content, piston speed, and corresponding responses selected were material removal, percentage improvement in surface finish. In this research paper, the responses were optimized by a combination of utility theory and meta-heuristic firefly’s algorithm. The utility theory based-firefly algorithm’s predicted global optimum parameters set, which was more suitable for reducing the finishing time and required surface finish. The confirmatory test validated this optimized parameter set and it was revealed that the meta-heuristic firefly algorithm embedded with utility theory had given optimized results in the MAFF process.

Using inverse replica fixture technique for improving nano-finishing of hip joint implant in abrasive flow finishing process

The total hip arthroplasty (THA) is considered as one of the most successful orthopedic surgeries, through which the damaged hip joint is replaced with hip joint prosthesis. Besides, automatic nano-finishing of femoral head is of great importance in improving tribological, biological, and metallurgical properties of hip joint implants and increases the productivity of manufacturing process. In the present effort, to satisfy these requirements, a new inverse replica fixture of femoral head has been proposed in the abrasive flow finishing (AFF) process. In addition, the effect of AFF parameters including extrusion pressure, number of finishing cycles, and abrasive mesh size has been investigated on the surface roughness of the femoral head which is made of ASTM F 138 (SS 316 L). For conducting the experimental tests, a setup of AFF process is designed and fabricated. The experiments are performed according to the design of experiments and the full factorial method. Statistical analysis of the experimental data shows that the most significant parameter is the abrasive mesh size. Moreover, the surface topographic parameters of Ra, Rq, Rp, Rv, and Rt of femoral head under experimental conditions; extrusion pressure of 9 MPa, number of finishing cycles of 100, and abrasive mesh size of 1000 have improved by 91.71%, 91.21%, 81.84%, 88.46%, and 85.44%, respectively. Furthermore, SEM and AFM images of the surface texture of the femoral head before and after the AFF process demonstrate the elimination of CNC lathe traces along with achieving mirror-like surface up to the range of 20.3 nm. In addition, regarding the XRF results, no considerable variation in the chemical composition of femoral head before and after the AFF process is observed.

Laser texturing of helical and straight bevel gears to enhance finishing performance of AFF process

Abrasive flow finishing (AFF) is an advanced finished process which finds many applications for nano-finishing of many industrial components, but it has many disadvantages which restrict its applications. While finishing the gears, it creates a lay pattern which is along the lay already generated by a gear machining process. This deteriorates performance and service life of the AFF finished gears. This paper reports on laser texturing of flank surfaces of helical and straight bevel gears to enhance finishing performance of AFF process. Fiber laser of 1064 nm wavelength was used to create homothetic texture across the lay profile generated by gear manufacturing process on flank surface of helical and straight bevel gears using identified optimum combination of focal length, laser power, and number of passes. Laser textured and untextured and helical and straight bevel gears were finished by AFF for different values of the finishing time and using previously optimized values of AFF process parameters. Enhancement in finishing performance of AFF was assessed by comparing microgeometry errors, surface roughness, morphology, microhardness, and wear characteristics of the laser textured helical and straight bevel gears with that of the untextured gears. It revealed that laser texturing helped AFF in enhancing microhardness, wear resistance, material removal rate, and percentage reductions in microgeometry errors and surface roughness of the textured gears than the untextured gears. Surface morphology of AFF finished laser textured gears was smoother than the corresponding untextured gears. This study proves that laser texturing is an effective, simple, and economical method to enhance performance of AFF for finishing different types of gears without any modifications in the existing system.

Rheological study of the developed medium and its correlation with surface roughness during abrasive flow finishing of micro-slots

Abrasive flow finishing (AFF) is an advanced finishing process employed for finishing macro- to micro-features of workpieces. Finishing improves the functioning of the components by reducing their surface roughness. AFF process uses a polymer-based flexible medium containing abrasive particles as a finishing tool. Medium used during the AFF process plays a vital role in deciding the final surface roughness on the workpiece surface. It is the medium properties in combination with AFF input parameters that decide the end surface roughness. Micro-features on the components are mostly machined with the help of processes involving thermal energy (electrical discharge micro-machining, laser beam micro-machining). This leads to the formation of hard recast layer on the micro-machined workpiece surface. Component size and hardness of the recast layer possesses a great challenge to the finishing processes. In the current article, an economic viscoelastic medium is developed for the finishing of micro-features and its detailed rheological study is carried out. Later, experimental study of the AFF process during the finishing of micro-slots (440 ± 10 µm width) in surgical steel is performed. Developed medium successfully finishes the micro-slots with an initial surface roughness of 3.54 µm to a final surface roughness of 0.21 µm (94.07% reduction in surface roughness).

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

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 investigations into magnetic abrasive flow finishing process on aluminium 6061-T6

The magnetic abrasive flow finishing (MAFF) process has been developed and investigated as an advanced fine finishing process. It is used for a surface finish (SF) of the straight and complex intricate profile using the ferromagnetic nature of abrasive media. This article presents an experimental investigation on the newly developed MAFF attachment, which was mounted on a shaper machine. A custom design workpiece fixture was used in MAFF attachment for the finishing of a straight hollow cylinder shape workpiece, which can easily modify based on workpiece shapes. A curved workpiece seat was prepared and fasting with two brass plates by nut and bolts arrangement. Taguchi design of experiment approach applied for experimentation on aluminium 6061-T6 workpiece material by MAFF setup. The main process parameters considered for experimentation are magnetic flux density (MFD), number of cycles, abrasive concentration, and piston speed while responses are material removal (MR) and surface finish (SF). The results found after finishing by MAFF were also compared with the AFF. It was identified that remarkable enhancements observed in MAFF responses. The finished surfaces were also observed by scanning electron microscope (SEM) and X-ray diffraction (X-RD).

A critical review of past research and advances in abrasive flow finishing process

Abrasive flow finishing (AFF) is an advanced nano-finishing process using abrasive-laden self-deformable putty for finishing, deburring, radiusing, chamfering, stress-relieving, and mirror-like polishing of the complicated components and inaccessible areas which are difficult or impossible to finish by other processes. Since its inception during 1950s, continuous research and advances in AFF are being reported globally. This paper presents comprehensive and critical review of the past research and developments on process modeling, rheological characterization of the AFF medium, development of finishing medium, development of various hybrid, derived, and hybrid-derived processes of AFF, and some novel applications of AFF for complicated shapes and difficult-to-finish materials. Major findings and observations, details of the workpiece material, finishing medium, process parameters, and responses have been presented in a tabular format for quick reference. It also covers some novel applications of AFF in the field of avionics, automobiles, biomedical, gears, additive manufacturing, cutting tool inserts, die and mold manufacturing, and recast layer removal. Finishing results for various materials such as mild steel, brass, aluminum, and its alloys, tool steel, copper, metal matrix composite, and photopolymer resin are also included. It also identifies directions for future research and provides an invaluable list of literature on past research works on AFF process. This review article will be very useful for the researchers working in micro- and nano-finishing applications and the industries involved in manufacturing of the automobiles, aero-engines, avionics components, biomedical implants, gears, impellers, dies and molds, and defense equipment.

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

Surface roughness is one of the critical parameters that affect the component performance during its working life. To develop any process to its full potential, it is necessary to understand the physics of that process. Abrasive flow finishing (AFF) is one of the advanced finishing processes. In the current research work, an effort is made to understand physics and mechanism of surface roughness improvement during the AFF process. This research paper is divided into two sections. Firstly, the amount of finishing stresses and forces generated during the finishing of microholes fabricated on surgical stainless steel (316L) workpieces are computed by using the finite element method. Finishing stresses are generated in the viscoelastic medium. So, to compute finishing stresses, finite element analysis of the viscoelastic medium is carried out by incorporating its experimentally measured rheological properties. Finishing stresses are calculated along the circumferential direction of the microhole. Later, at the same workpiece surface location, simulated and experimentally measured surface roughness value are compared. Secondly, a new simulation model is proposed to predict the surface roughness on the microhole wall surface for various AFF input parameters. Maximum percentage change in surface roughness error of 8% is observed between simulated and experimental results after AFF process.

Nanofinishing of Microslots on Surgical Stainless Steel by Abrasive Flow Finishing Process: Experimentation and Modeling

Miniaturization of components is one of the major demands of the today's technological advancement. Microslots are one of the widely used microfeature found in various industries such as automobile, aerospace, fuel cells and medical. Surface roughness of the microslots plays critical role in high precision applications such as medical field (e.g., drug eluting stent and microfilters). In this paper, abrasive flow finishing (AFF) process is used for finishing of the microslots (width 450 μm) on surgical stainless steel workpiece that are fabricated by electrical discharge micromachining (EDμM). AFF medium is developed in-house and used for performing microslots finishing experiments. Developed medium not only helps in the removal of hard recast layer from the workpiece surfaces but also provides nano surface roughness. Parametric study of microslots finishing by AFF process is carried out with the help of central composite rotatable design (CCRD) method. The initial surface roughness on the microslots wall is in the range of 3.50 ± 0.10 μm. After AFF, the surface roughness is reduced to 192 nm with a 94.56% improvement in the surface roughness. To understand physics of the AFF process, three-dimensional (3D) finite element (FE) viscoelastic model of the AFF process is developed. Later, a surface roughness simulation model is also proposed to predict the final surface roughness after the AFF process. Simulated results are in good agreement with the experimental results.

On simultaneous improvement of wear characteristics, surface finish and microgeometry of straight bevel gears by abrasive flow finishing process

Improvement in operating performance, service life and transmission efficiency and reducing the noise of straight bevel gears (SBG) requires their better wear resistance, surface finish and microgeometry. Viscosity of the medium used in abrasive flow finishing (AFF) process and finishing time play very important role in achieving these objectives. This paper reports on simultaneous improvement of wear characteristics, surface finish and microgeometry of SBG by abrasive flow finishing (AFF) process by studying the effects of viscosity of AFF medium and finishing time so as to identify their optimum values through twenty experiments. Average and maximum surface roughness were used to study improvement in surface finish while, microgeometry was evaluated in parameters of pitch deviation and runout. Friction force, coefficient of friction, specific wear rate coefficient, wear volume, microhardness and microstructure of the worn surfaces were used to study the wear characteristics and wear mechanism of the best finished SBG. Use of AFF has significantly improved the wear characteristics, surface finish and microgeometry and quality of SBG. Reduced wear characteristics will reduce the frictional heating which will result in lower operating temperature of the bevel gears. Lower wear volume will improve their service life and mechanical efficiency. Microstructure study of the AFF best finished bevel gear flank surfaces revealed that they are free from hobbing cutter marks, cracks, burrs, pits, surface roughness peaks, thermal distortion. The worn flank surface of the best finished bevel gear have shown very less amounts of worn debris, pits and displacement of material and indicate scuffing mode of wear. This work helps in establishing AFF as an economical, sustainable and productive alternative process for finishing the gears made of any material which can simultaneously improve surface finish, wear characteristics, microgeometry and quality of the bevel gears.

Nano-finishing Studies Using Elastically Dominant Polymers Blend Abrasive Flow Finishing Medium

Abrasive flow finishing (AFF) process is one of the advanced finishing processes that uses polymer rheological abrasive medium to finish simple to complex surface features. AFF process comprises of machine set-up, tooling and medium. Among these three AFF process components, medium plays an important role. Depending on medium constituents and its quantity, the rheological property as well as its finishing abilities varies. In the current research work, soft styrene polymer and silicone polymers are blended along with additives and silicon carbide abrasive particles to make medium. The viscous and elastic properties of base polymers blend are varied using softeners (stearate), plasticizers (hydrocarbon oils) and abrasive particles. Finishing experiments are conducted on Al alloy/SiC (10%) metal matrix composites using central composite rotatable design as well as the responses are modeled using response surface methodology. The best surface finish achieved with optimally blended abrasive medium on Al alloy/SiC (10%) metal matrix composite (MMC) is 110nm.

Simulation and experimental investigations into abrasive flow nanofinishing of surgical stainless steel tubes

ABSTRACTSurface roughness is one of the critical properties that affect the performance of biomedical devices and human implant's functions. Higher surface roughness leads to the comparatively higher probability of body fluid retention in the surface valleys. Surface roughness peaks can easily obstruct the flow of body fluid and drug. Abrasive flow finishing (AFF) is an advanced finishing process, which can produce nano-level surface finish in complex components. In this paper, experimental investigations, including parametric study on nanofinishing of surgical stainless steel 316L tubes using AFF process has been reported. Indigenous multiple polymers blended base medium was developed to perform the nanofinishing experiments. Based on the experimental results, statistical model has been presented. To understand the AFF process in depth, finite element approach has been implemented to determine the finishing forces generated during the AFF experiments. Initial surface roughness on the internal surface of the workpiece varies in the range of (0.67–0.50) µm. The best surface finish of 48 nm with a percent improvement (% ΔRa) of 92.20% has been achieved after processing the workpiece with AFF process. Simulated results are validated with the experimental results and the deviations are in the acceptable range.

Improving spur gear microgeometry and surface finish by AFF process

ABSTRACTThis paper describes improving microgeometry and surface finish of spur gears by abrasive flow finishing (AFF) by experimentally identifying optimum values of finishing time and AFF medium viscosity. An experimental apparatus was developed for gear finishing by AFF using a medium of silicon carbide as abrasives, silly putty and silicone oil as blending agents. A special fixture was developed comprising of two metalon cylindrical disks having circumferential holes for back and forth movements of AFF medium between two adjacent flanks of 20MnCr5 alloy steel spur gear teeth. Twenty experiments were conducted varying AFF medium viscosity at four levels and finishing time at five levels to study their influence on error reduction in total profile, total lead, total pitch, runout, and average surface roughness. Results showed considerable reduction in the microgeometry deviation and surface roughness with AFF medium viscosity increase and existence of optimum finishing time for attaining maximum improvement in microgeometry and surface finish. Consequently, 25 min and 135 kPa. s were identified as optimum values and corresponding gear’s microgeometry and microstructure were studied. It revealed that AFF-finished gear flank surfaces are free from cracks, cutter marks, thermal distortions. This proves AFF as economical and productive alternative for gear finishing.