Effect of Finishing Time on Surface Finish of Spur Gears by Abrasive Flow Finishing (AFF) Process

Author(s):  
Anand C. Petare ◽  
Neelesh Kumar Jain ◽  
I. A. Palani
2019 ◽  
Vol 2 (2) ◽  
pp. 133-151 ◽  
Author(s):  
Jayant ◽  
V. K. Jain

Magnetorheological abrasive flow finishing (MRAFF) is an advanced hybrid process for producing ultrafine finished surfaces. Such surfaces reduce frictional forces and thereby minimize wear and tear to increase functional lifetime of the components. In the present research work, a model has been developed for simulating the results of MRAFF process. First, magnetic field is simulated and then a detailed study on the rheology of the magnetorheological polishing (MRP) fluid is conducted to develop a viscosity model for the flow of non-Newtonian shear thinning fluid. To calculate the forces acting in the process of material removal, the flow of MRP fluid around an asymmetric workpiece (knee joint) in a spatially varying magnetic field is simulated. Finishing forces exerted by the abrasive particles on the workpiece surface are analysed to develop a model for predicting surface roughness. A methodology has been proposed to evolve a variable correction factor to determine active abrasive particles at different locations on the workpiece surface for accurate simulation of surface finish operation. It is found that the magnetic field greatly influences the process performance by governing the viscosity of the MRP fluid and the distribution of the abrasive particles in the medium. During finishing of an asymmetric workpiece, the surface finish obtained at different locations on the workpiece surface is different. The developed model is capable to predict final surface finish within the acceptable accuracy when compared with the experimental results.


2020 ◽  
Vol 70 (2) ◽  
pp. 190-196
Author(s):  
Sachin Singh ◽  
M. Ravi Sankar

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.


Author(s):  
Mithun Sarkar ◽  
VK Jain

Freeform complex surfaces have become an essential part of many devices to perform the required functions. Many of these components require nanometer-level surface finish to perform the desired functions efficiently. In this work, an attempt has been made to improve the external morphology of freeform surfaces, especially knee joint, by abrasive flow finishing process. A uniform mirror finished surface with improved finishing rate is achieved for stainless steel knee joint. Extrusion pressure is varied to reduce final surface roughness value and finishing time. Experimentally, good surface finish ranging from ( Ra) 42.9 to 62.5 nm is achieved at various locations of the knee joint which are within the recommended American Society for Testing and Materials standard (≈100 nm) of knee joint prosthesis. Effects of abrasive flow finishing process parameters are investigated to develop “know how” of the process on the freeform surfaces. Abrasive flow finishing process has given 76.56% reduction in finishing time as compared to the time required by “ball end” type tool used for finishing knee joint.


Author(s):  
Pawan Kumar Yadav ◽  
S. C. Jayswal

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.


2021 ◽  
Vol 06 ◽  
Author(s):  
Irfan Ahmad Ansari ◽  
Dipti Sharma ◽  
Kamal K. Kar ◽  
Janakarajan Ramkumar

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.


Author(s):  
Dennis P. Townsend

Abstract Two groups of carburized, hardened, and ground spur gears that were manufactured from the same heat of vacuum-induction-melted vacuum-are-remelted (VIM-VAR) AISI 9310 steel were endurance tested for surface fatigue. Both groups were manufactured with a standard ground 16-rms surface finish. One group was subjected to a shot-peening intensity of 7 to 9A, and the second group was subjected to a shot-peening intensity of 15 to 17A. All gears were honed after shot peening to a surface finish of 16 rms. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a gear temperature of 350 K (170 °F), and a speed of 10 000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The following results were obtained: The 10-percent surface fatigue (pitting) life of the high-intensity (15 to 17A) shot-peened gears was 2.15 times that of the medium-intensity (7 to 9A) shot-peened gears, the same as that calculated from measured residual stress at a depth of 127 μm (5 mil). The measured residual stress for the high-intensity-shot-peened gears was 57 percent higher than that for the medium-intensity-shot-peened gears at a depth of 127 μm (5 mil) and 540 percent higher at a depth of 51 μm (2 mil).


2020 ◽  
Vol 20 (1) ◽  
pp. 1-11
Author(s):  
Palwinder Singh ◽  
Lakhvir Singh ◽  
Sehijpal Singh

Abstract Magnetic abrasive flow finishing (MAFF) is an unconventional process capable of producing fine finishing with machining forces controlled by a magnetic field. This process can be utilized for hard to achieve inner surfaces through the activity of extrusion pressure, combined with abrasion activity of a magnetic abrasive powder (MAP) in a polymeric medium. MAP is the key component in securing systematic removal of material and a decent surface finish in MAFF. The research background disclosed various methods such as sintering, adhesive based, mechanical alloying, plasma based, chemical, etc. for the production of bonded MAP. This investigation proposes bonded MAP produced by mechanical alloying followed by heat treatment. The experiments have been conducted on aluminum tubes to investigate the influence of different parameters like magnetic field density, extrusion pressure and number of working cycles. The bonded magnetic abrasive powder used in MAFF is very effective to finish tubes’ inner surfaces and finishing is significantly improved after processing.


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