scholarly journals Surface Evaluation of a Multi-Pass Flexible Magnetic Burnishing Brush for Rough and Soft Ground 60/40 Brass

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4465
Author(s):  
Ayman M. Alaskari ◽  
Abdulaziz I. Albannai ◽  
Meshal Y. Alawadhi ◽  
Abdulkareem S. Aloraier ◽  
Tatiana Liptakova ◽  
...  

Burnishing is an advanced finishing process that produces higher-quality surfaces with better hardness and roughness than conventional finishing processes. Herein, a flexible magnetic burnishing brush comprising stainless steel pins under permanent magnet poles was used to investigate the influence of multiple passes and directions on the produced surface of soft and rough ground prepared brass. In total, five different samples were burnished on each of the two brass samples prepared. Four samples were processed in the same direction for up to four passes and the fifth sample was processed with two passes in the opposite direction. Results indicate that there was approximately a 30% increase in hardness and an 83% increase in microroughness for rougher-surface brass samples. For smoothly prepared surfaces, there was approximately a 14% increase in hardness and a 35% increase in microroughness. In the same direction of multi-pass burnishing, increasing the number of passes negatively affected surface roughness; for rougher surfaces, the surface hardness reduced and process uniformity increased owing to surface over-hardening and flaking mechanisms, and for smoother surfaces, the hardness, roughness, and process non-uniformity increased with the number of passes owing to repeated surface deformation at some locations and high flaking at other locations. Compared to single-pass burnishing, wherein the surface roughness and microhardness showed almost no change with high process uniformity, in burnishing with two opposite-direction passes, the produced surface exhibited better surface roughness, process uniformity, and microhardness improvements owing to a reverse strain mechanism. Hence, opposite burnishing passes are recommended.

2020 ◽  
Vol 4 (1) ◽  
pp. 110-116
Author(s):  
Pavana Kumara ◽  
V. Vijendra Bhat ◽  
G. K. Purohit

Burnishing is becoming a promising surface finishing process to enhance materials surface properties.  The control of the various process parameters yields the desired surface characteristics in brass materials. In the current work, free machining brass specimens were burnished by Abrasive Assisted Burnishing(AAB) process and Plain Burnishing (PB) process using ball burnishing tool.  Response Surface Methodology was used to design the experiments in which Burnishing Force, Speed, Feed and Number of Passes were chosen as the process parameters. The minimum surface roughness achieved by PB and AAB was 0.1451 µm and 0.1041 µm respectively. The maximum surface hardness achieved using PB and AAB on the brass specimen was 207 HV and 248 HV respectively. The ball burnishing of free machining brass by AAB resulted in better surface characteristics as compared to the PB process.


Author(s):  
Sachin Singh ◽  
M Ravi Sankar

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.


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):  
Manpreet Singh ◽  
Anant Kumar Singh

The copper cylindrical roller plays an important role in the printing operation. The copper roller requires fine and uniform finishing to uniformly distribute the colours and ingot material. Fine and uniform finishing of copper cylindrical rollers get difficulty using the traditional finishing processes due to their ductility and low hardness. Therefore, to achieve this fine finishing requirement, the rotary rectangular tool core-based magnetorheological (MR) finishing process is employed. Initially, the suitable MR polishing fluid composition is selected for the effective fine finishing of the surface of the copper cylindrical rollers. Furthermore, the central composite design is used to optimize the MR finishing process parameters. The surface roughness profiles, surface texture, and reflection tests are performed on the initial ground surface and the MR finished surface of the copper roller. The surface roughness value gets reduced from 190 nm to 25 nm after 4 hrs MR finishing with the optimum parametric conditions over the copper cylindrical roller surface having a dimension of 120 mm in length and 25 mm in diameter. The present MR finishing process found effective to significantly reduce the surface roughness value and enhance the surface characteristics of the copper cylindrical rollers. The geometrical dimensions in terms of circularity and straightness are also checked on the initial ground surface and finished surface of the copper cylindrical roller using the coordinate measuring machine and waviness test. The enhancement in surface characteristics, dimensional accuracy, and surface hardness after the present MR finishing process is found to be beneficial for improving the functional performance of the copper cylindrical rollers in the printing processing machine.


2015 ◽  
Vol 649 ◽  
pp. 112-119
Author(s):  
Quoc Nguyen Banh ◽  
Fang Jung Shiou

This study aims to optimize the small ball-burnishing process parameters in order to simultaneously improve the surface roughness and superficial surface hardness of the STAVAX material. A newly developed load cell embedded double spring mechanism burnishing tool was designed and fabricated. By utilizing the hybrid grey-based Taguchi method with principal component analysis (PCA) and entropy measurement the optimal process condition was the combination of the burnishing force at 10 N, the step-over at 6 μm, the number of passes at 3 times, the grease for lubricant, and the burnishing speed at 500 mm/min. The burnishing force, step-over, and the number of passes were found to have the main effects on the burnished surfaces among the five chosen control factors. The burnished surface of STAVAX material under the optimal condition was improved from Ra 0.85 to Ra 0.079 for average surface roughness, and from 67.3 HR30N to 72.7 HR30N in term of superficial hardness.


2021 ◽  
Vol 5 (4) ◽  
pp. 106
Author(s):  
Henning Zeidler ◽  
Rezo Aliyev ◽  
Florian Gindorf

In many cases, the functional performance of additively manufactured components can only be ensured by finishing the functional surfaces. Various methods are available for this purpose. This paper presents a procedure for selecting suitable processes for finishing laser beam melting additive–manufactured parts which is ultimately based on technological knowledge. It was experimentally proven that the use of several consecutive finishing processes is beneficial to achieve better surface quality. One finishing process chain was particularly effective (namely particle blasting/vibratory grinding/plasma electrolytic polishing) and the technological limits of this method were investigated in this study. The optimal parameters for this process combination ensured a surface roughness Sa < 1 µm.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Hamaid M. Khan ◽  
Tolga B. Sirin ◽  
Gurkan Tarakci ◽  
Mustafa E. Bulduk ◽  
Mert Coskun ◽  
...  

Abstract This paper attempts to improve the physical and mechanical properties of selective laser sintered polyamide PA2200 components through a vibratory surface finishing process by inducing severe plastic deformation at the outer surface layers. The industrial target of additive manufacturing components is to obtain structures having surface roughness, hardness, and other mechanical properties equivalent to or better than those produced conventionally. Compared to the as-built SLS PA2200 samples, vibratory surface finishing treated specimens exhibited a smooth surface microstructure and more favorable roughness, hardness, and tensile strength. Also, the duration of the vibratory surface finishing process showed a further improvement in the surface roughness and hardness of the SLS samples. Compared to the as-built state, the roughness and hardness of the surface-treated samples improved by almost 90% and 15%, respectively. Consequently, microstructural analysis indicates that lower surface roughness and enhanced surface hardness is a crucial factor in influencing the overall tensile strength of SLS-PA2200 components. We consider that the combination of VSF and SLS processes can successfully handle a wide range of potential applications. This study also highlights the efficiency and applicability of the vibratory surface finishing process to other additive manufacturing processes and materials. Graphic abstract


Author(s):  
Sachin Singh ◽  
Deepu Kumar ◽  
Mamilla Ravi Sankar

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.


Author(s):  
Yahya Choopani ◽  
Mohsen Khajehzadeh ◽  
Mohammad Reza Razfar

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.


Author(s):  
Ravi Datt Yadav ◽  
Anant Kumar Singh ◽  
Kunal Arora

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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