Surface Finish
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2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sugavaneswarn M. ◽  
Prashanthi B. ◽  
John Rajan A.

Purpose This paper aims to enhance the surface finish of the fused deposition modeling (FDM) part using the vapor smoothening (VS) post-processing method and to study the combined effect of FDM and VS process parameters on the quality of the part. Design/methodology/approach Analysis of variance method is used to understand the significance of the FDM and VS process parameters. Following this, the optimized parameter for multiple criteria response is reported using the technique for order preference by similarity to ideal solution. The process parameters alternatives are build orientation angle, build surface normal and exposure time and the criteria are surface roughness and dimensional error percentage. Findings The result observed contradicts the result reported on the independent parameter optimization of FDM and VS processes. There is a radical improvement in the surface finish on account of the coating process and an increase in the exposure time results in the decrease of the surface roughness. Minimum surface roughness of 0.11 µm is observed at 1,620 build angle and the least dimensional error of 0.01% is observed at build orientation angle 540. The impact of VS on the up-facing surface is different from the down-facing surface due to the removal of support material burrs and the exposure of the surface to vapor direction. Originality/value A study on the multi-criteria decision-making to ascertain the effect of post-processing on FDM component surface normal directed both to downward (build angle 0°–90°) and to upward (build angle 99°–180°) are reported for the first time in this article. The data reported for the post-processed FDM part at the build angle 0°–180° can be used as a guideline for selecting the optimal parameter and for assigning appropriate tolerance in the CAD model.


2021 ◽  
Vol 63 (9) ◽  
pp. 878-884
Author(s):  
Kandasamy Suganeswaran ◽  
Rathinasamy Parameshwaran ◽  
Thangamuthu Mohanraj ◽  
Balasubramaniyam Meenakshipriya ◽  
Nagarajan Nithyavathy

Abstract Magnetic abrasive finishing (MAF), an unconventional process, enhances the surface finish of a material. The current research focuses on its use with SS310s. The finite element analysis (FEA) result shows the effect of control parameters on the magnetic flux density. In FEA analysis, it was decided to maintain an air gap of 1.5-2 mm and a voltage of 10-20 V. A response surface methodology (RSM) desirability function is used to identify the optimal process parameters. Experiments are conducted for optimizing the process parameters like voltage, rotational speed, machining gap, mixing ratio, and mesh number to enhance the material removal rate (MRR) and surface roughness (Ra). A series of 62 experiments are conducted using optimized process parameters at different levels. Moreover, analysis of variance (ANOVA) is used to identify the percentage contribution of each process parameter in %ΔRa and MRR. From this, the mesh number of the abrasives plays an important role in the finishing process owing to the increased number of cutting edges and because of the uniform normal force (Fn) distribution. The optical microscopic image result and the wear test confirms that the surface finish of SS310s has been improved using MAF.


2021 ◽  
Author(s):  
Adeniyi Adeleke ◽  
Abou-El-Hossein Khaled ◽  
Odedeyi Peter

Abstract The desire for quality infrared lens with better surface finish has brought about the usage of brittle materials like germanium to be machined via a single point diamond turning machining process. However, achieving the required surface finish is complex if special machining techniques and approaches are not employed. In this paper, the effect of two different tool nose radius parameters on surface roughness of single point diamond turned germanium workpiece were studied and analyzed. The machining parameters selected for this experiment were feed, speed and depth of cut. Box-Behnken design was adopted to optimally create a combination of cutting parameters. Measurement of surface roughness after each run in both experiments was achieved using a Taylor Hobson PGI Dimension XL surface Profilometer. The resulting outcomes show that at most experimental runs, the surface roughness value decreased with an increase in nose radius. Mean absolute error was also used to compare the accuracy validation of the two models.


Author(s):  
Raphael Lima de Paiva ◽  
Rodrigo de Souza Ruzzi ◽  
Rosemar Batista da Silva

The elevated heat generation in grinding can develop high temperatures at the contact zone, which can adversely affect the surface integrity of the workpiece, especially when grinding hardened steels with conventional abrasives. Thus, the correct selection of cooling-lubrication condition is essential to avoid or attenuate any possible negative effect to workpiece surface integrity. However, the literature lacks work comparing different cutting fluid application technique (e.g. flood and minimum quantity lubrication – MQL) using the same fluid on both techniques. In this context, this work aims to contribute to the selection of cutting fluid type and its application technique for the grinding of bearing steel. Experimental trials were conducted comparing the use of semisynthetic and synthetic cutting fluids, both applied via conventional (flood) and MQL techniques. Different cutting conditions were also tested. A 24 full factorial design of experiment (DOE) was carried out with the following factors: fluid application technique, type of fluid, workspeed, and radial depth of cut. An analysis of main effects and interactions was performed for surface finish (Ra parameter) results, including a prediction model based on the analysis of variance (ANOVA). The morphology of ground surface and microhardness below machined surface were also analyzed. The results showed that the ground surface finish was strongly dependent on the cutting fluid type and its application technique combination: superior finishing was observed with the combination of semisynthetic fluid delivered via flood technique and with synthetic fluid delivered via MQL technique. From the surface morphology analysis, it was observed that the inferior lubrication capacity of synthetic fluid applied via flood condition deteriorated the surface finish and morphology. The surfaces ground with semisynthetic fluid provided, in general, lower values of Ra and lower microhardness variation. The prediction model for Ra showed a maximum error of 14% in comparison to the measured values.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1287
Author(s):  
Fernando Bautista-Monsalve ◽  
Francisco García-Sevilla ◽  
Valentín Miguel ◽  
Jesús Naranjo ◽  
María Carmen Manjabacas

Single point incremental forming (SPIF) is a cheap and flexible sheet metal forming process for rapid manufacturing of complex geometries. Additionally, it is important for engineers to measure the surface finish of work pieces to assess their quality and performance. In this paper, a predictive model based on machine learning and computer vision was developed to estimate arithmetic mean surface roughness (Ra) and maximum peak to valley height (Rz) of Ti6Al4V parts obtained by SPIF. An image database was prepared to train different classification algorithms in accordance with a supervised learning approach. A speeded up robust feature (SURF) detector was used to obtain visual vocabulary so that the classifiers are able to group the photographs into classes. The experimental results indicated that the proposed predictive method shows great potential to determine the surface quality, as classifiers based on a support vector machine with a polynomial kernel are suitable for this purpose.


2021 ◽  
Author(s):  
Karan Singh Jamwal ◽  
Anant Kumar Singh ◽  
Kunal Arora ◽  
Sunil Kumar Paswan

Abstract Aerostatic bearing is an ultra-precision component that uses a spindle surrounded by a thin film of air. Due to the high accuracy of aerostatic bearing, the demand for these components is very high in electronic, instrumentation, healthcare, and other manufacturing or processing industries. In the present work, the main focused area is on the experimental determination of the effect of roughness parameter on the performance of the aerostatic journal and thrust bearings. To achieve the aim, the aerostatic bearing is designed based on theoretical analysis. The present design is numerically investigated by simulation of airflow in ANSYS Fluent with computational fluid dynamics module. The results from the simulation are validated by the results generated for pressure distribution in previous researches. After performing the finishing on the bearing and spindle surface, the manufactured components are assembled for analysing the variation in radial and axial loads acting on the spindle with the spindle displacement (1-5 μm) in the direction of the load at supply pressures (3-6 bar) in the clearance of 30 μm. For surface improvement of the air bearing, three different techniques are used namely machining, grinding, and magnetorheological finishing. For each roughness reduction technique, the variation in axial and radial loads acting on the spindle is determined with variation in spindle displacement. The experimental results showed the increase in load capacity due to improvement in the surface finish for journal bearing and thrust bearing at 5 µm displacement in the spindle is found to be 0.68 N for machining to grinding and 2.0 N from grinding to magnetorheological finishing respectively. The results determined for the surface finish parameter reveals the effect of surface roughness on the load-carrying capacity of the aerostatic journal and thrust bearing. The current study on the surface finishing of aerostatic bearing is found effective for the applications such as drives in production machines where good grade of surface finish are the major parameters for improving the overall functional efficiency.


Author(s):  
Baik Jin Kim ◽  
Joseph Oh ◽  
Alan Palazzolo

Abstract Hirth coupling transmits high torques in the rotating assemblies of compressors and turbines. Their mating surface contacts cause local changes in lateral shaft stiffness. This is affected by the teeth geometry, contact surface area, coupling preload, and surface finish at the contact faces. Industry practice ignores localized lateral flexibility from the Hirth coupling, or is guided by limited experience-based rules of thumb. The authors provide a novel modeling approach utilizing 3D solid finite elements which accounts for contact deformations, intricate interface teeth geometries, stress concentration, and surface finish. This provides an increased accuracy localized stiffness model for the Hirth coupling, to improve rotordynamic response predictions. Free-free natural frequencies of a test rotor including a Hirth coupling are experimentally measured. The rotor is instrumented with strain gauges for preload force measurements, and the Hirth coupling contacting surface profiles are measured with a stylus type surface profiler. A GW contact model is obtained from the measured surface profiles. An iterative computation algorithm is utilized to calculate Hirth coupling contact stiffness and contact pressure at the complex-shaped contact surfaces. Predicted and measured natural frequencies are compared vs. preload.


2021 ◽  
Vol 2002 (1) ◽  
pp. 012042
Author(s):  
Liyuan Zhao ◽  
Yuedong Yuan ◽  
Long Chen ◽  
Rui Ma

Author(s):  
Fulvio Lavecchia ◽  
Maria Grazia Guerra ◽  
Luigi Maria Galantucci

AbstractFused filament fabrication (FFF) is one of the most extensively used 3D printing process for its several advantages and the possibility to obtain complex geometries. Different materials can be processed and polylactic acid (PLA), a thermoplastic biodegradable cost-effective material, is widely used for consumer FFF. Typically, PLA printed parts have high surface roughness, due to the staircase effect, the slice-to-slice construction texture and the filament deposition. In this work, authors propose a quantitative analysis of the effects of a chemical treatment based on ethyl acetate vapors, to improve the surface finish of PLA printed parts. The solvent was selected for its low toxicity, easy availability, and low cost. To validate the treatment, a 23 full factorial plan was designed and a roughness analysis before and after the chemical treatment was performed to highlight the influence of each parameter involved.


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