Modeling and Prediction of Surface Roughness in Ultra-High Precision Diamond Turning of Contact Lens Polymer Using RSM and ANN Methods

2018 ◽  
Vol 928 ◽  
pp. 139-143 ◽  
Author(s):  
Muhammad Mukhtar Liman ◽  
K. Abou-El-Hossein ◽  
Peter Babatunde Odedeyi

In this paper, Single point diamond turning tests were carried out on rigid gas permeable contact lens (ONSI-56), using monocrystalline diamond cutting tools. During the tests, the depth of cut, feed rate, and cutting speed were varied. Turning experiments were designed based on Box-Behnken statistical experimental design technique. An artificial neural network (ANN) and response surface (RS) model were developed to predict surface roughness on the contact lens turned part surface. In the development of predictive models, cutting parameters of cutting speed, depth of cut and feed rate were considered as model variables. The required data for predictive models are obtained by conducting a series of turning test and measuring the surface roughness data. Good agreement is observed between the predictive models results and the experimental measurements. The ANN and RSM models for ONSI-56 contact lens turned part surfaces are compared with each other for accuracy and computational cost.

2019 ◽  
Vol 298 ◽  
pp. 135-140
Author(s):  
Muhammad Mukhtar Liman ◽  
Khaled Abou El Hossein

The electrostatic charges encountered by a cutting tool when turning advanced contact lenses are important as they reflect the quality and condition of the tool, machine, fixture, and sometimes even the surface finished which is responsible for tool wear and poor surface quality. This study investigates the influence of cutting parameters namely cutting speed, feed rate and depth of cut on electrostatic charge (ESC) which play the leading role in determining the machine economics and quality of machining contact lens polymers. An electrostatic charge model based on response surface statistical method is developed for reliably predicting the values of static charging based on its relationship to cutting parameters in ultra-high precision diamond turning of contact lenses. It is clearly seen that all the model terms are significant with cutting speed having the highest degree of significance followed by feed rate and the interaction of speed and feed. However, depth of cut has the lowest degree of significance on the electrostatics charge.


2017 ◽  
Vol 753 ◽  
pp. 183-187 ◽  
Author(s):  
Muhammad M. Liman ◽  
Khaled Abou-El-Hossein ◽  
Abubakar I. Jumare ◽  
Peter Babatunde Odedeyi ◽  
Abdulqadir N. Lukman

Contact lens manufacture requires high accuracy and surface integrity. Surface roughness an important response because it has direct influence toward the part performance and the production cost. Hence, choosing optimal cutting parameters will not only improve the quality measure but also the productivity. This research work is therefore aimed at developing a predictive surface roughness model and investigate a finish cutting conditions of ONSI-56 contact lens polymer with a monocrystalline diamond cutting tool. In this work, a novel surface roughness prediction model, in which the feed rate, cutting speed and depth of cut are considered is developed. This combined process was successfully modeled using a Box–Behnken design (BBD) with response surface methodology (RSM). The effects of feed rate, cutting speed and depth of cut were investigated. Analysis of variance (ANOVA) showed that the proposed quadratic model effectively interpreted the experimental data with coefficients of determination of R2 = 0.89 and adjusted R2 = 0.84. The worse surface value was obtained at high feedrate and low spindle speed.


2007 ◽  
Vol 339 ◽  
pp. 78-83 ◽  
Author(s):  
Jing He Wang ◽  
Shen Dong ◽  
H.X. Wang ◽  
Ming Jun Chen ◽  
Wen Jun Zong ◽  
...  

The method of single point diamond turning is used to machine KDP crystal. A regression analysis is adopted to construct a prediction model for surface roughness and cutting force, which realizes the purposes of pre-machining design, prediction and control of surface roughness and cutting force. The prediction model is utilized to analyze the influences of feed, cutting speed and depth of cut on the surface roughness and cutting force. And the optimal cutting parameters of KDP crystal on such condition are acquired by optimum design. The optimum estimated values of surface roughness and cutting force are 7.369nm and 0.15N, respectively .Using the optimal cutting parameters, the surface roughness Ra, 7.927nm, and cutting force, 0.19N, are obatained.


2020 ◽  
pp. 251659842094172
Author(s):  
Kuldeep A. Mahajan ◽  
Raju Pawade

Single-point diamond turning (SPDT) is an emerging process for achieving nanometric surface finish, required in various optical devices made from metals like aluminum, copper, and nonmetals like polymers. The optical devices are manufactured in different shapes and profiles, preferably flat and curved surfaces. During the manufacturing of optical devices, controllable and noncontrollable parameters affect the desired surface finish. In this article, controllable machining parameters such as the incremental distance of X slide, feed rate, spindle speed, and depth of cut are selected to study their effect on surface finish and vibration generation of the curved surface. The chosen workpiece material is polymethylmethacrylate (PMMA). Design of experiment (DoE) is used to find out the optimum parameters of surface finish and infeed vibration responses. According to the Taguchi and analysis of Variance (ANOVA) analysis, the feed rate is the most influencing parameter for surface roughness, and incremental distance is for infeed vibration. A confirmation test is carried out to verify the experimental responses with a mathematical regression model, and it shows a close difference within 2.7 percent. Further, minimum surface roughness is perceived as 12.4 nm, corresponding to an infeed vibration amplitude of 4.9 µm/s2, which is signified at a lower frequency.


2020 ◽  
Vol 305 ◽  
pp. 117-121 ◽  
Author(s):  
Zvikomborero Hweju ◽  
Khaled Abou-El-Hossein

This paper is a presentation of a comparative study of the effect of water and kerosene coolants on surface finish during ultra-high precision diamond turning (UHPDT) of Rapidly Solidified Aluminium alloy (RSA 443). The percentage relative difference between the coolants’ surface roughness values is denoted by the ΔRa parameter. The accuracy of the Response Surface Method (RSM) in predicting surface roughness of water and kerosene-based results is investigated in this paper. The cutting parameters used in the investigation are cutting speed, feed rate and depth of cut. The Taguchi method was used to design the experiment since it provides relatively fewer experimental runs when compared to classical experimental design methods. Mean Absolute Percentage Error (MAPE) values are used to compare RSM’s surface roughness prediction accuracy on both water and kerosene-based results. It is observed that the surface roughness profiles for either coolant are similar, and the use of water coolant yields smoother surface finishes when compared to the use of kerosene. It is also observed that RSM displays better accuracy in predicting water-based surface roughness.


In this study the effect and optimisation of machining parameters on surface roughness in a facing operation of Ti6Al4VELI by single point diamond machining have been investigated. The experimental studies carried under varying cutting speeds, feed rates, different tool nose radius and depths of cut. The orthogonal array, signal-to-noise ratio (S / N) and variance analysis (ANOVA) were used to examine the performance characteristics of the Ti6Al4VELI alloy turning by using single-point diamond cutting tool. The influential factors on the surface roughness after machining are feed rate and cutting speed after the conclusions revealed. Whereas the feed rate had the most significant effect on tool life. Minimal surface roughness achieved after machining is in nano-level which is better than other conventional precision machining.


2010 ◽  
Vol 447-448 ◽  
pp. 51-54
Author(s):  
Mohd Fazuri Abdullah ◽  
Muhammad Ilman Hakimi Chua Abdullah ◽  
Abu Bakar Sulong ◽  
Jaharah A. Ghani

The effects of different cutting parameters, insert nose radius, cutting speed and feed rates on the surface quality of the stainless steel to be use in medical application. Stainless steel AISI 316 had been machined with three different nose radiuses (0.4 mm 0.8 mm, and 1.2mm), three different cutting speeds (100, 130, 170 m/min) and feed rates (0.1, 0.125, 0.16 mm/rev) while depth of cut keep constant at (0.4 mm). It is seen that the insert nose radius, feed rates, and cutting speed have different effect on the surface roughness. The minimum average surface roughness (0.225µm) has been measured using the nose radius insert (1.2 mm) at lowest feed rate (0.1 mm/rev). The highest surface roughness (1.838µm) has been measured with nose radius insert (0.4 mm) at highest feed rate (0.16 mm/rev). The analysis of ANOVA showed the cutting speed is not dominant in processing for the fine surface finish compared with feed rate and nose radius. Conclusion, surface roughness is decreasing with decreasing of the feed rate. High nose radius produce better surface finish than small nose radius because of the maximum uncut chip thickness decreases with increase of nose radius.


2020 ◽  
Vol 36 ◽  
pp. 28-46
Author(s):  
Youssef Touggui ◽  
Salim Belhadi ◽  
Salah Eddine Mechraoui ◽  
Mohamed Athmane Yallese ◽  
Mustapha Temmar

Stainless steels have gained much attention to be an alternative solution for many manufacturing industries due to their high mechanical properties and corrosion resistance. However, owing to their high ductility, their low thermal conductivity and high tendency to work hardening, these materials are classed as materials difficult to machine. Therefore, the main aim of the study was to examine the effect of cutting parameters such as cutting speed, feed rate and depth of cut on the response parameters including surface roughness (Ra), tangential cutting force (Fz) and cutting power (Pc) during dry turning of AISI 316L using TiCN-TiN PVD cermet tool. As a methodology, the Taguchi L27 orthogonal array parameter design and response surface methodology (RSM)) have been used. Statistical analysis revealed feed rate affected for surface roughness (79.61%) and depth of cut impacted for tangential cutting force and cutting power (62.12% and 35.68%), respectively. According to optimization analysis based on desirability function (DF), cutting speed of 212.837 m/min, 0.08 mm/rev feed rate and 0.1 mm depth of cut were determined to acquire high machined part quality


Author(s):  
Mahendran Samykano ◽  
J. Kananathan ◽  
K. Kadirgama ◽  
A. K. Amirruddin ◽  
D. Ramasamy ◽  
...  

The present research attempts to develop a hybrid coolant by mixing alumina nanoparticles with cellulose nanocrystal (CNC) into ethylene glycol-water (60:40) and investigate the viability of formulated hybrid nanocoolant (CNC-Al2O3-EG-Water) towards enhancing the machining behavior. The two-step method has been adapted to develop the hybrid nanocoolant at various volume concentrations (0.1, 0.5, and 0.9%). Results indicated a significant enhancement in thermal properties and tribological behaviour of the developed hybrid coolant. The thermal conductivity improved by 20-25% compared to the metal working fluid (MWF) with thermal conductivity of 0.55 W/m℃. Besides, a reduction in wear and friction coefficient was observed with the escalation in the nanoparticle concentration. The machining performance of the developed hybrid coolant was evaluated using Minimum Quantity Lubrication (MQL) in the turning of mild steel. A regression model was developed to assess the deviations in the tool flank wear and surface roughness in terms of feed, cutting speed, depth of the cut, and nanoparticle concentration using Response Surface Methodology (RSM). The mathematical modeling shows that cutting speed has the most significant impact on surface roughness and tool wear, followed by feed rate. The depth of cut does not affect surface roughness or tool wear. Surface roughness achieved 24% reduction, 39% enhancement in tool length of cut, and 33.33% improvement in tool life span. From this, the surface roughness was primarily affected by spindle cutting speed, feed rate, and then cutting depth while utilising either conventional water or composite nanofluid as a coolant. The developed hybrid coolant manifestly improved the machining behaviour.


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2998 ◽  
Author(s):  
Kubilay Aslantas ◽  
Mohd Danish ◽  
Ahmet Hasçelik ◽  
Mozammel Mia ◽  
Munish Gupta ◽  
...  

Micro-turning is a micro-mechanical cutting method used to produce small diameter cylindrical parts. Since the diameter of the part is usually small, it may be a little difficult to improve the surface quality by a second operation, such as grinding. Therefore, it is important to obtain the good surface finish in micro turning process using the ideal cutting parameters. Here, the multi-objective optimization of micro-turning process parameters such as cutting speed, feed rate and depth of cut were performed by response surface method (RSM). Two important machining indices, such as surface roughness and material removal rate, were simultaneously optimized in the micro-turning of a Ti6Al4V alloy. Further, the scanning electron microscope (SEM) analysis was done on the cutting tools. The overall results depict that the feed rate is the prominent factor that significantly affects the responses in micro-turning operation. Moreover, the SEM results confirmed that abrasion and crater wear mechanism were observed during the micro-turning of a Ti6Al4V alloy.


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