Surface Roughness Model for High Speed End Milling of Soda Lime Glass Using Carbide Coated Tools with Compressed Air Blowing

2012 ◽  
Vol 576 ◽  
pp. 107-110
Author(s):  
M.A. Mahmud ◽  
A.K.M. Nurul Amin ◽  
Muammer Din Arif
Keyword(s):  
Mathematical Model ◽  
Surface Roughness ◽  
Gas Turbines ◽  
High Speed ◽  
End Milling ◽  
Soda Lime ◽  
Depth Of Cut ◽  
Soda Lime Glass ◽  
Machining Parameters ◽  
Machined Surface

Glass materials play a vital role in advancement of science and technology. They have found wide spread application in the industry, in laboratory equipment and in micro-gas turbines. Due to their low fracture toughness they are very difficult to machine, moreover there are the chip depositions on the machined surface which affects surface finish under ductile mode cutting conditions. In this research, high speed end milling of soda lime glass is performed on CNC vertical milling machine to investigate the effects of machining parameters i.e. spindle speed, depth of cut, and feed rate on machined surface roughness. Design of experiments was performed following Central Composite Design (CCD) of Response Surface Methodology (RSM). Design Expert Software was used for generating the empirical mathematical model for average surface roughness. The model’s validity was tested to 95% confidence level by Analysis of Variance (ANOVA). Subsequent experimental results showed that the developed mathematical model could successfully describe the performance indicators, i.e. surface roughness, within the controlled limits of the factors that were considered.

Achievement of Ductile Regime Machining in High Speed End Milling of Soda Lime Glass by Using Tungsten Carbide Tool Insert

2015 ◽  
Vol 1115 ◽  
pp. 39-42
Author(s):  
A.K.M. Nurul Amin ◽  
A.A. Che Omar ◽  
M.A. Mohammed Kamal ◽  
Mahmoud M.A. Nassar ◽  
N.F. Mohd Zaib ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Tungsten Carbide ◽  
Gas Turbines ◽  
High Speed ◽  
End Milling ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Ductile Regime Machining ◽  
Micro End Milling ◽  
Tungsten Carbide Tool

Soda lime glass is widely used in optics, chemical apparatus, camera lens, micro gas turbines, light bulbs etc. on account of its high hardness, corrosion resistance, and excellent optical properties. These require high dimensional accuracy and flawless surface finish. However, soda lime glass is inherently brittle leading to subsurface crack propagation and fracture which compromise its functionality. To avoid these defects, the machining needs to be performed under ductile mode conditions. Therefore, this research investigates the viability and requisite conditions for achieving ductile regime machining (DRM) in high speed micro-end milling of soda lime glass. Machining was performed at high cutting speeds (30,000 to 50,000 rpm), feed rate (5 to 15 mm/min), and depth of cut (3 to 7 μm). A surface profilometer was then used to measure the surface roughness and a scanning electron microscope (SEM) used to scrutinize the resultant machined surfaces. The results demonstrate that ductile streaks and rounded gummy chips (without sharp or jagged edges) are produced in all runs. In addition, there are no subsurface cracks and the minimum surface roughness attained is 0.08μm. These indicate that DRM of soda lime glass is obtainable using high-speed micro end milling in a conventional end mill with tungsten carbide inserts.

Effect of Cutter Diameters on Surface Roughness Attained in High Speed End Milling of Soda Lime Glass

2015 ◽  
Vol 1115 ◽  
pp. 51-54 ◽  
Author(s):  
A.K.M. Nurul Amin ◽  
A.A. Che Omar ◽  
M.A.Mohammed Kamal ◽  
Mahmoud M.A. Nassar ◽  
N.F. Mohd Zaib ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
End Mill ◽  
Machined Surface ◽  
Ductile Mode ◽  
Ductile Regime Machining ◽  
Brittle Fractures

Soda lime glass is used extensively in camera lens, micro gas turbines, light bulbs, tablewares, optics, and chemical apparatus owing to its high hardness, excellent optical properties, and good corrosion and chemical resistance. Such applications of soda lime glass demand high machining and finishing precision. On the other hand, machining of glass poses significant challenges due to its inherent brittleness. The process of removal of material from glass, if not done in ductile mode, can generate subsurface cracks and brittle fractures which have adverse effects on its functionality. This research investigates the high speed micro-end milling of soda lime glass in order to obtain ductile regime machining. It has been found by other researchers that ductile mode machining can avoid sub-surface cracks and brittle fractures. However, in ductile mode machining, the gummy chips settle permanently on the machined surface affecting adversely the surface finish. In order to avoid such chip settlement, compressed air was directed using a special air delivery nozzle to blow away the resultant gummy chips, thereby preventing them from settling on the machined surface. Response surface methodology (RSM) and a commercial NC end mill were used to design and perform the machining runs, respectively. Machining was done using: high spindle speeds from 30,000 to 50,000 rpm, feed rates from 5 to 15 mm/min, and depth of cuts from 3 to 7 μm. Three different diameter carbide tools were used: 0.5, 1, and 2 mm. A surface profilometer was used to analyze the surface roughness of the resultant machined surface. Subsequently, the data was used for finding the best combination of cutting parameters required to obtain the lowest surface roughness. The results demonstrate that high speed machining is a viable option for obtaining ductile regime machining and generating machined surfaces with very low surface roughness in the range of 0.08μm – 0.22 μm, using 0.5 mm carbide end mill cutter.

Optimization of Cutting Parameters in High Speed End Milling of Soda Lime Glass with Coated Carbide Tools Using Directional Compressed Air Blowing

2012 ◽  
Vol 576 ◽  
pp. 111-114
Author(s):  
M.A. Mahmud ◽  
A.K.M. Nurul Amin ◽  
Muammer Din Arif
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Soda Lime ◽  
Compressed Air ◽  
Soda Lime Glass ◽  
Machining Parameters ◽  
Design Expert ◽  
Air Blowing ◽  
Optimization Of Cutting Parameters

An experimental study of high speed machining of soda lime glass using directional compressed air blowing for removal of the ductile chips from the machined surface, is presented. High speed end milling of soda lime glass is performed on a vertical CNC milling machine to observe the effects of machining parameters i.e. spindle speed, depth of cut and feed rate on the resultant surface roughness. The design of the experiments was performed following the Central Composite Design (CCD) of the Response Surface methodology (RSM) using the Design Expert Software. Optimization of machining parameters was conducted using desirability function of the Design Expert software based on minimum surface roughness criterion. Finally, experimental verification tests were conducted to validate the predicted optimized value.

Modeling and Optimization of Critical Depth in High Speed End Milling of Soda Lime Glass

2012 ◽  
Vol 576 ◽  
pp. 36-40
Author(s):  
M.A. Mahmud ◽  
A.K.M. Nurul Amin ◽  
M.D. Arif
Keyword(s):  
Mathematical Model ◽  
High Speed ◽  
End Milling ◽  
Plastic State ◽  
Soda Lime Glass ◽  
Machining Parameters ◽  
Critical Depth ◽  
Display Time ◽  
Machined Surface ◽  
Good Surface

One of the most hard and brittle material is glass. Due to the properties of low fracture toughness it is very difficult to being machined having good surface quality. Hence it is required to be machined in such a way that brittle fracture does not appear in the new machined surface, which is only possible in ductile mode machining or the removal of material in the plastic state. Above all machining of glass is the most challenging in current state of mechanical machining. The experimental results show that the developed mathematical model can effectively describe the performance indicators within the controlled limits of the factors that are being considered. This paper presents the mathematical model and optimization results of an experimental study of high speed end milling by the consideration of amplitude time display (Time Domain), FFT Diagram (Frequency Domain) and surface characteristics to find out the maximum critical depth for higher material removal which is crack free surface having good surface finishes. Mathematical model of the response parameter, the critical depth is subsequently developed using RSM in terms of the machining parameters. The model was determined, by Analysis of Variance (ANOVA), to have a confidence level of 95%. The optimization was carried out by the optimization features of Design Expert software.

scholarly journals Optimization of Surface Roughness in Micro-High Speed End Milling of Soda Lime Glass Using Uncoated Tungsten Carbide Tool with Compressed Air Blowing

2014 ◽  
Vol 607 ◽  
pp. 103-107 ◽  
Author(s):  
A.K.M. Nurul Amin ◽  
Mahmoud M.A. Nassar ◽  
Muammer Din Arif
Keyword(s):  
Surface Roughness ◽  
Brittle Fracture ◽  
High Speed ◽  
End Milling ◽  
Desirability Function ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Machined Surface ◽  
Air Blowing ◽  
Tungsten Carbide Tool

Soda lime glass is a very important material in diverse manufacturing industries, including automotive, electronics, and aerospace. In these applications, the glass surface needs to be defect free and without impurities. However, the machining of glass is difficult due to its inherent brittleness which leads to brittle fracture and easy crack propagation. This research investigates the high speed micro-end milling of soda lime glass in order to attain ductile regime machining. It has been found by other researchers that ductile mode machining can avoid brittle fracture and sub-surface cracks. Also, in this study, a special air delivery nozzle is used to blow away the resultant chips and keep the machined surface clean. To accomplish this, Design Expert software and a commercial NC end mill were used to design and perform the machining runs, respectively. The surface roughness of the resultant surfaces was later analyzed with a surface profilometer. Microphotographs of the machined surfaces were also taken in order to see how effective the air blowing method is. The results of surface roughness measurements were then used to develop a quadratic empirical model for surface finish prediction. Finally, desirability function and genetic algorithms were used to predict the best combination of cutting parameters needed to obtain the lowest surface roughness. The predictions were later tested by experiments. The results demonstrate that this type of machining is viable and the roughness obtained is very low at 0.049 μm.

Prediction of Surface Roughness in Compressed Air Jet Assisted High Speed End Milling of Silicon Using Diamond Coated Tools

2012 ◽  
Vol 576 ◽  
pp. 41-45
Author(s):  
A.K.M. Nurul Amin ◽  
M.A. Mahmud ◽  
M.D. Arif
Keyword(s):  
Mathematical Model ◽  
Surface Roughness ◽  
Surface Finish ◽  
High Speed ◽  
End Milling ◽  
Silicon Wafers ◽  
Compressed Air ◽  
Machining Parameters ◽  
High Quality ◽  
Ductile Mode

The majority of semiconductor devices are made up of silicon wafers. Manufacturing of high-quality silicon wafers includes numerous machining processes, including end milling. In order to end mill silicon to a nano-meteric surface finish, it is crucial to determine the effect of machining parameters, which influence the machining transition from brittle to ductile mode. Thus, this paper presents a novel experimental technique to study the effects of machining parameters in high speed end milling of silicon. The application of compressed air, in order to blow away the chips formed, is also investigated. The machining parameters’ ranges which facilitate the transition from brittle to ductile mode cutting as well as enable the attainment of high quality surface finish and integrity are identified. Mathematical model of the response parameter, the average surface roughness (Ra) is subsequently developed using RSM in terms of the machining parameters. The model was determined, by Analysis of Variance (ANOVA), to have a confidence level of 95%. The experimental results show that the developed mathematical model can effectively describe the performance indicators within the controlled limits of the factors that are being considered.

Investigation of Heat Assisted High Speed End Milling of Soda Lime Glass for Surface Generation

2017 ◽  
Vol 740 ◽  
pp. 145-151
Author(s):  
Mohamed Konneh ◽  
Mst. Nasima Bagum ◽  
A.K.M. Nurul Amin ◽  
Amira Fatin Asyah
Keyword(s):  
Surface Finish ◽  
Feed Rate ◽  
High Speed ◽  
End Milling ◽  
Heating Temperature ◽  
Soda Lime ◽  
Surface Generation ◽  
Quadratic Model ◽  
Depth Of Cut ◽  
Soda Lime Glass

Brittle materials like soda lime glass can be machined in ductile mode under controlled machining conditions (feed rate, depth of cut, small tool edge radius) using high speed to generate a desired surface finish. The heat generated in high speed machining tends to promote ductile machining. In this paper, heat assisted high speed end milling is investigated to explore machinability of the soda lime glass. The heat assisted machining thus generates low surface finish on the machined workpiece. The heat assisted high speed end milling of soda lime was carried out using uncoated 2 flute carbide end mill at a constant depth of cut 25 μm, while the spindle speed and feed rate were varied from 30,000 to 50,000 rpm and 45 to 75 mm/min, respectively. The applied temperature was varied from 200 °C to 300 °C. The observations of machined surface were done on Surf-test (SV-514) and Scanning Electron microscope (SEM). A quadratic model for roughness (Ra) was developed using Central Composite Design of experiment. The optimum Ra, 0.10 μm was achieved at 49,570 rpm, 58 mm/min feed rate and heating temperature at 238°C. It is found that cutting speed has the greatest influence on the surface roughness value, followed by feed rate and heating temperature.

A New Experimental Approach to Determination of Critical Depth in High Speed Machining of Soda-Lime Glass

2012 ◽  
Vol 576 ◽  
pp. 23-27
Author(s):  
M.A. Mahmud ◽  
A.K.M. Nurul Amin ◽  
M.D. Arif
Keyword(s):  
High Speed ◽  
End Milling ◽  
Soda Lime ◽  
Depth Of Cut ◽  
Soda Lime Glass ◽  
Critical Depth ◽  
Good Surface ◽  
Transition Depth ◽  
Good Surface Finish

Soda-Lime glass is a very hard and brittle material which is commonly used as window panels and many other common applications. Due to its low fracture toughness it is very difficult to machine and obtain good surface finish under nornal cutting conditions. Hence, machining has to be done in ways to avoid brittle fracture on the finished machined surface. Such machining is only possible under ductile mode machining conditions when the removal of material is performed in the plastic state. However, ductile mode machining requires that during machining the temperature generated in the cutting zone in the working temperature range of glass to avoid crack formation during machining. This makes all types of machining of glass an extremely challenging affair, given the current state and mode of mechanical machining. This research paper elucidates the results of an experimental study for determination of critical depth of cut as a function of cutting parameters in high speed end milling of soda-lime glass. The critical depth is defined as the depth of cut at which crack formation the material is initiated for a given high speed attachment. In determining the critical depth as well as the ductile brittle transition depth, machining was performed on a tapered surface. Vibration signals from an accelerometer in time domain (amplitude vs. time display) and the surface characteristics were used in identifying the critical depth of cut. The new method has been found to be useful in online determination of the critical depth, as well as the brittle-ductile transition depth, for generating crack-free surfaces with good surface finish in high speed end milling of soda lime glass.

Comparison of Surface Roughness Attainable in High Speed End Milling of Silicon with Air Blowing on Conventional and CNC Milling Machines

2012 ◽  
Vol 576 ◽  
pp. 19-22
Author(s):  
A.K.M. Nurul Amin ◽  
Siti Nurshahida Mohd Nasir ◽  
Noor Syairah Khalid ◽  
Muammer Din Arif
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
End Milling ◽  
Compressed Air ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Ductile Mode ◽  
Milling Machines ◽  
Air Blowing ◽  
Machined Surfaces

Review of past research indicated that ductile mode machining of silicon can produce surface roughness values as low as 0.22 µm, which is about half of 0.40 µm, the usual standard roughness value to avoid fine grinding and rough polishing operations. The current research investigated and compared the surface roughness and integrity attained in high speed end milling of silicon (using diamond coated tools) under ductile mode machining conditions. Two different types of end milling machines were utilized, CNC and conventional milling machines. Additionally, the effect of compressed air on the resultant surface roughness was investigated. The air blowing fixture, designed for mounting the compressed air hose, consisted of fixed and movable jaws, air blower clamp, fasteners, and the air gun. Air blowing was used to prevent silicon chips from settling on the machined surface, since it was observed to be an acute problem in high speed ductile mode machining of silicon. The three machining parameters: spindle speed, depth of cut, and feed rate were varied within the ranges 60,000 to 80,000 rpm, 10 to 20 µm, and 5 to 15 mm/min respectively. The resultant machined surfaces were analysed using Wyko NT 1100 and SurfTest SV-500 profilometers in order to measure the attaine surface roughnesses and surface profile. The machined surfaces had almost no deposition and was of excellent finish.

Statistical Approach to Modeling & Optimization of Surface Roughness in High Speed End Milling of Silicon with Diamond Coated Tools

2012 ◽  
Vol 576 ◽  
pp. 28-31 ◽  
Author(s):  
A.K.M. Nurul Amin ◽  
Noor Syairah Khalid ◽  
Siti Nurshahida Mohd Nasir ◽  
Muammer D. Arif
Keyword(s):  
Surface Roughness ◽  
Response Surface ◽  
High Speed ◽  
End Milling ◽  
Desirability Function ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Coated Tools ◽  
Milling Machines ◽  
Air Blowing

This research demonstrated the use of conventional milling machines with diamond coated tools, high speed attachments, and air blowing mechanisms for ductile mode machining of silicon and subsequently modeling and optimizing the resultant surface roughness. Spindle speed, depth of cut, and feed rate, ranges: 60,000 to 80,000 rpm, 10 to 20 µm, and 5 to 15 mm/min respectively, were considered as the independent machining parameters for the modeling process. Compressed air at 0.35 MPa was also provided to prevent chip deposition on the finished surfaces. The resultant surfaces were analysed using Optical and Scanning Electron (SEM) Microscopes as well as Wyko NT 1100 and SurfTest SV-500 profilometers. The response, surface roughness, was then modeled using a small Central Composite Design (CCD) in Response Surface Methodology (RSM). The quadratic relation was found to be most suitable following Fit and Summary and ANOVA analyses. The relation was then optimized using Desirability Function (DF) in Design of Expert (DOE) software. The optimum attainable surface roughness, which was validated using experimental runs, was found to be 0.11 µm which may be considered quite satisfactory.

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