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.

An Experimental Approach to Determine the Critical Depth of Cut in Brittle-to-Ductile Phase Transition During End Milling of Soda-Lime Glass

2016 ◽  
Vol 41 (11) ◽  
pp. 4553-4562 ◽  
Author(s):  
A. K. M. Nurul Amin ◽  
Mst. Nasima Bagum ◽  
Noor Fathiah ◽  
Mohamed Konneh ◽  
Tasnim Firdaus Bt. Mohamed Ariff
Keyword(s):  
Phase Transition ◽  
Experimental Approach ◽  
End Milling ◽  
Soda Lime ◽  
Depth Of Cut ◽  
Soda Lime Glass ◽  
Critical Depth ◽  
Ductile Phase ◽  
Critical Depth Of Cut

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.

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.

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.

scholarly journals Machinability of Soda Lime Glass in High Speed End Milling

2018 ◽  
Vol 290 ◽  
pp. 012036
Author(s):  
Mohamed Konneh ◽  
Mst. Nasima Bagum ◽  
Tasnim Firdaus Bt. Mohamed Arif ◽  
Mohammad Yeakub Ali
Keyword(s):  
High Speed ◽  
End Milling ◽  
Soda Lime ◽  
Soda Lime Glass

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.

An Experimental Study on Microcutting of Soda-Lime Glass by Milling Process

2010 ◽  
Vol 447-448 ◽  
pp. 116-120
Author(s):  
Muhammad Arif ◽  
Mustafizur Rahman ◽  
Yoke San Wong
Keyword(s):  
Free Surface ◽  
End Milling ◽  
Cutting Speed ◽  
Soda Lime ◽  
Milling Process ◽  
Dominant Factor ◽  
Depth Of Cut ◽  
Soda Lime Glass ◽  
Brittle Ductile Transition ◽  
Radial Depth

Glass is an important engineering material. It is widely used in semiconductor, optical, micro-electronics and many other fields. However, glass is not amenable to machining with conventional approach because of its low fracture toughness. To achieve high quality surface finish on optical components, glass must be machined in ductile mode. Compared to single point cutting processes, end-milling can achieve improved material removal rate in machining fracture free surface on brittle material. This paper presents the results of an experimental investigation into microcutting of glass by end-milling. Side-cutting tests have been performed on soda-lime glass workpiece at multiple feeds and radial depth of cuts to obtain fracture free machined surface. The tests were designed to investigate the effect of feed per edge and radial depth of cut on the cutting mechanism at low cutting speed. Experimental results indicate that feed per edge is the most dominant factor that dictates the occurrence of brittle-ductile transition point in the milling process of glass. It has been proved experimentally that fracture free surface can be machined on glass at high radial depth of cut if the feed per edge is sufficiently small.

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.

Machining Schemes for Dicing Soda Lime Glass

2010 ◽  
Vol 126-128 ◽  
pp. 263-268
Author(s):  
Jhy Cherng Tsai ◽  
Hong Shin Chen
Keyword(s):  
Front Surface ◽  
Soda Lime ◽  
Fracture Analysis ◽  
Back Surface ◽  
Depth Of Cut ◽  
Soda Lime Glass ◽  
Critical Depth ◽  
Ductile Machining ◽  
One Step ◽  
Critical Depth Of Cut

This research investigates machining schemes for dicing soda lime glass in order to reduce the damage in the processes. Ductile machining and brittle machining of glass are first analyzed based on fracture mechanics and then verified by experiments. Experiments with various machining schemes including scribing-then-breaking, direct-dicing and dicing-then-breaking processes for soda lime glass are then conducted. Experimental observations showed the following results. (i) The critical depth of cut (CDOC) for soda lime glass is between 0.4μm and 0.8μm that matches theoretical prediction, 0.78μm, based on fracture analysis. (ii) The scribing-then-breaking machining scheme results in less damage than the regular slicing process. The DOC of scribing, however, must be in the ductile-brittle region to achieve this result. (iii) Defect due to dicing on the back surface is higher than that on the front surface in one-step dicing through process. Dicing defects can be effectively reduced by decreasing the feed rate or increasing the dicing speed.

Sign in / Sign up

Export Citation Format

Share Document