High speed end milling of soda lime glass using coated carbide tools with compresses air application /
Soda lime glass has versatile engineering application owing to its high hardness, good corrosion and chemical resistance. However, the low fracture toughness of the material does not permit machining using conventional approaches. It is challenging to machine this brittle material in ductile mode av...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur:
Kulliyyah of Engineering, International Islamic University Malaysia,
2013
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| Subjects: | |
| Online Access: | http://studentrepo.iium.edu.my/handle/123456789/4857 |
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| Summary: | Soda lime glass has versatile engineering application owing to its high hardness, good corrosion and chemical resistance. However, the low fracture toughness of the material does not permit machining using conventional approaches. It is challenging to machine this brittle material in ductile mode avoiding brittle fracture. This master thesis employed high speed end milling to ensure the development of high strain rate during machining of soda lime glass to achieve ductile mode machining through the development of high hydrostatic pressure in the cutting zone to convert the material in this zone to ductile state so that the cutting could proceed in the ductile mode without causing any brittle fracture and sub surfaces damages. It is established by researchers that in order to obtain ductile cutting regime, the chip thickness should be smaller than a critical value. Hence, one of the objectives of this was to identify the critical depth of cut for given limits of rotational speed of the high speed attachment and commonly available feed to achieve ductile mode machining. In this method, high rpm of the spindle (30000 to 50000 rpm) and low feed rate (6 to 18 mm/min) were used to enable the application of low depth of cut (micro-meter level) to ensure super finished machined surface that could avoid the need for further grinding, polishing and traditional photolithographic operation. It was found that, at the 40,000 rpm of spindle speed it was possible to obtain the highest critical depth of cut compared to those at the 30,000 and 50,000 rpm of spindle speed. It was also observed earlier that in the ductile range it is again challenging to achieve good surface finish due to the deposition and settlement of ductile chip on the machine surface. In this work an attempt has been made to ensure complete removal of chips from the machined surface by applying compressed air. It was found that the compressed air blowing significantly improves the surface roughness by blowing the yielded chips generated on the machined surface. However, the inclination of the air blowing nozzle could be important in raising the efficiency of chip removal. The developed universal air-blowing fixture was used to investigate the influence of the air blowing angle and it was found that the blowing angle in the range 25° to 30º gave the best results. Mathematical models were developed for the output response of average surface roughness (Ra). Investigation of multiple response optimizations of RSM and Genetic Algorithm (GA) were accomplished to obtain the best viable responses. Maximum desirability of 90% was obtained with Ra value of 83.58 nm and Material Removal Rate value of 5.8 mm3/min. The optimized values were experimentally validated and found to be in reasonable agreement with the predicted values. |
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| Physical Description: | xviii, 147 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 132-137). |