A Study on Dicing and Scribing Processes of Glasses

• Main Authors: Hung-Hsin Chen, 陳宏信
• Other Authors: 蔡志成
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/13789790174295539049

碩士 === 中興大學 === 機械工程學系所 === 94 === Glasses have good optical properties which can be applied to various optical devices such as optical lens and liquid crystal display. The demand of glasses is vast while still increasing year by year. As glasses are brittle materials with high hardness and extremely high fragility, it is common to damage the material, such as breakage, breach and crack, in the machining process. This research is aimed to investigate machining schemes for cutting glasses to reduce the damage in the processes. Ductile machining and brittle machining of glasses are first analyzed based on fracture mechanics. Experiments with different schemes including scribing-then-breaking, dicing-then-breaking, direct-dicing and two-step-dicing processes for soda lime glass and borosilicate glass are then conducted. Major results of this study include the followings. (i) Results by scribing experiments showed that critical depth of cut (DOC) for soda lime glass is between 0.4μm to 0.8μm and between 0.3μm to 0.5μm for borosilicate glass. The results match theoretical predictions based on fracture analysis that DOC for the soda lime glass and for the borosilicate glass are 0.78μm and 0.47μm respectively. (ii) The best machining scheme that results in least damage is the scribing-then-breaking process. The DOC of scribing, however, must be in the ductile-brittle region to generate a middle crack while avoiding lateral crack. (iii) Least damage can be achieved by reducing feed, increasing spindle speed in two-step-dicing process. (iv) Although back-surface defect can be avoided by dicing-then-breaking process, direction of crack generated in the process is not regular. Furthermore, size error can be induced as dicing width is higher than cracking width, not to mention that post grinding and lapping process must be employed to eliminate the scratches and burs.