Abstract: The liquid crystal display (LCD) glass substrate cutting is one of the key processes in manufacturing LCD screens.In order to achieve highly-efficient and high-quality precision cutting of LCD glass substrates,a new LCD glass substrate cutting method based on double scribe-wheels is proposed,in which the first scribe-wheel is used to scribe a plastic groove on the cutting surface and then the scribed LCD glass substrate is cut by the second scribe-wheel along the plastic groove.Then,the critical load of medial crack initiation is determined by the inden- tation experiments using a symmetric wedge,and the crack initiation and propagation laws during the second inden- tation of the symmetrical wedges along the plastic groove that is generated in the first indentation are investigated.Experimental results show that (1) no lateral cracks occur during the second indentation; (2) the length of the vertical cracks increases slightly with the increase of the load imposed in the first indentation,and it increases line- arly with the increase of the load imposed in the second indentation; (3) when no lateral cracks occur,it is possi- ble to obtain the perfect fractographs without edge chippings or microcracks ［1］; and (4) the length increase of the vertical cracks makes the splitting of the substrate on the flip side unnecessary during the second cutting based on the double scribe-wheels.

Key words: liquid crystal display glass, cutting, indentation, cracks