A technique based on the generation of highly localized thermal stresses has been devised as a means of cutting both flat and curved glass sheets of thicknesses between 30 and 600 µm. The technique is reliable, accurate, and economical. The technique can be used, for example, to cut thin glass sheets for microscope slides and for covers on laptop-computer displays and other flat-panel displays.
Heretofore, thin glass sheets have been cut, variously, by use of lasers or by use of diamond tips and knives. Laser cutting is expensive. Diamond tips and knives generate microfractures that make glass sheets more susceptible to breakage along lines other than the intended cut lines. Cutting of thin, curved glass sheets by use of diamond tips and knives is expensive and difficult.
In the present technique, an electrically heated tungsten tip is applied to the glass to be cut. Because of the low thermal conductivity of glass, a large amount of heat can be concentrated in a narrow region surrounding the heated tip. The local concentration of heat gives rise to thermal stresses that can be large enough to break the glass locally and smoothly. As a result, from a macroscopic perspective, the heated tip works like a knife that cuts through the glass.
This work was done by William W. Zhang and Delmar H. Arbogast of Goddard Space Flight Center. For more information, contact the Goddard Commercial Technology Office at (301) 286-5810. Refer to GSC-14364.