This innovative technique was developed by SCHOTT to produce glass sheets with the tightest thickness tolerance and lowest total thickness variation (TTV), regardless of dimension. The down-draw process also produces a pristine surface with minimal roughness on both sides.
The down-draw process produces thin and ultra-clear flat glasses. The process involves a ribbon of molten glass being pulled down from above before moving across various drums and through a cooling track. This results in a pristine surface that can accommodate processes such as coating, bonding and etching, with very tight thickness tolerances of ± 10µm, and a TTV < 10µm.
- Extremely flat and smooth surface on both sides.
- Very low bulk and cosmetic defects.
- Wide thickness from direct hot forming, without the need for polishing or thinning.
- Very tight thickness tolerances to accommodate different processing methods.
- Outstanding chemical strengthening performance.
SCHOTT’s unique method for melting glass into flat glass sheets has proved popular in fields such as advanced optics thanks to the sheets’ excellent clarity and flawless texture and appearance. It can be drawn directly into wide thicknesses without the need for bulk glass processing or further polishing.
The groundbreaking up-draw process was perfected by SCHOTT to manufacture thin and ultra-clear flat glasses. The technique involves a ribbon of molten glass being pulled up across various drums and then through a cooling track, resulting in a fire-polished surface with an outstanding surface roughness of < 0.5nm. With a thickness spectrum ranging from 0.9 mm to 10 mm, this process can be used to create supremely clear ‘ultra-white’ glass sheets.
- Pristine fire-polished surface on both sides, with no need for further polishing.
- Defined initial thickness resulting in minimal material loss during processing.
- Enables high quality production of unique glass materials unsuited to float processing.
SCHOTT uses state-of-the-art microfloat technology to create glass sheets with an outstanding level of homogeneity, as well as a mirror-like surface and excellent optical quality. This makes the float method ideal to produce glass for a wide range of markets, from the automotive industry to consumer electronics.
Floated glass sheets such as SCHOTT’s renowned BOROFLOAT® are created using a sophisticated process in which a continuous strip of molten glass is guided over a bath of molten tin. The glass ‘floats’ over the tin and cools to form a very flat surface on both sides of the glass, with the top fire-polished due to the effect of hot gases. The resulting sheets have a very high chemical stability, outstanding thermal resistance and strong transparency, while being mechanically robust and resistant to scratching and abrasion. The hot forming process also enables a broad thickness range.
- Outstanding transparency and optical qualities.
- Very high thermal shock resistance, so suitable for tough environments.
- Excellent mechanical strength and resistance to damage.
- Highly homogenous material ensuring reliable performance.
- Available in a wide range of thicknesses.