Method for producing perforated workpieces in a stress-relieving manner
AssigneeSchott AG
InventorsKurt Nattermann, Ulrich Peuchert
Life of this patent
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Abstract
A method for producing perforated work pieces from glass, glass ceramics, or semiconductors in a stress-relieving manner is provided. The method includes heating the work piece up to the glass transition temperature and perforating the work piece using a high-voltage electric field of suitable frequency or pulse shape. Then, the perforated work piece is allowed to cool down from the transition temperature range to room temperature at a rate at which the mechanical stresses generated by the perforation process relax.
Claims8
1-7. (canceled)
A method for producing a perforated work piece from glass, glass ceramics, or semi-conductors in a stress-relieving manner, comprising the steps of:
- providing the work piece to be perforated, the work piece having a transition temperature at which a material of the work piece softens;
- heating the whole work piece up to a temperature range close to the transition temperature to provide a softened work piece having a viscosity between 1012 and 1014 dPa·s;
- perforating the softened work piece using an electrical high voltage field of a suitable frequency or pulse shape so that an increasing electrical current flows at the location to be perforated to evaporate the material and provide a perforated work piece;
- and
- cooling the perforated work piece from the transition temperature to room temperature at a cooling rate sufficient to relax mechanical stresses generated by the perforation.
The method as claimed in claim 7, wherein the heating and cooling steps are accomplished in a furnace.
The method as claimed in claim 7, wherein the cooling rate is in a range from −0.5 to −5° C./min.
The method as claimed in claim 7, wherein, when the work piece is made of alkali-free or low-alkali glasses, a heating temperature in a range from 650° C. to 730° C. is used.
The method as claimed in claim 7, further comprising heating the perforated work piece before being cooled down to room temperature.
Dependencies are inferred from the claim text.