Methods for strengthening edges of laminated glass articles and laminated glass articles formed therefrom
Methods for strengthening edges of a laminated glass article comprising a glass core layer positioned between a first glass clad layer and a second glass clad layer are disclosed. The methods may comprise polishing the cut edges of the laminated glass article with a slurry of polishing media applied to the edges of the laminated glass article with brushes. An edge strength of the laminated glass article is greater than or equal to about 400 MPa after polishing.
1. A method for strengthening an edge of a glass laminate article, the method comprising:
creating a stack having an edge profile, the creating comprising:
applying adhesive to a top surface of the first glass laminate article;
placing a second glass laminate article on the top surface of the first glass laminate article, wherein each glass laminate article comprises a glass core layer positioned between a first glass clad layer and a second glass clad layer; and
applying pressure to a top surface of the second glass laminate article to create a first segment of the stack, wherein the first and second glass laminate articles of the first segment of the stack are adhesively but releasably bound;
polishing the edge profile of the stack by delivering a loose abrasive material to the edge profile to create a polished stack; and
separating the polished stack into two or more polished glass laminate articles, wherein the edge of each polished glass laminate article has an average strength value of greater than or equal to 400 MPa.
2. The method of claim 1 , wherein the loose abrasive material is delivered with a rotating brush.
3. The method of claim 2 , wherein the rotating brush is circular and comprises nylon bristles.
4. The method of claim 1 , wherein the loose abrasive material comprises a slurry comprising CeO 2 particulates having a density of about 1.3 g/cm 3 .
5. The method of claim 1 , wherein the polishing the edge profile comprises removing a portion of the edge profile to a removal depth of about 0.05 mm.
6. The method of claim 5 , wherein the removing a portion of the edge profile comprises a series of consecutive removal passes, wherein each pass removes from about 8 μm to about 10 μm of material.
7. The method of claim 1 , further comprising grinding the edge profile of the stack before polishing the edge profile.
8. The method of claim 7 , wherein a grinding spacing between adjacent laminated glass articles during the grinding step is less than a polishing spacing between adjacent laminated glass articles during the polishing step.
9. The method of claim 8 , wherein the grinding spacing is 20 μm to 100 μm and the polishing spacing is 100 μm to 220 μm.
10. The method of claim 7 , further comprising, separating the ground stack into two or more ground glass laminate articles and stacking the two or more ground glass laminate articles before polishing the edge profile.
11. The method of claim 7 , wherein the edge profile of the stack is ground with at least a rough abrasive wheel having fixed abrasive particles and a fine abrasive wheel having fixed abrasive particles.
12. The method of claim 11 , wherein the rough abrasive wheel is metal bonded and has fixed abrasive particles in the range of from about 240 grit to about 400 grit.
13. The method of claim 11 , wherein the fine abrasive wheel is electroplated and has fixed abrasive particles in the range of from about 800 grit to about 1200 grit.
14. The method of claim 11 , wherein the fine abrasive wheel is metal bonded and has fixed abrasive particles in the range of from about 500 grit to about 800 grit.
15. The method of claim 11 , wherein the fine abrasive wheel is resin bonded and has fixed abrasive particles in the range of from about 500 grit to about 3000 grit.
16. The method of claim 1 , wherein the creating further comprises:
removing excess adhesive from the edge profile of the stack;
adjusting and aligning the edge profile of the stack; and
repeating the creating a segment of a stack steps to create one or more additional segments of the stack, wherein each segment of the stack is adhesively but releasably bound to at least another segment of the stack.