Embossing for electro discharge textured sheet
An apparatus and method for applying an EDT texture to an aluminum sheet has a rolling stand with at least one EDT surfaced roll capable of rolling the sheet at reductions <1%. The rolling is conducted with residual or no lubrication and imparts a texture on the scale of about 1 μm to the surface of the sheet at low roll force.
1. A method for applying texture to a metal sheet, comprising:
cold rolling the metal sheet at a rolling stand with a roll having an EDT surface,
wherein the roll applies a roll force to the metal sheet,
wherein the roll force reduces a thickness of the metal sheet by <1%,
wherein the roll force produces a texture on the metal sheet, and
wherein after the cold rolling the metal sheet has a surface roughness of from 1 μm to 5 μm with a transfer percentage of >80%.
2. The method of claim 1 , wherein, the roll force is maintained by at least one of at least one hydraulic cylinder or mechanical actuator.
3. The method of claim 1 , wherein, the roll force is maintained from +/−0.3 to 0.5% of total roll force.
4. The method of claim 1 , wherein, the roll force is maintained from +/−1 to 5 tons of total roll force.
5. The method of claim 1 , wherein, the roll force is measured by load cells or pressure transducers and force data is used to control hydraulic or mechanical actuator(s) that regulate the roll force.
6. The method of claim 1 , wherein the surface roughness on the metal sheet is from 1 to 1.5 μm Sa.
7. The method of claim 1 , wherein a surface of the metal sheet is redistributed by the step of cold rolling to a depth of from 1 to 2 μm.
8. The method of claim 1 , wherein the metal sheet has a width of from 1.5 m to 1.85 m and the roll force exerted by the roll having the EDT surface is from 200 to 350 metric tons.
9. The method of claim 1 , wherein the step of cold rolling is conducted by a 2 high rolling stand.
10. The method of claim 9 , wherein the 2 high rolling stand is an embossing mill with at least one roll being the roll having the EDT texture.
11. The method of claim 10 , wherein both rolls of the 2 high rolling stand are EDT textured.
12. The method of claim 1 , wherein, after the step of cold rolling, the metal sheet has a peak count of 20 to 100 peaks/cm using a cutoff threshold +/−Sa/2.
13. The method of claim 1 , wherein the roll having an EDT surface has a radius from 300 to 500 mm.
14. The method of claim 1 , wherein the roll having the EDT surface has a crown of 0.635 mm.
15. The method of claim 1 , wherein the metal sheet is pulled through the rolling stand and drives the roll having the EDT surface.
16. The method of claim 1 , wherein the metal sheet is driven through the rolling stand.
17. The method of claim 1 , wherein the metal sheet is an output of a rolling mill.
18. The method of claim 1 , wherein, prior to the step of cold rolling, the metal sheet is from 0.03 mm to 0.100 mm in thickness.
19. The method of claim 1 , wherein, prior to the step of cold rolling, the metal sheet is from 0.5 mm to 20 mm in thickness.
20. The method of claim 1 , wherein, prior to the step of cold rolling, the metal sheet is not greater than 1.1 mm in thickness.
21. The method of claim 1 , wherein, prior to the step of cold rolling, no lubricant is applied to the metal sheet.
22. The method of claim 21 , comprising, prior to the step of cold rolling, cleaning the metal sheet.
23. The method of claim 1 , comprising, after the step of cold rolling, cleaning the roll having an EDT texture.
24. The method of claim 1 , wherein a line speed of the metal sheet during the step of cold rolling is from 50 to 500 m/min.
25. The method of claim 1 , wherein the rolling stand is selectively positionable in a roll line to allow running the roll line with or without the rolling stand.
26. The method of claim 1 , wherein the rolling stand is selectively on/off line or open/closed in a roll line to allow running the rolling line or processing line with or without the rolling stand.
27. The method of claim 1 , comprising forming a vehicle panel from the metal sheet after the step of rolling.
28. A sheet produced by the method of claim 1 .