Edge break details and processing

• US 8,892,238 B2
• Filed: 01/26/2010
• Issued: 11/18/2014
• Est. Priority Date: 10/06/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Sweet, Edward T., Ortega, Roberto, Davidson, Andrew, Lancaster, Simon, Johannessen, Thomas
• Primary Examiner(s): Shechtman, Sean
• Assistant Examiner(s): GARLAND, STEVEN R
• Application Number:
  US12/694,083
• Publication Number:
  US 20110081828A1
• Time in Patent Office: 1,757 Days
• Field of Search: 700/164, 700/170, 700/172, 700/175, 700/176, 451/5, 451/57, 451/278, 451/254, 451/182, 451/43, 451/44, 451/259, 451/260, 451/913
• US Class Current: 700/164
• CPC Class Codes: B24B 29/005 using brushes
• CPC Class Codes: B24B 29/02 designed for particular workpieces
• CPC Class Codes: B24B 51/00 Arrangements for automatic control of a series of individual steps in grinding a workpiece if applicable to other machine tools, G05B takes precedence
• CPC Class Codes: B24B 9/20 of plastics

Abstract

A method and an apparatus for shaping an edge at a juncture of two adjoining surfaces of a part. A first surface and a second surface of the part are abraded by contacting a polishing surface of a polishing wheel to the first surface and to the second surface. The polishing surface spins in opposite rotational directions about an axis parallel to the edge when contacting the first and second surfaces respectively. The polishing surface moves at different translational speeds and the polishing wheel spins at different rotational speeds along straight segments and along curved segments of the edge. The shaped edge has a visually smooth and geometrically uniform appearance.

Claims

1. A method for smoothing an edge of a part, the edge defined by a first planar surface and a second planar surface, the method comprising:

operating a rotating polishing wheel comprising a polishing surface in accordance with a first set of polishing parameters to form a first curved surface at the edge and the first planar surface, the first set of polishing parameters comprising a first set of rotational speeds, a first set of translational speeds and a first contact angle of the polishing surface relative to a horizontal reference line relative to the first planar surface; and

operating the rotating polishing wheel in accordance with a second set of polishing parameters, different that the first set of polishing parameters, to form a second curved surface at the edge and the second planar surface, the second set of polishing parameters comprising a second set of rotational speeds, a second set of translational speeds and a second contact angle of the polishing surface relative to the horizontal reference line relative to the first planar surface different than the first angle,

wherein the first curved surface and the second curved surface cooperate to form the smoothed edge.

2. The method of claim 1, wherein the first set of polishing parameters includes a first rotational speed and a second rotational speed different than the first rotational speed, wherein the first rotational speed is used to polish the first planar surface and the second rotational speed is used to polish the edge.

3. The method of claim 2, wherein the first rotational speed is higher than the second rotational speed.

4. The method of claim 1, wherein the first set of polishing parameters includes a first translational speed and a second translational speed different than the first translational speed, wherein the first translational speed is used to polish the first planar surface and the second translational speed is used to polish the edge.

5. The method of claim 4, wherein the first translational speed is lower than the second translational speed.

6. The method of claim 1, wherein the first angle is smaller than the second angle.

7. The method of claim 1, wherein the first set of polishing parameters or the second set of polishing parameters is adjusted for smoothing an edge of a second part to account for a change in shape of the polishing surface of the polishing wheel.

8. The method of claim 1, wherein the first set of polishing parameters includes a first depth of interference and the second set of polishing parameters includes a second depth of interference, the first depth of interference defining a first distance between the part and a center of the polishing wheel and the second depth of interference defining a second distance between the part and a center of the polishing wheel, wherein the first depth of interference is different than the second depth of interference.

9. An apparatus configured to shape an edge defined by a first planar surface and a second planar surface of a part, the apparatus comprising:

a polishing wheel configured to rotate about a central axis at a plurality of rotational speeds in a first rotational direction and in a second rotational direction opposite the first rotational direction, the polishing wheel having a perimeter with a polishing surface;

and a positioning assembly configured to control the polishing surface to smooth the edge using at least a first pass and second pass,

wherein the first pass comprises translating the polishing surface along the first planar surface and the edge in accordance with a first set of polishing parameters, the first set of polishing parameters comprising a first set of rotational speeds, a first set of translational speeds and a first contact angle of the polishing surface relative to a horizontal reference line of the polishing wheel,

wherein the second pass comprises translating the polishing surface along the second planar surface and the edge in accordance with a second set of polishing parameters different that the first set of polishing parameters, the second set of polishing parameters comprising a second set of rotational speeds, a second set of translational speeds and a second contact angle of the polishing surface relative to a horizontal reference line of the polishing wheel different than the first angle.

10. The apparatus of claim 9, wherein the polishing surface is configured to remove burrs from the part.

11. The apparatus of claim 9, wherein the first set of polishing parameters includes a first rotational speed and a second rotational speed different than the first rotational speed, wherein the first rotational speed is used to polish the first planar surface and the second rotational speed is used to polish the edge.

12. The apparatus of claim 11, wherein the first rotational speed is higher than the second rotational speed.

13. The apparatus of claim 9, wherein the first set of polishing parameters includes a first translational speed and a second translational speed different than the first translational speed, wherein the first translational speed is used to polish the first planar surface and the second translational speed is used to polish the edge.

14. The apparatus of claim 13, wherein the first translational speed is lower than the second translational speed.

15. The apparatus of claim 9, wherein the first angle is smaller than the second angle.

16. The apparatus of claim 9, further comprising:

a fixture configured to stabilize the part and to reveal the first planar surface, the second planar surface, and the edge of the part.

17. The apparatus of claim 16, wherein the fixture includes a wall that protects a portion of the first planar surface during a shaping operation.

18. The apparatus of claim 9, wherein the polishing wheel includes a nylon brush.

19. A non-transitory computer readable medium storing computer program code executable by a processor for controlling a computer aided manufacturing operation for smoothing an edge of a part defined by a first planar surface and a second planar surface, the computer readable medium comprising:

computer program code for operating a rotating polishing wheel comprising a polishing surface in accordance with a first set of polishing parameters to form a first curved surface at the edge and the first planar surface, the first set of polishing parameters comprising a first set of rotational speeds, a first set of translational speeds and a first contact angle of the polishing surface relative to a horizontal reference line relative to the first planar surface; and

computer program code for operating the rotating polishing wheel in accordance with a second set of polishing parameters, different that the first set of polishing parameters, to form a second curved surface at the edge and the second planar surface, the second set of polishing parameters comprising a second set of rotational speeds, a second set of translational speeds and a second contact angle of the polishing surface relative to the horizontal reference line relative to the first planar surface different than the first angle,

wherein the first curved surface and the second curved surface cooperate to form the smoothed edge.

20. The non-transitory computer readable medium of claim 19, further comprising:

computer program code for adjusting the first set of polishing parameters or the second set of polishing parameters for smoothing an edge of a second part to account for a change in shape of the polishing surface of the polishing wheel after smoothing the edge of a first part.

21. The non-transitory computer readable medium of claim 19, wherein the first set of polishing parameters includes a first rotational speed and a second rotational speed, wherein the first rotational speed is used to polish the first planar surface and the second rotational speed is used to polish the edge.

22. The non-transitory computer readable medium of claim 21, wherein the first rotational speed is higher than the second rotational speed.

23. The non-transitory computer readable medium of claim 19, wherein the first set of polishing parameters includes a first translational speed and a second translational speed, wherein the first translational speed is used to polish the first planar surface and the second translational speed is used to polish the edge.

24. The non-transitory computer readable medium of claim 19, wherein the first angle is smaller than the second angle.