ULTRASONIC POLISHING SYSTEMS AND METHODS OF POLISHING BRITTLE COMPONENTS FOR ELECTRONIC DEVICES

• US 20170087687A1
• Filed: 09/29/2016
• Published: 03/30/2017
• Est. Priority Date: 09/30/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hoffman, Alexander M., Kamireddi, Srikanth
• Granted Patent: US 10,144,107 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B24B 19/009 for grinding profiled workpieces using a profiled grinding tool
• CPC Class Codes: B24B 37/042 operating processes therefor
• CPC Class Codes: B24B 37/07 characterised by the movement of the work or lapping tool
• CPC Class Codes: B24B 57/02 for feeding of fluid, sprayed, pulverised, or liquefied grinding, polishing or lapping agents

Abstract

Ultrasonic polishing systems and methods of polishing brittle components for electronic devices using ultrasonic polishing systems are disclosed. The ultrasonic polishing system may include an ultrasonic driver and a polishing head operatively coupled to the ultrasonic driver. The ultrasonic drive may have a surface shape that corresponds to a non-planar feature formed in the brittle component. The ultrasonic polishing system may also include an abrasive slurry configured to be disposed between the non-planar feature of the brittle component and the polishing head. The ultrasonic driver may be configured to displace the polishing head toward and away from the non-planar feature formed in the brittle component.

Claims

1. An ultrasonic polishing system for polishing a non-planar feature formed in a brittle component, the system comprising:

an ultrasonic driver;

a polishing head operatively coupled to the ultrasonic driver and having a surface shape that corresponds to the non-planar feature formed in the brittle component; and

an abrasive slurry configured to be disposed between the non-planar feature of the brittle component and the polishing head;

wherein

the ultrasonic driver is configured to displace the polishing head toward and away from the non-planar feature formed in the brittle component.

2. The ultrasonic polishing system of claim 1, wherein the abrasive slurry comprises a solid abrasive material suspended in a liquid, the solid abrasive material having a hardness greater than the brittle component.

3. The ultrasonic polishing system of claim 2, wherein a gap formed between the polishing head and the non-planar feature of the brittle component is greater than a grain size of the solid abrasive material.

4. The ultrasonic polishing system of claim 3, wherein the polishing head is displaced to:

contact the non-planar feature of the brittle component; and

to form the gap between the polishing head and the non-planar feature of the brittle component that is approximately 150% of the grain size of the solid abrasive material.

5. The ultrasonic polishing system of claim 1, further comprising an actuating gantry coupled to the ultrasonic driver and configured to move the polishing head in at least one of:

a first direction; and

a second direction, perpendicular to the first direction.

6. The ultrasonic polishing system of claim 1, wherein the non-planar feature formed in the brittle component comprises at least one of:

a substantially non-linear transition portion formed between a base portion and a sidewall of the brittle component;

a groove formed partially through the brittle component;

a protrusion extending from a portion of the brittle component;

or

an aperture formed through the brittle component.

7. The ultrasonic polishing system of claim 1, further comprising an insert surrounding the brittle component and configured to substantially secure the brittle component while the ultrasonic driver displaces the polishing head.

8. The ultrasonic polishing system of claim 1 further comprising a media flow system in fluid communication with the abrasive slurry, the media flow system configured to recirculate the abrasive slurry.

9. A method for polishing a non-planar feature of a brittle component, the method comprising:

positioning a polishing head adjacent the non-planar feature of the brittle component, the brittle component at least partially submerged in an abrasive slurry disposed within a housing;

moving, at an ultrasonic frequency, at least one of the housing or the polishing head in at least one of;

a first direction;

or

a second direction, perpendicular to the first direction; and

in response to moving at least one of the housing of the polishing head, displacing the abrasive slurry to abrade and polish the non-planar feature of the brittle component;

wherein

the polishing head comprises a surface shape that corresponds to the non-planar feature of the brittle component.

10. The method of claim 9, wherein moving the polishing head comprises repeatedly displacing the polishing head toward and away from the non-planar feature of the brittle component.

11. The method of claim 10, wherein displacing the polishing head comprises moving the polishing head to:

contact the non-planar feature of the brittle component; and

form a gap between the polishing head and the non-planar feature of the brittle component, the gap equal to approximately 150% of a grain size of a solid abrasive material of the abrasive slurry.

12. The method of claim 9, wherein moving the housing comprises repeatedly displacing the brittle component toward and away from the polishing head.

13. The method of claim 9, wherein displacing the abrasive slurry to abrade and polish the non-planar feature of the brittle component comprises continuously recirculating the abrasive slurry over the non-planar feature.

14. The method of claim 9, further comprising securing the brittle component within the housing prior to positioning the polishing head adjacent the non-planar feature of the brittle component.

15. An ultrasonic polishing system comprising:

a housing for receiving a brittle component comprising a non-planar feature;

a polishing head positioned within the housing, the polishing head having a surface shape that corresponds to the non-planar feature formed in the brittle component;

an abrasive slurry positioned within the housing, the abrasive slurry comprising a solid abrasive material suspended in a liquid; and

an ultrasonic driver configured to move at least one of the housing or the polishing head at an ultrasonic frequency to polish the non-planar feature of the brittle component using the abrasive slurry.

16. The ultrasonic polishing system of claim 15, wherein:

the non-planar feature of the brittle component comprises a groove; and

the polishing head comprises a projection having a shape that corresponds to the groove.

17. The ultrasonic polishing system of claim 15, wherein:

the non-planar feature of the brittle component comprises a protrusion; and

the polishing head comprises a recess having a shape that corresponds to the protrusion.

18. The ultrasonic polishing system of claim 15, wherein:

the non-planar feature of the brittle component comprises an aperture; and

the polishing head comprises a T-shaped structure having a shape corresponding to the aperture and a portion of the brittle component surrounding the aperture.

19. The ultrasonic polishing system of claim 15, wherein a gap formed between the polishing head and the non-planar feature of the brittle component is greater than a grain size of the solid abrasive material.

20. The ultrasonic polishing system of claim 15, wherein the solid abrasive material has a hardness greater than the brittle component.