GRINDING APPARATUS AND GRINDING METHOD

• US 20110065066A1
• Filed: 04/06/2009
• Published: 03/17/2011
• Est. Priority Date: 06/26/2008
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Sugata, Fumio, Hamano, Seiji, Segawa, Terutsugu
• Application Number:
  US12/993,413
• Publication Number:
  US 20110065066A1
• Time in Patent Office: Days
• US Class Current: 433/201.1
• CPC Class Codes: A61C 13/0006 Production methods
• CPC Class Codes: A61C 13/12 Tools for fastening artificial teeth; Holders, clamps, or stands for artificial teeth A61C8/0089 takes precedence
• CPC Class Codes: B23Q 11/1007 by submerging the tools or work partially or entirely in a liquid
• CPC Class Codes: B24B 1/04 subjecting the grinding or polishing tools, the abrading or polishing medium or work to vibration, e.g. grinding with ultrasonic frequency polishing or abrading surfaces on work by means of tumbling apparatus B24B31/00, involving oscillating or vibrating containers B24B31/06; superfinishing surfaces on work, e.g. by means of abrading blocks reciprocating with high frequency, B24B35/00
• CPC Class Codes: B24B 19/22 characterised by a special design with respect to properties of the material of non-metallic articles to be ground
• CPC Class Codes: B24B 55/02 Equipment for cooling the grinding surfaces, e.g. devices for feeding coolant cooling or lubricating during dressing operation B24B53/095; incorporated in grinding wheels B24D

Abstract

A grinding apparatus (100) includes: a rotating grinding tool (102) for grinding a workpiece (101) immersed in a cooling liquid (106); vibration generating mechanisms (107a) to (107f) for applying vibrations to the cooling liquid (106) and generating cavitation; and a controller (108) for causing the vibration generating mechanisms (107a) to (107f) to generate the cavitation when the rotating grinding tool (102) is operated. The controller (108) turns on/off the vibration generating mechanisms (107a) to (107f) and adjusts amplitudes of the vibrations of the cooling liquid (106) generated by the vibration generating mechanisms (107a) to (107f) depending on a region in the workpiece (101) to be machined and one out of a plurality of machining steps to be performed.

Claims

1. A grinding apparatus comprising:

a rotating grinding tool for grinding a workpiece immersed in a cooling liquid;

vibration generating mechanisms for applying vibration to the cooling liquid and generating cavitation; and

a controller for causing the vibration generating mechanisms to generate the cavitation when the rotating grinding tool is operated.

2. The grinding apparatus according to claim 1, wherein the controller controls the vibration generating mechanisms to generate a longitudinal wave in the cooling liquid in which a half wavelength of the longitudinal wave corresponds to a length obtained by dividing a length from a side to an opposite side of a tank in which the cooling liquid is stored by an integer.

3. The grinding apparatus according to claim 1, wherein the controller controls the vibration generating mechanisms to generate a longitudinal wave in the cooling liquid in which a half wavelength of the longitudinal wave corresponds to a length obtained by dividing a length from a bottom of a tank in which the cooling liquid is stored to a liquid level of the cooling liquid by an integer.

4. The grinding apparatus according to claim 1, wherein the controller turns on/off the vibration generating mechanisms and adjusts amplitudes of the vibrations of the cooling liquid generated by the vibration generating mechanisms depending on a region in the workpiece to be machined and one out of a plurality of machining steps to be performed.

5. The grinding apparatus according to claim 1, wherein the workpiece is made of a ceramic material which is a raw material of a dental prosthesis.

6. A grinding method, wherein a workpiece is immersed in a cooling liquid and ground by means of a rotating grinding tool, the method comprising a vibration generating step for applying vibrations to the cooling liquid, thereby generating cavitation in the liquid.

7. The grinding method according to claim 6, wherein in the vibration generating step, a longitudinal wave is generated in the cooling liquid, wherein the longitudinal wave has a wave motion which propagates in a first direction along a rotation axis of the rotating grinding tool or a second direction that intersects the rotating axis.

8. The grinding method according to claim 6, wherein in the vibration generating step, a longitudinal wave is generated in the cooling liquid, a half wavelength of the longitudinal wave corresponds to a length obtained by dividing a length from a sides to an opposite side of a tank in which the cooling liquid is stored by an integer.

9. The grinding method according to claim 6, wherein in the vibration generating step, a longitudinal wave is generated in the cooling liquid, a half wavelength of the longitudinal wave corresponds to a length obtained by dividing a length from a bottom of a tank in which the cooling liquid is stored to a liquid level of the cooling liquid by an integer.

10. The grinding method according to claim 6, wherein in the vibration generating step, a first vibration or a second vibration is selectively applied to the cooling liquid, the first vibration has a first frequency, and the second vibration has a second frequency different from the first frequency.

11. The grinding method according to claim 6, wherein in the vibration generating step, the vibrations are applied in a state in which a region in the workpiece to be machined is disposed near a portion where variations in density of a longitudinal wave generated in the cooling liquid are large.

12. The grinding method according to claim 6, wherein:

a first portion where a density of longitudinal wave generated in the cooling liquid varies largely is generated, and

the vibration generating step further comprises the step of moving the rotating grinding tool to a part not in contact with the workpiece in the first portion.

13. The grinding method according to claim 6, wherein in the vibration generating step, the generating of vibration of the cooling liquid is turned on/off and amplitudes of the vibrations of the cooling liquid is adjusted depending on a region in the workpiece to be machined and one out of a plurality of machining steps to be performed.

14. The grinding method according to claim 13, wherein in the vibration generating step, the vibrations are adjusted by switching the amplitude of the vibration in two levels.

15. The grinding method according to claim 6, wherein the workpiece is made of a ceramic material, which is the workpiece is ground to fabricate a dental prosthesis.