Method and assembly for slurry delivery and utilization during ultrasonic impact grinding

1 . An ultrasonic impact grinding assembly comprising:

a vessel configured to contain an abrasive slurry, the vessel having an open top disposed opposite a base;

at least one mixing mechanism disposed in the vessel, the at least one mixing mechanism configured to agitate the abrasive slurry to maintain abrasive particles in suspension;

a fixture disposed on the base, the fixture configured to retain a workpiece for ultrasonic impact grinding within the abrasive slurry;

an ultrasonic impact grinding machine having a tool tip disposed to contact the abrasive slurry in the vessel during an ultrasonic impact grinding operation to remove material from the workpiece, the tool tip having a shape configured to form a hole or slot in a machining surface of the workpiece via ultrasonic impact grinding, wherein the ultrasonic impact grinding machine is configured to move the tool tip relative to the workpiece to increase a depth or size of the hole or slot; and

an actuating platform connected to the vessel configured to rotate the vessel about at least two different axes to tilt and turn the vessel and workpiece relative to the tool tip.

2 . The ultrasonic impact grinding assembly of claim 1 , and further comprising a protective layer disposed on surfaces of the fixture configured to contact the workpiece.

3 . The ultrasonic impact grinding assembly of claim 2 , wherein the protective layer comprises a polymer.

4 . The ultrasonic impact grinding assembly of claim 1 , wherein the ultrasonic impact grinding machine is configured to operate with six degrees of freedom.

5 . The ultrasonic impact grinding assembly of claim 1 , wherein the vessel has a depth sufficient to contain the abrasive slurry when a machining surface of the workpiece is submerged in the abrasive slurry.

6 . The ultrasonic impact grinding assembly of claim 1 , wherein the abrasive slurry comprises a plurality of abrasive particles suspended in an aqueous solution and wherein the at least one mixing mechanism is configured to provide agitation sufficient to maintain a concentration of the abrasive particles between a machining surface of the workpiece and the tool tip of the ultrasonic impact grinding machine during ultrasonic impact grinding operation.

7 . The ultrasonic impact grinding assembly of claim 6 , wherein the at least one mixing mechanism is a pump having an inlet and an outlet disposed in the vessel.

8 . The ultrasonic impact grinding assembly of claim 6 , wherein the at least one mixing mechanism comprises an ultrasonic transducer disposed in the abrasive slurry and separated from the tool tip, vessel, and workpiece, the ultrasonic transducer configured to agitate the abrasive slurry by ultrasonic vibration.

9 . The ultrasonic impact grinding assembly of claim 1 , wherein the vessel is configured to contain a plurality of workpieces with machining surfaces submerged in the abrasive slurry.

10 . A method for machining a ceramic workpiece, the method comprising:

submerging a first machining surface of the ceramic workpiece in an abrasive slurry contained in a vessel having an open top;

fixing the ceramic workpiece to a base of the vessel;

positioning a tip of an ultrasonic impact grinding machine in proximity with the first machining surface and into contact with the abrasive slurry;

applying ultrasonic vibration to the tip to remove material from the first machining surface of the ceramic workpiece to form a feature in the ceramic workpiece of a desired geometry;

agitating the abrasive slurry with a mixing mechanism disposed in the abrasive slurry to maintain abrasive particles in suspension;

advancing the tip into the ceramic workpiece or along the ceramic workpiece to increase a depth or size of feature of desired geometry formed in the ceramic workpiece via ultrasonic impact grinding;

moving the tip and/or the ceramic workpiece to position the tip in proximity with a second machining surface submerged in the abrasive slurry; and

rotating the vessel about at least two different axes to tilt and turn the vessel and ceramic workpiece relative to the tip.

11 . The method of claim 10 , wherein agitating the abrasive slurry comprises drawing the abrasive slurry through a pump having an inlet and an outlet disposed in a vessel containing the ceramic workpiece.

12 . The method of claim 10 , wherein agitating the abrasive slurry comprises applying ultrasonic vibrational energy to the abrasive slurry in the vessel containing the ceramic workpiece via an ultrasonic transducer disposed in the abrasive slurry and separated from the ultrasonic impact grinding machine, the vessel, and the ceramic workpiece.

13 . The method of claim 10 , wherein fixing the ceramic workpiece comprises securing the ceramic workpiece to a fixture disposed in the vessel containing the abrasive slurry.

14 . The method of claim 13 , and further comprising providing a protective layer between the ceramic workpiece and the fixture, wherein the protective layer seals a contact interface of the ceramic workpiece and fixture from incursion of abrasive particles in the abrasive slurry.

15 . The method of claim 14 , wherein the rotating of the vessel about the at least two different axes positions the second machining surface in proximity to the tip.

16 . The method of claim 14 , and further comprising moving the tip with five degrees of freedom into proximity with the second machining surface of the ceramic workpiece.

17 . The method of claim 10 , wherein the feature of desired geometry is a hole or a slot.