US 10,293,443 B1Granted

Precision pneumatic drilling spindle and method

OwnerDonald L. Ekhoffinventor

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Abstract

A precision pneumatic drill spindle and method provides reduced spin axis error and increased rate of forming holes in a microelectronic substrate. The spindle includes a press-fit collar that accepts drill bits and incorporates turbine blades around the collar, which is rotated by directing pressurized air through a number of nozzles distributed around the collar within a housing of the spindle. The collar is supported by air bearings above and below the collar. The turbine blades may be provided by concavities in the collar forming a Pelton wheel type rotation system that concentrates the air flow to improve energy transfer from the pressurized air directed by the nozzles to the collar, increasing the rotation rate of the collar. Exit air may be directed downward toward the tip of the drill bit by inclined channels within the lower air bushing assembly, improving the debris removal rate.

Claims18

Dependent claims

A precision pneumatic drill spindle, comprising:

a housing;
an inlet disposed on an exterior surface of the housing for receiving a source of pressurized gas;
a collar within a chamber inside the housing, the collar having a plurality of turbine blades formed therein and having a hole formed therethrough for accepting a shank of a drill bit, wherein the collar includes a ring portion, and wherein the plurality of turbine blades are concave cavities formed in the ring portion thereof and that have a tapering depth extending around a circumference of the ring portion;
a plurality of nozzles within the housing and in fluid communication with the inlet to receive the pressurized gas and for constricting the flow of the pressurized gas to a corresponding plurality of outlets directed at the turbine blades of the collar to cause rotation of the collar, wherein the plurality of nozzles are arranged around the circumference of the ring portion to direct the pressurized gas at the concave cavities as the collar rotates with respect to the plurality of nozzles, wherein the concave cavities form dual symmetric concave shapes about a plane parallel to the circumference of the ring portion, and wherein the dual symmetric concave shapes define an edge at their intersection with the plane, whereby the pressurized gas directed from the nozzles is divided as the gas is directed into the dual symmetric concave shapes;
a first air bushing within the housing for supporting an upper end of the shank opposite a tip of the drill bit;
and
a second air bushing at a lower end of the housing for supporting a lower portion of the shank below the collar.

4 more elements

A precision pneumatic drill spindle, comprising:

a housing having a cylindrical void at a bottom side thereof;
a first inlet disposed on an exterior surface of the housing for receiving a first source of pressurized gas;
a collar disposed within a chamber inside the housing, the collar having a hole formed therethrough for accepting a shank of a drill bit, the collar having a ring portion with a plurality of concave cavities that have a tapering depth extending around a circumference of the ring portion;
a substantially cylindrical nozzle assembly body configured to fit into the cylindrical void at the bottom side of the housing and between the first air bushing and the second air bushing, wherein the nozzle assembly body has a central void forming the chamber in which the collar is located, and wherein the nozzle assembly body defines conical holes extending from an outer circumference of the nozzle assembly body to the central body, wherein the plurality of nozzles are nozzle inserts inserted through the conical holes of the nozzle assembly body, wherein tips of the nozzle inserts are located within the chamber, wherein the nozzle inserts are in fluid communication with the inlet to receive the pressurized gas from the first source and for constricting the flow of the pressurized gas to a corresponding plurality of outlets directed at a plurality of turbine blades of the collar to cause rotation of the collar;
a second inlet disposed on an exterior surface of the housing for receiving a second source of pressurized gas;
a substantially cylindrical first air bushing within the cylindrical void of the housing and at an upper end thereof, for supporting an upper end of the shank opposite a tip of the drill bit, wherein the first air bushing includes a second plurality of nozzles in fluid communication with the second inlet for receiving pressurized gas from the second inlet and directing the pressurized gas received from the second inlet toward the shank;
and
a substantially cylindrical second air bushing within the cylindrical void of the housing at a lower end thereof for supporting a lower portion of the shank below the collar, wherein the second air bushing includes a third plurality of nozzles in fluid communication with the second inlet for receiving pressurized gas from the second inlet and directing the pressurized gas received from the second inlet toward the shank, wherein the second air bushing further includes inclined channels that vent gas downward from the central void of the nozzle assembly to direct the exiting gas toward the tip of the drill bit for removal of drilling debris and cooling of the tip of the drill bit.

5 more elements

A method of drilling a microelectronic substrate, the method comprising:

providing a source of pressurized gas to an inlet provided on a housing of a drill spindle;
rotating a drill bit by directing the pressurized gas at a collar within the housing having a plurality of turbine blades formed therein and having a hole formed therethrough for accepting a shank of the drill bit from a plurality of nozzles within the housing and in fluid communication with the inlet to receive the pressurized gas so that the nozzles constrict the flow of the pressurized gas to a corresponding plurality of outlets directed at the turbine blades of the collar to cause rotation of the collar, wherein the collar includes a ring portion, wherein the plurality of turbine blades are concave cavities formed in the ring portion thereof and that have a tapering depth extending around a circumference of the ring portion, wherein the plurality of nozzles are arranged around the circumference of the ring portion to direct the pressurized gas at the concave cavities as the collar rotates with respect to the plurality of nozzles, wherein the concave cavities form dual symmetric concave shapes about a plane parallel to the circumference of the ring portion, and wherein the dual symmetric concave shapes define an edge at their intersection with the plane, whereby the pressurized gas directed from the nozzles is divided as the gas is directed into the dual symmetric concave shapes;
supporting an upper end of the shank of the drill bit opposite a tip of the drill bit with a first air bushing within the housing;
and
supporting a lower portion of the shank below the collar with a second air bushing at a lower end of the housing.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/638,297Filed 29 Jun 2017 · us provisional application
Priority: 29 Jun 2016
Granted: 21 May 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

B23Q 5/06
Rotary shafts, e.g. working-spindles: driven essentially by fluid pressure or pneumatic power
B23B 41/14
Boring or drilling machines or devices specially adapted for particular work ; Accessories specially adapted therefor: for very small holes
B23Q 11/005
Devices for removing chips: by blowing
H05K 3/0047
Mechanical working of the substrate, e.g. drilling or punching: drilling of holes