Browse Prior Art Database

Air Preload Alignment Device

IP.com Disclosure Number: IPCOM000037372D
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Danton, J: AUTHOR [+2]

Abstract

Disclosed is a device that is used in a matrix drilling machine spindle that allows misalignment between precise elements and the rest of the machine.

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Air Preload Alignment Device

Disclosed is a device that is used in a matrix drilling machine spindle that allows misalignment between precise elements and the rest of the machine.

A ball joint 5 in the spindle is necessary because the thrust air bearings 4 need to come to an equilibrium position before the rotor 6 turns at 100,000 rpm. Any type of dimensional "tilt" between the rotor and the air bearing surfaces 4 would result in a lower rpm at the rotor. If the rotor was allowed to touch the bearing surface at 100,000 rpm, one of the materials would melt and start galling and the rotor would quickly stop.

Blind hole drilling has become a very important process, partly because of surface mount components. The depth of blind hole drilling must be accurately maintained for dense electronic packaging and for noninterference with different conductive layers in the board. A preloaded ball joint would be ideal for accurately drilling to a depth. However, preloading causes some sticking action, which may cause a lack of misalignment for the thrust assembly.

The best of both worlds is the solution. The ball joint 5 as shown, has a loose fit. It is mounted in the machine in a relaxed condition. The air is then energized to the journal bearing (not shown) which aligns and stiffens the shaft of the rotor. Air is also supplied simultaneously to the thrust bearings which (if the ball joint is loose) aligns perfectly and stiffens the rectangular thrust assembly. The turbine ai...