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Sensitive Microdrilling Apparatus

IP.com Disclosure Number: IPCOM000079022D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Kranik, JR: AUTHOR [+2]

Abstract

In drilling very small diameter holes through light stock it is difficult if not impossible to adequately gauge, by indicators or the like, the speed of stock removal, and many times this results in destruction of the material being drilled. It is well known that a skilled operator can "feel" the quantity of material being removed by a drill, if the drill is sensitive enough.

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Sensitive Microdrilling Apparatus

In drilling very small diameter holes through light stock it is difficult if not impossible to adequately gauge, by indicators or the like, the speed of stock removal, and many times this results in destruction of the material being drilled. It is well known that a skilled operator can "feel" the quantity of material being removed by a drill, if the drill is sensitive enough.

Such a drill is illustrated in Fig. 1, wherein a spindle 10 with a collet or drill chuck 11 runs in an air bearing 12. The air bearing comprises a chamber 13 having a collar 14 composed of porous bronze which permits air, entering the chamber 13 through a hose 15, to automatically effect frictionless centering of the spindle 10. The spindle 10 is attached to a thin-walled bellows 16, the bellows being connected to a drive shaft 17 which is rotated by a continuously variable speed motor via an O-ring 18 and pulley sheave 19. The drive shaft 17 contains a central bore 20 which is connected to a chamber 21 through an aperture 22, into which air pressure may be applied by hose 23. A yoke 24, adjacent the spindle 10 and mounted thereon by instrument bearings 25, provides the drilling pressure, the yoke preferably having a long, very light arm to provide excellent vibration transmission.

To accelerate chip removal on easily drillable materials, like certain types of plastic, brass, etc., it is desirable to provide a peaking motion for the drill. With the structure shown, this is accomplished by providing excess drilling pressure through pressurization of the bellows 16 and rapidly turning the pressure on and off, for example twenty to fifty times per second.

The drill illustr...