Browse Prior Art Database

Making Holes in Thermoplastics

IP.com Disclosure Number: IPCOM000077589D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Badder, JE: AUTHOR [+4]

Abstract

A process for making holes in thermoplastic parts in general comprises forming a hole which is undersized, and then enlarging it to size using a plug which is ultrasonically vibrated.

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Making Holes in Thermoplastics

A process for making holes in thermoplastic parts in general comprises forming a hole which is undersized, and then enlarging it to size using a plug which is ultrasonically vibrated.

The undersized hole 10 may be formed in thermoplastic parts 11 either by a machining operation or as part of the molding process. In general, for a part of substantial thickness, the hole 10 is somewhat irregular in dimension and contour. Afterwards, a plug 12 made to the desired dimension is forced through the initial undersized hole 10, while the plug 12 is vibrated by an ultrasonic transducer 13. As the plug 12 is pressed through the hole, the ultrasonic energy applied to it causes the thermoplastic material 11 in contact with surface of plug 12 to generate heat through internal friction. This causes localized flow of the thermoplastic material in the vicinity of the hole and enlargement of the hole to dimension represented by dotted line 14.

In addition to providing the making of precision holes in thermoplastics, this technique provides the additional advantage of maintaining or restoring the desirably long wearing skin-effect properties of the thermoplastic surface. If the part is made of glass filled material, the glass is not exposed in the surface of the finished hole, since the glass particles become embedded in the reflowed thermoplastic surface. Also, if the hole were made by a machining operation which produced voids, these voids would bec...