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Flush Molding of Printed Circuitry

IP.com Disclosure Number: IPCOM000093656D
Original Publication Date: 1966-Jan-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Webb, EJ: AUTHOR [+3]

Abstract

Etched circuitry can be molded flush into objects such as core plane frames.

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Flush Molding of Printed Circuitry

Etched circuitry can be molded flush into objects such as core plane frames.

A composite foil with a copper core 10 and two layers 12a and 12b of an alloy consisting 96% copper and 4% phosphorous is adhered to base 14 of a plastic such as TEFLON* by heat and pressure. The foil is then covered with resist 16. The latter is selectively removed to define a circuit pattern such as lines 18. Then, the composite foil is etched to form printed circuit lines 20. The latter have concave sides as shown because of the different etching rates of alloy layers 12a and 12b and copper core 10. * Trademark of E. I. du Pont de Nemours and Co.

To mold these printed circuit lines into some object, TEFLON base 14 with lines 20 on it is placed into the mold cavity for the object. Base 14 is against the sidewall of the mold cavity and lines 20 face towards the center of the mold cavity. Then, molding material is injected, or poured, into the mold cavity and allowed to cure. When the curing is complete, molded object 22 is removed from the mold cavity and base 14 stripped from the surface of the molded object 22. The concave sides of lines 20 form a bond which locks such lines into the molded object 22. Thus, lines 20 are not stripped off with base 14.

In some applications, it is desirable that lines 20 extend off the molded object 22 or extend around two or more sides of molded object 22. This is accomplished by the positioning of base 14 in the mold....