Browse Prior Art Database

Enameling Process for Square, Rectangular and Flat Wire

IP.com Disclosure Number: IPCOM000084606D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Johnston, LH: AUTHOR [+2]

Abstract

In the process of applying enamels to flat metal surfaces, the natural tendency of the enamels is to flow away from the edges during the curing cycle leaving the edges bare or with very little coverage, while the flat surfaces are adequately covered.

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Enameling Process for Square, Rectangular and Flat Wire

In the process of applying enamels to flat metal surfaces, the natural tendency of the enamels is to flow away from the edges during the curing cycle leaving the edges bare or with very little coverage, while the flat surfaces are adequately covered.

Attempts have been made to solve this problem by changing enamel viscosity, either higher or lower, and by using various applicator configurations, such as, a dieless roll wiper with a third roll for wiping enamel from the top surface of the wire, and metal and felt wiping fingers. All of these resulted in either bare edges or "dog boning" with excessive build up of materials at the edges.

It was found that the best uniformity of insulation was obtained with enamel bath viscosities between 150-175 centipoises and curing temperature of 400 degrees F at the oven entrance and 800 degrees F at the exit. The speed of wire feed was dependent on the length of the oven being used. When properly cured, the enamel was extremely tough having excellent adhesion and abrasion characteristics. These conditions prompted the theory that it would be possible to form the conductor after enameling.

Initially, a 20 mil diameter wire was insulated with polyimide without regard for core size or insulation thickness. The wire was then rolled in a factory rolling mill down to approximately 6 mils thick. The results showed that the core edges remained nicely covered with uniform thicknes...