Browse Prior Art Database

Ionograph Cleaning

IP.com Disclosure Number: IPCOM000046196D
Original Publication Date: 1983-Jun-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Ameen, JG: AUTHOR [+4]

Abstract

An IONOGRAPH* machine is used to clean printed circuit products. The cleaning device comprises a tank containing a working fluid of alcohol and water, pumps to circulate the fluid, and ion exchange cartridges. The fluid is continuously circulated through the ion exchange resins to keep the fluid pure. In this way, printed circuit products immersed in this fluid may be cleaned to any desired megohm level. By doing so, the circuits cleaned successfully test because all corrosive agents will have been removed.

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Ionograph Cleaning

An IONOGRAPH* machine is used to clean printed circuit products. The cleaning device comprises a tank containing a working fluid of alcohol and water, pumps to circulate the fluid, and ion exchange cartridges. The fluid is continuously circulated through the ion exchange resins to keep the fluid pure. In this way, printed circuit products immersed in this fluid may be cleaned to any desired megohm level. By doing so, the circuits cleaned successfully test because all corrosive agents will have been removed.

In the past, the alcohol-to-water ratio was 3 to 10. Because of safety concerns about the flash point of the mix, the ratio was changed to 1 to 10. When this was done, the length of processing time was greatly increased. This is due to the fact that carbon dioxide from the atmosphere dissolves in the water and competes with the ion exchange resin as it tries to raise the megohm level of the tank. The diffusion of carbon dioxide is the gating item in determining the length of time it takes to reach the desired end point.

It is proposed that by blowing nitrogen gas over the tank after the tank lid is placed in position, the processing time to reach a desired megohm level can be greatly reduced. This may be carried out by using a tube connected to a hole in the lid. The nitrogen gas does not have to be on continuously. Merely filling the void between the liquid level and the bottom of the lid will suffice.

The nitrogen gas prevents contaminants...