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Contamination Tester for Circuit Manufacture

IP.com Disclosure Number: IPCOM000087156D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Carbone, SP: AUTHOR [+5]

Abstract

The drawing shows a conventional apparatus for measuring contaminants on a test subject 2. As an example, the apparatus is useful for testing a circuit module for flux that may undesirably remain after a soldering operation. The apparatus includes a tank 3 that holds a solvent 4, which is usually a solution of water and alcohol. A pump 5 circulates the solvent through an apparatus 6 that measures the conductivity of the solvent. When the test subject contains ionic contaminants, the conductivity of the solvent rises, and apparatus 6 produces an output represented by line 7 that indicates the rate at which the ionic contaminants are picked up from the sample. Apparatus 6 also has a filter that removes the contaminants.

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Contamination Tester for Circuit Manufacture

The drawing shows a conventional apparatus for measuring contaminants on a test subject 2. As an example, the apparatus is useful for testing a circuit module for flux that may undesirably remain after a soldering operation. The apparatus includes a tank 3 that holds a solvent 4, which is usually a solution of water and alcohol. A pump 5 circulates the solvent through an apparatus 6 that measures the conductivity of the solvent. When the test subject contains ionic contaminants, the conductivity of the solvent rises, and apparatus 6 produces an output represented by line 7 that indicates the rate at which the ionic contaminants are picked up from the sample. Apparatus 6 also has a filter that removes the contaminants. Typically, the conductivity rises steeply from a background level to a peak and then falls slowly to about the background level.

Most tests are intended to show the total amount of the contaminants of the test subject rather than to show only the instantaneous rate at which the contaminants are released. This amount can be found by plotting the signal on line 7 as a function of time and measuring the area under the plotted curve. An electronic integrator circuit 8 performs this operation and produces an output that is represented by line 9, which gives the contamination level of the sample.

The background level of conductivity tends to vary. It has been found that carbon dioxide in the air, which dissolve...