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Scope

1.1 This test method defines a resistance probing test for detecting the presence of foreign matter on Printed Wiring Board (PWB) contacts or fingers that adversely affects electrical performance. This test method is defined specifically for such fingers coated with gold. Application of this test method to other types of electrical contacts or to fingers coated with other materials may be possible and desirable but may require some changes in fixturing, procedures, or failure criteria.

1.2 Practice B 667 describes another contact resistance probe method that has more general application to electrical contacts of various materials and shapes. Practice B 667 should be used for more fundamental studies. This test method provides a fast inspection method for printed wiring board fingers.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar will all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety and health practices, and determine the applicability of regulatory limitations prior to use.

Significance and Use

This test method provides a way to detect contamination on printed wiring board fingers that affects the electrical performance of such fingers. Such contamination may arise during PWB manufacture, circuit assembly, or service life and may include solder mask, solder flux, hardened lubricants, dust, or other materials. This test method provides a nondestructive method of inspecting such fingers at any point in the life of the product including after original manufacture, after assembly of circuit components to the PWB, and after time in service such as when returned for repair. Because this test method uses two probes to finger contacts in series, it provides a sensitive test for contaminants that may increase electrical resistance when the fingers are plugged into an edgecard connector that typically makes contact to the finger through only one contact to finger interface.

Practice B 667 describes a more general procedure for measuring contact resistance of any solid material in practically any geometrical form. The method in Practice B 667 should be used for general studies and fundamental studies of electrical contact materials.

Keywords

contact resistance; contamination; edgecard connector; printed wiring board fingers; Contact resistance; Contamination; Edgecard connector; Electrical contact materials; Foreign matter content; Printed wiring board (PWB) contacts/fingers; Wiring boards; ICS Number Code 31.180 (Printed circuits and boards)

To find similar documents by ASTM Volume:

02.04 (Nonferrous Metals--Nickel, Cobalt, Lead, Tin, Zinc, Cadmium, Precious, Reactive, Refractory Metals and Alloys; Materials for Thermostats, Electrical Heating and Resistance Contacts, and Connectors)

To find similar documents by classification:

31.180 (Printed circuits and boards)

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