ASTM B885-97(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:B885–97(Reapproved2003)
Standard Test Method for
Presence of Foreign Matter on Printed Wiring Board
Contacts
This standard is issued under the fixed designation B 885; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method defines a resistance probing test for 3.1 Definitions—Terms used in this test method related to
detecting the presence of foreign matter on Printed Wiring electrical contacts are defined in accordance with Terminology
Board (PWB) contacts or fingers that adversely affects electri- B 542.
cal performance. This test method is defined specifically for 3.2 Definitions of Terms Specific to This Standard:
such fingers coated with gold. Application of this test method 3.2.1 edgecard connector, n—an electrical connector de-
to other types of electrical contacts or to fingers coated with signed to connect physically and electrically with a compatible
other materials may be possible and desirable but may require PWB equipped with gold fingers.
some changes in fixturing, procedures, or failure criteria. 3.2.2 printed wiring board (PWB) contacts, PWB fingers,
1.2 Practice B 667 describes another contact resistance n—areas near the edge of a printed wiring board coated with
probe method that has more general application to electrical gold and designed to function as electrical contacts when the
contactsofvariousmaterialsandshapes.PracticeB 667should board is plugged into a compatible edgecard connector.
be used for more fundamental studies. This test method
4. Summary of Test Method
provides a fast inspection method for printed wiring board
4.1 Two closely spaced electrodes are brought into contact
fingers.
1.3 This standard does not purport to address all of the withasinglePWBfingerinsuchamannerthattheycontactthe
surface with a minimum of wipe.Afixture loads each electrode
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to become familiar to apply a force in the range of 0.5 to 0.7 N to the surface of
the finger. Two electrical leads attached to each electrode are
will all hazards including those identified in the appropriate
used to make a four–wire resistance measurement to detect
Material Safety Data Sheet for this product/material as pro-
vided by the manufacturer, to establish appropriate safety and elevated resistance indicative of the presence of a film or other
contaminant on the finger.
health practices, and determine the applicability of regulatory
limitations prior to use.
5. Significance and Use
2. Referenced Documents
5.1 This test method provides a way to detect contamination
2.1 ASTM Standards: on printed wiring board fingers that affects the electrical
performance of such fingers. Such contamination may arise
B 539 Test Methods for Measuring Contact Resistance of
Electrical Connections (Static Contacts) during PWB manufacture, circuit assembly, or service life and
may include solder mask, solder flux, hardened lubricants,
B 542 Terminology Relating to Electrical Contacts and
Their Use dust, or other materials. This test method provides a nonde-
structive method of inspecting such fingers at any point in the
B 667 Practice for Construction and Use of a Probe for
Measuring Electrical Contact Resistance 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
This test method is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
a sensitive test for contaminants that may increase electrical
B02.11 on Electrical Contact Test Methods.
resistance when the fingers are plugged into an edgecard
Current edition approved June 10, 2003. Published July 2003. Originally
connector that typically makes contact to the finger through
approved in 1997. Last previous edition approved in 1997 as B 885 - 97.
Annual Book of ASTM Standards, Vol 02.04. only one contact to finger interface.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B885–97 (2003)
5.2 Practice B 667 describes a more general procedure for 6.4 Two Springs, one for each electrode, having a spring
measuring contact resistance of any solid material in practi- constant and a pretension that will apply a load in the range of
cally any geometrical form. The method in Practice B 667 0.5 to 0.7 N when the electrode is brought to rest on the finger
should be used for general studies and fundamental studies of being tested. Other mechanisms that achieve the same result
electrical contact materials. are acceptable.
6.5 Mechanism, that will move the electrode fixture from an
6. Apparatus
open position to the closed position on the finger in such a
6.1 Four-Wire mV Meter, with a resolution of 0.0001 V or manner that the electrodes meet the surface of the contact with
better, capable of performing dry circuit resistance measure- a minimum of wipe.
ments in accordance with Test Methods B 539.
6.6 Lens Tissue, for cleaning the electrodes.
6.2 Two Gold-Tipped Electrodes (Probes), with a radius not
6.7 Beakers, 100-mL size, two required.
less than 3.0 mm a
...