ASTM B885-09(2020)
(Test Method)Standard Test Method for Presence of Foreign Matter on Printed Wiring Board Contacts
Standard Test Method for Presence of Foreign Matter on Printed Wiring Board Contacts
SIGNIFICANCE AND USE
5.1 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.
5.2 Practice B667 describes a more general procedure for measuring contact resistance of any solid material in practically any geometrical form. The method in Practice B667 should be used for general studies and fundamental studies of electrical contact materials.
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 B667 describes another contact resistance probe method that has more general application to electrical contacts of various materials and shapes. Practice B667 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, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B885 − 09 (Reapproved 2020)
Standard Test Method for
Presence of Foreign Matter on Printed Wiring Board
Contacts
This standard is issued under the fixed designation B885; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method defines a resistance probing test for
B539 Test Methods for Measuring Resistance of Electrical
detecting the presence of foreign matter on Printed Wiring
Connections (Static Contacts)
Board (PWB) contacts or fingers that adversely affects electri-
B542 Terminology Relating to Electrical Contacts and Their
cal performance. This test method is defined specifically for
Use
such fingers coated with gold. Application of this test method
B667 Practice for Construction and Use of a Probe for
to other types of electrical contacts or to fingers coated with
Measuring Electrical Contact Resistance
other materials may be possible and desirable but may require
some changes in fixturing, procedures, or failure criteria.
3. Terminology
3.1 Definitions—Terms used in this test method related to
1.2 Practice B667 describes another contact resistance
electrical contacts are defined in accordance with Terminology
probe method that has more general application to electrical
B542.
contacts of various materials and shapes. Practice B667 should
be used for more fundamental studies. This test method
3.2 Definitions of Terms Specific to This Standard:
provides a fast inspection method for printed wiring board 3.2.1 edgecard connector, n—an electrical connector de-
fingers. signed to connect physically and electrically with a compatible
PWB equipped with gold fingers.
1.3 The values stated in SI units are to be regarded as
3.2.2 printed wiring board (PWB) contacts, PWB fingers,
standard. No other units of measurement are included in this
n—areas near the edge of a printed wiring board coated with
standard.
gold and designed to function as electrical contacts when the
1.4 This standard does not purport to address all of the
board is plugged into a compatible edgecard connector.
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to become familiar
will all hazards including those identified in the appropriate 4.1 Two closely spaced electrodes are brought into contact
Material Safety Data Sheet (MSDS) for this product/material with a single PWB finger in such a manner that they contact the
surface with a minimum of wipe. A fixture loads each electrode
as provided by the manufacturer, to establish appropriate
to apply a force in the range of 0.5 to 0.7 N to the surface of
safety, health, and environmental practices, and determine the
the finger. Two electrical leads attached to each electrode are
applicability of regulatory limitations prior to use.
used to make a four-wire resistance measurement to detect
1.5 This international standard was developed in accor-
elevated resistance indicative of the presence of a film or other
dance with internationally recognized principles on standard-
contaminant on the finger.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5. Significance and Use
mendations issued by the World Trade Organization Technical
5.1 This test method provides a way to detect contamination
Barriers to Trade (TBT) Committee.
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
This test method is under the jurisdiction of ASTM Committee B02 on
Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee
B02.05 on Precious Metals and Electrical Contact Materials and Test Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2020. Published October 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1997. Last previous edition approved in 2015 as B885 – 09 (2015). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/B0885-09R20. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B885 − 09 (2020)
may include solder mask, solder flux, hardened lubricants, shall be attached at any convenient location that is at least 0.5
dust, or other materials. This test method provides a nonde- mm farther away from the tip than the attachment point of the
structive method of inspecting such fingers at any point in the voltage lead.
life of the product including after original manufacture, after
6.3 Fixture, to hold the PWB securely while it is being
assembly of circuit components to the PWB, and after time in
probed and a fixture to hold the two electrodes, such that the
service such as when returned for repair. Because this test
distance between the centers of the electrodes is 2.0 to 2.5 mm
method uses two probes to finger contacts in series, it provides
and both electrodes will be centered roughly on a single PWB
a sensitive test for contaminants that may increase electrical
finger. Fig. 1 shows an example of a suitable fixture. Other
resistance when the fingers are plugged into an edgecard
fixtures that provide the same capability may be used. Locate
connector that typically makes contact to the finger through
this fixture to minimize shock and vibration reaching the
only one contact to finger interface.
probes. Placement on a foam pad on a bench top has been
5.2 Practice B667 describes a more general procedure for found suitable.
measuring contact resistance of any solid material in
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