ASTM_B_885_-_09_2015.pdf

Designation:B88509(Reapproved 2015)Standard Test Method forPresence of Foreign Matter on Printed Wiring BoardContacts1This standard is issued under the fixed designation B885;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method defines a resistance probing test fordetecting the presence of foreign matter on Printed WiringBoard(PWB)contacts or fingers that adversely affects electri-cal performance.This test method is defined specifically forsuch fingers coated with gold.Application of this test methodto other types of electrical contacts or to fingers coated withother materials may be possible and desirable but may requiresome changes in fixturing,procedures,or failure criteria.1.2 Practice B667 describes another contact resistanceprobe method that has more general application to electricalcontacts of various materials and shapes.Practice B667 shouldbe used for more fundamental studies.This test methodprovides a fast inspection method for printed wiring boardfingers.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to become familiarwill all hazards including those identified in the appropriateMaterial Safety Data Sheet(MSDS)for this product/materialas provided by the manufacturer,to establish appropriatesafety and health practices,and determine the applicability ofregulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B539 Test Methods for Measuring Resistance of ElectricalConnections(Static Contacts)B542 Terminology Relating to Electrical Contacts and TheirUseB667 Practice for Construction and Use of a Probe forMeasuring Electrical Contact Resistance3.Terminology3.1 DefinitionsTerms used in this test method related toelectrical contacts are defined in accordance with TerminologyB542.3.2 Definitions of Terms Specific to This Standard:3.2.1 edgecard connector,nan electrical connector de-signed to connect physically and electrically with a compatiblePWB equipped with gold fingers.3.2.2 printed wiring board(PWB)contacts,PWB fingers,nareas near the edge of a printed wiring board coated withgold and designed to function as electrical contacts when theboard is plugged into a compatible edgecard connector.4.Summary of Test Method4.1 Two closely spaced electrodes are brought into contactwith a single PWB finger in such a manner that they contact thesurface with a minimum of wipe.Afixture loads each electrodeto apply a force in the range of 0.5 to 0.7 N to the surface ofthe finger.Two electrical leads attached to each electrode areused to make a fourwire resistance measurement to detectelevated resistance indicative of the presence of a film or othercontaminant on the finger.5.Significance and Use5.1 This test method provides a way to detect contaminationon printed wiring board fingers that affects the electricalperformance of such fingers.Such contamination may ariseduring PWB manufacture,circuit assembly,or service life andmay include solder mask,solder flux,hardened lubricants,dust,or other materials.This test method provides a nonde-structive method of inspecting such fingers at any point in thelife of the product including after original manufacture,afterassembly of circuit components to the PWB,and after time inservice such as when returned for repair.Because this testmethod uses two probes to finger contacts in series,it providesa sensitive test for contaminants that may increase electricalresistance when the fingers are plugged into an edgecard1This test method is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of SubcommitteeB02.11 on Electrical Contact Test Methods.Current edition approved May 1,2015.Published May 2015.Originallyapproved in 1997.Last previous edition approved in 2009 as B885 09.DOI:10.1520/B0885-09R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 connector that typically makes contact to the finger throughonly one contact to finger interface.5.2 Practice B667 describes a more general procedure formeasuring contact resistance of any solid material in practi-cally any geometrical form.The method in Practice B667should be used for general studies and fundamental studies ofelectrical contact materials.6.Apparatus6.1 Four-Wire m Met