Through Hole Solder Joint Evaluation IPC

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Table of Contents Page Introduction Classification. Introduction 2,Classification 2,Terminology 3 Introduction. Acceptance Criteria 5 This Through Hole Solder Joint Evaluation Training and Reference Guide provides. Lead Free 5 visual examples of acceptability requirements defects and conditions found in. Condition Levels 6 Through Hole solder joints on electronic assemblies This manual is intended for. use as an illustrated support document to assist in the training and practice of. Dimensional Criteria Through Hole solder joint evaluation and therefore it references portions of the fol. Land Coverage 7 lowing IPC standard,Solder Destination. Side Excess Solder 8 The IPC A 610 Rev G Acceptability of Electronic Assemblies which illustrates the. requirements for many types of solder connections,Vertical Fill 9. Wetting Lead Barrel 10,Classification, Through Hole solder joint requirements are divided into three classes depending. Wetting of Lead Land Barrel 11 on the ultimate use life expectancy and operating environment of the electronic. Solder Source Contact Angle 12 assembly Those classes are as follows. Discerning the Lead 13 Class 1 General Electronic Products. Includes products suitable for applications where the major requirement is the func. tion of the completed assembly not necessarily for extended life reliability of ser. Solder Conditions Solder Balls 14,vice or cosmetic perfection.
Solder Bridging 15 Class 2 Dedicated Service Electronic Products. Cavities 16 Includes products where continued performance and extended life is required and for. Cold Solder Joint 17 which uninterrupted service is desired but not critical Typically the end use environ. ment would not cause failures through extremes of temperature or contamination. Coating Meniscus in Solder Joint 18, Corrosion Surface Appearance 19 Class 3 High Performance Electronic Products. Disturbed Solder Joint 20 Includes products where continued high performance or performance on demand is criti. Exposed Basis Metal 21 cal equipment downtime cannot be tolerated end use environment may be uncommonly. harsh and the equipment must function when required These high reliability type prod. Foreign Object Debris FOD 22 ucts are used in such systems as life support and aerospace. Lead Cutting Fractured Solder Joint 23, Lead Protrusion 24 Note The inspector does not select the class for the part under inspection. Lead Protrusion Clinched 25 Documentation which specifies the applicable class for the part under inspection. Nonwetting of Solder 26 should be provided to the inspector. Projections 27,Residue 28,Splashes of Solder Webbing 29. 1 Through Hole Solder Joint Evaluation Training and Reference Guide Through Hole Solder Joint Evaluation Training and Reference Guide 2. Terminology Terminology, Below are the definitions of terms you will run across while using this manual taken. from IPC T 50 Terms and Definitions for Interconnecting and Packaging Electronic Circuits Nonwetting The partial adherence of molten solder to a surface that it has con. tacted and basis metal remains exposed, Clinched Lead A component lead that is inserted through a hole in a PWB and is.
then bent or clinched to hold the component in place and to make metal to metal Pinhole A small hole that penetrates from the surface of a solder connection to a. contact with a land before soldering void of indeterminate size within the solder connection. Cold Solder Connection A solder connection that exhibits poor wetting and that Plated through hole A hole with plating on its walls supported hole that makes. is characterized by a gray porous appearance an electrical connection between conductive patterns on internal layers external. layers or both of a printed board, Component An individual part or combination of parts that when together. perform a design function Residue Any visual or measurable form of process related contamination. Conductor A single conductive metal path in a conductive pattern Solder A metal alloy with a melting temperature that is below 427 C 800 F. Contact angle The angle formed by the edge of the solder fillet and the land s Solderability The ability of a metal to be wetted by molten solder. Soldering The joining of metallic surfaces with solder and without the melting of. Dewetting A condition that results when molten solder coats a surface and then the base material. recedes to leave irregularly shaped mounds of solder that are separated by area. that are covered with a thin film of solder and with the basis metal not exposed Solder bridging The unwanted formation of a conductive path of solder between. conductors, Disturbed solder connection A solder connection that is characterized by the. appearance that there was motion between the metals being joined when the Spatter Extraneous fragments of solder with an irregular shape. solder was solidifying, Webbing A continuous film or curtain of solder that is parallel to by not. Excess solder connection A solder connection that is characterized by the necessarily adhering to a surface that should be free of solder. complete obscuring of the surfaces of the connected metals and or by the. presence of solder beyond the connection area Wetting The formation of a relatively uniform smooth unbroken and adherent film. of solder to a basis metal, Fillet A normally concave surface of solder that is at the intersection of the. metal surfaces of a solder connection, Flux residue A flux related contaminant that is present on or near the surface of Cross section View of a Target Plated Through Hole.
a solder connection Solder,Destination Solder Destination Side The. Side side of a through hole assem, Icicle solder projection An undesirable protrusion of solder from a solidified sol. der joint or coating bly containing the most com,ponent bodies Also called the. primary side or sometimes, Land A portion of a conductive pattern that is usually used for making electrical the component side. connections for component attachment or both,Solder Source Side The side.
Lead The wire or formed metal conductor that extends from a component to that is coated with solder in. serve as a mechanical and or electrical connector the solder wave machine Also. Source called the secondary side,continued Side, 3 Through Hole Solder Joint Evaluation Training and Reference Guide Through Hole Solder Joint Evaluation Training and Reference Guide 4. Acceptance Criteria Condition Levels, In this Training and Reference Guide criteria are given for each class in one or. more of the following levels of condition Target Class 1 2 3. A condition that is close to perfect how,ever it is a desirable condition and not. Target always achievable and may not be neces,sary to ensure reliability of the assembly. Acceptable in its service environment,Process Indicator.
Acceptable Class 1 2 3, Photographs or illustrations of each condition are shown in the left column This characteristic indicates a condition. examples on opposite page The level of acceptance class es and descrip that while not necessarily perfect will. tion of the illustration are all contained in the right column In the following maintain the integrity and reliability of the. examples definitions of each acceptance criterion are printed to the right assembly in its service environment. of sample photographs For easier viewing colored bars connect each photo. graph or illustration to each description with a different color used for each. acceptance level, Note Accept and or reject decisions must be based on applicable documentation. such as contract drawings specifications such as IPC A 610 and IPC J STD 001. or other referenced documents Process Indicator Class 1 2 3. A process indicator is a condition that,does not affect the form fit and function. Lead Free Soldering of a product However process indicators. The primary difference between the solder connections created with processes using signal a lack of good workmanship to the. tin lead alloys and processes using lead free alloys is related to the visual appear customer and should be used to improve. ance of the solder the manufacturing process even though. the product is considered usable, Acceptable lead free and tin lead connections may exhibit similar appearances but. lead free alloys are more likely to have,Surface roughness grainy or dull.
Greater wetting contact angles Defect Class 1 2 3,All other solder criteria are the same. A defect is a condition that is insufficient, Wetting cannot always be judged by surface appearance The wide range of solder to ensure the form fit or function of the. alloys in use may exhibit from low or near zero degree contact angles to nearly 90 assembly in its end use environment The. degree contact angles as typical manufacturer shall rework repair scrap. or use as is based on design service and,Pb Denotes Lead Free Image customer requirements. 5 Through Hole Solder Joint Evaluation Training and Reference Guide Through Hole Solder Joint Evaluation Training and Reference Guide 6. Solder Destination Side Land Coverage Solder Destination Side Excess Solder. Target Class 1 2 3 Target Class 1 2 3, Properly wetted solder fillet covers 100 Solder fillet ends below lead bend area. of solder destination side land area and,feathers out to a thin edge on land area.
Acceptable Class 1 2 3 Acceptable Class 1 2 3, 0 of the solder destination side land Solder in lead bend area does not contact. area is covered with wetted solder the component body or end seal. Solder does not obscure the stress relief,bend of the component lead. Defect Class 1 2 3,Solder in lead bend area comes in contact. with the component body or end seal or,obscures the stress relief bend of the. component lead,References References,A 610G 7 3 5 3 Table 7 4 A 610G 7 3 5 6 7 3 5 7.
7 Through Hole Solder Joint Evaluation Training and Reference Guide Through Hole Solder Joint Evaluation Training and Reference Guide 8. Barrel Vertical Fill of Solder Barrel Wetting of Lead Barrel. 75 fill Acceptable Class 2 3 Target Class 1 2 3, A minimum of 75 solder fill or a maximum 100 360 circumferential wetting pres. of 25 depression including both solder ent on solder destination side of lead and. source and solder destination sides is barrel Vertical fill at 100. permitted Component lead is visible in,solder source side of the connection. Minimum acceptable condition for vertical Acceptable Class 2. fill of solder on Class 1 assemblies is not, specified A minimum of 180 circumferential wetting. Less than 100 solder fill may not be 50 present on solder destination side. acceptable in some applications of lead and barrel. e g thermal shock electrical performance,Minimum acceptable condition for cir. 50 fill Acceptable Class 2 14 Leads cumferential wetting of lead and barrel on. solder destination side for Class 1 is not,Defect Class 2 14 Leads specified.
Defect Class 3, Vertical fill criteria for Class 2 is based on Acceptable Class 3. the number of componet leads and if the,A minimum of 270 circumferential wetting. lead is connected to a thermal plane,75 present on solder destination side. of lead and barrel,Class 2 components with,Less than 14 leads 75 fill. Less than 14 leads connected to,thermal plane 50 fill.
14 leads or more 50 fill,Class 3 requires 75 vertical fill. Maximum 25 depression allowed on one,side or total of both sides. References References,A 610G 7 3 5 1 Table 7 4 A 610G 7 3 5 2 Table 7 4. 9 Through Hole Solder Joint Evaluation Training and Reference Guide Through Hole Solder Joint Evaluation Training and Reference Guide 10. Solder Source Side Wetting of Lead Land Barrel Solder Source Side Contact Angle. Target Class 1 2 3 Target Class 1 2 3, 100 solder fillet and circumferential wet The solder fillet. ting present on solder source side of forms a contact. solder joint angle of 90,Acceptable Class 1 2 Acceptable Class 1 2 3.
A minimum of 270 circumferential 75 The solder fillet forms. wetting present on solder source side of a contact angle of. lead land and barrel more than 90 due,to quantity of solder. extending over the,edge of the land,Acceptable Class 3 Defect Class 1 2 3. A minimum of 330 circumferential Nonwetting results in. approx 90 wetting present on solder the solder forming a ball. source side of lead and barrel or beading on the sur. face The fillet is convex,and the contact angle,is greater than 90 but. solder does not extend,over the land See notes on page 5 lead. free wetting contact angles, A minimum of 270 circumferential 75 Very poor wetting results in the solder.
wetting for the land clumping on the surface No feathered edge. is apparent Contact angle is irregular,References References. A 610G 7 3 5 4 7 3 5 5 A 610G 5 5 1, 11 Through Hole Solder Joint Evaluation Training and Reference Guide Through Hole Solder Joint Evaluation Training and Reference Guide 12. Solder Source Side Discerning the Lead Solder Balls. Target Class 1 2 3 Acceptable Class 1 2 3, Lead and land are well wetted solder Encapsulated solder ball that does. source side lead is clearly visible Solder not violate minimum electrical. fillet is concave clearance,Acceptable Class 1 Defect Class 1 2 3. Solder balls not entrapped in no clean, Process Indicator Class 2 3 residue or encapsulated with conformal.
Through Hole Solder Joint Evaluation IPC DRM PTH G References IPC A 610 Rev G OCT 2017 1 Through Hole Solder Joint Evaluation Training and Reference Guide Solder Destination Side Barrel Solder Source Side Introduction amp Classification Introduction This Through Hole Solder Joint Evaluation Training and Reference Guide provides visual examples of acceptability requirements defects and

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