IEC 61191-3:1998 pdf download – Printed board assemblies -Part 3: Sectional specification – Requirements for through-hole mountsoldered assemblies

IEC 61191-3:1998 pdf download – Printed board assemblies -Part 3: Sectional specification – Requirements for through-hole mountsoldered assemblies.
IEC 61191-3 prescribes requirements for lead and hole solder assembly. The requirements pertain to those assemblies that are totally lead and hole, through-hole mounting technology (THT). or the THT portions of those assemblies that include other related technologies (i.e. surface mount, chip mounting, terminal mounting).
1.2 Classification
This specahcation recognizes that electrical and electronic assemblies are subject to classif ications by intended end-item use. Three general end-product classes have been established to reflect differences in producibility, complexity. functional performance requirements, and verification (inspection/test) frequency. These are the following:
Level A: General electronic pioducts
Level B: Dedicated service electronic products
Level C: High performance electronic products
The user of the assemblies Is responsible for determining the level to which his product belongs. It should be recognized that there may be overlaps of equipment between levels. The contract must specify the level required and indicate any exceptions or additional requirements to the parameters, where appropriate.
2 Normative references
The following normative document contains provisions which, through reference in this text, constitute provisions of this part of IEC 61191. At the time of publication, the edition indicated W55 valid. All normative documents are subiect to revision, and panics to agreements based on this part of IEC 81191 are encouraged 10 investigate the possibility of applying the most recent edition of the normative document indicated below Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 61191-1:1998. Printed board assemblies — Part 1: Generic specification — Requirements for soldered electrical and electronic assemblies using surface mount and related assembly technologies
3 Through-hole technology (THT)
Technology that permits electrical connection of components to a conductive pattern by the use
of component holes.
4 Through-hole mounting of components
This clause covers I he assembly of components with leads inserted into through.holes and soldered by machine andior manual processes.
4.1 Placement accuracy
Placement accuracy for components inserted either manually or by machine methods shall be sufficieni to insure that the component is properly positioned alter soldering. If suitable process controls are not in p’ace to ensure compliance with this requirement and the intent of annex A. the detailed requirements of annex A shall be applicable.
4.2 Through-hole component requirements
4.2.1 Lead preforming
Part and component leads shall be peformed to the final conhguration. excluding the final clinch or retention bend, before assembly or installation.
4.2.2 Tempered leads
When it is necessary to cut tempered leads, the governing work instructions must specify cutting tools which do not impart detrimental shock to connections internal to the component.
4.2.3 Lead forming requirements
Leads shall be formed in such a manner that the lead-to-body seal is not damaged or degraded. Leads shall extend at least one lead diameter or thickness but not less than 0,8 mm from the body or weld before the start of the bend radius (see figure 1).
Exposed core metal is acceptable if reduction in the cross-sectional area does not exceed 5 $ of the diameter of the lead. Occurrence of exposed core metal In the formed area of the lead shall be treated as a process indicator.