International standards for electronic pad requirements

- Nov 03, 2018-

International commission IEC 6118 standard InternationalEletrotechnicalCommission electronic technology to realize the welding fillet or solder bump conditions of the needs of different target.This new international standard identifies two basic methods for providing information on the development of pad shapes:

1).Accurate information based on industrial component specification, PCB board manufacturing and component placement accuracy.These pads are limited to a specific element and have a number that identifies the shape of the pads.

2).Some equations can be used to alter the given information to achieve a more robust welding connection, which is used in special cases where the precision assumed in the placement or installation of the equipment is more or less different than in determining the details of the pad.

The standard defines the maximum, medium and minimum material conditions for the pads used to attach various pins or component terminals.This standard marks all three "desired targets" as level 1, 2, or 3 unless otherwise indicated.

Level 1: maximum - for low density product applications, "maximum" pad conditions for wave crest or flow welding of non-pin sheet elements and pin finned elements.The geometric configuration of these elements and the "T" type pin elements inward can provide a wider process window for manual and reflow soldering.

Level 2: medium - a product with medium component density may consider using this "medium" solder pad geometry.Very similar to the ipc-sm-782 standard pad geometry, a medium pad for all component types will provide a robust welding condition for the reflux welding process and should provide appropriate conditions for crest or flow welding of pin and fin type elements.

Level 3: minimum - products with high cell density  usually portable product application can be considered "minimum" welding plate geometry.The selection of minimum pad geometry may not be appropriate for all products.Before the minimum pad shape is adopted, use this to take into account product constraints and test based on the conditions shown in the table.

The welded plate geometries provided in ipc-sm-782 and configured in IEC61188 should incorporate component tolerances and process variables.While the solder pads in the IPC standard have provided a robust interface for most of the user's assembly applications, some companies have expressed the need for minimal solder pad geometry for portable electronics and other unique high-density applications.

The international standard (IEC61188) understands the requirements for higher part density applications and provides information on the geometry of the pads used for specific product types.The purpose of this information is to provide the appropriate dimensions, shape and tolerances of the surface-mounted pad to ensure adequate areas for proper welding of rounded corners and also to allow inspection, testing and rework of these welding points.