How to avoid short circuits in close-pin ics during SMT assembly?

SMTShort circuits, a poor processing phenomenon in surface mount technology (SMT) processing, mostly occur in the dense pinsICMiddle, dense feetICUsually, the pointer pins are relatively denseICComponents, and the spacing between the pins is small, with dense pinsICSome conditions are required to weld well. BelowSolder paste manufacturerLet me briefly introduce to you some common ways to avoid thick feetICThe method of short circuit:

1. Steel mesh

For0.5Millimeters and belowICThe opening method of the steel mesh remains unchanged in the length direction, but the width is usually0.5to0.75The width of the pad and the thickness are generally0.12to0.15For millimeters, the steel mesh must be made by laser cutting technology and polished to ensure that the opening shape is an inverted trapezoid and the inner surface is smooth, so as to achieve a good tinning and forming printing effect.

Ii. Solder paste

inSMTFor the dense pins in the patchICThe granularity needs to be selected20~38um(PITCH≤0.4mm)The viscosity is160~220pa.sThe solder paste, the activity of the solder paste is generally adoptedRMAGrade.

Iii. Printing

Solder paste printing forSMTThe soldering effect of surface mount technology (SMT) processing also has a direct impact. Solder paste printing usually needs to pay attention to the following aspects:

1The types of scrapers: Scrapers are mainly made of plastic and steel. For fine-pin chips, steel scrapers should be chosen to facilitate the formation of solder paste.

2The Angle of the scraper: The scraper should45°The operation Angle of solder paste printing can improve the imbalance phenomenon of different steel mesh openings facing upwards.

3Printing speed: AtSMTThe speed of the squeegee is also a key parameter in the solder paste printing of surface mount technology. If the speed is too fast, it may cause the solder paste to be missed. If the speed is too slow, the solder paste may stop rolling, resulting in poor resolution of the solder paste on the pad, usually for those with dense pinsIC PCBPrinting speed10~20mm/s.

4Printing methods: In actual production and processing, the common printing methods mainly include contact printing and non-contact printing. Contact printing has higher precision and is more suitable for fine-pitch solder paste printing.

Iv. Mounting Height

SMTFor processing plantsPITCH≤0.5mmtheICIt should be adopted during mounting0Distance or0~-0.1mmThe mounting height should be adjusted to prevent the solder paste from forming and collapsing due to an excessively low mounting height, which could cause a short circuit during backflow.

15For many years, JJY has been dedicated to the research and development, production and sales of solder paste, providing customers with a complete set of electronic soldering solutions. If you want to learn more about solder paste, please keep following JJY Solder Paste Manufacturer and leave a message online to interact with us.