Flux

Flux chemically removes oxide film from the metal surface to be soldered, thereby exposing the solderable metal surfaces. Flux is therefore indispensable in all soldering processes, including soldering of PC boards and special metals. It requires high reliability and soldering properties that match the application. SMIC has long experience in developing various types of flux, including PC board flux, all of which provide unrivaled performance.

SPARKLE FLUX ES SERIES

ES series Sparkle Flux is a post-flux developed for the Lead-Free soldering of PC boards. Lead-Free solder has rather poor solder wettability compared with existing Sn-Pb solder. However, solder bridges, icicles, blow holes and other problems in Lead-Free soldering can be reduced to a level equivalent to those of existing Sn-Pb solders with the use of the ES series Sparkle Flux.

Products	Solid content	Chroline content	Specific gravity (20°C)	Remarks
ES-1061SP-2	15%	0.09%	0.826	Prevents bridging of ES-1061, good finish in through-hole
ES-1077	7%	0.04%	0.804	Low residue
ES-0307LS	15%	0.07%	0.826	Low Ag content, Sn-Cu alloy, good wettability, good lusterless finsh
ES-0307LS-PD	15%	0.07%	0.826%	Point soldering

SPARKLE FLUX ESR SERIES

ESR series Sparkle Flux is a highly reliable post-flux. If existing flux for Sn-Pb soldering is used for Lead-Free soldering, a large number of solder bridges, icicles and blow holes may be generated. ESR series Sparkle Flux exhibits the highest degree of wettability among RMA type fluxes and produces excellent soldering results.

Products	Solid content	Chroline content	Specific gravity (20°C)	Remarks
EZR-01S	7%	0.01%	0.086	RMA type, low residue
ESR-250T4	15%	0.0%	0.822	RMA type, best for both sides P.C.B.
ESR-280	9%	0.012%	0.810	Lower solid content type of ESR-250T4

Recommended soldering conditions

Flux application

Flux must be applied by foaming, spraying, etc.
Use a stainless steel container for storing flux.

Preheating

Preheating must be implemented in order to ensure the evaporation of solvent, heating of the PC board pad and parts electrode and activation of the flux.
Recommended preheating temperature is 100 - 130°C (at the soldering surface).
Limit to 100 - 110°C to prevent PC board warping.
If through-hole spreading is poor, set the temperature at around 120 - 130°C (at the soldering surface).
Although the recommended preheating time is 30 - 60 seconds, solvent can be vaporized with longer preheating. Preliminary heating with hot air is also effective.