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Sunday, March 21, 2021

How to Choose the Correct Solder as per Application

How to identify the best suitable Solder Quality


Lets start with basics of Solder composition available in the market like we have solder in the combination of Tin (SN), Lead (PB), Copper (CU) and Silver (AG).

Normal Tin/Lead Solder ratios commonly used are (SN/PB): 10/90, 15/85, 20/80, 25/75, 30/70, 35/65, 40/60, 45/55, 50/50, 55/45, 60/40 and 63/37. 

These are also referred as Leaded Solder Qualities.

Now the days consciousness related to environment and human health have increased thus companies have started using ROHS , NON-Leaded Solder Wires with their application, usually governed by European Norms and used by exporting companies in their products and by MNC's.

Normal Lead-Free Solder wire composition available are Tin/Copper (SN/CU), Tin/Silver/Copper in the ratio of 99.3/0.7 (SN/CU), 99/1 (SN/CU). 99/0.3/0.7 (SN/AG/CU) and 96.5/3/0.5 (SN/AG/CU) aka SAC 305.

SAC 307 also primarily used these days 96.3/3/0.7.

Today, with technological advancement and to reduce cost Antimonial, bismuth containing solder are produced which are hard and have high melting temperature thus doesn't suit every application but are economical than normal silver containing solder wires.

There are many factors that determine the choice of suitable solder quality:

1. Melting Temperature

Your product requirement in relation to its body material and temperature it can sustain affects the selection of solder, for example, in making bulb holder eye, higher melting temperature solder are used so that it can sustain high temperatures through its life.

In other words, What is the maximum temperature that the PCB/product can be exposed to without damaging the product performance?

Consider that some alloys(solder composition) really need from 25°C to in some cases 100°C hotter (above the melting point) to flow well and wet the mating surfaces.  Can the product tolerate this elevated solder temperature?

Below is the melting temperature of each solder composition type




2. Application


As mentioned above each application is different and has level of temp.tolerance along with design of PCB, product specific demands in terms of micro, mini, size of solder able area among others.

Also, each product type require solder area to be exposed thus demands good solder shine appealing to human eye or no to negligible solder shine.

For example, In artificial jewelry, low quality with higher lead percentage solder wires are used as product is economical and solder joints are hidden from human eye as they are polished.
In Lead batteries, Medium to low quality solder wire is used with higher lead content for same purpose of economics along with temperature requirement of the product.

Higher Lead content Solder wires are economical where higher Tin percentage solder is expensive.
High Tin Containing Solder emits good shine like 60/40 (Sn/Pb) and 63/37(Sn/Pb) solder.

Our many products are applied to numerous applications. For example, our:
  • solders are used for mechanical joining, electronics manufacturing, semiconductor device assembly, and more.
  • alloying expertise finds use in applications ranging from thermal management to thin-film technology to fusible devices.
  • inorganic compounds are critical ingredients in dry cell batteries, are precursors in the LED MOCVD process, and are used to optimize fiber optic devices, to name a few.

Explore these common applications of our many products, then contact us to tell us how we can work for you.


3. Flux Type Solder Wire

Solder wires are fluxed cored means they have flux in their core for ease of Soldering. The are two types of Solder wires i.e Solid Solder Wire and Flux Cored Solder Wire.

With advancement of technology, there are many flux variants used having different properties in terms of Flux residue, smoke , wetting and spread ability among others.

 We have below Solder flux Core Solder Wires for varied application:

A. Rosin Cored Solder Wire

Available composition: (SN/Pb) 63/37, 60/40, 55/45, 50/50, 45/55, 40/60, 35/65, 30/70, 25/75, 20/80, 15/85, 10/90
B. Resin Cored Solder Wire (RMA)- Low Smoke, Low Post soldering Residue
Available Composition: (SN/Pb) 63/37, 60/40, 55/45, 50/50


Available Composition: (SN/Pb) 63/37, 55/45, 60/40


Available Composition: (SN/Pb) 40/60, 50/50

After the above consideration the technical point to be kept in mind is the Flux ratio and wire diameter to be selected.

Flux ratio is the percentage of Flux in the solder wire. Its affects the solder wetting, spreadability and smoke level of solder wire. Also, the strength of Solder Joints and efficiency of soldering to get good productivity.

Please note  we have solder wire in 1.6 / 1.8 / 2.2 / 2.4 / 2.6 /2.8 /3.0 % Flux Ratio(percentage) available in 12 / 14 / 16/ 18 /20 /22 swage(Wire Diameter) and made to order in 24 / 26 swage.

Contact us for Purchase.

Best Regards,
B.I.C Solder Team

BAJAJ INSULATION CO. MANUFACTURERS SOLDER WIRE, SOLDER STICKS, SOLDER FLUXES, PCB CLEANING SOLVENTS, DIP SOLDERING MACHINES, TIN-COPPER WIRE, TIN-ZINC WIRE AND ALLIED CHEMICALS IN DELHI.

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