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Solder melting point and solders in PCB industry


In electronic industry, solder is commonly used. Solder is a metal alloy which plays a vital role in the production of electronic devices, it can create bonds of copper joints in PCBs (Printed Circuit Board).This article will focus on the types of solder and solder melting point.

What is solder melting point in PCBA process?

Solders that is one of the metallic components that is fused and with the help of fusing metallic piece of the solders with heat, it melts and becomes hard when cooled.

PCBs are another name of the circuit boards that consist of a well-furnished board containing several components. Soldering is an important feature in PCBA process, because choosing not to solder your PCB can cause design failure as the components would start to fall off. Therefore, solder melting point is also considered to be essential.

Solder melting point can range from 90 to 40 degree Celsius. This difference is caused by solders because of their several components of alloy.

Based on solder melting point, it can be classified into two types, first is eutectic solder and the other is non-eutectic solder both are used in PCB manufacturing. It keeps melting until it reaches its max melting point, at which point it becomes molten (liquid form).

How many types of solder are there?

There are several types of solders existing within the solder family.

1. Lead Alloy Solder


Lead Alloy solder contains a metallic component of lead that is mixed along with the other components of alloy in order to achieve the desired power and temperature. This solders are also nicknamed as soft solders. However, along with the lead, there is another component that is mixed within this mixture, Tin which makes up 60% of the total components in the mix. The melting point of lead alloy solder ranges from 1800-1900 degrees.

2. Lead Free Solder


Since it contains no lead, this kind of solder is suitable for water supply lines. It is used to solder electronics and is intended for use in plumbing application such as those involving refrigerator, cooling equipment, and heat ducts, which frequently experience high temperature changes and vibrations.

There is no shelf life limit and the melting range is between 183-361 C.

3. Silver Alloy Solder


Silver alloys solder are often regarded as the solders that are excluded from lead. Since, lead is considered as harmful for the environment. Another upside to using this solder is the exceptional joints that it yields, when used.

4. Flux-core Solder


This variety of the solders are mostly used for cutting the wires that are present on the cylinder. The phenomenal aspect of using this solder is that through the procedure of soldering, the additional oxidization that has been adopted by the metal is removed, thus assists in easy soldering.

5. Solder with Acid Core


A stronger more aggressive type of cleaning flux called an acid based flux is used to fill hollow core of solder that has been formed into a wire form and called acid core solder. Metal oxides that might obstruct the establishment of a solid solder connection can be removed and prevented by the application of solder flux.

6. Rosin core Solder


Rosin core solder is also formed using the hollow core of solder wire and a milder flux composed of rosin, a solid kind of resin derived from conifers like pine. Because flux residue is non-corrosive, rosin core solder is utilised in electrical applications where it may be difficult to remove the flux residue after the soldering procedure has been completed.

7. Solder with Solid Cores


In contrast to acid or rosin core solders, solid core solders do not have a hollow core filled with flux. Contrarily, these solders are made from a solid wire that is made of the solder alloy or substance. When using solid core solder, separate flux treatments are required.

Melting Point of all solders

Following are different solder melting point:Melting-Point-of-all-solders

Metal CompositionsMelting Point
Lead Alloy Solder188 °C (370 °F)
Lead Free Solder217°C/422°F
Silver Alloy Solder221°C ±4°C
Flux- Core Solder190°C
Acid Core Solder180-190°C
Rosin Core Solder178-183 °C
Solid Core Solder180-190 °C
Copper Solder235°C
Soft Solder180-190 °C
Tin Solder180-190°C
Hard Solder250°C
50/50 Solder361° – 421°F
60/40 Solder188°C (370°F)
95/5 Solder220°C (428°F)
Soldering Wire232 °C and 328 °C
Solder Paste90° C and 450° C

What is High Melting Point solder?

High Melting Point (HMP) solder uses paste that require high temperature melting range 268° C – 299° C.

What is Low Melting Point solder?

Low Melting Point, use low temperature solder paste that melt at a heat below 180° C.

What’s the difference of high and low melting point solder?


Solder melting point that range 268° C – 299° C is known as high melting point solder and that heats below 180° C is known as low melting point solder.

Major difference between low and high melting point solder is the composition or alloy used, for low melting point bismuth, tin and lead alloy are selected because they offer extremely low solder melting point of 117°F to 138°F. Whereas, Zinc/Aluminum alloy are used because they have high solder melting point of 382° C (719.6° F).

How to melt the solder in PCB fabrication and PCBA process?

Reflow soldering is the term for one of the PCBA process’s several processes, where solder is melted. After the components and liquid solder paste have been assembled, reflow soldering is performed. A heavy-duty industrial oven is built by passing the PCB Card through this sizable reflow oven. The board is progressively heated in this oven to a temperature of roughly 250 or 480 degrees Fahrenheit. The solder in the solder paste will melt at this temperature. Solder paste is solidified by a succession of coolers as the PCB is passed through after the solder has completely melted. The melting point of solder varies according to alloy or composition.How-to-melt-the-solder-in-PCB-fabrication-and-PCBA-process


We hope this article will help you better understand the knowledge about solder and melting point. You can also browse other articles on our website to read more articles about solder joints, solder, solder resist, etc. Also, if you are looking for a one-stop PCBA companies that can provide PCB manufacturing, PCB design, and PCB assembly, then IBE would be a good choice.



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