Solder & Flux

Solder Wire

Definition:
Solder wire is a composition of metal alloys, typically tin and lead, that is used in the process of joining electronic components to a printed circuit board (PCB) or other materials. It is available in various diameters and alloy compositions to suit different soldering applications.

Function:
The primary function of solder wire is to create a strong, electrically conductive bond between components and the PCB. When heated, the solder wire melts and flows into the joint, filling the space between the components and the board. Upon cooling, it solidifies, creating a secure and conductive connection.

Application:
Solder wire is widely used in electronics manufacturing for assembling circuit boards, repairing electronic devices, and joining metal parts in various industries. It is essential in the assembly of computers, smartphones, televisions, and other electronic devices.

Selection Criteria:
When selecting solder wire, consider the following:
1. Alloy composition: Common alloys include tin-lead (Sn-Pb), tin-silver-copper (Sn-Ag-Cu), and lead-free options like tin-copper (Sn-Cu).
2. Diameter: Choose the appropriate diameter for the soldering iron tip and the application's requirements.
3. Flux core: Some solder wires have a flux core that aids in the cleaning and flow of the solder, while others are rosin-core or no-clean.
4. Temperature range: Ensure the solder's melting point is compatible with the soldering process and materials being joined.

Solder Paste

Definition:
Solder paste is a semi-fluid mixture of solder particles, flux, and a vehicle (usually a thickening agent) used in surface-mount technology (SMT) for the assembly of electronic components onto PCBs.

Function:
Solder paste's function is to provide a precise amount of solder to the designated pads on the PCB. During the reflow soldering process, the paste is heated, causing the flux to activate and the solder particles to melt and flow, creating a solder joint between the component and the board.

Application:
Solder paste is used in automated SMT processes, where components are placed onto the PCB by machines and then subjected to a reflow oven to create the solder joints. It is essential for high-volume, high-speed assembly lines.

Selection Criteria:
When choosing solder paste, consider:
1. Alloy type: Like solder wire, the alloy composition should be suitable for the application.
2. Particle size: The size of the solder particles affects the paste's viscosity and the quality of the solder joint.
3. Flux type: The type of flux (e.g., no-clean, water-soluble, or rosin-based) should be chosen based on the cleaning requirements and the soldering process.
4. Viscosity: The paste's viscosity should be appropriate for the printing process and the specific placement equipment used.

Soldering Aid

Definition:
Soldering aid, also known as flux, is a chemical cleaning agent used to remove oxides and other impurities from the surfaces being soldered, ensuring a clean and strong bond.

Function:
The primary function of a soldering aid is to chemically clean the surfaces of the materials being joined, allowing the solder to flow and create a strong, conductive bond. It also helps to prevent the oxidation of the solder during the soldering process.

Application:
Soldering aids are used in various soldering processes, including manual soldering, wave soldering, and reflow soldering. They can be applied as a , paste, or in the core of solder wire or paste.

Selection Criteria:
When selecting a soldering aid, consider:
1. Type: Choose between rosin-based, water-soluble, or no-clean flux based on the cleaning requirements and the soldering process.
2. Activity level: The flux should have the appropriate activity level for the materials being soldered and the soldering temperature.
3. Compatibility: Ensure the flux is compatible with the solder alloy and the materials of the components and PCB.
4. Safety: Consider the environmental and health safety aspects of the flux, especially if it will be used in a production environment.
Please refer to the product rule book for details.