What is Solder Paste?

Solder paste is a kind of gray paste, a new soldering material applied to PCB SMT assembly, which helps to fix electronic components on PCB boards, making electrical connections and mechanical bonds between PCB pads and surface mount devices.

Solder paste is mainly composed of flux and solder powder (Flux & Solder Powder)

The role of flux

• Removes oxides from metal surfaces
• Protects the components to be soldered
• Holds the device in the proper position

What are the factors that affect the function of the solder paste?

• Uniformity of solder paste particles
• Percentage of solder powder in the flux
• Viscosity of the solder paste
• Thixotropic index and metal content of the solder paste
• Reflow process

What are the types of solder paste?

According to the flux type, solder can be divided into rosin-based solder paste, no-clean solder paste, water-soluble flux solder paste.

Solder paste in PCB SMT assembly

Reflow Soldering

For reflow soldering in PCB SMT assembly

Create solder joints

Solder paste as a homogeneous mixture of solder alloy and flux, solder paste helps to create reliable solder joints.

Leaded Components

Solder paste helps increase component density and reduce PCB manufacturing costs when assembled with leaded components

Stencil Printing

It helps in adding components to PCBs in established patterns

Jet Printing

Jet printing solder pastes are made from different formulations and therefore the solder paste has a higher fluidity.

Points to note when using solder paste

Make sure the stencil is accurate

Poorly printed stencils can hinder the application of solder paste.

Make sure the screen printer is programmed correctly

Accurate measurement and calibration of the solder paste screen printing equipment is key.

The right amount of solder paste

Excessive amounts and small amounts can lead to errors.

Correct process

You can choose between metal screen printing and mesh screen printing.

Safe handling

Solder paste contains organic solvents. When handling, try to avoid inhaling the fumes released by the solvents during operation, and avoid contact with skin and mucous membrane tissues for too long.

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