How to Select and Evaluate the Solder Paste?

Solder paste is a homogeneous mixture consisting of a mixture of solder and gold metal powder, paste flux, and some additives, with a certain viscosity and good thixotropic paste. At room temperature, the solder paste can paste the electronic components in a given location, when heated to a certain temperature it can make components and pads connected together to form a permanent connection solder joints. How to choose a suitable solder paste? It is a quality assurance in PCB assembly and PCB manufacturing.

The Problem of Choosing Solder Paste You should Pay Attention To

1, the Consistency of Solder Paste Batch

When selecting solder paste, it is best to ensure that the supplier has the ability to ensure the consistency of the quality of each batch of solder paste and the adequacy of process control and inspection procedures to ensure consistent solder paste quality.

2, Reliability

The final selected solder paste must have long-term reliability on the PCB and must comply with the SIR and electromigration of GR-78 requirements.

How to Evaluate Solder Paste

1, the Flow Characteristics of the Solder Paste

The chemical reaction between the solder paste flux and the solder alloy affects the flow characteristics of the solder paste, and rheology is critical to the solder paste printing performance.

2, the Stencils Life of Solder Paste

Any solder paste has to be printed well on the stencil, and the same paste has a good printability after several hours on the stencil.

3, Solder Paste Adhesion

As the different of lead-free solder paste and lead solder paste formulations are vary widely, it is necessary to determine whether the lead-free solder paste has good adhesion and the ability to maintain component placement stability.