Выбор идеальной паяльной пасты для пайки печатных плат

Summary

The video explains how to select solder paste for PCB assembly. The main considerations are alloy, flux, and particle size.

Alloy

Solder paste alloys include leaded, lead-free, low-temperature, high-temperature, and specialty options. The right choice depends on the product and manufacturing requirements.

Flux

Flux selection depends on production speed, oxidation, the condition of the board and components, and the required cleaning process. The presenter recalls that fluxes have around 16 classifications and recommends checking the specific classification rather than relying on broad labels such as “No Clean.”

Particle size and paste type

Smaller particles are needed for fine-pitch components and small stencil apertures. The presenter gives these approximate particle-size ranges:

Paste type Approximate particle size Type 3 25–45 μm Type 4 20–40 μm Type 5 15–25 μm Type 6 5–15 μm

As a rule of thumb, at least five particles should fit across the width of the smallest stencil aperture. Fewer particles may increase the risk of clogging or producing an unsuitable print. The presenter says 0201 components require at least Type 5 paste.

Another method is to ask the PCB designer for the smallest aperture width. The video gives these approximate matches:

Paste type Approximate aperture width Type 3 0.19–0.24 mm Type 4 0.14–0.19 mm Type 5 0.14 mm Type 6 0.1 mm

These guidelines assume a properly made stencil, clean squeegees, suitable room conditions, and correctly stored, unexpired paste.

Labels and documentation

The presenter reviews several solder paste containers. Some identify the alloy or particle size, while others provide only vague descriptions such as “No Clean” or “lead-free.” The recommendation is to check the technical documentation—especially the flux classification and cleaning requirements—instead of relying on unclear labels.

Viscosity is described as a secondary consideration compared with alloy, flux, and particle size.

Practical checks

• Check the smallest stencil aperture and component sizes before choosing paste.
• Apply the five-particle-across-the-aperture guideline, or ask the PCB designer for aperture dimensions.
• Confirm the alloy and flux classification, and determine the appropriate cleaning process from the flux specification.
• Ensure the stencil and production conditions are suitable before judging paste performance.

Main speaker and source

A single presenter from the Electronics manufacturing technologies channel; no individual name is given.