Gluing and pouring glue methods for SMT assembly

SMT assembly is a significant process in electronic products manufacturing, among which gluing and
filling are the vital processes.

Gluing and pouring glue packages and protects electronic components, improves the product's waterproof,
dustproof, and shockproof properties, and plays a role in heat conduction and insulation.

The difference between gluing and filling

Gluing and pouring glue are two different processes.

Gluing means squeezing the glue directly to where it needs to be stuck while pouring glue means
injecting the gum into the reserved space.

We use the gluing for bonding small areas. The pouring glue is used for bonding large areas or spaces
that need to be filled.

Method of gluing patch processing

There are two main methods of gluing in patch processing: dispensing and potting.

1) Glue dispensing

Glue dispensing is to squeeze glue through a needle or nozzle to the location where it needs to be
bonded. The glue dispensing process is simple and suitable for small-batch production.

There are two main dispensing methods: contact dispensing and non-contact dispensing.

• Contact dispensing: The needle or nozzle directly contacts the surface of the adherend to squeeze out
the glue.

The advantage of contact dispensing is that it is easy to operate. But it has low precision and is prone
to bubbles.

• Non-contact dispensing: The needle or nozzle does not directly contact the surface of the adherend. It
uses air pressure or vibration to squeeze out the glue.

Non-contact dispensing has higher precision. It is less likely to produce bubbles, but the operation is
more complicated.

2) Potting

Potting is injecting glue into the reserved space.

The potting process is suitable for high-volume production. There are three main potting methods:
manual, mechanical, and automatic.

• Manual potting: Use hand tools to inject glue into the reserved space. Manual potting has a lower cost
but lower efficiency and is not easy to ensure accuracy.

• Mechanical potting: Use mechanical equipment to inject glue into the reserved space. Mechanical
potting is more efficient but more expensive.

• Automatic potting: Use automatic equipment to inject glue into the reserved space. Automatic potting
is the most efficient but also the most expensive.

SMT processing glue and glue filling process

Generally, gluing and filling the patch includes the following steps:

1) Preparation

It includes cleaning the surface of the adherend, selecting the appropriate glue, and configuring the
glue.

Gluing or pouring glue: Choose the appropriate gluing or pouring gum method according to your needs.

2) Curing

After curing the glue, check the gluing or pouring gum effect.

Precautions for glue filling in patch processing

When gluing and filling the SMT mount, should pay attention to some notes:

• The surface of the adherend should be clean and dry, free of oil, dust, etc.

• The selected glue should meet the requirements of the adherend's material.

• When preparing glue, please strictly follow the instructions.

• When gluing or pouring gum, should operate specifications to avoid generating bubbles.

• After the glue is cured, we should check the gluing or filling effect to ensure that they meet the
requirements.

Application of glue filling in patch processing

SMT's gluing and pouring gum technology is widespread in electronic product manufacturing, mainly
including the following aspects:

Encapsulation and protection of electronic components: Gluing and potting can effectively prevent
electronic components from being damaged by water, dust, vibration, and other factors.

Improve the waterproof and dustproof performance of the product: Gluing and filling can effectively
improve the waterproof and dustproof performance of the product. It extends the service life of the
product.

Play the role of heat conduction and insulation: Gluing and pouring gum can play the role of heat
conduction and insulation, thereby improving the product's performance.

Conclusion

Gluing and filling is one of the important processes in patch processing, which has a significant impact
on the electronic product's performance and reliability.

When performing SMT gluing and pouring gum, we should strictly follow the process requirements to ensure
the quality of gluing or gluing and improve the quality and reliability of the product.