Comparing Application Methods and Equipment for Electronics Encapsulation

For decades, Chase Corporation and our Humiseal brand have been the originators and recognized leaders in PCB protection with conformal coatings. Humiseal also provides products and technical support for a complete line of encapsulants. While conformal coatings provide adequate protection in most instances, sometimes you just need a little more coverage! Humiseal encapsulants add a whole new level of protection against extreme temperature and chemical exposure.

So, if you currently use Humiseal conformal coatings, there are certain industry-established methods, both manual and automated, for applying them. This usually involves either spraying them, manually hand brushing conformal coatings, or dipping the entire board. Encapsulants are quite different and the following are some common application methods with pros and cons to help in your decisions.

Related Article: Epoxy for High-Temperature Potting and Encapsulation

Manual Dispensing “Guns”

One of the first approaches most people consider to dispense and apply encapsulants is a basic, manual extrusion “gun”. Using a cartridge gun is a low barrier to entry method of application.

These cartridge guns are essentially the same type of products found at your local hardware superstore for work around your kitchen or bathroom with caulking.

They involve attaching a cartridge or syringe to a moving plunger with a trigger. They are capable of simple single-component products, and can also be designed to apply two-component chemical cure materials. In the case of two-component products, the main component comprises two side-by-side cartridges; mixing is accomplished by attaching a static mixing tube to the nozzle of the gun. 

Advantages 

• Generally cheap/inexpensive approach 
• Manual process allows reaching small or complex shapes 
• Quick change of cartridges/mixing tips 

Disadvantages 

• Not very accurate or consistent dispensing bead 
• Quality can be operator-dependent 
• Workers may be exposed due to proximity to hazardous chemicals or vapors 
• Not well suited to high-speed needs 
• Incapable of large packaging sizes such as pails or drums 

Semi-Automated Equipment 

A small step up in both cost and consistency for applying encapsulants is the use of “semi-automated” equipment. In this instance, encapsulants are still supplied in either single or dual cartridges, the same as fully manual processes. This type of equipment improves over application guns by replacing a manual trigged with an air or fluid pressure approach, powered by an electronically controlled on/off valve. This consistent pressure allows for a more uniform application while requiring applicator input. 

Advantages 

• Relatively cheap/inexpensive approach 
• Manual process allows reaching small or complex shapes 
• More consistent on/off control and uniform bead thickness control 

Disadvantages 

• Quality is still often operator-dependent 
• Workers still may be exposed due to proximity to hazardous chemicals or vapors 
• Not well suited to high-speed needs 
• Incapable of large packaging sizes such as pails or drums 

Benchtop Robotic Application  

Benchtop robotics are portable machines that, when fed PCBs, will apply a preprogrammed distribution of encapsulant. The customizability of these machines is powerful, offering a solution to just about any shape board or selective area. 

These machines do not dispense from cartridges, enabling larger packaging sizes, like pails and drums. These are costly, but the results are undeniable. That said, these do require hand-feeding boards, so they are not suitable for factory-line levels of output. Still, these automate much of the time, energy, and effort typically spent on manual or semiautonomous applications.

Advantages 

• Very accurate and repeatable thickness application 
• Less exposure of workers to hazardous chemicals 
• Potential for medium-volume production speeds 

Disadvantages 

• A moderate level of investment required 
• Not capable of high levels of production 
• Not capable of using large packaging styles such as pails and drums 

Automated Stand-Alone Application 

The top-of-the-line for applying encapsulants! Fully automated, stand-alone application equipment can be a substantial investment, but it is standard equipment where large-scale high-speed production is required. There are many different configurations and options available from a large number of commercial suppliers. 

Advantages 

• Very accurate and repeatable thickness application 
• Minimal exposure of workers to hazardous chemicals 
• Potential for highest volume production speeds 
• Capable of handling the largest packaging sizes such as pails and even drums 

Disadvantages 

• Substantial level of investment required 
• Often not ideal for short or smaller production runs 

Choosing the Right Encapsulation Material for PCB Protection

Once your method of application has been decided, you then need to evaluate the material for optimal PCB protection. Unfortunately, there really is no one right answer. Different materials, especially thermally conductive encapsulation polymers, come with a wide range of advantages and disadvantages. Much like choosing a method of encapsulation, the material itself will depend heavily on your specific project and operational requirements. Luckily, HumiSeal has your back, offering a wide range of single and two-component encapsulants for many end uses. 

As a supplier of all major forms and chemistries of conformal coatings, Chase Corporation and HumiSeal® can help you with an unbiased approach to evaluating your application and process. We’ll show you how to maximize efficiency, minimize cost, and improve product reliability. Our outstanding manufacturing and technical support groups can provide your organization with reliable global supply, unmatched quality, and superior technical support. 

Please contact us today to discuss your application. Leave a comment below or hit the contact us button to connect with a team member.