Automated conformal coating is the use of a computerized machine to apply a thin layer of moisture-resistant chemical coating to a printed circuit board to protect electronic circuits from harsh environments and external contaminants. This layer of protection helps to extend the lifespan of the electronic device and improve its overall performance.
There are several types of conformal coatings available, including acrylic, silicone, and polyurethane. Each type has its own unique properties and is suitable for different applications. Acrylic coatings are hard and provide good protection against dust and moisture, while silicone coatings are flexible and resistant to high temperatures. Polyurethane coatings are a combination of both, offering a balance of hardness and flexibility.
Methods of Automated Conformal Coating
Traditionally, conformal coating has been applied manually, using a brush, spray gun, or dipping process. However, with the advent of automation, it is now possible to apply conformal coating using robotic systems. This has several advantages over manual coating methods, including improved accuracy and consistency, increased productivity, and reduced labor costs.
Automated conformal coating systems typically consist of a robotic arm, a dispensing system, and a control unit. The robotic arm is responsible for moving the circuit board through the coating process, while the dispensing system is responsible for applying the coating material to the surface of the board. The control unit is responsible for overseeing the entire process and ensuring that the coating is applied correctly.
Benefits of Automated or Robotic Conformal Coating
One of the benefits of automated conformal coating is the ability to customize the coating process to meet the specific requirements of each circuit board. For example, it is possible to program the system to apply different coatings to different parts of the board, or to apply multiple layers of coating for added protection. It is also possible to set up the system to apply coatings at different thicknesses, depending on the needs of the circuit board.
Another advantage of automated conformal coating is the ability to automate the inspection process. This can be done using machine vision systems, which are able to detect defects in the coating and alert the operator to any issues. This helps to ensure that the final product is of high quality and meets the required standards.
There are a few considerations to bear in mind when using automated conformal coating systems. One is the cost of the equipment and the training required to operate it. While automated systems can provide significant cost savings in the long run, they can be expensive to purchase and set up initially. It is also important to ensure that the system is properly maintained and calibrated to ensure optimal performance.
Disadvantages of Conformal Spray Coating
Coating printed circuit boards with conformal spray coating, whether by manual or automated spray process has several major disadvantages including:
- Extensive board prep (masking, capping, taping, post-spray wash, etc.)
- Overspray waste
- Excessive fumes
The actual spray coating of a PCB is fast however, to prevent overspray from landing on critical switches, connectors and components that cannot be coated, extensive board prep is required. This pre/post spray prep consists of component masking, demasking, board washing, etc., and the time involved is extensive and often manual. In addition, overspray creates wasted material, driving up materials cost and creates excessive fumes which must be evacuated.
A new entrant into the automated conformal coating industry is the a robotic brush, such as the Raphael 4040 created by Invention House. The robotic brush is computer guided along an X,Y, & Z axis moving around keep away areas, delivering an even layer of conformal coating. The brush is fed by precision pumps that extract conformal coating and thinner from their original containers. Since there is no overspray, there is no need for masking and less material is used overall. No over spray means less fumes, better working conditions and faster overall production speeds.
Summary of Automated Conformal Coating
Overall, automated conformal coating is a powerful tool for protecting electronic circuits from harsh environments and ensuring their longevity. It provides a consistent and reliable coating process, with the added benefits of customization and automatic inspection. While there are some upfront costs involved, the long-term benefits of automation make it a worthwhile investment for many manufacturers.