RAFI MICON 5 and RACON ST Tactile Switches – Robustness in Miniature Format

Table of contents

1. MICON 5 from RAFI: Small pushbutton with a big effect
2. RACON ST from RAFI: Small pushbutton, particularly robust
3. Excursus: What protection methods are available for printed circuit boards?
4. MICON 5 and RACON ST: New option for nano coating on short-travel key switches

MICON 5 S & MICON 5 SL: The features at a glance

• Compact dimensions
• Service life up to 10 million switching cycles (MICON 5 SL)
• Actuating forces from 1.5 N to 7 N
• Gold contacts for safe switching at low currents
• Unique tactile feedback
• Protection class IP67 (front and rear)

MICON 5 Safety: The features at a glance

• Unique worldwide: 1 NC contact + NO contact
• Operating temperature -40 °C to +125 °C
• Service life up to 1 million switching cycles
• Actuating forces from 2.9 N to 5.6 N
• Unique tactile feedback
• Protection class IP67 (front and rear)

RACON ST from RAFI: Small pushbutton, particularly robust

The customized RACON ST product series fits seamlessly into any operating system and offers the right short-travel key switch for every project. The new RACON ST series in the format of 12 mm x 12 mm or 8.4 mm x 8.4 mm with SMT or THT connection has been optimized by RAFI for all the PCB protection methods mentioned.

Thanks to its sealed design, the RACON ST can be used on PCBs that are optimally protected against environmental influences and contamination, whether by potting, painting or nanocoating. With its impressive temperature resistance from -40 °C to +125 °C, the RACON ST offers outstanding performance for automotive and other outdoor applications.

In addition to its impressive temperature resistance, the RACON ST features a dense, robust and gold-based contact system that ensures absolute switching reliability and resilience. With a guaranteed reliability of at least one million actuation cycles, the product series can ensure reliable operation.

RACON ST: Features at a glance

• Gold contacts
• IP67
• Operating temperature -40°C to +125°C
• Up to 10 million switching cycles

Excursus: What protection methods are available for printed circuit boards?

Safety through the potting process

In the manufacturing of electronic assemblies for applications that are susceptible to corrosion and dirt, the potting process is currently still preferred to ensure permanent protection against moisture and dust. In potting, the printed circuit board is either partially or completely filled with a medium such as epoxy resin, polyamide or polyurethane and admixed hardener. The viscous filling compound with a layer thickness of at least 1 mm not only prevents the penetration of dirt and moisture, but also improves heat dissipation.

In addition, the potting process prevents functional impairment due to mechanical effects. This makes the process particularly suitable for applications in construction and agricultural machinery. However, the costs are higher compared to protective coating and nanocoating, and it requires a time investment for potting and curing the medium.

Micrometer-fine protective coating

Another way of protecting printed circuit boards from external influences is the application of protective lacquer by means of dip coating, spray coating or selective machine coating. Depending on the medium and method used, coating thicknesses of 20 to over 100 μm can be achieved. The applied coating layer protects the electronics from dew, contamination and electrostatic discharge. The most common agents are acrylic and polyurethane coatings, but hybrid solutions such as silicone protective coatings are also used.

In the dip process, all exposed areas of the PCB are sealed – as long as there is sufficient clearance between the individual components. Before coating, components that could be damaged by the paint must be masked. This makes the process relatively material- and time-intensive.

In spray coating, lacquers with lower viscosity or diluted lacquers with solvents are generally used and sprayed onto the printed circuit board manually or automatically. This process is also used in selective coating, where only selected critical areas of the PCB are sealed to reduce material usage. A fast and homogeneous coating of the sections to be sealed without prior masking is achieved depending on the spraying precision and PCB design.

Nano Coating

Nano coating technology offers a particularly fast and economical method for liquid encapsulation of electronic assemblies. In this process, a fluoropolymer is usually used to immerse the assembly in a solvent bath such as hydrofluoroether. The dipping process ensures that all areas and components are coated with a homogeneous, extremely fine layer thickness of only 400 nm.

The nanocoating meets the requirements of the IEC 60068-2 group of standards for temperature and moisture resistance as well as protection against condensation and other climatic influences. The low material application, the short process time of just a few minutes, and the fact that masking and curing are not required make the nanosealing process extremely time- and cost-efficient.

In addition, the application of the process is environmentally friendly, harmless to health and free of unpleasant odors. Only PFOS-free, REACH- and ROHS-compliant substances are used. Nanocoating does not use conventional solvents or propellants, and thus differs from conventional protective coatings or potting processes.

It is repair-friendly, and components that can be desoldered can be easily replaced. Defective areas can be sealed with protective lacquer or the entire coating can be renewed. Due to these properties, the process is suitable across all industries for sealing electronic components that do not require increased vibration protection.

MICON 5 and RACON ST: New option for nano coating on short-travel key switches

Until now, there was no option for the use of nano coatings on printed circuit boards equipped with short-travel switches. The problem: During the dipping process, the solvent penetrates into the interior of the switches due to the capillary effect and settles on the switching contacts as a thick protective layer. This impairs the switching function. With the introduction of the MICON 5 and RACON ST product series, RAFI is the first manufacturer to offer a solution to this problem in the manufacturing of electronic assemblies.

With the tactile switches, which are suitable for all common coating processes, circuit boards with electromechanical actuators can now also be protected against corrosion, dust and dirt using a nano coating. This process-safe, time- and cost-efficient method increases cost-effectiveness, especially for standard assemblies manufactured in large batches.

The innovative micro short-stroke switches offer a new option for PCB coating for a wide range of industries from automotive manufacturing to maritime applications and power generation.