Miniaturization in electronic devices is a long-standing trend that demands that their components become increasingly smaller. In many cases, electroplating challenges increase as the size of parts decrease. Several considerations must be made to provide quality and consistent plating, within the customer’s stated specifications. Further, several processes are available, including one that was specifically designed for this use. So it’s important to understand which method is ideal for a particular part run. Today, we’ll look at the considerations, as well as the various plating techniques available for properly plating very small or microscopic parts.
Cleaning, Activation and Conductivity
Successful electroplating of these components is heavily reliant on cleaning and activation as well as good electrical conductivity in the plating solution. The cleaning and activation steps need to have good solution exchange in and around the parts.
As with any part being plated, success of these factors depends on its geometry. For complex parts with blind holes, preparation is critical. Any chemical must be able to flow into the blind holes and still be exchanged with fresh solution. This is necessary if the intended cleaning or activation is to be effective.
Flushing out those chemicals that you worked so hard to get in the holes is equally important. No chemical residue can be left behind, especially if the chemical isn’t compatible with the electroplating solution. Microscopic parts need to have some type of mechanical help to exchange these solutions.
Vibratory Plating is One Option, But Limited
Traditional preparation in a basket followed by barrel plating will not get the job done. Vibratory plating improves solution flow by liberating air entrapped in the inner diameter. This method, however, has limitations.
Vibratory plating requires enough surface area of parts being plated to cover the cathodes within the unit. This process might work with very small parts, but not for microscopic ones. With microscopic parts, the order size may not have enough volume to cover the cathodes within the unit and may require filler media to process successfully. However, this increases cost, and the media can separate from the parts due to weight or geometry differences.
Spouted Bed Electrode Plating to the Rescue!
Spouted Bed Electrode (SBE) is the best option for the smallest components. It has been developed over the last 20 years in response to the electronics miniaturization movement. SBE plating uses an electrolyte jet to move parts in the plating chamber but can also be used for cleaning, activation, and rinsing. The SBE unit allows for very uniform plating compared to barrel plating. However, load sizes are limited to 50 to 400 ml’s of material, so other methods, such as vibratory, should be considered for larger parts.
Spouted Bed Electrode Plating (SBE) Advantages:
- Ideal for plating small parts.
- Excellent solution exchange due to the high velocity of solution movement.
- Minimal part-to-part plating thickness variation.
- Small volumes of parts can be plated with no media.
- Flat parts do not stick together when wet.
- Nesting in general is almost eliminated due to the constant random position the parts are in.
SBE’s shortcomings are that most parts need to be less than ½ inch long to move properly in the SBE unit but still large enough to not get stuck in the 0.010 mesh of the unit.
Not sure which approach is best for plating your small parts? Contact us, we’re happy to help!