Conformal Coating

Introduction

Transcend Information offers conformal coating as a customization option on its full range of embedded-use flash and DRAM products to increase their protection against a wide variety of environmental conditions such as moisture, dust, corrosion, and chemical contaminants.

Coating Methods

Conformal coatings can be applied via a range of methods including manual brushing, manual spraying, dipping, or by automated spraying machines. Transcend utilizes automated spraying machines for its conformal coating application due to their speed and accuracy. With automated spraying application, Transcend is able to maintain a precise coating thickness with optimal results.

Coating Materials

Due to the wide range of applications that require conformal coatings, different materials—each having unique strengths and weaknesses—may be utilized. The coating, which encapsulates the entire printed circuit board (PCB), provides a physical barrier against moisture, dust, and other environmental contaminants. The most common coating materials are acrylic, silicone, urethane, and epoxy. Silicone and epoxy coatings can withstand exposure to high temperatures, while urethane has good chemical resistance. Acrylic coatings have excellent moisture and electrical resistance, and therefore are the preferred choice for the majority of applications.

Transcend offers an acrylic conformal coating solution supplied by HumiSeal, one of the leading conformal coating manufacturers. The acrylic coating is quick–drying and features excellent flexibility, moisture protection, electrical isolation, and fungus resistance. It is also compliant with MIL, IPC, RoHS, and UL standards, and is well-suited to most applications. Transcend also offers different coating materials for specific application needs.

Transcend's Conformal Coating

Transcend's conformal coating is applied directly to the module surface (except for the "gold-fingers") to completely encapsulate the PCB and all mounted components. The coating shields the DRAM or flash module from environmental factors, increasing the durability and reliability of the system. See Figure 1.

To guarantee that Transcend offers the highest quality embedded solutions, our coating process meets IPC-A-610D standards, which specify coating color, coverage, and thickness. Our coating material contains fluorescents to aid final inspection of the product. The coating is 100% inspected under UV light for distribution, quality, and uniformity. See Figures 2 and 3.

Transcend recommends conformal coated flash and memory modules for use in harsh environments with high moisture (forests), high dust (factory, desert), or chemical contaminants. These include chemical refinery plants, automotive applications, military environments, railroad systems, and traffic control systems.