Eight common uses for temporary solder mask

What is temporary solder mask?

Temporary solder mask is a material used in electronics manufacturing to safeguard certain sections of a printed circuit board (PCB) throughout the soldering procedure. After the soldering is complete, this mask can be conveniently removed by peeling or washing. Although its primary application involves covering exposed vias in wave soldering, operators often come up with inventive applications for the mask to solve manufacturing challenges.

8 Common Uses for Temporary Solder Mask

  1. Wave Soldering

    During the process of wave soldering, where an entire PCB is moved across a molten solder wave, temporary solder mask can be applied to protect areas that should not be soldered. These areas include gold-plated contacts, components with through-holes, or connectors that require a different soldering method. This is the most common use of temporary solder mask, as it provides greater adaptability compared to alternatives like Kapton tape or pre-molded silicone boots.

  2. Selective Soldering

    In the context of selective soldering, specific areas of a PCB are soldered using a concentrated stream of solder. Temporary solder mask can be employed to define the precise areas where solder is applied, enabling precise control over the soldering process.

  3. Component Protection

    Temporary solder mask is applied to protect vulnerable electronic elements like connectors, switches, and fragile surface-mounted devices (SMDs) against unintended soldering or the splatter of flux throughout the assembly phase.

  4. Rework & Repair

    When reworking or repairing a PCB, temporary solder mask can be used to conceal nearby components that requires shielding from heat or direct contact with a soldering iron. This measure guarantees that only the intended area is exposed to the rework process.

  5. Conformal Coating

    A temporary solder mask can act as a temporary barrier while the conformal coating procedure takes place. This process involves the application of a protective coating to the PCB. The temporary mask obstructs the conformal coating from attaching to specific areas, like connectors or test points, that need to remain accessible.

  6. Adhesive for Reflow of Two-sided PCBAs

    Temporary solder mask offers an alternative to permanent adhesives for securing components during the assembly of PCBAs. It functions as a temporary adhesive, ensuring components remain in place throughout the reflow process. This is especially valuable when a double-sided board is flipped for a secondary run.

  7. Painting & Powder Coating

    Although temporary solder mask is not frequently utilised in painting and powder coating procedures, it provides a level of flexibility that alternatives like masking tapes, silicone plugs, or custom-molded silicone caps do not offer. It's advised to use peelable masks made of natural latex, such as WonderMASK PX and Techform TC-533, due to their strong tensile strength which helps avoid breakage when being removed.

  8. Anodizing & Plating

    Using a temporary solder mask during the anodizing and plating process can be useful for safeguarding specific areas of a metal surface against coating or plating. The solder mask functions as a barrier, preventing the anodizing or plating solutions from accessing the areas covered by the mask.
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