What is a Peelable Solder Mask?

The term “Peelable Solder Mask” can lead to some confusion. At Bittele Electronics, we have received questions from many of our Complete PCB Assembly clients, who are curious about how this type of solder mask differs from the more commonly known LPI (Liquid Photo-Imageable) Solder Mask. Some clients understandably question whether they have to choose between a Peelable or LPI Solder Mask for their board, but this is not the case. In fact, the Peelable Solder Mask is a different entity altogether, and in many cases the PCB Assembly Process requires that both of these masks be applied to the board.

The Peelable Solder Mask is meant to serve a very specific purpose: to protect specific areas on the PCB during the Reflow Soldering, Wave Soldering, or Surface Finish process. When certain parts on the board are marked by our client as DNI (Do Not Install), we will apply a Peelable Solder Mask over the pads or plated through holes for that part prior to PCB Assembly to prevent an accumulation of excess solder on the empty pads. The Peelable Solder Mask is also necessary for parts that will be manually installed after Automated PCB Assembly is complete. Selective surface finishes such as the Soft Gold PCB Surface Finish or Hard Gold PCB Surface Finish also require a Peelable Solder Mask to ensure that the correct finish is only applied to the desired areas of the PCB.

The familiar LPI Solder Mask acts to protect the bare copper of the board, lengthening shelf life of the product and facilitating High Quality PCB Assembly, as well as giving the board its distinct Solder Mask Colour; as such, it is permanently exposed onto the surface PCB. The Peelable Solder Mask, conversely, is applied and subsequently removed during the PCB production process, in all likelihood never to be seen by the client. It operates simply as a tool for PCB Fabrication and PCB Assembly.

As a PCB designer, you normally do not even need to specify that a Peelable Solder Mask is required for your project; our production team will apply one when necessary, at no additional cost or lead time. For more zero-cost options, see our list of PCB Options at a Standard Price. If you do have a special requirement for Peelable Solder Mask in specific areas at specific points in the process, or if you would like the Peelable Solder Mask left on your completed boards after assembly, we can happily accommodate that request as well. Simply include this requirement in your PCB Design Files, and mention it to your Bittele account manager during the quoting stage of your project.

If you still find yourself with any questions about Peelable Solder Masks, or to get started on an official PCB Assembly Quote for your design today, feel free to Contact Us any time! You can reach us over email at sales@7pcb.com, or call us toll-free at 1-888-812-1949.

Bittele is a full-service provider of low-cost Canada-Based PCB Assembly solutions. In business since 2003, we have established ourselves as a leader in the PCB production industry, and we offer a variety of tailored solutions to meet your specific needs.