Peelable Mask vs LPI Mask: which to choose?
When designing and manufacturing PCBs, many factors come into play. One of them is choosing the right solder mask to use. Solder mask, also known as solder resist, is a dielectric layer that covers the copper traces and vias on a PCB to protect them from oxidation and contamination during the soldering process. There are several types of solder mask, but two of the most common ones are Peelable Mask and Liquid Photo-Imageable (LPI) Mask. Let's compare them to see which one is better suited for your needs.
Peelable Mask
Peelable Mask is a temporary solder mask that can be peeled off after assembly, leaving a clean and shiny surface. It is usually green or blue and comes in a liquid form that is applied onto the PCB surface using a dispenser or a stencil. Peelable Mask is used for protecting gold fingers, edge connectors, and other sensitive areas that require a temporary mask during the assembly process.
Peelable Mask has several advantages over LPI Mask. For example, it does not require any special equipment or process to remove it, and it is more affordable than LPI Mask. Moreover, Peelable Mask is more robust and can withstand high-temperature soldering without degrading or melting.
On the downside, Peelable Mask is not suitable for fine pitch and high-density components, as it tends to leave residues and smudges that can affect the quality of the solder joints. Additionally, it requires a separate process step to apply and remove the mask, which can increase the production time and cost.
LPI Mask
LPI Mask is a permanent solder mask that is applied using a photoimageable process. It is usually green, but other colors are available as well. LPI Mask is applied as a dry film or a liquid that is exposed to UV light through a photomask to create the desired circuit pattern. After the exposure, the unexposed areas are removed using a developer solution, leaving a cured and durable solder mask.
LPI Mask has several advantages over Peelable Mask. For example, it is more precise and can achieve finer features and higher resolution than Peelable Mask. It is also better suited for high-density and fine-pitch components, as it does not leave any residues or smudges. Moreover, LPI Mask is faster and more efficient than Peelable Mask, as it does not require a separate process step to remove the mask.
On the downside, LPI Mask is more expensive than Peelable Mask, and it requires specific equipment and processes to apply and cure the mask. Additionally, LPI Mask is less durable than Peelable Mask, as it can degrade over time and under harsh environmental conditions.
Conclusion
Both Peelable Mask and LPI Mask have their strengths and weaknesses, and the choice between them depends on the specific requirements of the PCB design and manufacturing process. Peelable Mask is a good choice for temporary masks and low-density components, while LPI Mask is a better choice for permanent masks and high-density components.
We hope this comparison has helped you make an informed decision about which solder mask to use. As always, if you have any questions or comments, feel free to contact us.