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Solder mask on the PCB surface


The solder mask is actually the place where we can see the green or other colors. After the PCB is made, its front and back sides are smooth and unprotected copper layer. In the presence of water conditions, pure copper in contact with air is extremely easy to be oxidized, and then become a poor conductor of electricity, seriously affecting the electrical performance of the board.

In order to prevent copper oxidation and protect the PCB surface, as well as to distinguish between welded and non-welded parts, engineers use solder resist ink on the PCB surface to form a layer of thickness of the solder mask.

What is solder mask used for?

What-is-solder-mask-used-forThis is a splendid polymer that is put to engraving on the sheets. The tight spot cover is expected to safeguard the fundamental electrical follows from sogginess and debasement and control tie motion change.

The head PCB part is the external covering of pitch called the solder mask that is a solidified tar with colored hides that is carried out to the board in a silkscreen plan. The justification for cover is to safeguard the electronic follows under from suddenness and buildup and to control the movement of fluid tie.

At the point when you consider making a printed circuit board, it ought to be a solid part that endures as far as might be feasible in your gadget. One of the most mind-blowing ways of boosting board surface security for greatest strength is to utilize a Solder Mask.

The mask shapes the ultimate layer step in PCB manufacturing. These methods are reiterated to make different PCBs. In diverse PCBs, the layers are related with each other using express between connectors.

What is the material of solder mask?

The solder mask frames the last layer step in PCB producing. These means are rehashed to make complex PCBs. In multifaceted PCBs, the layers are associated with one another utilizing explicit between connectors.

Polymer is used as the material for solder masks. It is a crucial component in circuit construction projects because it protects the PCB from oxidation. This is, be that as it may, by all accounts not the only use case and advantage of weld covers with regards to the development of circuit sheets.

Various materials are utilized relying upon the financial plan, size of the board, the thickness of copper follows, variety and size of openings, etc. developing next are referred to a few widely known substances used:
1.Epoxy Liquid
2.Liquid Photo Imageable (LPI)
3.Dry Film

Epoxy Liquid

Epoxy-LiquidEpoxy is the most generally involved innovation in this present reality. Epoxy is the least expensive option among Solder Mask. Epoxy is a polymer that is silk screened onto the PCB.
Silk screening is a printing method that aids an image by using a woven lattice ink impeding example. The cross section permits regions open for ink move to be distinguished. In the last step of the cycle, warm relieving is utilized.

Liquid Photo Imageable (LPI)

Liquid-Photo-Imageable-(LPI)By utilizing a combination of polymers and covering solvents, LPI solder mask accomplish a slim covering that works for essentially every PCB surface, making it a powerful swap for customary PCB coatings. It is restored on the board with an UV light after the board is cleaned and scoured.

LPI solder mask is by a wide margin the most well-known kind of mask oppose utilized today. LPI is more solid, can be printed precisely, and connects with the outer layer of the board and the copper highlights on which they’re applied to secure.

LPI weld veil is an epoxy-based material, so it is entirely sturdy and almost difficult to eliminate whenever they have been relieved. There is different strategies to apply LPISM ink, for example, screen printing, shade covering, electrostatic shower, air splash, etc.

Dry Film (DFSM)

Dry-Film-(DFSM)Dry Film solder mask is a long term used material that utilized for circuit protection on uper layer of inflexible PCB, IC substrates and other unbending sheets. Timeless is exceptional to meet clients’ extraordinary application prerequisites.

This DFSM is a watery processible, dry film photopolymer bind cover, using epoxy science materials notable for their electrical insulation, chemical opposition and layered strength properties.

The DFSM portrayed here consolidates the properties of visual selectivity, mechanical strength, and simplicity of reproducible application. It gives further developed circuit security during fastening activities and ensuing dealing with. The new weld veil offers significant expense and execution benefits over screened covers to planners, printed wiring board fabricators, part constructing agents, and end clients.

Is solder mask toxic?

Yes, of course. Solder mask is toxic as it uses various chemicals which are harmful for breathing and its fumes are harmful for eyes.

Why do you need a solder mask in PCB?

Why-do-you-need-a-solder-mask-in-PCBAt the point when metal is presented to dampness and oxygen a response happens where the metal loses electrons and its properties are changed, this is otherwise called rust. A few metals like iron transform into a fragile ruddy powder when oxidized. Copper, then again, holds its primary honesty when oxidized, be that as it may, it loses its electrical properties all things considered.

This can be a seriously enormous issue for PCBs since they rely upon the electrical properties of copper to accurately work. This is where patch cover turns out to be profoundly helpful in that it seals the uncovered copper away from the climate hence forestalling any oxidation.

What are the properties of solder mask?

What-are-the-properties-of-solder-maskSettling on a proper solder mask relies upon the actual elements of your board, openings, parts, and guides, the surface design, and the last application for your item. The properties of the solder mask are actually the properties of its material solder resist.

Soldering resistance

After the solder mask is applied to the PCB surface, the components will be soldered outside the solder mask. If the solder resist ink has poor solder resistance, it will directly affect the quality of the PCB assembly and electronic products.

Solvent resistance

Solder resist ink has many different colors, and it can be said that it is a pigment of different colors. The solvent resistance is one of the important properties of pigment, mainly refers to the solubility of pigment when it is colored as a colorant, and the color bleeding and floating phenomenon due to the different solubility of pigment between different phases of coloring matter (spreading colorant, plasticizer).

Viscosity and thixotropy

Thixotropy is a physical property of a liquid, i.e., its viscosity decreases in the mixing condition, and then quickly recovers its original viscosity after standing. After mixing, the effect of thixotropy continues for a long time, enough to make its internal structure from scratch. To achieve high-quality screen-printing effect, the thixotropy of the ink is very important.


Pigments and mineral fillers are generally in solid form, and are precision ground to a particle size of no more than 4/5 microns and in solid form to form a homogeneous flow condition. Therefore, it is very important to require the ink to have precision.

In the first place, on the off chance that you have a PCB drill oppose that will be utilized in aviation, telecom, clinical, or other “high dependability” businesses, mind industry guidelines around bind cover, and your planned application overall.

How do I print a solder mask?

How-do-I-print-a-solder-maskThere are a few guidelines to observe to apply the solder mask and It is quite difficult. Besides, solder mask producing contains different stages that require high exactness levels springing from cutting edge innovations, high assembling experience, and best in class offices.

The application interaction of patch includes right off the bat, applying the bind material on the board, and afterward following it up with making openings into the material for the copper parts. Engineers that specialty circuit sheets will make these openings, frequently by utilizing photolithography procedures.

The process can be roughly divided into four steps.
1) spraying ink on the circuit board to form an ink layer

2) flattening the ink layer on the circuit board

3) exposure, development and curing of the ink layer on the printed circuit board in turn to form a solder resist layer

4) Ablation of the residual ink in the NPYH hole and/or the residual ink in the target area located on one side or on opposite sides of the circuit board using a laser beam.

Difference between solder mask and solder paste

A mask is applied on the face of PCB to cover the copper follows and safeguard them from external harm.

Solder paste is a wax that is applied to the outer layer of SMD parts to guarantee that the parts fit together or have an association.

Solder mask is a window overall surface of cover by veil oil the item is to allow securing as per usual the locale without fix cover layer should be different color oil.

The solder paste is used to make the stencil and the stencil can unequivocally put the weld stick on the fix pads that ought to be fixed which is used for the heap of the SMT.

How do you remove PCB solder mask?

At the point when you created the PCB, there is a layer called solder mask which indicates regions which and which are not covered with the solder mask. There will be a spot in the film where solder mask isn’t to be applied, for example, on cushions for through opening parts and cushions for SMT parts and any cushions you need to uncover as in test focuses. You ought to have determined this layer accurately


The solder mask is the last step in PCB production and an important part of the PCBA assembly before it begins. With the solder resist mask, it helps to distinguish the soldering and non-soldering parts, and then the component soldering can be completed successfully.

PCB is an important part of an electronic product, is the carrier of components and circuits. The solder mask can protect the electrical properties and improve the service life of the PCB. The durability of the circuit board is improved, so that the quality of electronic products better, longer service life.



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