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What are the Pros and Cons of Immersion Silver PCB Surface Finish?

By | Date posted: | Last updated: January 12, 2022
Immersion Silver PCB Finish

Before we delve into the relative merits and demerits of Immersion Silver as a surface finish, it will be worthwhile to define what a surface finish exactly is and the functions it performs.

PCB surface finish is typically applied to exposed copper conductors and connectors on the PCB. It performs several important functions, primary among them being that it serves as a protective layer for the copper connectors during storage. It also ensures good solderability between the PCB and the components during PCB assembly. Post assembly, it helps preserve the integrity of the solder joint.

Commonly used surface finishes include:

  • Hot Air Solder Leveling (HASL)
  • Organic Solderability Preservative (OSP)
  • Immersion Tin (ImSn)
  • Immersion Silver (ImAg)
  • Electroless Nickel/Immersion Gold (ENIG)
  • Electroless Nickel/Electroless Pd/Immersion Gold (ENEPIG)

Each of these come with their own set of advantages. Let us look at Immersion Silver as a surface finish in some detail.

Immersion Silver as a surface finish

Immersion silver also popularly known as IM silver, IMag or ENIAg is a popular surface finish when it comes to PCBs. Essentially, it refers to depositing a thin layer of silver on the copper finishes of the custom printed circuit boards. The chemical reaction involved is a displacement reaction where silver and copper are spontaneously displaced.

Everything you need to know about Immersion Silver

Essentially, Immersion Silver is a transitional technique between OSP & ENIG when it comes to performance. Immersion silver is high on solderability and solder joint strength, however it is not as strong as gold when used as a contact surface.

As far as the process goes, the displacement reaction sees a pure silver coating at a sub-micron level. The Immersion silver finish is known for its electrical properties and its excellent weldability even when it is exposed to heat, moisture and contamination. Of course, in terms of physical strength it cannot compete with ENIG. Also, another drawback of Immersion Silver is the electron migration of silver. When exposed to moisture and on application of voltage, silver is prone to electromigration. To circumvent this problem, it is advisable to add organic compounds to the silver.

Pros & Cons of Immersion Silver PCB Surface Finish

Advantages:

  • Immersion Silver is known for the immersion finish and flatness that it offers. Especially as opposed to HASL finish, its advantages totally stand out.
  • That it is lead-free and RoHS complaint works in its favor.
  • It is known for its low loss for signal integrity applications.
  • On account of its tighter tolerances, it can be held for plated holes.
  • It works particularly well when it comes to fine pitch, BGA PCB assembly and small components.
  • In terms of costs too, it works well when it comes to its lead-free finish.
  • Given proper packaging, it has a decent shelf life when it comes to storage.
  • That it is reworkable, adds to its repertoire of advantages.

Disadvantages:

  • When it comes to handling, it requires a lot of sensitivity. Without the use of gloves, it can lead to tarnishing issues.
  • It requires specialized packaging. Also, once the package is opened and all boards aren’t used, immediate resealing is required.
  • A disadvantage of this coating also stems from the fact that there is a short window between assembly stages
  • Also, the supply chain options for this finish are limited.
  • While it is more cost-effective than ENIG, it is less cost effective than Immersion Tin.

Use Cases of Immersion Silver PCB Coating

  • It works well for products with high-speed signals. It therefore finds extensive use in industries such as automobile, computers, communications.
  • It is a great option when it comes to complex PCBs with QFN or BGA packages.
  • PCBs built for commemorative purposes benefit from Immersion Silver surface finish.

To sum up

Immersion silver works well on account of its flatness as well as joint strength. That it is a cheaper option compared to ENIG, makes it a preferred finish. Immersion Silver is also known for its electrical properties and for its use in high-frequency signals. It is also the coating of choice on account of its ease of assembly as well as easy inspectability.

It is its sensitivity to tarnishing and voids in solder joints that restricts its application.

Mer-Mar Electronics is an ISO 9001:2015 certified company and ITAR (International Traffic in Arms Regulations) compliant manufacturer that delivers PCB manufacturing services with specialized support, reliable testing, and multi-functional features. Our consistent quality and quick turnaround endear itself to our customers, who look on us as a one-stop-shop for all their PCB requirements. In case if you have any questions or require more information about PCB assembly and fabrication services, contact us via sales@mermarinc.com or call us on (760) 244-6149.

Custom Printed Circuit Boards: Top Advantages and Disadvantages

By | Date posted: | Last updated: December 17, 2021
Custom Printed Circuit Boards

Increasingly, electronic devices call for complex circuitry in a limited space. With miniaturization of devices, you need to use small electronic components and make every attempt to save space. Little surprise then that you cannot make do with standard PCBs that are available and need to opt for custom printed circuit boards that can do justice to your bespoke requirements.

Custom printed circuit boards (PCBs), however, come with their advantages as well as disadvantages. Let us delve into them in detail:

Pros of Custom Printed Circuit Boards

Size

First things first; size is one of the most crucial factors when it comes to custom printed circuit board services. A conventional circuit board may not be able to meet the exact requirement of your electronic appliance. However, if you opt for a custom printed board, you can get not just the exact size but also the shape required by you. The advantage of space-saving, condensed circuitry cannot be overstated. This is something that you can achieve with a custom PCB.

Durability

With conventional circuit boards you may face the issue of them being broken easily. Additionally, the wiring they come with often loosens up. With a custom PCB you can rest assured that durability isn’t compromised. With accuracy and quality of custom PCBs being maintained, the reliability of the electronic device is a given.

Appearance

Since you are getting the PCB designed to your unique requirements, what you also tend to gain is the professional look and feel of the PCB. All parts are spaced evenly and there isn’t any exaggerated wiring. Besides, you could also have interesting artworks added as per your choice.

Cost

While the mutual understanding is that the cost of a custom PCB is higher than that of a standard PCB, in the long run this isn’t always true on account of the following factors:

  • Custom printed circuit boards typically require less rework and hence if you look at long term costs, you are clearly talking about cost savings.
  • Once the PCB has been designed and built, the schematics, Gerber files and bill of materials can be used to build another prototype at a low cost.
  • With the ability to recycle schematics for future iterations of the same device, you tend to save device time & cost for the future.

Some of the other advantages of custom printed circuit boards include:

  • Direct printing legends eliminates the need for decals.
  • Integrated LED lights provide easy verification of its functionality.

Cons of Custom Printed Circuit Boards

This is not to say that custom PCBs do not come with their own set of challenges, notable among them being:

  • The initial design time as also the tooling required is high. In case you are working on extremely tight timelines custom PCBs may not work well.
  • It is difficult to revise custom PCB multiple times.
  • Troubleshooting can sometimes get difficult, particularly if you have enclosures to protect the PCB from the working environment.
  • With rapid changes in PCB technology, the components can become obsolete quickly. In such cases, it becomes very hard to repair or replace them.
  • Custom PCBs aren’t particularly suited for low volume applications, particularly those that change often. In cases where your design is revised frequently or the custom low volume PCB assemblies are such that they don’t really bring a return when it comes to design or tooling costs, it isn’t an ideal option.

Are custom printed circuit boards right for your industrial requirements?

The answer to this question lies on a number of factors that include:

  • The complexity of the project.
  • The volume.
  • Your budget.
  • Commitment to quality.

While custom PCBs require a commitment to a particular design, take some time and minor upgraded cost (although it depends on your requirements). They also come with an inherent robustness, offer the ability to recycle a PCB design and significantly reduce the cost of rework. You can select the best option by analyzing your requirements.

What can an electronics contract manufacturer offer you?

An experienced electronics contract manufacturer can produce custom PCB assemblies, box builds as well as cable assemblies. They can also help test at the board level as also test capabilities of the box build, as required.

In case you already have a custom printed circuit board design available with you, a contract manufacturer can help with:

  • Assembly that conforms to industry standards.
  • Testing PCB and the components using state-of-the-art testing methods.

At Mermar Electronics, we have years of experience in custom PCB assembly. We cater to a wide range of industries and their unique requirements while following the highest quality standards and being RoHS (Restrictions of Hazardous Substance) compliant.

With consistent product quality, quick turnaround time and excellent customer service, you can count upon us to meet and exceed your requirements. Whether your requirement involves simple boards or complex multilayer ones, we offer prototyping as well as custom production facilities, catering to your volume requirements. From offering Design for Manufacturing checks to having your design manufactured, we are a one-stop shop for custom PCB production that you can rely upon.

Get a free quote by submitting your requirements via PCB assembly quote form or get in touch with us via email at sales@mermarinc.com or call us at 760/244-6149.

What’s the Difference Between PCB Conformal Coatings and PCB Potting?

By | Date posted: | Last updated: December 13, 2021
Conformal Coating vs Potting

With PCB being a crucial component of an electronic device, it is extremely important that it be protected against damage. There are 2 main methods in use to do so, namely:

  • PCB Conformal Coating
  • PCB Potting

Both these methods use organic polymers to protect the PCB. However, the 2 techniques work differently. Let us look at them in detail:

What is PCB Conformal Coating?

Broadly the process involves coating the substrate with a non-conductive material. The coating can be applied either manually or through a robotic device. A light option, a conformal coating is between 25 to 250 microns. It goes a long way in offering protection against moisture, corrosion, particulate matter and more.

There are several coating materials that are available such as epoxy, silicone compounds, acrylic, parylene and more.

What is PCB Potting?

It involves filling the substrate’s enclosure with a potting compound or encapsulation resin. Potting is largely done for the entire circuit board but can also be done for individual components.

The big advantage with PCB potting is that it provides resistance to:

  • Heat
  • Chemicals
  • Other Environmental Hazards

Some of the material used for PCB potting includes epoxy, polyurethane, and silicone compounds.

Similarities Between PCB Potting and Conformal Coating

Essentially, both potting and conformal coating use organic polymers to protect the PCB. Some of the other points of similarity between the two include:

  • Both prevent the substrate when it comes to harsh environments.
  • They offer protection against corrosion.
  • They shield the circuit board and improve electrical performance.

Pros & Cons of PCB Potting

Pros

  • Potting is quick and is easy to apply especially when it comes to high-volume production.
  • They offer more durability as opposed to conformal coatings.
  • They offer high resistance to heat, chemicals and other environmental hazards.
  • They offer protection against water.
  • With the use of dark-colored potting compounds, they offer design security.

Cons

  • It is far more challenging to repair a device that is protected by PCB potting, as opposed to one that is coated.
  • Potting causes the weight of the PCB to increase.
  • It adds to inflexibility.
  • There are a number of steps that need to be followed when it comes to potting.
  • It comes at an excessive cost.

Pros And Cons of PCB Conformal Coating

Pros

  • Since conformal coatings are thin, they work well when tolerances are tight.
  • On account of their translucent quality, they work well as the item is visible.
  • It offers protection against corrosion.
  • It does not increase the weight of the device too much.
  • It is extremely durable.
  • It comes at a low cost.
  • PCBs with conformal coatings aren’t challenging when it comes to repair or rework.

Cons

  • Coating does not offer the same level of durability as potting.
  • On account of the same, it cannot offer full proof protection.

What works better – PCB potting or PCB conformal coating?

The choice of the right option depends upon the PCB assembly application and the device’s intended use. Additionally, the conditions in which the device has to function is also an important determinant of the methodology that should be put to use. Some of the other considerations to be kept in mind include:

  • The elements in the external environment that the device will be subject to.
  • The design of the enclosure where the PCB will be housed
  • Is there any other protection from environmental factors?

Clearly then in choosing PCB conformal coating versus potting, the choice of selection will depend upon the PCB’s purpose. Elements such as durability offered as also the increase in weight are some of the crucial factors that will help you make your choice.

Use cases for both PCB Potting and PCB Conformal Coating

Typically, PCB Potting works well in the following use-cases:

  • Heavy-duty applications.
  • High-voltage electrical devices.
  • Power plants, mines, and other environments with extreme conditions.
  • High-volume and high-speed production environments.

The use cases for PCB conformal coating, on the other hand, include:

  • Sensitive components and devices.
  • Smartphones and other handheld electronics, since it offers a thin application and is light weight.

At Mermar Electronics, we are extremely committed to not just fabricating quality PCBs but also keeping them well-protected with our high-quality PCB conformal coating services and PCB potting services. Simply put, it is extremely important as it protects the PCB against any environmental hazards.

You could get an instant quote on submitting your custom requirements. You could also write to us at sales@mermarinc.com or call us at (760) 244-6149 for nay clarifications. We will be happy to hear from you and offer bespoke solutions.

What are the Most Significant Benefits of Multilayer Printed Circuit Boards?

By | Date posted: | Last updated: January 12, 2022
Multilayer Printed Circuit Boards

The demand for multilayer printed circuit boards is ever increasing, led largely by the need for compact, miniature, and lightweight appliances that offer sophisticated functionality.

Before we look at the many advantages that multilayer PCBs offer, it will be worthwhile to understand what a multilayer PCB really is.

What is a Multilayer Printed Circuit Board?

As its name suggests, as opposed to a single layer board, a multilayer board contains three or more layers of conductive material. Other layers, often comprising of often copper foil, stack on this core. They are clearly more complex than, single-sided or double-sided PCBs. A single layer printed circuit board has a single layer of conductive material while a double-sided one functions with more layers than a single layer board but fewer than a multilayer PCB.

Advantages of Multilayered Printed Circuit Boards

The significant benefits offered by multilayered PCBs include:

  • A significant increase in functionality with the incorporation of multiple layers. Multilayer boards result in high-quality, reliable products.
  • With the extra layers what opens up is added real estate. Signal and power traces can be shifted to the internal layers where there is space for direct connections. What it also does is frees space on the board’s external layers for additional components.
  • On account of their innate electrical properties, they offer high capacity and speed. They also solve electrical performance issues such as:
    • EMI Shielding: It is possible to configure the layer structure so that multiple ground planes are included. In turn, these ground planes act as a shield against electromagnetic interference.
    • Signal integrity It is possible to configure multilayered boards with microstrip and to sandwich high-speed transmission lines. In turn, these ensure better signal paths as also reduce noise.
    • Power integrity: With full metal power and ground planes power is distributed well. Besides the planes also absorb any power spikes.
    • Thermal control: Multilayered boards ensure heat dissipation throughout the board layer stackup.
  • They significantly reduce the need for multiple connectors. Not only does this result in simplifying construction, importantly, it also results in reducing its weight.
  • Multilayer PCBs also lend themselves to both rigid and flexible boards.
  • The high density also results in increased durability.
  • The boards lend themselves to stringent testing processes resulting in a high quality product.

By contrast, single layer PCBs face the following challenges:

  • They are suited for use in simple electronic devices and hence aren’t too versatile.
  • Often, they aren’t as durable as multilayered ones.
  • They do not offer the speed that their multilayered counterparts do.
  • They are rather restricted when it comes to their circuit design.

This is not to say that multilayer PCBs do not come with their own set of challenges, primary among them being:

  • Since specialized processes are involved in the manufacturing of multilayer printed circuit boards, the cost involved is higher than that of single and double-layered boards.
  • On account of the sophisticated functionality, there is the need to conduct extensive tests when it comes to multilayered boards.
  • The complexity of boards can also have an impact on the manufacturing cycle.
  • Repair of a multilayer PCB can prove to be difficult. In case of failure therefore, there may be the need to replace the board.

Needless to mention, however, that these issues not withstanding, the usage of multilayered PCB is only slated to grow.

Uses of Multilayered Printed Circuit Boards

On account of the significant advantages that multilayered PCBs offer they find extensive application in a range of appliances including but not limited to:

  • GPS and satellite systems
  • Computers and ancillaries
  • Medical Devices
  • Military use
  • Consumer products
  • Home monitoring equipment
  • Industrial controls, and more.

Processes for Manufacturing Multilayer Printed Circuit Boards

Manufacturing of multilayer PCBs involves the following processes with utmost quality assurance:

  • Combining alternating layers of prepreg and core materials into a single unit. Heat and high pressure is used to ensure uniform encapsulation of conductors.
  • Careful drilling of holes among the various layers. It is important to ensure symmetrical layout across layers. This ensures that there isn’t a chance of twisting when heat and pressure is applied.
  • In identifying the right fabricator, it is important to understand their capabilities. It is imperative that Design for Manufacturing Techniques (DFM) be followed by the fabricator so that there aren’t any costly errors at a later date.

It is imperative to go with a fabricator who has the necessary expertise and experience who can balance the layers in the board stack-up as also analyze how the configuration of the multilayered board will impact the signal integrity of the PCB design.

Mer-Mar Electronics is an ISO 9001:2015 certified company and ITAR (International Traffic in Arms Regulations) compliant manufacturer that delivers multilayer PCB assembly with specialized support, reliable testing, and multi-functional features. Our consistent quality and quick turnaround endear itself to our customers, who look on us as a one-stop-shop for all their PCB requirements. In case if you have any questions or require more information about multilayer PCB assembly and fabrication services, get in touch with us via sales@mermarinc.com or call us on (760) 244-6149.

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