Practical guidelines on PCB thermal relief for efficient PCB manufacturing!

By Mer-Mar Electronics | Date posted: | Last updated: October 17, 2022
PCB Thermal Relief Guidelines

When it comes to the efficiency of a circuit board, managing and conducting heat efficiently is extremely important. Whether your PCB is a single layer, simple PCB or a complex multi-layer printed circuit board, it is likely to have large areas of metal on it. This large metal area, whether it is a network of wide traces or a large, filled power plane, can, in turn, cause issues with soldering. Some of these include:

  • Through-hole component pins: If these pins do not get enough heat for soldering, you can land up with a cold solder joint. What could also happen is that if you try to unsolder a through-hole, you could land up applying too much heat on it. In turn, this heat can damage components and/or traces.

  • Surface mount component pins: In two-pinned SMT parts there could be an issue if there is unbalanced metal between the pins. In such case the solder could melt faster on one side than the other. This could move the part away from the other pin.

With design engineers wanting to use a lot of metal for electrical purposes, what you typically see is a conflict between the board’s electrical needs and its manufacturing requirements. Thermal relief is therefore the need of the hour.

For through-hole component pins, thermal relief can be offered by way of a connecting pad with small voids in it. These voids create metal spokes that, in turn, restrict the heat that is conducted from the barrel of the hole during soldering to the rest of the metal trace. In case of a surface mount part also spokes are used to connect the solder pad to the metal trace.

Here are some practical guidelines for PCB thermal relief, which if followed effectively, will lead to efficiency of the custom printed circuit board:

PCB Thermal Relief Guidelines:

  • A thermal relief pad is used wherever a through-hole pin is connected to a metal or power plane.
  • Where SMT parts are soldered to large metal areas, there needs to be thermal relief between their solder pad and the metal.
  • The amount of power conducted by the pin determines the number as well as the width of spokes in a thermal relief pad. For example, if the power needs a minimum trace width of 30 mils, you need to ensure that the thermal relief pad should have 30 mils of spokes attached to it.
  • Vias typically do not need a thermal relief pad as they do not have a pin soldered to them. However, in case of nets with high current levels, there could be power traces that conduct too much heat to the surface mount pins. In such cases a thermal relief pin is needed.
  • It is imperative that the rules of setting up thermal relief pads in CAD systems are fully understood. Basis the rules, you will need to work out the following:

    • Size of spokes
    • Its shape
    • Number of spokes
    • Width of spokes
    • Minimum spokes possible
  • It is also important to adhere to rules to do with minimum thermal relief connections. There can be issues if the thermal relief pads are too close or if they are being used in a split plane.
  • Ensure that you know the terminologies associated with components and pads such as:

    • Termination and termination width
    • Tolerance
    • Overlap

A thorough knowledge of the underlying rules before you start the layout can go a long way in ensuring success. In fact an experienced electronic contract manufacturer can go a long way in helping you with these issues. Not only will the contract manufacturer know what is needed with thermal relief to create good solder joints, they are also aware of any issues that you may face based on the material used, the layers as well as the manufacturing processes.

To sum up

Thermal relief makes a huge difference in the functionality and performance of the circuit board. Reliable PCB manufacturers have the skills and the expertise to determine what kind of thermal relief your design needs. They can therefore suggest the alternatives depending on viability as well as cost-effectiveness of the various alternatives.

As a leading electronic contract manufacturer in USA, we provide one stop solution for electronic contract manufacturing services with specialized support, reliable testing, and multi-functional features. To know more contact us at or call us on (760) 244-6149.

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Questions to Ask a PCB Manufacturer Before Hiring Them

By Mer-Mar Electronics | Date posted: | Last updated: March 7, 2023
questions to ask a pcb manufacturer

When you need something as critical as Printed Circuit Boards for your electronic product, the ability to ask the right questions can be a game changer. First things first, asking the relevant questions will help you find out the manufacturer’s capabilities and whether they suit your requirements. Areas such as quality, processes, certifications held can be assessed at this stage. Importantly, it will also lead to a healthy exchange of ideas. A professional PCB manufacturer will be armed with industry best practices that will ensure you do not have to reinvent the wheel.
Let us look at some critical questions to ask a PCB manufacturer that will help you build confidence that you will receive a quality product:

Questions to ask a PCB manufacturer

Question to ask PCB assembly manufacturer

1. Which PCB files are required before starting assembly/fabrication?

While this may sound like a trivial question, it is anything but that. It is essential to be on the same page as the manufacturer to avoid communication errors. Ensuring that information is sent in a format that the manufacturer can read is a critical piece when it comes to manufacturing the final product.

2. Can you source all my materials for me?

This is a rather critical question as sourcing the components keeping lead times in mind, can make or break your project. With time-to-market being a critical piece when it comes to competitive advantage, this is a must-check piece. A professional manufacturer will also have ongoing relationships with component suppliers helping him achieve economies of scale. The right sourcing, therefore, will help you control costs & improve cost-efficiency.

3. Is there any refund policy?

It is best to check if the contract manufacturer has a refund policy & if so, what does it entail. That way you can be prepared for eventualities.

4. Can you work with my board specifications?

The technology that they use, their ability to review boards & product designs and more are all crucial elements in determining whether they will be the right partner in your project.

5. How do you test PCB?

Error detection is especially important, especially as the electronic device’s functioning depends on the PCB’s working. A robust discussion on the efficiency & effectiveness of the PCB therefore needs to focus on the quality control procedures adopted.

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6. How long will it take you to validate the BOM (Bill of Materials)?

This is a critical question as validating the BOM as also sourcing the components keeping lead times in mind, at the right cost, can make or break your project. With time-to-market being a critical piece when it comes to competitive advantage, this is a must-check piece.

7. What is the company’s manufacturing policy & what makes you unique?

An in-depth analysis will help you understand what their competencies are. You could be dealing with manufacturers that place a premium on quick deliveries & low costs. On the other hand some manufacturers may pride themselves on the fact that they undertake a through stakeholder analysis & hence can customize the product.

8. Can you explain your full PCB manufacturing process?

Process control is an especially important aspect of maintaining PCB quality. It will, therefore, be worthwhile to understand the detailed process & sub processes of manufacturing. These processes, must in turn, match the design specifications that you have- whether it is creating multilayered boards, drill vias or apply the required finish. If you need a PCB for an aerospace or medical application, for example, which is mission critical, you may also want to spend time discussing the specific board cleaning procedures.

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9. Does any part of their process take place offshore?

This is an oft missed but important question. You may not be comfortable with an offshore process as that could have quality implications. Also, it could have a bearing on the shipping costs as well as your timelines.

10. Is your quality management system (QMS) in compliance with ISO 9001?

Check compliance with proven quality management standards like ISO 9001 is imperative. If the manufacturer is in complaint with ISO 9001, you can rest assured that they follow a robust quality management system that is comprehensive and that includes but is not limited to operations, support, performance management & more. Additionally, you may also want to check for compliance with RoHS standards in the manufacturing process.

11. What kind of experience do they have when it comes to the circuit board technology required by you?

It is imperative that you map the contract manufacturer’s capabilities with your own bespoke requirements. While most contract manufacturers may be able to deliver a standard circuit board requirement, if you need a hybrid or flex PCB design or if your circuit board must operate under harsh environmental conditions, you need to make sure that the contract manufacturer can do justice to your requirements.
Similarly, if you want to have a prototype developed, you will want to make sure that the contract manufacturer deals with prototype quantities. You also want to know that they are agile to any changes required in the prototype. Going forward, when you want to get into a full production run, you want to make sure the contract manufacturer can handle that too.
Additionally, a fair idea of their facilities and equipment can give you the confidence you need to know that they will be able to handle your circuit board requirements.

12. What certifications do they carry?

If there is one thing you cannot sacrifice when it comes to custom printed circuit boards, it must be quality. Particularly in mission-critical operations, you cannot risk circuit board failure as you cannot afford to have any downtime. To have a fair idea of the contract manufacturer’s commitment to quality, it will be good to look for their certifications. You would want to find out if the contract manufacturer has ISO 9001 certification. Beyond this, you may want to look for specific certifications depending on your industry, whether it is medical equipment or industrial electronics. You would also like to find out if the contract manufacturer conducts regular training programs for its staff and if they keep their certifications up to date. These will be the much-needed confidence boosters for you before you hand over your project.

13. What engineering resources do they have?

Particularly when it comes to developing prototypes and new product introductions, engineering expertise is invaluable. The following expertise is a must-have, not just good-to-have:

  • Component engineering
  • Purchasing agents
  • Design engineering
  • Layout engineers to ensure adherence to design for manufacturing requirements
  • Test engineering
  • Documentation control

14. What kind of customer handling do they display?

It will be great to deep dive into the contract manufacturer’s process controls as well as their handling of problems and changes. The kind of communication protocols that they follow and how they keep the customer updated on progress are all issues that you need to be aware of at the outset, to avoid any rude shocks later.

15. What kind of company culture do they have?

Last but definitely not least, it is fairly important to determine if the contract manufacturer broadly has the same business values and ethics as you. With common value systems, it will be much easier to work together without any friction.

Points to Note While Choosing PCB Manufacturer

  • Shipping time
  • Quality
  • Support
  • Their PCB technology and machine

To Sum Up

A professional PCB manufacturer can go a long way towards the success of your product. From making recommendations to the design team to ensuring prototype requests they can handle such requests deftly. It is incisive questioning that can determine whether they are equipped to handle all such issues.

With over 4 decades of experience, we provide fast and reliable PCB manufacturing services. Mer-Mar Electronics has become the go-to solution for all kinds of PCB assembly and manufacturing service and highly appreciated by various industry leaders for quick turnaround time, error-free, and consistent quality for small to large volume services in the USA. All the applications are carefully manufactured with specialized support, reliability testing and certified workmanship.

Get a free quote by submitting your requirements via printed circuit board quote form or get in touch with us via email at or call us at 760/244-6149.

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FR4 Printed Circuit Boards In Electronics Application – How to Choose Right one?

By Mer-Mar Electronics | Date posted: | Last updated: September 14, 2022
FR4 Printed Circuit Boards

PCBs are an integral part of all electronic appliances. The choice of right material for the PCB however, depends on several factors including the environment in which the PCB has to function. Of the many materials used to make custom printed circuit boards, FR4 has emerged as a popular material. Not without reason. Here are the many reasons and aspects of FR4 that you need to know to be able to make the right FR4 PCB:

What is FR4 PCB Material?

FR4 is a fiberglass-reinforced epoxy laminated sheet, with the FR in FR4 standing for flame retardant. On account of fiberglass, material is known for its structural stability. The fiberglass, in turn, is covered with flame-resistant epoxy resin. FR4 is known for its strong mechanical properties as well as durability which explain its widespread use.

Examples of FR4

  • Standard FR4: It is known for its heat resistance of the order of 140°C to 150°C.
  • High TG FR4: It has a higher glass transition (TG) of around 180°C.
  • High CTI FR4: Its Comparative Tracking Index is higher than 600 Volts.
  • FR4 with no laminated copper: It is ideal for insulation plates and board supports.

Properties of FR4 Material

Let us look at some of the other properties of FR4 material that result in its widespread popularity:

  • It has high dielectric strength and hence high electrical insulation properties.
  • It is known for its lightweight and thus finds extensive use in today’s environment where miniaturization is key.
  • It is moisture resistant and finds use in a wide variety of applications where moisture in the environment is a given.
  • It is known for its cost efficiency. Other laminate material like ceramic or Arlon comes at a higher price and can impact your overall project.

FR4 PCB Types Based on Classification

FR4 printed circuit boards are classified based on several attributes. Some of these include:

1. FR4 PCB Thickness

While the standard FR4 thickness is 0.78 mm, it is available in a wide variety of thicknesses. Copper-clad FR4 boards are available in 18µm to 140µm

2. Source of FR4 Material

FR4 Printed Circuit Boards are available in types such as Rogers FR4 PCB, FR4 Isola PCB, and more basis the manufacturing companies.

Thermal Properties of FR4 PCB

1. Glass Transition Temperature

The standard FR4 material has a glass transition temperature of 130 to 140 centigrade. However, factors such as coefficient of expansion, dielectric value, and others determine its standard nature.

The glass transition temperature value of an RF4 material determines the kind of application in which it can be used. An FR4 that has a high glass transitional temperature can withstand far higher frequencies. Such material can also withstand high operating temperatures.

2. Decomposition Temperature

It is the temperature at which the FR4 PCB sheet is permanently decomposed. The FR4 Printed Circuit Board decomposition temperature comes at the highest TG value of 180 degrees centigrade. Beyond this point, the FR4 changes its chemical properties permanently.

How to Select the Right FR4 Material for Our PCB?

Here’s how to make the choice of FR4 material for your PCB:

  • Thin FR4 material comes in handy where you have a space constraint. Not only can the thin material support delicate components, but it also works well for space-saving designs.
  • Once again thin FR4 material works for applications that demand flexibility. It is therefore widely used for automotive and medical PCBs.
  • On the other hand, for designs that have grooves, thin material needs to be avoided on account of the high risk of damage.
  • Needless to mention that the thickness of the material impacts the weight of the PCB. Where miniaturization and a lightweight electronic appliance are a requirement, thin FR4 boards need to be chosen.

To Sum Up

With a wide variety of FR4 materials available in the market with diverse capabilities, it is easy to choose the right PCB material that suits your bespoke needs. The boards created using FR4 material are strong, durable, and water-resistant besides offering insulation, reducing interference, and backing excellent signal integrity. Your PCB Contract manufacturer will be in the best position to guide you through your choices.

Our experienced PCB material management team and advanced material management system can efficiently manage your projects and requirements. We have the resources available to locate the parts and materials you need to eliminate the delay and reach quickly to the result.

Request a quote to inquire about our PCB assembly and manufacturing services.

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What’s the Difference Between DFM, DFA & DfMA?

By Mer-Mar Electronics | Date posted: | Last updated: January 13, 2023

With a large percentage of production costs being determined by design decisions, it stands to reason that Design for Manufacturing has become a huge role in manufacturing. With help of proper DFM, DFA and DFMA process companies can produce high-quality product too. So, let’s talk about all three terms and find difference between DFM, DFA and DFMA.

Difference Between DFM DFA & DfMA

difference between dfm and dfma

What Is DFM

DFM stands for Design for Manufacturing which is a design method that goes a long way in reducing the complexity of manufacturing operations. It also has a positive implication on the overall cost of production including the cost of raw materials.


DFA stands for Design for Assembly which is a design method that facilitates the assembly operations of components of a product.


DFMA stands for Design for Manufacturing and Assembly which is an engineering technology or method that prioritizes both ease of manufacture as well as simplified assembly of the parts, during the early design phases of the product lifecycle. It, therefore, helps bring down time-to-market as well as total production costs. As a singular philosophy, it brings together what was so far considered to be two distinct methodologies, namely DFM & DFA.

Reduce Manufacturing Costs Through DFMA

How DFMA reduce PCB cost

Given that DFMA is a comprehensive, balanced approach that combines DFM & DFA practices, let us look at what are some of the main levers when it comes to reducing PCB manufacturing costs through the DFMA approach.

1. Reduction in Number of Parts

Reducing the number of parts not only reduces the cost of PCB assembly, it also has an implication of a number of other costs including but not limited to:

  • Administrative and logistical costs
  • Cost of testing and reliability

2. Using Standard Parts

Using standard parts as opposed to customized ones can prove to be more cost-effective. The fact that they are easily available also adds to ease of production.

3. Adopting a Modular Design

The use of modules offers a wide range of benefits including:

  • Reducing the number of components. This also reduces the indirect costs.
  • Reducing redesign costs by using existing modules.
  • Taking advantage of production scale for modules that are common.

Modularity, however, is limited by the increase in PCB assembly costs with an increased number of connections.

4. Designing Multifunctional Parts

Use of a multifunctional part reduces the need for an increased number of parts.

5. Error-proof Parts

This involves designing parts that cannot be assembled in the wrong way or be assembled on other products.

6. Designing Parts to facilitate Assembly

Parts can also be designed to facilitate assembly as well as testing.

7. Limiting Tolerance Constraints

It is important to ensure that the binding tolerances are reduced, and any over-specifications aren’t followed, as these could result in higher costs on account of the following:

  • Need for more robust processes.
  • Need for sophisticated equipment.
  • Need for extensive quality control.

8. Limiting Fasteners

As a thumb rule, separate and complicated fasteners need to be limited as they increase costs.

9. Facilitating Handling

The parts need to be designed in a manner such that they are easy to handle. Sharp edges, parts that are too large etc. for example are best avoided from the handling perspective.

10. Reducing Assembly Directions

Wherever possible all the parts need to be assembled in one direction.

DFMA Methods

There are a wide variety of methods that aid DFMA. Noteworthy among the following are:

  • Collaboration between design and manufacturing teams. It is important that all stakeholders are a part of the process so that there are no last-minute surprises.
  • Design for Testability, to ensure that it is easy to test while in production. This is often a part of the Design for Manufacturing mandate.
  • Design for Maintainability, which ensures easy, less costly maintenance for manufacturing equipment and which ensures there is no downtime.

To Sum Up

DFMA, a combination of Design for Manufacturing (DFM) and Design for Assembly (DFA), enables a product design to be efficiently manufactured and easily assembled with minimum labor cost. Through the use of DFM best practices as well as DFA, a company can do the following:

  • Prevent manufacturing inefficiency.
  • Eliminate waste.
  • Not dealing with costly errors.

For effective application of DFM/A, the two activities must work together to ensure success.

Mer-Mar Electronics is one of the leading PCB design and manufacturing companies, providing all in one PCB assembly and fabrication solutions. Our consistent quality and quick turnaround endear itself to our customers, who look on us as a one-stop-shop for all their PCB manufacturing requirements. In case if you have any questions or require more information about PCB assembly and fabrication services, contact us via or call us on (760) 244-6149.

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