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Top PCB Design Consideration for Aerospace Assembly and Military Grade PCB!

By | Date posted: | Last updated: March 22, 2021

Aerospace assembly and military PCBs are expected to be tough and reliable and there is no room for any error especially when the systems are mission ready. Imagine your system results in a technical glitch during critical mission operations. This would have some serious repercussions and damage beyond measure, isn’t it? You need not only quality systems but also reliable, secure, and strong that show the same performance for a longer time.

This isn’t as easy as it seems, in fact, it is quite challenging to manufacture and deploy PCBs for military and aerospace when compared to commercial applications. Deep knowledge and understanding of what entail in the high-reliability circuit boards are essential for the longevity of the products. Most people find it difficult and hence focus on finding an electronic company that maintains quality standards and has enough experience to handle the design demands of these projects.

Before we discuss some design considerations, remember one cardinal principle – keep learning! Yes, there is always something new out there – new technologies, new working processes, or new testing options. If your aim is to produce high-quality products, install innovation at every step. Ok, let’s get started.

1. Prepare a quick Layout of PCB Designs

Designing for PCB military and aerospace assembly involves a wide array of design options, materials, and carefully curated manufacturing processes. Before you jump into the design, understand how harsh environments wreak havoc on your PCBs and prepare some tips to safeguard them from being ruined. This ensures reliability and safe-operating boards for the years to come. You can get quick sketches of the designs before they hit the production floor.

2. Construction Materials

Aerospace and military grade PCBs must be strong, durable, and reliable to the extreme temperatures and harsh conditions. A PCB manufacturer must be skilled and have expertise in different materials, composites, and substrates. Materials like aluminum and copper can be used to withstand extreme heat. Anodized aluminum is also used for minimizing the heat-induced oxidation effects.

3. Coating and Surface Finishes

Special surface coating and finishes are mandatory during PCB Assembly for military and aerospace applications. This acts as a protective shield in harsh environmental conditions like heat, humidity, vibration, and water. You can also use thermal compounds that will insulate components, protect them from heat, and reduce vibrations that result in solder cracks. Use high-quality acid or acrylic-based sprays can be used to coat the boards. Another option is using immersion silver for surface finishes.

4. Through-hole PCB Assembly

Through-hole technology (THT) is the best way of mounting during PCB assembly as boards manufactured with THT are highly durable. This is due to the soldering from both the top and bottom of the board that creates very strong physical bonds between both the board and components. Your PCB manufacturer must be able to minimize vibrations while mounting the components.

5. Meet High Standards

Military and aerospace electronic products typically need to meet high standards for better performance. For instance, IPC, the global trade association that has been serving the PCBs and electronic assembly industries has laid down the IPC-A-610E standard for high-performance products. Its goal is to make sure there is no downtime, no critical issues in end-use environments so that the equipment works well under all harsh environmental conditions.

6. Less about design and more about PCB Manufacturing

Yes, you heard it right! When your aim is to build robust products that are less prone to failure, manufacturing details matter the most. Different manufacturers design the same products with subtle changes and hence it’s not always about design. Your PCB designs should fit the manufacturing process for yielding better results. You can use automated tools for identifying the differences between the components and designers can also verify that the manufacturer’s methods will not result in performance compromises.

7. Avoid Counterfeit Parts

Counterfeiting can lead to product failures and revenue loss which would affect the PCB assembly process critically especially when you are fulfilling military and aerospace contracts. You can avoid counterfeiting by choosing a proper PCB contract manufacturer who is well-versed with the procedure and practices certified processes such as avoiding fraudulent distributions and doing source assessments. They should have a trusted and well-vetted chain of suppliers to guarantee the quality of PCBs.

8. Qualified PCB Manufacturer

The PCB manufacturer you choose must have the capabilities and necessary certifications for handling military and aerospace electronics systems. The certifications are indicators of your CM’s commitment to quality. For instance, the International Traffic in Arms Regulation (ITAR) regulated by the Department of State is required for military and aerospace appliances. It mandates that your PCBs must adhere to the updated guidelines to reflect changes in the current technological trends, political as well as security climates. Any sensitive information relating to the design and production of these intelligence devices should be protected. This degree of security ensures trust in the manufacturer.

9. Test with DFM

The Military and aerospace PCBs should be tested with Design for manufacturability (DFM) after making even the slightest of the changes. You can use x-ray tests as the standard for all your military and aerospace electronics. Device a test strategy for your PCB designs that suits your time and budget. Are you considering physical tests like the Highly Accelerated Life Test (HALT)? Beware that it will destroy your prototype. Choose alternatives like virtual HALT simulation and run a few test iterations.

10. Identify your Failures

While running the tests, the focus should be on analyzing the results for understanding the defects and finding out the source of the defect. Allot time and effort to analyze real-time failures of your products and establish some working methods to prevent these failures to be recurring in the future. It is important to investigate the cause of failure starting with the source of the failure and observe how they behave under different simulations. You can also rely on data mining to understand the stability of your designs. Instead of focusing on the immediate and short-term solutions, drive your efforts on conducting research and finding conclusions. This comes in handy even for your future designs.

Conclusion

The military and aerospace electronics industry should show fewer product failures and uncompromised quality as design complexities increase. Measures should be taken to build stable and high-quality products within the stipulated time. How to go about it then? The decision in this direction starts with picking up the right electronics company that has adequate experience in designing a tough product.

Mermar Electronics is one such organization that has highly skilled engineers building high-quality printed circuit boards, assemblies, prototyping, fabrication, turnkey PCB assemblies with proper design considerations. You can count on us to meet and exceed your Aerospace PCBs needs. We are ever committed to staying ahead of the curve, when it comes to meeting the growing demand for evolved PCBs.

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Top Factors affecting Military and Aerospace PCB assembly process!

By | Date posted: | Last updated: March 20, 2021
Aerospace Printed Circuit Board Assembly

Military and Aerospace are the two industry sectors that require the most sophisticated electronic components and applications. PCB systems used in both these industry sectors need to deliver superior performance, reliability, and high precision as these are exposed to extreme and harsh environmental conditions and contaminants. To maintain high performance and ensuring zero downtime, these systems are mandated to adhere to IPC standards. Hence, PCB manufacturers have been committed to delivering PCB components with high precision and detail-oriented.

This is just the tip of the iceberg, there are many factors that have been influencing the PCB assembly process. Military and aerospace PCBs require special attention throughout the process of fabrication, design, assembly, and deployment.

Let’s get started to know more.

Before delving into the factors affecting military and aerospace applications, let us quickly see the industry applications of PCBs in both the military and aerospace sectors.

Military Industry Applications Using PCBs

PCB designs for military applications need to be mindful of the expectations like longer product lifecycles, extreme temperatures, and use cases. They are expected to be more robust, rugged, reliable than normal products. PCBs used in military applications also require strict design constraints.

  • Defense navigation and communication systems
  • Satellite subsystems using embedded processors
  • Cyber counterintelligence systems
  • Automatic search jamming systems
  • Base protection and security
  • Command and control systems
  • Artillery and mortars
  • Cryptanalysis systems
  • Robotic systems
  • Unmanned vehicles
  • Ruggedized computers

Aerospace Industry Applications Using PCBs

  • Digitalized signal and microwave processing systems
  • Full Authority Digital Engine Control Systems (FADEC)
  • Advanced Medium Range Air to Air Missiles (AMRAAM)
  • Electronic flight instrumentation systems
  • Central Air Data Computers (CADC)
  • Satellite equipment
  • Ground station applications
  • Passive detection systems

Factors Affecting Military and Aerospace PCB Assembly Process

Nature of Construction Material

PCB assemblies used in both these industry sectors must be resistant enough to withstand high temperatures as aluminum and copper substrates which are high-temperature laminates are used in PCBs for military and aerospace applications. Of late, anodized aluminum is also used to minimize the heat-induced oxidation effects. These varied aluminum substrates when used in conjunction with thermally conductive pre-pegs are known to offer weight benefits.

Avoid Thermal Dissipation

Did you ever notice some components on your PCB dissipating heat in high proportions? Quite often, isn’t it? This heat would damage the PCBs unless dissipation is controlled. you can mount the components about 20 MILs from the board surface. Alternatively, you can also use a spacer between the component and the heat sink which provides an adequate clearance to protect the PCB components and surface. These strategies are successful in controlling heat dissipation in military and aerospace PCBs. This, in turn, increases the reliability aspect of the PCB.

Reduction of EMI and Attenuation

Have you ever wondered why we dip a stranded wire into the hot melted solder during the PCBA for military and aerospace applications? It is left to dry and then solidified for achieving tensile strength. In this process, a stranded wire is transforming into a solid wire with the elimination of air gaps to facilitate stable air flows. This entire process improves the reliability of military and aerospace PCBs while reducing the impacts of Electromagnetic interference (EMI) and attenuation.

Conformal Coating and Surface Finish

The very nature of military and aerospace applications is that they are subjected to harsh environmental conditions like constant exposure to moisture, extreme temperature, humidity, and water. So, to safeguard the PCB components, your applications go through the appropriate conformal coating. Usually, acid-based sprays are used for this purpose, but there are other types of surface finishing and coating as well like HASL, ENIG, immersion silver, etc.

Lead-free PCBs

Lead alloys usually melt at low temperatures that cause damage to electronic components during the assembly process. However, lead is known for its reliability. So, some military applications still use lead-based PCBs. But things have started to change, many electronic manufacturers have been making a switch to lead-free PCBs owing to the damage concerns, harmful effects on human health as well as environmental concerns.

Minimize Vibrations

While durability, reliability, and strength form the cardinal principles of military and aerospace applications. PCB manufacturers should be able to minimize vibrations while mounting the components. Through-hole technology is hence considered to be the best way of mounting during the PCB Assembly process as PCBs manufactured through THT are considered to be extremely durable.

Extra Cushioning

PCBs that are used in military and aerospace applications must use mil-spec components that have tighter tolerances of 1 to 2%. This is because, quite often, PCB designs in military circuitry get a high current flow that is beyond commercial grade circuitry. You need to add an extra cushion to make sure that the products or applications do not fail under any extreme conditions. This extra cushion is to augment strength and efficiency.

Other Design Considerations

Also, follow the design considerations to meet IPC standards.

  1. Design the PCBs that can handle the maximum power load.
  2. Differentiate low-frequency components from high-frequency to lower the impact of the waveforms produced by the high-frequency components on the low-frequency ones as these may disrupt the signal quality by unnecessary noise which is a big NO for military and aerospace applications.
  3. Shield the clock signals and keep them clean by resorting to physical shielding using some material enclosures such as aluminum ones.
  4. Use thermal compounds when you need heat dissipation.
  5. Increase clearance space when you are mounting the high heat-producing components to protect the nearby components and PCBs from over-heating.
  6. Pre-tin the braided and stranded wires for improved solderability.
  7. Use high-quality heat-resistant materials to make the metallic core components withstand high temperatures.
  8. Use finishing materials like an electrolytic nickel with Immersion gold coating (ENIG), lead-free HASL, Immersion silver, electrolytic nickel, and gold, etc. to support the PCBs to withstand harsh environmental conditions.
  9. Acrylic-based sprays should be used in conformal coating for protecting the PCBs
  10. For smooth power transmission through the circuit, maintain PCB routings at 45-degree or lesser angles.
  11. High-quality simulation programs should be used to verify the loads at varied locations to understand any PCB design alterations to be made.
  12. Make sure the PCB components manufactured for military and aerospace comply with – Performance standards – MIL-PRF-38534, MIL-PRF-38535, MIL-PRF-55342, MIL-PRF-55681, and MIL-PRF-123, MIL-PRF-50884, MIL-PRF-55110, and MIL-PRF-31032 – Testing standards – MIL-PRF-19500, MIL-STD-883, MIL-STD-750-2, MIL-STD-202G
  13. Solder the press-fit components to avoid vibrations
  14. You can avoid component damages by rechecking the thermal profiles for the wave and reflow the soldering process.
  15. Understand how your PCB works in real-time through pre-layout simulations.

Conclusion

If you want to have a highly curated PCB assembly process, then we recommend you to get them sourced from a certified manufacturer. Mermar electronics provide PCB assemblies for diverse industry sectors including military and aerospace. We ensure utmost-precision and high-performance PCB assembly services to meet the exact specifications for these industries.

Mermar electronics has successfully earned and maintained its ITAR certification. Mermar Electronics is your one-stop solution for Aerospace Electronics services from PCB Prototyping, PCB Assembly, PCB Fabrication, Quick Turn PCB Assembly, Cable Harness Assembly, SMT PCB Assembly, Low Volume PCB Assembly, High Volume PCB Assembly, Full and Partial Turnkey Assembly, Electromechanical Assembly, Multilayer PCB Assembly, PCBA Rework and all the way to Box Build Assembly. All Our PCB assemblies are proudly made in USA. Get in touch with us today to see how we can assist with your next project.

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What are the Advantages of RoHS Compliant PCB Assembly & why it is different from Others?

By | Date posted: | Last updated: April 20, 2021
RoHS PCB Assembly

The one thing, manufacturers of PCB Assembly have been increasingly contending with, is the rising concerns about the use of hazardous materials as well as the environmental impact that accrues on account of it. It isn’t surprising, therefore, that all over the world, new and stringent regulations are being imposed to deal with this growing issue. One such important legislation is to do with the Restriction of Hazardous substances or RoHS compliance, as it is popularly called.

If you are keen to know what exactly does this compliance entail and importantly what are its benefits, then you are at the right place. Read on for the complete details:

History of RoHS Compliance

The compliance came into effect in the European Union and prohibits the use of hazardous substances in electronic production. The directive came into effect as of July 1, 2006. What it means is that if you sell any electronic products or PCBs in the European Union, you need to adhere to this regulation.

Simply put, to be RoHS compliant as a manufacturer, the use of the following 6 materials in PCBs and other electronic items, have been restricted.

  • Mercury
  • Lead
  • Cadmium
  • Hexavalent Chromium
  • Polybrominated Diphenyl Ethers
  • Polybrominated Biphenyls and Phthalates

The maximum levels of these restricted material is also specified in the regulation. The limits are as below.

  • Mercury should not be more than 100 ppm
  • When it comes to Lead, the limit is 1000 ppm
  • For Cadmium it is 100 ppm
  • Polybrominated Biphenyls are restricted at 1000 ppm
  • For Hexavalent Chromium, the limit is again set at 1000 ppm
  • Polybrominated Diphenyl Ethers are set at 1000 ppm
  • For Phthalates also the limit is 1000 ppm

When you have a RoHS compliant PCB Assembly, you can offer a whole lot of services that are distinct from others. Some of the main distinguishing features of such a PCB Assembly include:

  • Lead-free surface finishes
  • ROHS compliant substrate materials such as S410, Polyclad 370HR. These, in turn, assure standard performance
  • Primary and secondary services such as lead trimming

The important bit, is also to know what are the benefits that accrue from having a RoHS complaint PCB Assembly. Some of these include:

Environmental Impact

The big advantage of a RoHS PCB Assembly, is to do with its environmental impact. With obsolete electronic equipment being thrown in landfills, they have a devastating impact on the environment. With restrictions being put on the use of hazardous substances in case of RoHS compliant assemblies, the impact on the environment is significantly stymied.

Safety for users

Users can now be secure in the knowledge that the product they are using is being manufactured in an RoHS compliant PCB assembly and therefore is lead and mercury free.

Thermal stability

What also follows from lead free PCBs is improved thermal stability. In fact, with halogen free laminates the thermal stability can go up to as much as 300 degree Centigrade.

Improved sales for manufacturers

The improved safety of the product, in turn, also leads to improved sales for the manufacturer. By not complying with the RoHS regulations, on the other hand, you will significantly reduce your customer pool. Not only is RoHS compliance required to sell in the European Union, it is also needed to sell to resellers and distributors who sell in these countries.

In choosing a PCB Assembly Service that is RoHS compliant, you tend to reap the following advantages:

  • Have a compliance strategy in place for your products
  • Have a large customer base with the ability to supply to EU countries
  • Gain customer trust
  • Contribute to a green environment

At Mermar Electronics, we specialize in providing lead free and RoHS compliant PCB Assembly services. Our high quality lead-free PCBs are manufactured using environmental friendly components. Little surprise then that in the four decades of our existence, we have been the go-to supplier for a wide variety of industries. Our consistent quality and quick turnaround time endear itself to our customers, who look at us as a one stop-shop for all their PCB requirements.

If you have any questions or requirement related to RoHS Compliant PCB assembly, explore our PCB assembly services.

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Speed Up the Efficiency of Custom Low-Volume PCB Assembly Production

By | Date posted: | Last updated: July 27, 2021

When it comes to PCB Assembly Manufacturing and Production, the need for customization is extremely pronounced. Each board has different functional objectives, components, prototyping iterations and more. Besides boards are different for different industries, which require specialized designs and are often required to be produced in low quantities.

Before we look at how the efficiency of low-volume PCB Assembly production can be geared up, it will be worthwhile to understand what the difference between PCB manufacturing and PCB production is. Even though the two terms are often used interchangeably, there is a difference between the two:

PCB Assembly Manufacturing – This refers to a two-step process. The first process is that of fabrication. That involves converting the raw materials into a PCB. The next process is of assembly. That involves attaching the electronic components to the board. The PCBA manufacturing process is employed in creating prototypes as well as finished boards.

PCB Assembly Production – When it comes to PCBA production, it is essentially the implementation of the manufacturing process to create a finished assembly. In turn, PCB Assembly can be of two types- low volume Assembly and high volume Assembly.

While high volume PCBA manufacturing and PCB Assembly can amount to the same thing, as it involves creating the same finished product in large quantities, this is not the case when it comes to low volumes. It is common to have several prototype iterations with extremely low numbers. Think industries such as aerospace or medical devices!

How to increase the efficiency of custom Low Volume PCB Assembly Production?

When we speak about efficiency of low volume PCB Assembly, the metrics we are primarily looking at, include:

  • Yield Rate
  • Quick turnaround
  • Optimal costs

Let us look at each of these metrics individually and ensure how they can be optimized:

1) Yield Rate

First up, let us define the yield rate. Simply put, it is the ratio of usable boards to the total number of boards produced. To improve the yield rate, it is imperative that the design for manufacturing guidelines, are stringently followed. It is essential that the design quality is optimized at the prototype stage itself.

Speaking of prototypes, there are two prototyping options for low volume PCB Assembly:

Sequential

In this approach small design changes are incorporated in each cycle

Parallel

In this approach, a number of manufacturing runs are reduced. Therefore, multiple design changes are made to a small number of boards and then tested.

Whether a sequential or parallel option is opted, the assembly options could include a wide range of strategies:

Do not place (DNP)

  • In this case, while one component is being tested, the others are not placed.

Using different variants

  • In this format, different sets of components are placed on different boards for testing.

Using leaded solder

  • Since prototyping involves re-work, it is better to use leaded solder.

Using a re-workable surface finish

  • Again as rework is a possibility, it is better to use a surface finish that lends itself to rework.

2) Improved Turnaround Time

Whether we speak of high or low volume PCB Assembly Service, the one thing that is fairly important is turnaround time. These days with time-to-market being a source of competitive advantage, it is all the more important that this be optimized. Of course, speed cannot be at the expense of quality. To ensure this it is critical to choose fabrication and assembly services carefully.

3) Optimal Costs

When it comes to cost, the traditional thinking remains that cost needs to be the lowest. However, what is really important is that the cost is optimal when you take into account your turnaround time and yield rate.

At Mermar, we have years of experience in low volume custom PCB Assembly. We cater to a wide range of industries and their unique requirements while following the highest quality standards and being RoHS 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.

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