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Digital thread in PCB manufacturing – Improve it with software-based approach!

By Mer-Mar Electronics | Date posted: | Last updated: September 12, 2022
digital thread in manufacturing

PCBs play an extremely key role in developing several modern technologies. Right from wearable devices to space launch systems, everything relies on PCBs! In many of these industries, several of which are mission-critical, speed is of the essence. However, the concept-to-market product lifecycle is long. This means that there could be many weeks before the engineer can have a working prototype in his hands and many more weeks before the final product is made available.

Traditional PCB Design Approach

The traditional design, build and test cycle typically works as follows:

  • Step 1- The engineer creates the design.
  • Step 2- The design is next sent to the manufacturer to build.
  • Step 3- The manufacturer builds it & sends it back to the engineer for testing it.
  • Step 4- The engineer identifies flaws, if any, and it is sent back to the manufacturer for rectification.

The loop repeats and several iterations may be necessary before the engineer is satisfied with the final prototype. The process can take weeks or months. The common causes of delays include:

  • Information sent to the manufacturer is lost or misinterpreted.
  • There are communication errors.
  • Resolution of questions could come with their own set of issues.
  • There is lack of connectivity & the manufacturing process may work in silos. This, of course, not only slows down operations but also keeps the engineer isolated.

One way to overcome these issues, and to accelerate PCBA (Printed Circuit Board Assembly) manufacturing, is to use software-driven automation.

Digital thread in manufacturing – Software PCB design approach

One way to speed up the excruciatingly slow PCBA manufacturing cycle is to leverage software automation. It helps to create a digital thread. In turn, the information flow from the engineer to the factory floor is automated. The engineer, therefore, can communicate directly with the manufacturer through the process of the DBT cycle. Needless to say, this adds both speed & accuracy. The other advantage with this automation is that operations are streamlined as communication no longer remains analog. With IoT devices integrated throughout the operations, various control systems can be monitored. This way data can be gathered & shared & continuous improvements made and the build process optimized.

What is digital thread?

The digital thread in PCB manufacturing provides the ability of access, transformation, integration, and analyzing data from systems to product lifecycle. It includes a communication framework which helps in streamlining an integrated view and data flow of products through its lifecycle.

To put it simply, Digital thread manufacturing does not rely on a physical connection between various stakeholders. Instead, there is a digital communication network, which connects various systems as well as users. Digital thread manufacturing, therefore, uses digital means of communication to link the manufacturing processes, principles & equipment.

In turn, this lends itself to real-time monitoring & control of the product throughout the manufacturing process. The big advantage here is that people may be spread across various geographical locations and there could be many diverse types of equipment.

Key advantages of digital thread manufacturing

Digital Thread Manufacturing offers a wide range of benefits, that include but are not limited to:

  • It allows for full process control, by virtue of which potential issues can be easily identified. Importantly it also helps improve yields.
  • You can monitor the real time process and therefore streamline operations. It also minimizes downtime as well as any potential delays.
  • It is understood that it facilitates transparent communication and helps with white-box manufacturing.
  • It facilitates agile manufacturing and hence it helps make changes quickly without any loss of quality. Also, it helps with data & information exchange.
  • It is highly cost-effective as the costs for data processing and storage are significantly reduced with the use of clouds. Importantly, there is a lot of cost saving as it helps you to identify and mitigate risks early on.
  • This ensures you do not have to contend with costly errors later in the cycle. Also, it helps respond to design changes quickly, thereby it saves time & also ensures that there is minimal wastage.

To sum up

The traditional prototyping process acts as a bottleneck when it comes to speedy product development. It also inhibits the engineers’ ability to innovate. With software automation and IoT networks, many of these issues that plague traditional manufacturing are solved. It works far better in terms of both quality and cost.

Mer-Mar Electronics provides a full range of PCB manufacturing services including PCB assembly, PCB fabrication, and prototyping services. We provide service according to your requirements.

Fill out the form below to request a quote or contact us at sales@mermarinc.com or call us at (760) 244-6149.

PCB manufacturing tolerances and its impact on fabrication and assembly process!

By Mer-Mar Electronics | Date posted: | Last updated: August 22, 2022
PCB manufacturing tolerances

It is imperative that when you offer the documentation for PCB manufacturing, all the requisite details are provided. Very often there are missing details that, if provided, can go a long way in quoting the right cost as well as manufacturing PCBs that match up to your bespoke requirements. Robust data needs to include tolerances as they will ensure there are no defaults in manufacturing as well as no production delays. Let us look at these tolerances in some detail:

Important PCB Tolerances

1. PCB Component Tolerances

When it comes to components, tolerance refers to the acceptable variant to be able to ensure proper functioning. Tolerance in this case also refers to the difference in between the lower & upper dimensions of the component parameters.

The overall functionality of the PCB is dependent on how the components perform with each other and therefore it is important to know the limit of each component. Component tolerance modeling is thus a crucial step that ensures reliability testing of the board to determine if the board components succeed in performing as a unit. In fact component tolerance modeling allows the quantification of how individual components relate to the output. The more accurate the tolerance, the more reliable the final product will be. Component tolerance modeling, therefore is an important function of the design as well as the manufacturing process.

What is important to remember is also that since each component brings its own component limit, what needs to be considered is the tolerance stack-up or what is the additive effect of various component tolerances. The tolerance stack-up estimates the effects of the accrued variations & is defined on an engineering design.

2. PCB Material Tolerances

When it comes to PCB laminate materials, it is important to provide specific Tg ratings. Additionally providing a stack-up with specific dielectrics is important. What you also need to provide so that the right material can be selected is the overall printed circuit board thickness. What is needed here is a certain material tolerance since it will be impossible to meet the exact details. If your requirement is for a tolerance less than 10 percent, you might need a change in the core as well as a tighter process control. In turn this will lead to added costs. Materials & cores therefore need to be correctly chosen at the prototype stage as if this is done at the production stage, it can prove to be far more costly.

3. PCB Drill Tolerances

What is also needed when creating a fabrication document is the need to look at PCB manufacturing tolerances to avoid PCB fabrication errors.

For example, plated and non-plated holes need to come with different tolerances as drills cater to specific sizes with strict tolerance. It is important to remember that there are many factors that affect the size of the hole. Some of these include:

  • Plating baths
  • Time in & out of the tanks
  • Additional plating
  • Etching
  • Finished Plating

The need for tolerances is therefore a given. However it is important to remember that not all drills are exact, so some amount of tolerance is required. Where tighter tolerances are required, it is imperative that they should be noted clearly.

In fact, larger holes, plated or non-plated above the size of 0.200”, will require a tolerance of +\-0.005”.

4. PCB Routing Tolerances

When it comes to routing, tolerances are required right from slotting tools to routing cutoffs. Typically, a tolerance of +\-0.005” is the default standard on the size or cut.

Other standard PCB tolerance that you should know

Following is the analysis of outer layer (width annular ring, min annular ring, NP to copper, KO to copper, etc.):

Outer copper thickness 1OZ 2OZ 3OZ 4OZ
Compensation value 0.01mm 0.02mm 0.03mm 0.04mm
Normal trace/spacing 0.12MM 0.15MM 0.2MM 0.25MM
Normal Width between pads 0.12MM 0.15MM 0.2MM 0.25MM
Normal Width between pad and trace 0.12MM 0.15MM 0.2MM 0.25MM

Normal Width between pad or tarce and copper area

0.2MM 0.2MM 0.2MM 0.2MM
Normal VIA pad single side width 0.15mm 0.16mm 0.17mm 0.18mm
Normal PTH pad single side width 0.2mm 0.21mm 0.22mm 0.23mm
Normal Width between NP   holes and copper 0.2mm 0.2mm 0.2mm 0.2mm

Normal Width between profile and copper

0.3mm 0.3mm 0.3mm 0.3mm
Normal width between via and copper 0.2mm 0.2mm 0.2mm 0.2mm
Max trace/spacing 0.1MM 0.13MM 0.18MM 0.23MM
Max width between pads 0.1MM 0.13MM 0.18MM 0.23MM
Max width between pad and trace 0.1MM 0.13MM 0.18MM 0.23MM
Max width between pad or trace and copper area 0.18MM 0.18MM 0.18MM 0.18MM
Min width between NP holes and copper 0.15mm 0.15mm 0.15mm 0.15mm
Min Width between profile and copper 0.25mm 0.25mm 0.25mm 0.25mm
Min width between V-Cutline and copper 0.35mm 0.35mm 0.35mm 0.35mm
Min width between via and copper 0.18mm 0.18mm 0.18mm 0.18mm

To sum up

Tolerance modeling is a wonderful way to achieve a balance between performance & cost as otherwise the less the tolerance, the more the cost of production. Tolerance modeling therefore is the key aspect that reduces manufacturing cost while ensuring that the quality is maintained.

Of course, in case you do not specify the details in the manufacturing document, the contract manufacturer will refer to the IPC standards & performance specifications as a guide. However detailed information on aspects such as surface finish copper weights, material, hole sizes and more can go a long way in ensuring that the final product matches your bespoke needs.

One of the top PCB manufacturing firms, Mer-Mar Electronics offers complete packages for PCB assembly. Customers appreciate our reliable quality and quick turnaround, seeing us as a one-stop shop for all their PCB manufacturing needs.

Please do not hesitate to contact our team if you have any questions about our PCB assembly and PCB manufacturing service, or if you require immediate assistance. Send us an email at sales@mermarinc.com or give us a call at (760) 244-6149 with any questions you may have.

What are the different types of flexible multilayer PCB for various industries?

By Mer-Mar Electronics | Date posted: | Last updated: August 30, 2022
Flexible Multilayer PCB

Flexibility is the cornerstone of great design and that is something that is made possible by flexible multilayer PCB.

A flexible printed circuit is a circuit board with a flexible construction. It is also known as a flex circuit. It is used in small electronics. A flex circuit largely consists of two or more copper conductive layers with an insulation material between its layers. There is also an application of coverlay in the flexible areas that can protect the external circuitry of a flexible PCB.

Different configurations of flex printed & rigid-flex circuit boards

Flex and rigid-flex circuits are available in a wide range of configurations and can be found in different applications. These include:

  • Single-layer flex printed circuits – Such circuits adhere to IPC 6013, Type 1 standards & have a single copper conductive layer between two insulating layers. These work well in bend-to-fit applications.

  • Double-sided flex printed circuit – Adhering to IPC 6013, Type 2 standards, these consist of two copper conductive layers with insulating polyimides. Plated through-holes ensure circuit connectivity between the layers. Such circuits work well for dynamic flex as well as bend-to-fit applications.

  • Multilayer flex printed circuit – Adhering to IPC 6013- Type 3 standards, they have three or more conductive layers with insulating layers in between. They also make use of plated through-holes for ensuring connectivity between layers. They also use high-speed controlled impedance and work well for bend-to-fit applications.

  • Rigid-flex printed circuit – They adhere to IPC 6013-Type 4 standards. These have two or more copper conductive layers with insulation in between. They also have plated through-holes that cut through the rigid as well as flexible layers. In addition, there is an application of coverlay on the flex layers.

Of these, let us look at multilayer flex circuit boards in greater detail:

Multilayer Flexible Printed Circuit Boards

One can look at multilayer circuits as a combination of several single layer or double layer circuits. Multilayer circuits can in turn come with:

  • Continuous lamination
  • Without continuous lamination

The choice of the above depends upon whether you are looking at maximum flexibility in your multilayer PCB designs. For designs that need total flexibility, it is an easy decision that continuous lamination is not suitable. Multilayer flex circuits work particularly well in the following scenarios:

  • Specified impedance requirements
  • When you need to eliminate crosstalk
  • Where there is extreme component density, and more.

In fact, if one were to look at the benefits of multilayer flex printed circuits, these would include:

  • High circuit density
  • No need for mechanical connectors
  • Flexibility in design
  • Reduction in weight as also size
  • Ability to function in high operating temperature range
  • Reduction in wiring mistakes
  • Improved signal quality
  • Improved impedance control

In addition, with multilayer flex PCBs you also tend to benefit from:

  • Reduction in assembly errors. This is because they do not use hand-built wire harnesses and make use of automation in production.
  • Reduction in assembly time. Because the multilayer PCB assembly doesn’t require too much manual labor, both the assembly time & the cost are kept under check.
  • High applicability. Flexible circuits also offer a lot of design freedom and therefore lend themselves to many applications. They also offer flexibility during installation without losing functionality. Importantly, they lend themselves to high-density component placement which is a great plus in today’s times of miniaturization.
  • Improved airflow. With their designs offering improved airflow, increased product lifecycle is a given. Their compact design also lends itself to better dissipation of heat.
  • Increased reliability. With fewer interconnections what flexible multilayer printed circuit boards also offer is increased reliability. That they are durable and can withstand elevated temperature conditions is an added advantage.

Because of all these factors & particularly the fact that they lend themselves to small size applications, multilayer flex circuits are so much in vogue. That they can withstand harsh environmental conditions is another advantage as that means that they can be deployed in tough environmental conditions.

It is however important to select the right contract PCB manufacturer that has the requisite experience & expertise with multilayered boards. They are equipped with robust PCB design software as well as industry best practices that ensure you do not have to deal with costly errors later that can lead to product recall and even cost the company’s reputation. If you are dealing with mission-critical operations, the use of multilayer flex circuits particularly cannot be overestimated.

Mer-Mar Electronics is an ISO 9001:2015 certified company and ITAR (International Traffic in Arms Regulations) compliant manufacturer that delivers multilayer PCB fabrication services with specialized support, reliable testing, and multi-functional features. In case you have any questions or require more information about PCB assembly and fabrication services, get in touch with us via sales@mermarinc.com or call us on (760) 244-6149.

Best strategies for managing printed circuit board material in high frequency applications!

By Mer-Mar Electronics | Date posted: | Last updated: June 20, 2022
Printed Circuit Board Material

Effective material management is imperative in all aspects of our lives. However, for PCBs, especially those which work in high-frequency applications, the choice of the right material is beyond crucial. The performance of the board is often seen as a function of component placement and trace routing. However, it is the circuit board material that offers a strong foundation.

Let us look at some of the benefits that high-speed board materials offer:

Benefits of High-Speed Board Materials

The major benefits of high-speed board material include:

  • Impedance Control – High-speed board material has a dielectric constant of +/- 2% or better. For circuits that require controlled impedance routing this is extremely important.
  • Signal Performance – A lower dissipation factor that helps to reduce signal loss is extremely important especially as the frequency of transmission line increases.
  • Dimensional Stability – In a high-frequency design it is imperative that tight physical tolerances be maintained. Laminate materials that offer mechanical stability are therefore key.
  • Moisture absorption – A small amount of moisture can also come in the way & impact electrical performance.
  • Thermal Management- For boards that have to be used in harsh environments, materials with excellent thermal properties need to be chosen.

The above are the exact reasons why FR-4 has a number of operating limitations that affects its efficacy. Some of these include:

  • FR4 is rated at a dielectric constant of ± 10% or more, that does not give it the tolerance that is required for high-frequency designs.
  • It has a high dissipation rate when it comes to signal loss.
  • Its moisture absorption rating is nearly 50%, that can affect electrical performance of the board.
  • It also has limitations in terms of thermal management & therefore is not suitable for high-temperature operating conditions.

PCB Material Management for High-Frequency Designs

The demand for high-frequency PCB manufacturing is on the rise in several sectors including but not limited to:

  • Automotive radar systems
  • Satellite antennas
  • Cellular telecommunication systems
  • Broadcast satellites
  • RFID tags
  • Missile Guidance systems, and more.

For these and many other sectors, there are a number of circuit board materials that work particularly well. Some of these include:

  • Epoxy resins – This category, of course, includes FR4 which suffers from some weaknesses when it comes to higher frequencies.
  • Enhanced epoxy – These materials tend to improve the performance as opposed to standard FR 4 & related material.
  • Polyimide – Such material can withstand harsh conditions with their excellent thermal & mechanical properties. Additionally, they are chemical as well as moisture resistant.
  • PTFE (Polytetrafluoroethylene) – Also referred to as Teflon, such materials offer high impedance control as well as signal performance making them highly suitable particularly for wireless communication systems.
  • Thermoset hydrocarbon laminates – These are particularly known for their mechanical stability although at higher frequencies they may show dielectric loss.

There are a wide variety of materials available for high frequency applications. Some of the aspects to be mindful of, however, include:

  • Such material comes at a higher cost. You therefore need to look at a cost-performance trade-off in making your choice.
  • Sometimes you will need to evaluate exactly how much performance improvement your circuit needs. After a close evaluation, you may at times want to settle for FR-4 or one of its enhanced versions.
  • Many of them require non-standard fabrication processes adding to fabrication & assembly cost.
  • They may require changes in solder types as well as cleaning processes that impact both manufacturability & price.

To Sum Up

Given the criticality of the operation & the many factors to be considered in choosing the right material, the one thing that is non-negotiable is to choose an experienced electronic contract manufacturing partner who can guide you through the choice of material. The contract manufacturer will be able to undertake the right cost-benefit evaluation to choose a material that meets your criteria without escalating the cost to unacceptable levels. Additionally the contract manufacturer can also help you with the right board layer stack up strategy. You can also use some sophisticated design tools that are meant for high frequency designs.

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 parts and materials you need to eliminate the delay and reach quickly to the result. In case you have any questions or require more information about PCB Manufacturing, contact us via sales@mermarinc.com or call us on (760) 244-6149.

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