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PCB fabrication process – A step by step complete guide!

By Mer-Mar Electronics | Date posted: | Last updated: September 5, 2022
PCB fabrication process

The use of PCBs (Printed Circuit Boards) has become quite ubiquitous as they bring electronic equipment-simple or complex, to life. Particularly in mission-critical functions where failure can be fatal, it is imperative that there are no errors in PCB fabrication. Here is a handy guide to the various steps of the process.

PCB Manufacturing Process

1. Design

An important first step is the right design. At the PCB design stage itself, it is important to be in touch with the contract manufacturer. Among other things it is necessary to inform them of the design software being used so that there are no discrepancies. It is important that the design fulfills requirements for design for manufacturing (DFM) so that there are no issues faced at the fabrication stage.

2. From file to film

Post the DFM check, it is time for PCB printing. A special printer called a plotter is used for the process.

Each layer of the PCB and the solder mask gets its own clear & black film set. To ensure there is good alignment, registration holes are punched through the films.

3. Printing the Inner layers

In this step, the figure is printed on the film and onto a copper foil. The PCB comprises a laminate board where the core material is epoxy resin and glass fiber. Copper is pre-bonded on both sides. The whittling away of copper reveals the design of the films. Copper-sided laminate is cleaned. The clean panel next receives a photoresist, a layer of photo-sensitive film. Once the photoresist is exposed to ultraviolet light, it hardens. Once the board is prepared it is washed with an alkaline solution so that any photoresist that has not hardened is removed. The board is subsequently dried.

4. Removing the Unwanted Copper

At this stage, a powerful chemical is used to remove the excess copper. The desired copper, however, remains protected beneath the hardened layer of the photo resist. The hardened resist is now washed off with another solvent.

5. Layer Alignment and Optical Inspection

The inner layers are next aligned to the outer ones. The use of an optical punch ensures that registration holes are punched accurately. Automatic optical inspection of the panels is also carried out so that there are no errors.

6. Layer-up and Bond

In this step the layers are fused together. There are two steps involved

  1. Layer-up
  2. Bonding

The outer layer comprises of the prepreg. There is a copper foil that covers the top & bottom of the original substrate. To bond them together a heavy table with metal clamps is used. The prepeg layer is placed over the alignment basin. The substrate layer fits over the prepeg. Sheets of prepeg sit over the copper layer. Finally, aluminum foil & copper press plate are placed. Now it is ready for pressing.

The stack is heated up & then cooled in a controlled manner. The restraining pins are next removed, and the top pressure plate discarded

7. Drill

At this stage holes are drilled into the stack board. The use of an x-ray locator identifies the drill target spots after which the holes are bored. After the drilling is done the additional copper is removed with a profiling tool.

8. Plating and Copper Deposition

Chemical deposition is now used to fuse the different layers post drilling. The entire process of dipping, removal as well as procession is controlled using computers.

9. Outer Layer Imaging

At this stage photo resistance is applied to the outer layers of the panel. UV light is next passed on the photo resist. Unhardened resist is next removed.

10. Plating

The panel is electroplated with a thin copper layer. After the initial copper plating baths, they are followed by tin plating. The importance of tin is that it guards the panel which is meant to remain covered with copper during the etching stage.

11. Final Etching

During this stage, the tin protects the desired copper while the unwanted copper layer undergoes removal. Post this stage the conducting areas as well as the connections are properly established.

12. Solder Mask Application

The panels are now cleaned & covered with an epoxy solder mask. A blast of UV light ensures hardening. The board is finally passed through an oven to cure the solder mask.

13. Surface Finish

To add solderability to the PCB, they are plated with gold or silver. In some cases, hot air leveling is also carried out leading to the generation of surface finish. Explore many other types of PCB surface finishes and select the best for you.

14. Silkscreen

The completed board now receives ink-jet writing so that all vital information is captured.

You may also like: What is silkscreen in PCB?

15. Electrical Test

Electrical tests ensure that the PCB is functioning correctly & that it conforms to the original design. Flying Probe testing is particularly recommended to test electrical performance.

16. Profiling and V-Scoring

Finally, the boards are cut from the panel. For this either a router or a v-groove method is used. With either of these ways the completed board pops out of the panel.

The boards are now ready for shipping.

Mer-Mar Electronics takes care of every PCB fabrication step with predefined process. Get in touch with us via email on sales@mermarinc.com or give us a call at (760) 244-6149 to start the fabrication process of your requested PCBs.

Reduce the Cost of Supply Chain with PCB fabrication methods!

By Mer-Mar Electronics | Date posted: | Last updated: August 9, 2021
PCB Fabrication Methods

If you are aware of the printed circuit board assembly process, you know it is an expensive and rigorous process. Clients usually come up with some unique requirements and with a tight budget at the same time which makes the entire situation tricky as you need to balance out both of them. Things get tougher as you go for high-volume PCB manufacturing. So, it is important for you to find ways to keep your costs in-line without compromising on the quality and efficacy of the PCBs.

In this article, let’s dive in to understand how one can trim down the costs of the PCB fabrication process and keep your clients happy.

What are the costs involved in the PCB Fabrication Process?

To know what are the costs involved in the PCB fabrication process, first focus on the manufacturing pipeline. PCBs are small in size yet they involve extensive costs in getting the high-precision and high-quality product out into the market. There are numerous processes involved in developing PCBs like soldering, packing, shipping, multilayer printing, substrate creation, inspection, silk screening, surface finishing, and testing. With so many varied processes involved, the manufacturing costs are going to jump up.

Let’s walk you through a few ideas where you can cut back your costs and make your PCB manufacturing pipeline efficient.

1. Examine design choices

Address PCB fabrication costs by understanding various design choices like board material, blind/buried vias, vias on pads, panelization options. Taking off the blind/buried vias or vias on SMT components reduces the PCB fabrication costs greatly. Another way to optimize your PCB fabrication cost is the panelization option where multiple designs can be ordered together. Panelization of the designs together reduces the overall setup cost. You can also go for ENIG surface finish on your PCBs as it is a standard within the PCB fabrication method.

2. Size of the boards

Common misconception is that you can reduce PCB costs if you reduce your board size. But the size of the board may not be the right determinant. Of course, medium to large size boards usually cost higher. But reducing the PCB size may actually increase the cost as it requires high precision fabrication. Also, this may increase the cost as we have to add slots and drilled holes for which additional tooling is required.

3. Fair Assessment of Bill of Materials

Assess the clients’ bill of materials for all the full turnkey PCB orders. If there are any expensive components in the BoM, you can see if you can procure those components from any authorized vendor at lower prices. Discuss with your clients if they are willing to go for cheaper substitutes. If clients have a pre-arranged mechanism to procure parts, you can explore that way. Some contract manufacturers will have leftover stocks from the previous orders which can be used as they come at lower prices.

4. Optimize your Packages

Get rid of extremely small and miniature packages. You can instead opt for large production that can reduce your overall costs. Besides, there are lead-less packages like BGAs and QFNs that usually require special care and attention while assembling. You can go for alternatives by swapping your components for lead parts like QFPs. This reduces the overall PCB fabrication cost.

5. Follow best DFM practices

By following the best DFM practices, you can avoid excessive expenses in the PCB assembly. Optimize the layout for the soldering process and avoid any rework expenses. Don’t place the components forcefully through the manual assembly process. Smaller parts placement requires high precision to avoid rework. Leave enough room for debugging and automatic testing to ensure the efficacy of the PCB assemblies.

6. Components and Materials

Get your components and materials from multiple sources to avoid being at the whims of a single vendor. Never put all your eggs in one basket and lose the leverage in contract negotiations. If you are satisfied with the quality of the components, you can quickly move to other sources without causing any impediments to the manufacturing process. Relying on a single source may also result in delays due to unforeseen situations.

Never go for counterfeit components or illegitimate parts that result in premature failures and affect the board’s performance. Keep an eye on the component life cycles to make sure that they are in working condition for the entire duration of the PCB.

7. Put conflicting priorities to rest

PCB fabrication process is a costly and complicated process and some conflicting priorities are inevitable between the engineers and the clients. Focus on the cost reduction and set up a committee to arrive at a conclusion on where to trim your expenses. Stick to the precise designs and tools agreed upon. Maintain a solid partnership with the suppliers and vendors who can be reliable and responsible. This also reduces unnecessary overheads.

8. Choose your service provider wisely

Make sure your contract manufacturer is well-certified to have solid capabilities and follow appropriate quality regulations. With enough experience, they can prevent some costly mistakes early on. They must also have well-maintained equipment to provide uninterrupted and high-precision PCBs. Be sure of your projects’ requirements and budgetary limitations. Do your research on the company’s experience, projects, client satisfaction, quality check mechanisms, and success rate. This ensures to avoid unnecessary costs and keeps your reputation intact in delivering high-quality products.

Conclusion

Companies like Mer-Mar Electronics have been providing cost-effective PCB fabrication and assembly all the while maintaining high-quality standards. Whether you need a small volume or a high-volume production run, our brilliant engineering team strives to reduce the assembly and fabrication costs for our client’s PCBs. We take a fresh and case-by-case approach to determine what are the elements that are affecting the cost of production and how they can be tweaked or altered without compromising the functionality and quality of the PCBs.

You can reach out any time and ask our PCB assembly specialists about the quotes that match your budgetary targets. You may also contact our manager to review your quote and find out the cost-reducing options.

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How to overcome the most common PCB Fabrication errors?

By Mer-Mar Electronics | Date posted: | Last updated: April 20, 2021
PCB Fabrication USA

When it comes to PCB fabrication, we could be looking at a fair amount of complexity, as multi-layered boards with as many as 36 layers are being used extensively. What it brings in its fold, however, is the possibility of errors, which could turn out to be costly. There is, therefore, a pressing need to keep an eye on the common PCB fabrication errors so that they can be avoided. Here is a comprehensive list of errors to watch out for:

#1. Flex Cracking

What does it entail?

Simply put, this error occurs when the PCB bends excessively on account of the ceramic chip capacitor.

How can it be side stepped?

The simple solution to this problem is varying the size of the capacitor. The usage of a small capacitor can successfully solve this issue.

#2. Clearance constraint

What does it entail?

This is a fairly common PCB fabrication error. It occurs when in designing the board, the clearance constraint is not taken into account.

How can it be side stepped?

To ensure that this issue does not occur the manufacturing capabilities need to be understood prior to production, so that the board can be designed accordingly.

#3. Power shortage

What does it entail?

If there is a shortage of power during the building stage, it can impact the functionality of the board.

How can it be side stepped?

Visual inspections and cold tests can ensure that the board’s electricity is checked and that there is no inadvertent power shortage.

#4. Mechanical Issues

What does it entail?

A wide range of mechanical issues can take place if the components do not fit well on the board or if they are placed too close together.

How can it be side stepped?

It is imperative that all component dimensions are double-checked and that there is enough room for each component so that any issues can be avoided.

#5. Impedance Control

What does it entail?

Some PCB designs have components that require impedance controlled tracks. This requires that the specifications of the manufacturer are followed.

How can it be side stepped?

To ensure that no issues are faced, it is important that the manufacturer specifications are taken well in advance and strictly adhered to.

#6. Drill constraints

What does it entail?

The drill capacities of manufacturers are an important aspect to know before hand. Typically drill sizes range from 6 to 14 millimeters.

How can it be side stepped?

#7. Vias

What does it entail?

As part of the PCB fabrication service, it is important to drill holes for the vias. The holes are in turn plated. In case during the plating process the copper layer does not adhere to the surface, a discontinuity comes about. In turn, this could lead to a number of issues in the PCB.

How can it be side stepped?

To avoid this issue, it is important to ensure that the hole that is drilled is smooth. Rough or fast drilling can lead to the hole being defective as also cause uneven copper deposition. To ensure that this does not happen, it is necessary to use the recommended tools and to apply the right amount of force for the drilling. Any lapse in either of these two aspects is likely to lead to a PCB fab issue.

#8. Missing Solder Mask

What does it entail?

This issue erupts when the space between the pads is constrained. With closely packed pads, in turn, solder mask deposition is impacted. This could lead to short circuits besides impacting the life span of the PCB making it vulnerable to rusting.

How can it be side stepped?

This issue needs to be side stepped at the design stage itself. What is needed is strict adherence to issues such as:

  • Size of copper pads
  • Clearances
  • Copper trace

If these are taken care of, the copper masks in between the pads will not be an issue.

With Mermar Electronics, a credible PCB Fabrication service, USA, you can rest assured that the above issues are well taken care of. By virtue of our four decades of experience in the domain of fabricating complex PCB boards across industries, we can anticipate these issues well in advance and ensure that corrective action is taken. By partnering with us, not only are you assured of high quality PCB, but also complete peace of mind. For more information, Explore our PCB Fabrication Services.

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How Automation in PCB Fabrication is Meeting the Needs of Today’s Industries?

By Mer-Mar Electronics | Date posted: | Last updated: December 23, 2021
pcb-fabrication

Think of PCBs and you tend to increasingly think of complex, high-density, multi-layered boards. With industries such as computing, telecommunication and IoT especially, you are particularly talking about highly complex and miniaturized products necessitating such boards. We are already increasingly seeing trace and space widths of 1 mil being considered.

While in its early stages, PCB manufacturing was a manual job, today’s technology and the need for increasingly small boards, calls for the need for a high degree of automation. In fact, it would be near impossible to mass-produce these delicate boards without an automated assembly process. Besides the mass production of boards, automation also brings about a host of other benefits.

Benefits of automation in PCB Fabrication

Automation in PCB fabrication comes with a range of benefits, including but not limited to:

Cost advantage

Shorter assembly times

Low chances of error

Higher Quality

Miniaturization

  • Cost advantage – There are no doubts, that as opposed to manual assembly, which involves a sizeable labor cost, the running expenses when it comes to automation are far lower. In turn, this translates into optimal product pricing, which can be huge source of competitive advantage.
  • Shorter assembly times – With faster time-to-market being yet another important criterion in today’s hugely competitive world, what automation importantly also offers is a faster assembly time.
  • Low chances of error – Manual assembly can also come with high probability of manual errors, which in turn can lead to costly mistakes. Automation in PCB Fabrication, however, takes away the scope of these errors and ensures that you have a quality product and complete peace of mind.
  • Higher Quality – Reduced errors automatically translate into high quality PCB fabrication, which in turn determines the quality and reliability of the end product.
  • Miniaturization: As mentioned above, given the constantly reducing size of gadgets, the need of the hour is to create miniature PCBs with high component density. Again, this is a task that automation can achieve. Automated systems can go a long way in sorting out parts, placing components correctly and even perform testing. With a manual intervention most of this isn’t possible, given the high component density.

What are some of the automation used in PCB Manufacturing?

Typically, when you think of automation in PCB manufacturing, you tend to think largely of robotics in terms of assembly. However, there is a lot more to automation ranging right from component marking right up to packaging and testing. Some of the automated systems being used by a best-in-class PCB Manufacturing service today, include:

  • Automated system of marking and labeling components
  • Machines that can pick up small components and place them on the board
  • Automated soldering systems
  • Routing machines
  • Automated systems for inspection
  • Test systems such as in-circuit tests or flying probe tests to ascertain manufacturing integrity.
  • Conveyors for transporting boards
  • Bar code readers for tracking components
  • Packaging systems to seal the final products as and when they are ready.

In fact, as PCB technology continues to advance, reliable Contract Manufacturers will continue to look for new and improved automated manufacturing systems to further streamline processes and to add to their efficacy. These will also include newer testing techniques that ensure that any errors do not go undetected.

It is imperative, therefore, that you choose a PCB Manufacturing service that that is committed to maintain a high level of automation that in turn, ensures high quality PCBs at the lowest possible costs. By ensuring this, you are making sure that the PCB fabrication service is not only geared to handle your current requirements, but is also equipped to tackle the changed landscape that is sure to develop in times to come.

At Mermar Electronics, we offer a one-stop solution for contract manufacturing and PCB fabrication. With our goal being to provide consistent product quality with quick turnaround time, we rely on the highest degree of automation. It is on account of this that we are also able to provide the highest degree of customer service and reliability to our clients. You can count on us to meet and exceed your PCB Manufacturing needs. We are ever committed to staying ahead of the curve, when it comes to meeting the growing demand for different types of PCB Fabrication Services.

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