Bare PCB

In this guide, you will find all information you need about bare PCB.

So, if you want to learn more about bare PCBs, read this guide.

What are Bare PCBs?

Bare PCB

Bare PCBs refers to the printed circuit boards before you place the through holes and electronic components on them.

On a printed circuit bare board, here are the main components that you will find.

• Printed Circuit Board Substrates
• Metal Coating
• Conductive Patterns and Pathways

PCB Components

What are the Main Types of Bare Printed Circuit Board Testing?

You should consider testing the bare printed circuit board to ensure that it is in proper working condition.

It involves testing the isolation and continuity of the bare printed circuit board and the other connections.

Testing the bare PCBs will make sure that there are no open points that will impede the flow of current.

Apart from that, isolation testing involves testing resistance between different electrical connections.

Here are the main tests that you can use to test the bare printed circuit boards.

• Pinned Fixture Test
• Flying Probe Test

How Does the Pinned Fixture Test Compare to the Flying Probe Test?

Assembling and testing PCB

Well, you can either choose to use the flying probe test or the pinned fixture test to test the bare PCBs.

One of the most important differences that you will note is the cost and durations for testing.

Here is a comparison between the pinned fixture test and the flying probe test.

Flying Probe Test

Here, you will use robotic arms that are equipped with poles to verify the printed circuit board connections.

You must also have a software program that will send the flying probes across all the connections on the bare PCB.

Despite taking longer testing hours, the flying probe test is a very flexible and affordable process.

Pinned Fixture Test

When performing the pinned fixture test, you will use pogo pins to test the board connective surfaces all at once.

To ensure a connection between the bottom and the top plates you will apply pressure on the custom pin fixtures.

It is the best method that you can use to test numerous bare printed circuit boards at the same time.

As soon as you set up the pogo pins, you can test the bare PCB, in five seconds to complete test.

What are the Advantages of Bare Printed Circuit Board Testing?

As a bare board manufacturer, you have to ensure that the bare boards produced work well and are of high quality.

The only mode of ensuring the bare PCBs is in proper working condition is by performing bare board tests.

Here are the main benefits of conducting tests on the printed circuit boards.

Cost Savings

Here, you will perform extensive tests during the early designing stages of the bare printed circuit board.

In this case, you will save a lot of money in the process of testing early enough thus preventing costly repairs.

Streamline Production

You will be able to identify the issues early enough in the prototyping stage, the later production stages will be easier.

In other words, saving every detail within the right time frame will save you a lot time thus streamlining production.

Issue Resolution

You will also be in a better position to identify the problem with the bare printed circuit board early enough.

As soon as you identify the problem, you will be in position to solve the problem thus resolving the issue faster.

What are the Main Quality Certifications for the Bare Printed Circuit Boards?

Here are the main quality specifications that you have to adhere to when having bare PCBs.

• UL Quality Certifications
• CE Quality Certifications
• International Standards Organization (ISO) Quality Certifications such as ISO 9001:2015
• Current Good Manufacturing Practices (cGMP) Quality Certifications
• ANSI/AHRI Quality Certifications
• ITAR Quality Certifications
• NEMA Quality Certifications such as NEMA LI 1-1998
• IPC Quality Certifications such as IPC 6013 class III

Which Materials Do You Use to Make Bare Printed Circuit Boards?

Just like any other printed circuit board, you will use the same non-conductive substrate materials.

Apart from that, you will have conductive materials that are buried within the non-conductive materials.

The density or quantity of conductive and the non-conductive substrates will vary according to the number of layers.

PCB Material

Here are the main types of materials that you will use to manufacture the bare printed circuit boards.

FR4 Epoxy Prepreg and Laminate

This is the most popular type of substrate that you can use to make the bare printed circuit board.

This type of substrate belongs to FR4 group which is a material that adheres to the NEMA LI 1-1998 standards.

Polyimide Prepreg and Laminate

You can also opt for the polyimide prepreg and laminate which performs better under very high temperatures.

Apart from that, it also has better electrical transmission of signals and electrical performance in comparison to FR4 epoxy laminates.

Bonding Plies and Teflon Laminates

You will also use the bonding plies alongside the Teflon laminates thus offering excellent electrical properties.

This is the best combination that you can ever have whenever you are making bare PCBs for high-speed circuitry applications.

Flexible Laminates

You can also opt for the flexible laminates which are thin in nature and do not have the glass materials within.

Thy have the ability to bend and fit in very small spaces without losing the ability to conduct electric currents.

Other Materials

There are many bonding and laminate materials that you can opt for such as BT cyanate ester, blended systems and ceramics.

You can use the other materials that combine resins to get the mechanical and electrical performance of the bare PCBs.

Here are a complete guide to PCB material.

What Factors Do You Consider When Choosing Materials for Bare Printed Circuit Boards?

As a bare PCB designer or manufacturer, you have to consider the right type of materials.

With that in mind, you have to be very specific about the type of materials you are using on the bare PCB.

Here are some of the factors that you have to consider when choosing the right bare PCB materials.

Dielectric Constant

You should look at the dielectric constant as a key indicator for electric performance of the bare PCB materials.

Flame Retardance

You have to look at the flame retardance as part of the UL quality certification for bare printed circuit boards.

Transition Temperature

The glass transition temperature should also be high so as to withstand the high temperature for bare PCB assembly.

It must also be high in order to withstand the high application temperatures of the bare printed circuit boards.

Mitigated Loss Factors

You should also pay attention to the mitigated loss factors especially when you are working on high-speed applications.

It is one of the most important factors you need to consider especially when you value the PCB signal speed.

Mechanical Strength

Here, you will look at mechanical strength in terms of tensile and shear strength among other mechanical attributes.

It is a very important factor that you have to consider especially when you put the bare PCB into work.

Thermal Performance

In case you are making a bare PCB for elevated service environments, you have to consider the thermal performance.

You must make sure that the bare PCB materials you are choosing have the ability to withstand very high temperatures.

Dimensional Stability

In this case, you will look at how much the material can move and how consistent the materials can move.

You will look at the dimensional stability when you expose the bare PCB materials to humidity and different thermal cycles.

Do You Supply Hybrid Bare Printed Circuit Boards?

Rigid flex bare PCB

Yes, we do supply hybrid bare printed circuit boards by combining the laminate systems with hybrid systems.

One of the most common hybrid PCB systems that you can opt for is the rigid flex and flexible printed circuit boards.

In the case of rigid-flex, you will combine the flexible and the rigid printed circuit board materials.

It has flexible parts on it, which will allow you to bend the printed circuit boards into smaller and tighter spaces.

Apart from that, the rigid parts will allow you to have a bare PCB with very strong and functional electrical circuit systems.

How Do You Design a Bare Printed Circuit Board?

As you think of manufacturing the bare printed circuit board, you should definitely think about the design.

In other words, the design of the bare PCB will provide the main blueprint for manufacturing the bare PCB.

Here are the steps that you need to follow when designing the bare printed circuit boards.

Coming up With Design Idea

First, you must think of an idea of how your bare printed circuit board will look like.

Apart from that, you have to look at how the bare printed circuit board will perform.

Make sure that you also plan on the mounting details as well as the components.

After that, you should get a bare PCB design software which will do most of the designing work.

Some of the design software that you can use are OrCAD, KiCad, Eagle, or Altium designers among others.

Make the Schematic

As soon as you have the design, you will proceed with making the schematic.

In this case, having the schematic will act as the guiding principle for the bare printed circuit board design.

With the schematic in place, you can proceed with the designing process by importing all the key details.

In other words, you will determine the number of layers, types of materials as well as the arrangement of the materials.

The designing process will continue with proper placement of all the features of the bare printed circuit boards.

As soon as the design is complete, you can proceed with saving the design in the most appropriate file format.

How do you Manufacture Bare Printed Circuit Board?

With the bare printed circuit board design at hand, you will have a very easy manufacturing process.

You will use the bare PCB design as the main guiding template during the manufacturing process.

Here are the main steps that you will follow when manufacturing the bare printed circuit boards.

1)     Print the Film

You will begin the whole manufacturing process by doing a print from the design file to the main film.

You must make sure that you perform the DFM check on the design before print the design on the film.

The best machine for printing the design on the film is a printer known as a plotter.

2)     Manufacturing the Layer

In this case, you will cut the substrate to the right sizes and then shape them accordingly.

After that, you will print the design on the substrates or print the inner layers.

Make sure that you place enough copper on the substrate and then eliminate or remove the excess copper.

After that, you will proceed with layer alignment as well as optical inspection to ensure the layer is working well.

As soon as all the layers are in place and working well, you will layer every layer up and bond them together.

That will mark the end of the manufacturing process since it does not involve through-hole and component placement.

What Does Bare Printed Circuit Board Inspection Involve?

You can either test the PCB manually, or use an automated device to ensure that the PCB work well.

One of the most common inspection methods is the visual inspection which works for only two layers.

In case you have more than two layers of the bare PCB, you have to consider an electrical inspection or test.

In electrical inspection, you will proceed with either the flying probe test or the universal grid test.

Universal grid uses different fixtures to perform the tests on the bare printed circuit boards.

You can also refer to the universal grid test as the bed of nails test or the clamshell test.

In addition to that, you should also test the capacitance as well as the resistance of the bare PCB.

When conducting the capacitance test, you will be looking at the shorts or open circuits within the bare PCB.

On the flip side, the resistance test will help you determine the flow of electric current through the traces.

How Much Do the Bare Printed Circuit Boards Cost?

Depending on the type of bare PCB you intend to purchase, you will pay between 0.1 to 10 US dollars.

The price is a general price tag that you will find for one piece of different types of bare printed circuit boards.

Implying that, there are different types of bare printed circuit boards that attract different prices.

In addition to that, the higher the quality and functionality of the bare PCB, the higher the cost.

In case you want to purchase more pieces, you have to prepare to pay more and request for a discount.

What is the Difference between the Bare PCB and PCBA?

Bare PCB are the printed circuit boards that do not have the components and through holes mounted on them.

In other words, you will have it free of the many components and mounting holes on them.

On the other hand, PCBA is a type of printed circuit board that has all the components soldered to the board.

Implying that, it is a complete printed circuit board with all the components on the board.

Why Should you use Bare PCB?

Bare PCB guides electrical signal through various paths.

With the bare PCB, you will have both freedom and flexibility do design various electrical systems as you wish.

Additionally, they play a crucial role when performing bare board testing. This will help prevent possible mishaps that may occur in later stages during the assembly process.

Moreover, with the bare PCB, you can populate the boards with PCB components to perform various functions.

Do all Bare PCB have Solder Mask?

Not all – it will depend on your design requirements for the bare PCB.

Remember, all bare PCB come in different options which may include:

• With or without silkscreen
• With or without solder mask

In fact, there are circumstances where they are available as bare copper.

Is there Recommended Surface Finish for Bare PCB?

Well, this will also depend on your unique requirements and specifications.

You can choose from a number of PCB surface finishes depending on:

• Application of the printed circuit board
• Assembly technique for the printed circuit board
• Design of the bare printed circuit board

There are many surface finish for bare PCB you can choose from such as;

• Hot air solder levelling (HASL)
• Immersion tin and immersion silver
• Electroless nickel immersion gold (ENIG)

Different surface finishing options for bare PCBs

However, for bare PCB, ENIG and HASL are the most common options.

Also, you decide to upgrade from ENIG to HASL.

Most bare PCB manufacturers in China will conduct the upgrade at no extra cost.

Can you get Free Samples for Bare PCB?

Well, we do offer free samples.

However, we need to know your bare PCB requirements or orders.

Of course, this also applies to the MOQ for the bare PCBs.

You can contact us so that we discuss this with our team.

What are the Specifications for Bare PCB Fabrications?

Before you order for bare PCBs, there are certain requirements you must specify.

This will ensure the PCB performs to the required specifications.

Some of these specifications include;

• Type of material for the bare PCB
• Number of layers for the bare PCB
• Bare PCB thickness
• Copper thickness
• Trace width or space dimensions
• Solder mask – there are many color options to choose from such as yellow, purple, green, white, blue, etc.
• Bare PCB surface finish option where you can choose from OSP, HASL, ENIG, immersion tin or immersion silver
• Minimum hole sizes
• Bare PCB dimensions
• Via size and type
• Plated or non-plated holes, etc.

It is from these specifications that you can get an accurate quotation for your bare PCB design and fabrication project.

Is there need for Bare PCB Prototyping?

Yes, PCB prototyping is an important stage before any mass production of bare PCB.

There is nothing unique when it comes to bare PCB.

In fact, you will follow the normal process of producing PCB such as – design and layout, fabrication and testing.

It’s through bare PCB prototype that you will determine whether the final printed circuit board will be functional or not

Can you Include Vias in Bare PCB?

Different types of vias to use in bare PCB

Yes, depending on your bare PCB design requirements, we can include blind or buried vias.

Like any other PCB designs, bare printed circuit boards can also be customized to have unique features and specifications.

Which Types of Bare PCBs are there?

There are many type of bare PCBs you can choose from.

Depending on the nature of your applications, you can choose:

• Single sided bare PCB
• Double sided bare PCB
• Multilayer bare PCB
• Rigid bare PCB
• Flex bare PCB
• Rigid flex bare PCB

Of course, you can have other options such as high frequency bare PCB, high power bare PCB, and RF bare PCB, just to mention a few.

What is the Recommended Tolerance of Bare PCB Thickness?

In most case, it can be +/- 10%. However, this may very depending on your unique design requiremnts

Is there Maximum Bare PCB Size?

In most case the maximum size can be 25 inches by 17 inches.

However, we have custom bare printed circuit boards, whose sizes may vary depending on your requirements.

How do you Support OEM Business in Bare PCB Industry?

Our team will help you every stage of the bare PCB production process.

We start from bare PCB design and layout, bare PCB prototyping, bare PCB fabrication to bare PCB testing.

At Venture Electronics, we help you get high performance bare PCB depending on your unique requirements.

We can handle a range of PCB fabrication processes besides helping you choose a suitable PCB material.

Contact us today for all your bare PCB needs.