A Beginners Guide On How To Make Your Own Flex PCB

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Oakley Mae

Home » Blog » Flexible PCB » A Beginners Guide On How To Make Your Own Flex PCB

Learning to make your flex PCB can help you save costs and design a PCB with the exact features you want.

However, the process won’t be easy, especially if you don’t have the required skills and equipment. 

Just so you know, upon making your flexible PCB, you can use it in electronics like televisions, calculators, laptops, smartphones, and industrial machinery.

So the question is, how do you design and make flexible PCB? And that’s what we’re answering in today’s article.

Let’s get rolling. 

Table of Contents

What Is Flex PCB?

A printed circuit board has composite epoxy, laminate materials, and fiberglass designed with conductive pathways to link with different components, including ICs, resistors, and diodes.

Therefore, a flexible PCB is just a printed circuit board designed to bend and fold without damage.

And sometimes, they have stiffeners to offer physical and mechanical support. 

Since flex circuit boards fit in tight spaces, you can use them to design compact and lightweight devices.

This is why most wearables, like smartwatches, use flexible circuit boards. 

Most flex PCBs employ the following structure and materials:

  • Polyimide layer (PI): We use these materials as overlays to protect the circuit board against mechanical damage. Therefore, they function like solder masks in rigid circuit boards. 
  • Substrate: This is the circuit board core; we use polyester or polyimide. Manufacturers use this material for their flexibility and heat resistance. 
  • Conductive layer: Manufacturers use copper to create conductive pathways. However, there are still some that use gold and silver. 
  • Adhesive layer: Manufacturers use these materials to strengthen the bond between the layers. 
  • Stiffeners: Manufacturers add these materials to improve the PCB strength and act as link device interfaces and the circuit board. 
  • Vias: Finally, manufacturers drill through the circuit boards to connect the different layers. If vias go through all the circuit board layers, we call them plated-through holes. 

Flexible PCB DIY: Equipment You’ll Require

A digital electrical multimeter

(A digital electrical multimeter)

To successfully make your flexible circuit board at home, you need the following equipment:

  • An etching tray
  • Polyimide film
  • A laptop or PC
  • Solid ink printer
  • Etching chemicals
  • Multimeter
  • A heating element
  • A circuit board designing software like Proteus or EAGLE
  • A4 paper
  • Copper lamination sheets or pyralux copper lamination sheets

Make Your Flexible PCB: Steps To Follow

Engineers discussing more on circuit design

(Engineers discussing more on circuit design)

Designing a homemade circuit board is easy if you follow the steps below: 

Get Organized

We have all heard the saying that if you fail to plan, you’re planning to fail.

Therefore, before you start anything, you should plan and get organized by acquiring all the tools and equipment. 

For the best results, we recommend you stick with copper-coated film. Ensure you check the conduction and availability of thin polyimide sheets with copper on all sides. 

Design The Schematics

A photo of a schematic diagram

(A photo of a schematic diagram)

Creating schematics is the first phase of any design process.

This involves using symbols of the electronic components to represent the whole circuit.

Fortunately, you can use many design software specifically for this purpose, including Proteus, EAGLE, and SmartDraw. 

We have shown you how to design with SmartDraw to understand this guide.

And even if you’re new to PCB design, Smartdraw offers you a circuit diagram template. 

Below are the simple steps of designing with Smartdraw:

  • Firstly, you should collect all the electrical circuit symbols you’ll use in the design. You’ll find these symbols to the left of your drawing area. 
  • Secondly, you should draw a circuit represented by lines. By default, these lines have an arrow at one end. Also, the software allows you to change your line type from the line shape option. 
  • Thirdly, drag your circuit symbols and drop them into your circuit, consequently connecting them. Moreover, you have an option of modifying the symbol if need be. 
  • Finally, if by any chance two line cross, you should use a line hop or bridge. At this point, you can proceed to create a prototype. 

Do you remember the solid ink printer and the pyralux copper lamination film above? This is the time to put them into use. Therefore, the solid ink printer prints directly on your pyralux copper film. 

The print from the ink printer doesn’t rely on charging the paper surface locally, which could translate into challenges if the copper sheets were to replace paper. 

Etching

In this step, insert your sheet in the etching chemical for about five minutes.

The most effective chemical you can use is ferric chloride.

However, the etching time should strictly depend on the copper sheet thickness and temperature levels. 

Give the sheet time until the section made of copper dissolves. Also, the polyimide film should show up. 

Arrange and Inspect

Finally, you can clean and test the flexible PCB using an AVO meter or multimeter.

Also, this is the time to cut the board into smaller pieces. If time allows, place the different pieces on fiberglass and mount components. 

Benefits of Designing A DIY Flex PCB

flex circuit board in use in a smartphone

(flex circuit board in use in a smartphone)

If you design your flex PCB, it’s likely to meet your specification. Also, you’ll enjoy the following benefits:

Saves Time

Designing a flexible PCB will only consume much of your time during the design and fabrication phase.

However, afterward, the integration process is seamless.

This way, you’ll save more time than buying a circuit board and waiting for shipping. 

Less Labor Cost

We can attribute the high manufacturing costs and price of flex PCB to the high labor cost involved.

Therefore, a DIY design will eliminate all the unnecessary labor costs, thus reducing the overall costs.

Additionally, you can use the first schematics to create a new one. 

Technical Control

Designing the circuit board gives you technical control from start to end.

You won’t have to depend on others to complete your project, thus eliminating possible delays. 

Flexibility

Designing a circuit board by yourself gives you more flexibility and freedom.

You can make changes to the design anytime you wish like. Also, you’ll likely experience fewer errors if you design everything yourself. 

FAQs

Is making a circuit board at home expensive?

Not at all! It becomes cheaper than if you were to buy it from a store.

This is because you eliminate the high manufacturing costs that, in most cases, contribute to the high PCB prices. 

Can I use parts from rigid PCB for my flex PCB?

Yes! Nothing stops you from using rigid PCB parts on a flex PCB.

However, you’ll create a rigid-flex PCB with different characteristics from a flex PCB in this case.

A rigid-flex PCB combines features of rigid and flex PCB.

Therefore, it can still fold without breaking but is also rigid enough. 

How long will it take to create a flex PCB?

It will take you between one to three days to develop a flexible PCB.

However, the exact time depends on your knowledge and experience. Ofcos you’ll finish faster if you have more design experience. 

Conclusion

Flexible circuit boards have changed the way we design electronics.

We use these boards to design compact devices like medical devices, smartphones, and wearables.

However, the boards might be expensive, thus calling for a DIY design. 

As you have seen, making a flexible PCB at home is straightforward if you have the right knowledge and skills.

And if you don’t have the skills, you can still follow our guide for the best results.

Why waste money buying a flex circuit board if you can fabricate one? Just get the right tools and get to work.