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flex pcb manufacturing

Flexible PCB Manufacturing & Design Guide

Flexible printed circuit, also known as flexible PCB, is a lightweight and bendable circuit board designed to connect electronic components in limited or dynamic spaces. Compared with rigid PCBs, flexible circuits can fold, twist, and fit into compact electronic designs, making them essential in modern electronic products. At Flex Plus, we provide complete solutions for flexible PCB fabrication, design, and assembly. This page gives you a full overview of flexible PCB structure, materials, manufacturing process, and key applications.

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Flex PCB made by laminating a layer of copper foil (usually 17μm, 35μm, 70μm, etc.) to a substrate by hot pressing or chemical deposition, and then etching and other processes. Therefore, the flex PCB does not have a solid rigid support in structure, but relies on its own flexible material to support the layout of the circuit. Flex Plus is able to manufacture ultra-thin flex PCB with a thickness of only 5μm, providing more options for compact, lightweight, and high-performance applications.

What Is a Flexible PCB?

A flexible PCB is a copper circuit laminated on a flexible base film, typically polyimide (PI) or polyester (PET).

This construction allows the circuit to bend or fold without breaking the copper traces.

Flexible PCBs are commonly used in smartphones, medical devices, automotive electronics, and aerospace systems — where space saving and high reliability are required.

See our product types:

Structure and Materials

A flexible PCB is composed of several main layers:

  1. Base Film (PI or PET) – provides flexibility and insulation.

  2. Copper Foil – forms the conductive circuit.

  3. Adhesive (optional) – used in adhesive-based constructions.

  4. Coverlay Film – protects the copper traces while allowing openings for pads.

  5. Stiffener – adds mechanical strength to connector areas or component zones.

  6. PSA (Pressure Sensitive Adhesive) – used when bonding to other parts.

 

There are two major constructions:

Adhesive type flexible PCB – uses glue between copper and PI layers, lower cost but less heat resistant.

Adhesiveless type flexible PCB – directly laminated without glue, higher performance for fine-pitch or high-temperature designs.

 

For more design considerations, check our Flexible PCB Design Solutions.

Flexible PCB Manufacturing Process

The flexible PCB manufacturing process requires precision control at every step to ensure dimensional stability and consistent impedance. The general process includes:​

  1. Base Material Cutting

  2. CNC Drilling or Laser Drilling

  3. Pattern Imaging and Etching

  4. Plating (Through-hole / Surface)

  5. Coverlay Lamination and Curing

  6. Stiffener or PSA Attachment

  7. Profiling and Punching

  8. Electrical Testing and Visual Inspection

Each step must maintain cleanliness, accuracy, and temperature control to avoid dimensional shift or copper cracking.

Learn more in our Flex PCB Manufacturing Process.

See also: Flex PCB Testing Services.

Types of Flexible PCB

Type
Structure
Common Application
Image
Rigid-Flex PCB

Combines rigid and flexible layers in one board

Foldable devices, avionics, compact control units
Multi-Layer Flex PCB

Three or more copper layers

High-end medical, aerospace, or control systems
Double-Sided Flex PCB

Two copper layers connected by plated holes

Automotive sensors, battery packs
Single-Sided Flex PCB

One copper layer, simple structure

Printers, cameras, LED strips
多層フレックスPCB
両面フレックス PCB FPCB
片面フレックスPCB
リジッドフレックスPCB

Each structure provides different electrical and mechanical performance. For complex 3D assemblies, rigid-flex PCBs combine flexible and rigid sections in a single board.

Advantages and Limitations

Advantages:

  • Ultra-thin and lightweight

  • High flexibility and bend radius

  • Reduced wiring space and assembly weight

  • Excellent thermal dissipation

  • Suitable for dynamic or movable connections

Limitations:

  • Higher material and tooling cost

  • Complex manufacturing and assembly process

  • Requires strict handling to avoid damage

However, with proper design and supplier experience, flexible PCBs can provide unmatched reliability for compact electronics.

Related Resources

Looking for more about flexible PCB manufacturing and applications? Explore these related topics:

TPU回路

TPU Printed Circuit — Stretchable silver circuits for soft robotics and wearables.

FPCB Assembly — SMT and COB assembly for flexible PCBs.

Solid copper vs hatched copper in flex PCB

7 different surface finish types for flex pcb

How to choose a flex PCB substrate PI, PEN or PET?

Need a custom flexible PCB solution?

Our engineering team can help you select materials, optimize stack-up, and provide one-stop manufacturing.

Contact Flex Plus for your next project.

Stiffener Automation onto FPCB, Flex PCB

彫刻されたフレキシブル基板

これらの FPCB は、特定の機械的または電気的要件に対応するために導体トレースを選択的に薄くしたり厚くしたりする独自の構造になっています。

一般的な彫刻型フレキシブル回路にはピンがあり、スルーホールコネクタになっています。彫刻型端子ピンは内蔵されており、ポリイミド基板の境界を超えて伸びています。これらのピンはフレキシブル基板 の一連の穴に挿入され、はんだ付けされます。この回路設計は、一連の表面実装パッドにはんだ付けすることもできます。通常、ZIF コネクタの必要性とコストを削減するために選択されます。

彫刻されたフレックス PCB

FPCB の用語

スタガードエッチバック / ステップエッチバック

リジッドフレキシブル基板製造の文脈では、「スタッガード エッチバック」または「ステップ エッチバック」は、リジッドフレックス回路基板の銅トレースまたは導電層に制御された深さの変化を作成するために使用されるプロセスを指します。

このプロセスでは、導電層の一部を選択的にエッチングして、基板上のさまざまな場所でさまざまな銅の厚さを実現します。

スタッガード エッチバックの目的は、 リジッドフレキシブル基板の柔軟性と曲げ特性を最適化することです。銅の厚さを変えることで、基板は領域ごとに異なる柔軟性を持つことができ、電気的性能や機械的完全性を損なうことなく、希望の形状に曲げて適合させることができます。

スタッガード エッチバックは、リジッドフレックス回路基板の製造に不可欠な技術です。この技術により、基板はさまざまな機械的要件に対応し、複雑な形状に適合できるようになります。これは、スペースと重量の制約が重要な航空宇宙、医療機器、その他の電子機器などのアプリケーションでよく使用されます。

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