Tested and Reliable Introduction to Flex Board Manufacturing

Published on July 24, 2024 , Last modified on November 7, 2024
by Hommer Zhao

Flexible circuit boards are an important aspect of the modern slim and compact electronic products.

As a circuit board, it has the same functionality and arrangements but has a different support substrate for the components and the copper trace.

So, manufacturing such flexible circuits takes some special steps.

The overall process of flex board manufacturing includes few additional processes than the actual circuit board manufacturing process.

Designing

The manufacturing process starts with the CAD design as usual. However, the designer must take extra steps to position key components and fragile circuitry away from stress points.

In a flex board design, it’s essential to align components parallel to the direction of the intended bending position. This alignment helps minimize stress on the solder joints and the copper strip beneath them, enhancing durability and reliability.

For high-quality circuit board manufacturing, these careful design considerations ensure that flex boards can withstand bending without compromising performance.

Flex Board Laminate Preparation

After the CAD design, the flex PCB manufacturing heads to copper laminates for the flex board.

A thin layer of heat-resistant polymer or similar material is prepared and cut to the desired shape and size.

The sheet of heat heat-resistant base is coated with a heat-induced adhesive on of sides.

A thin layer of copper sheet is placed over the adhesive layer and heat-pressed for several hours to bond them together.

A second protective layer is usually added to the flex board manufacturing process to strengthen the surface and allow the board to withstand the temperature and stress.

Circuit Etching Process

The PCB design is converted to a graphical image and imposed on the flex board laminate with UV-curable masking paste and a computerized UV exposure.

This step marks the copper for the circuit connection and leaves the unwanted copper exposed.

The sheet is carefully transferred to the chemical treatment bath for etching the excess copper way.

A powerful industrial solvent is used to etch the copper.

The flex board manufacturing includes the number of washes to ensure the elimination of chemical and flux residue.

For the solder mask, unlike traditional methods, the flex pcb manufacturing process covers the entire copper trace with a thin layer of the laminate sheet in which the required holes are pre-pressed.

Assembly and Testing in Flex Board Manufacturing

The next step in flex board manufacturing is silkscreen layer printing, which marks the component’s outline and alignment.

As these flex boards are usually tiny, high-resolution mostly do the assembly.

Some of the complex components are soldered by hand.

The flex PCB manufacturing tests the board in each layer for defects and misalignments.

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Hommer Zhao
Hi, I'm Hommer Zhao, the founder and Chief Editor at WellPCB. With extensive experience in the PCB industry, I oversee all content to ensure it meets the highest standards of accuracy and insight. We proudly serve over 4,000 customers globally. For inquiries or more information, don't hesitate to reach out. Your satisfaction is my top priority!