Find a Trusted FPC Manufacturer – “FPC Company Map” for Flexible PCB Sourcing
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Find a Trusted FPC Manufacturer – “FPC Company Map” for Flexible PCB Sourcing " 【Sponsored Content】How to Avoid Troubles in FPC Design and Manufacturing?

How to Avoid Troubles in FPC Design and Manufacturing?

Potential Issues with Flexible PCBs

Circuit Shorts Due to Inadequate Clearance

One common cause of circuit shorts is having insufficient clearance (gap) between the copper plane (solid copper) and the circuit pattern. When these are too close, the etchant cannot properly flow between the copper layers, resulting in incomplete or incorrect pattern formation.

This is particularly problematic in areas with large copper pours, where it's even harder for the etchant to reach between features—potentially leading to defects in the final circuit pattern.

2. Shorts or Breaks Due to Lifted Dry Film

Sharp angles, extremely fine shapes, or minimal gaps (known as “slivers”) in the pattern data can result in unintended circuit formation. In the worst cases, this can lead to shorts or open circuits.

During the etching process, dry film can easily peel away from these slivers, and the detached film may float in the processing chemicals and attach to other boards, leading to further defects.

Router Bit Breakage Causing Defects

A router bit is used to create slits. Currently, a 2.0 mm slit width is standard because a thicker drill bit is often required. However, there are still occasions when a thinner router bit—such as φ1.0 mm—is used, which has a higher risk of breaking. This can lead to defects and, because you must slow down the process to prevent breakage, it can also increase manufacturing time.

Flexible Printed Circuits are Very Delicate;
How to Avoid Troubles

High-resolution flexible PCBs, with ultra-fine pitch and compact features, demand expert-level design and manufacturing. To avoid costly errors, partnering with experienced professionals is key.

In this regard, we would like to highlight Sanyo, a company with over 50 years of experience in designing and manufacturing flexible printed circuits.

Sanyo handles challenging areas such as flexible printed circuits with a 20-micron pitch, which is rarely seen elsewhere. The team at FPC Company Map sat down with Sanyo to find out what makes this possible.

Interview with Sanyo’s “Flexible PCB Specialists”

Understanding Customer Intent and Offering Better Solutions

Could you tell us the secret to creating high-definition flexible printed circuits?

One of the biggest strengths is our design expertise. Our designers are highly skilled at understanding customer intent—even going beyond specs to suggest better alternatives when needed. We always follow the spec sheet, but if we can deliver a better result, we’ll recommend it.

Another strength is our technical capability, which we think also reflects our passion. The narrower the pitch, the harder it is to match the design exactly. For example, with 20μm pitch patterns, masking and etching can easily lead to over- or under-etching depending on the overall board layout.

At Sanyo, we calculate these variables and may adjust design values accordingly. If we foresee challenges in matching the final product to the drawing, we explain the situation to the client and may propose modifications to the design.

Creating PCBs That Offer True Value to the Customer

Do you make proposals based on your past experience?

Exactly. Through our experience, we can predict to some extent how pitch widths will become narrower or wider. If it looks like the pitch will get too narrow, we may widen it in advance, accounting for how the copper will dissolve. We apply corrections so that when the copper dissolves, the dimensions end up just right.

This is the result of experience accumulated over many decades. First, we consider what can realistically be done at our company, and if something appears unfeasible, we make proposals to the client.

If a client says a certain part of the drawings is non-negotiable, how do you handle it?

Every client has certain requirements they cannot compromise on. In these cases, we discuss options thoroughly and identify the best final approach before we begin.

Just by looking at the drawings, we can’t know the customer’s absolute must-haves. But if we don’t preserve those critical points, the final board won’t hold any value for them.Rather than forcing them to adapt to our production constraints, we make every effort to understand the client’s vision and honor it.

We also find cases—albeit a certain percentage—where drawings contain inconsistencies, design errors, or misconceptions. At our company, we check for those issues as well, preventing trouble before it happens.

Daily Improvements in Quality and Efficiency Through Rigorous Management

Do you tackle production as a team?

Sometimes the design team alone can’t handle everything. At that point, we form a group of two or three people, including design, engineering, manufacturing, and sales—four or five members total. They pool their knowledge to get the job done.

How is your management system structured?

Basically, we follow ISO standards. At each production stage, the operators conduct inspections, and then our quality management team does additional checks at key checkpoints. The number of checks varies, but we typically have five or six inspection points.

We adjust the inspection methods depending on the objective and required precision. We also compile data at least once daily, sharing information on progress and any defective products with each department head. This allows us to continuously improve both quality and efficiency.

How long does it take to respond after receiving a request?

We don’t have a fixed “standard” turnaround time. If it’s a very simple specification, it could be about a week, while a more complex design could take nearly two months.We encourage customers to consult with us first. We’ll explore the best possible approach and then make recommendations.

Thank you for your time!

“FPC Company Map” Editorial Team’s Takeaway

We feel one of SANYO’s major strengths is its “customer-centric” approach. Instead of producing flexible PCBs in whatever way is easiest for them, SANYO listens to each client’s needs and non-negotiables and strives to get as close to the ideal as possible. This is only possible because of the designers’ high level of technical skill and genuine passion. If you request a flexible PCB from a team like SANYO’s, it seems likely you’ll end up with a truly ideal solution.

See Product Information On Sanyo's Official Website

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About SANYO: Serving a Variety of FPC Pitch Requirements

Sanyo's Strengths

Extensive Capabilities—Even for Challenging Projects Other Companies Decline

Sanyo’s greatest asset is its ability to handle everything from design to assembly in-house. They work closely with customers, so there are few instances where they have to say, “We can’t do this.”

Because they can handle narrow-pitch, high-precision FPC, they can also take on complex, difficult projects that other companies have turned down. They offer quick turnaround on prototypes, short lead times, and more—truly a manufacturer with wide-ranging capabilities.

Technical Excellence Demonstrated by 40 Years of Experience

SANYO has 40 years of hands-on experience in flexible PCB manufacturing, meaning it can reliably handle even the most intricate high-precision designs.

They can accommodate subtractive processes, semi-additive processes, and electroless metal deposition, enabling them to custom-make ultra-high-precision boards.

Ongoing Commitment to Quality Control

SANYO holds UL certification, ISO 9001, and ISO 14001, meeting various international quality standards.

Internally, they rely on experienced technical staff for quality checks and emphasize workforce training to maintain product consistency.They continually strive for “100% defect-free” production.

Sanyo Company Profile

See Product Information On Sanyo's Official Website

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