Flex Talk: The Myth About Rigid-Flex Costs


This column was co-written with Anaya Vardya, American Standard Circuits.

Do you cringe when you think of the option of rigid-flex? It is not an uncommon reaction when talking with designers and engineering managers about using rigid-flex to solve a packaging problem. Why? The most frequent answer is, “They are so expensive.” While it is true that a rigid-flex PCB is typically more expensive on the surface when compared to rigid-board solutions with cables and connectors, a lot is being missed with that mindset.


First, let’s discuss the many technical benefits associated with rigid-flex solutions. Rigid-flex PCBs can:

1. Serve as a remedy to natural product packaging problems

Flexible circuits are often chosen because they help solve problems related to adding electronics inside the product they serve. They are a true three-dimensional solution that allows electronic components and functional and operation elements (i.e., switches, displays, connectors, etc.) to be placed in optimal locations within the product, assuring ease of use by the consumer. They can be folded and formed around edges to fit the space allowed without breaking the assembly into discrete pieces.

2. Reduce both weight and volume requirements

Flexible circuits are appreciably lighter than their rigid circuit counterparts. Depending on the components used and the exact structure of the assembly and final products, they can save as much as 60% of the weight and space for the end-product compared to a rigid-circuit solution. Additionally, their lower profile can help a designer create a lower profile product than is possible with a nominal 1.5-mm rigid board.

3. Reduce assembly costs

Before the broad use of flexible circuits, assemblies were commonly a collection of different circuits and connections. This situation resulted in the purchasing, kitting, and assembly of many different parts. By using a flex circuit design, the amount of part numbers required for making circuit-related interconnections is reduced to one.

4. Eliminate the potential for human error 

Because flexible circuits are designed as an integrated circuit assembly with all interconnections controlled by the design artwork, the potential for human error in making interconnections is eliminated. This is especially true in the cases where discrete wires are used for interconnection. 

5. Facilitate dynamic flexing

Nearly all flexible circuits are designed to be flexed or folded. In some unusual cases, even thin rigid circuits have been able to serve to a limited degree. However, in the case where dynamic flexing of a circuit is required to meet the objectives of the design, flexible circuits have proven best. Modern disc drives, for example, need the flexible circuit endure anywhere millions of flexural cycles over the life of the product. Other products, such as laptop hinge circuits, may only require thousands of cycles, but it is the dynamic actuation capability enabled by the flex circuit that is key to its operation.

6. Improve thermal management due to being well-suited for high-temperature applications

High temperatures are experienced both in assembly with lead-free solder and in the operation of higher power and frequency digital circuits. Polyimide materials are well-suited to the management of high-heat applications. Not only can they handle the heat, but their thinness also allows them to dissipate heat better than other thicker and less thermally conductive dielectrics.

7. Improve product aesthetics 

While aesthetics may seem like a low-order advantage, people are commonly influenced by visual impressions and frequently make judgments based on those impressions. Flexible circuit materials and structures look impressive both to the seasoned engineer and the layperson. It can make a difference in the decisions made in some applications, especially those where the user gets exposure to the functional elements of the product. 

The increasingly sophisticated electronics being developed are pushing more designs to rigid-flex. Thinking through the benefits listed above, you become convinced that rigid-flex is the right direction for your next project. The next step is convincing your boss or program manager that this concept is the best solution. 

You are now battling that same perception; rigid-flex is more expensive. However, you cannot compare only the cost of the rigid board and cables to the rigid-flex. You need to look more holistically at the total cost of the design. 


Here are the key factors to consider when comparing the cost of rigid-flex to a PCB and cable solution:

1. Design

Because you are merging multiple boards, only one design is needed with a rigid-flex. With the rigid PCB and cable solution, multiple PCB and cable assembly designs are often required. The cost of generating each design should be included when doing a comparison of both options.

2. Cable and connectors

It is common for someone to compare the cost of the rigid boards with the cost of the rigid-flex and jump to the conclusion that the rigid-flex is too expensive. However, the cost of the cable and connectors should also be considered in this decision. This includes the cost of kitting for assembly, labor, in-process inspection, cable assembly test, final test, PCB tooling and test charges, and the cost of engineering time required for each of the items.

3. Assembly operation

Similar to the concept of the cost of the design, a rigid-flex solution requires only one assembly. The PCB and cable solution can require two, three, or even more individual boards to be assembled. The total cost of assembly should be included in this review.

This includes a similar list to the one in point two, along with multiple set-ups of the assembly equipment, and engineering time required for each assembly operation.

4. Testing

Not only does rigid-flex require one test operation compared to possibly several for individual boards connected by cable, but it also provides the ability to test the full assembly before installation.

5. Order processing

The cost associated with processing orders is often overlooked. Rigid-flex is one unit. Multiple boards, cables, and connectors can require several purchase orders to be placed, monitored, received, inspected, handled, stored, and payment processed. These costs should also be captured in a comparison of both options.

To read the full version of this article which originally appeared in FLEX007 Magazine, click here.



Flex Talk: The Myth About Rigid-Flex Costs


Do you cringe when you think of the option of rigid-flex? It is not an uncommon reaction when talking with designers and engineering managers about using rigid-flex to solve a packaging problem. Why? The most frequent answer is, “They are so expensive.” While it is true that a rigid-flex PCB is typically more expensive on the surface when compared to rigid-board solutions with cables and connectors, a lot is being missed with that mindset.

View Story

Flex Talk: Mina—RFID, LED and What Else?


“The science of today is the technology of tomorrow.” This Edward Teller quote is an apt description of the Mina product. This advanced surface treatment, recently developed to enable low-temperature soldering to aluminum in the RFID market, is not only finding success in that market, but quickly finding a home in other markets, including the LED market, where the incentive is both cost and improved LED performance.

View Story

Raising the Capability Ceiling: SMTA Upper Midwest Chapter Expo


An energetic and engaged crowd filled the recent SMTA Upper Midwest Expo & Tech Forum. The event, held in June 14 in Minneapolis, Minnesota, hosted 57 exhibiting companies and had over 100 pre-registered attendees. The underlying theme for the technical presentations was "Raising the Capability Ceiling!" Here's a wrap-up of the event.

View Story

Flex Talk: E-Textiles—the Wild Frontier


How many hours is your car sitting idle outside in your driveway or a parking lot? What if your car was used for solar harvesting—converting heat to energy? What about biometric sensors in automotives: skin sensors for preventing DUI, posture identification to monitor driver fatigue, monitoring exposure to hazardous materials in a load for truck drivers.

View Story

Flex Talk: Something New for Everyone


Whether you are new to single- and double-sided flex, moving into rigid-flex construction, thinking of using bookbinder technology, or investigating an additive process, working with new technology can be both exciting and challenging.

View Story

Flex Talk: Invited Guests to the Party


Hanging on the wall in my office is this quote from Jeff Bezos: “We see our customers as invited guests to a party, and we are the hosts. It’s our job every day to make every important aspect of the customer experience a little bit better.”

View Story


FlexFactor: Faith in the Future


Take just a minute and read through this list of new product ideas. Can you identify the common thread? Yes, they are all enabled by advanced technology, but would you believe that these products were all pitched in the last year by high school students?

View Story

Flex Talk: The Man Behind the Curtain


“Pay no attention to the man behind the curtain.” This famous quote from The Wizard of Oz conjures up the image of Dorothy, the Tin Man, the Cowardly Lion and the Scarecrow discovering that the great Wizard of Oz isn’t as grand or as magical as he seems.

View Story

Flex Talk: Knowledge is Power


“What can I do to help drive cost from my design?” This is a question that I am asked routinely. That question is often followed by, “Can I get these faster?” Both questions are even more predominant when talking about flexible circuits or rigid-flex.

View Story

Flex Talk: Mina—Trouble-Free Soldering to Aluminum


Thinking about the RFID market and the significant growth projected in this market, I decided to do a little research on RFID tag manufacturing. During this research, I learned of a relatively new offering, Mina, an advanced surface treatment technology that addresses the common constraints of large scale manufacturing of aluminum on polyester (Al-PET) circuits.

View Story

Flex Talk: Squink—Integrating Fabrication and Assembly in one Package


When walking through trade show expos, I tend to be drawn into product demonstrations on the show floor. Recently, at the IPC APEX EXPO, I stopped in front of a piece of desktop printing equipment that was demonstrating with a flexible circuit.

View Story

Flex Talk: Flex Material Handling—An Inside Peek


As increasingly more designs move to flexible materials to take advantage of space, weight or packaging benefits, it has been clear that flexible circuits require a different set of rules than their rigid counterparts. We spend substantial time working through the design to ensure that he flex is as robust as possible.

View Story

Flex Talk: Final Surface Finish—How Do You Choose?


There are so many final surface finish options to choose from today. How do you decide which is best? HASL—both tin-lead and lead-free—immersion tin, immersion silver, ENIG, OSP, and ENIPIG are the primary finishes used in PCB fabrication.

View Story


Flex Talk: A Glimpse into PCB Sales


Summarizing the feedback from both customers and manufacturers, the most successful PCB salespeople are organized, take a genuine interest in their customers’ needs and business challenges, have a better than average understanding of the PCB industry, fully understand the manufacturer’s strengths and capabilities and advocate for both to find the best solution.

View Story

Flex Talk: Troubleshooting Flex Circuit Applications for Mil/Aero Projects


I imagine that everyone has been in this position at one time or another: Despite everyone’s best attempt at creating the perfect design, PCB fabrication and assembly, something goes wrong and the troubleshooting begins.

View Story

Flex Talk: Inaugural West Coast Geek-A-Palooza a Fun-filled Success


Geek-A-Palooza kicked off the 2016 schedule May 12 in Irvine, California. Historically, Geek-A-Palooza has been held in Minneapolis but is expanding this year to include Orange County and Boston as well.

View Story

Flex Talk: PCB Sourcing? One Size Does Not Fit All


When analyzing a set of PCBs to improve yields and maximize profits, the first place to start is with a critical review of each PCB design. Are there any attributes that are pushing your manufacturer’s standard design rules? If so, is this necessary to the design or is there another approach that could improve the manufacturer’s yields, reduce cost, and ultimately increase profit?

View Story


Flex Talk: Thoughts on the IPC Flexible Circuits–HDI Forum


As an attendee at the IPC Flexible Circuits–HDI Conference held October 28–30, I found myself in a room of people, all eager for technical information, with the opportunity to reconnect with industry friends and to make new connections. The audience was diverse with young people, new to our industry, sitting alongside industry veterans willingly sharing their knowledge and passion for HDI design and flexible circuit technology.

View Story

Designing Flex Circuits for Domestic Prototyping


Designing a flex circuit to be prototyped domestically? No problem. Designing a rigid-flex circuit for production offshore? Got it. Designing a part that will be prototyped domestically with a seamless transition to offshore production? That can be a little more challenging.

View Story

Rigid Flex: Total Cost Comparison


The transition to a rigid-flex design from the traditional approach of using cable assemblies to join two or more PCBs has obvious benefits—space, weight, packaging, reliability and increased currently carrying capabilities. Yet many times the perception that rigid-flex is a high-cost solution causes designers and engineers to hesitate.

View Story

Primary Cost Drivers for Flex Circuit Designs


Someone once told me that the potential applications for flexible circuits are really only limited by our imaginations. After pondering that a bit, I had to agree. In fact, one of the things I like best about what I do is that moment during a discussion when I can see the light bulb go off in a designer's head.

View Story

The Flex-to-Fit Approach


The flex-to-fit concept reminds us that creativity and engineering go hand-in-hand. When there is not ample space for a conventional approach, this process, which is the convergence of the mechanical world and the electronics world, results in the ability to design a flexible circuit along the contour of an existing, irregularly shaped structure.

View Story
Copyright © 2019 I-Connect007. All rights reserved.