Fresh PCB Concepts: Recommendations for Track Welding and Open Circuit Repair

Mike_Marshall_300_NCAB.jpgTrack welding is what some factories may opt for if they find an open circuit. The technique is to attach/stick/weld a thin piece of copper across the broken track. Sounds okay, right? But how reliable is the repair? And how does IPC cover this subject?

Well, IPC doesn’t have too much to add on this subject other than mentioning that the customer and supplier should agree whether repairs are acceptable or not. Therefore, if the customer does not advise it is not acceptable, then it is acceptable by default. In my experience, the issue is rarely discussed between the supplier and customer. The lack of front-end discussions all too often comes to light after the fact when anomalies are detected on the finished PCB assembly.

Poor repairs can lead to open circuits being supplied; even a “good” repair has a risk of failure under load conditions (vibrations, etc.) leading to potential field failures.

To repair a PCB, the operator must remove the solder mask properly to expose the copper. Plus, the solder mask must be removed in the correct area without exposing the adjacent track and this can lead to a risk of short circuits. Then, copper must be welded very accurately to a thin track and ensure good enough registration. Finally, there must be enough contact to the original track. Even if the repair is reliable, many times the track is reduced by more than the acceptable IPC allowance for reduction limits.

We recommend having in place a strict policy when it comes to track welding: Do not allow repair of open circuits or track welding. Period. Any supplier utilized should also have track welding terms in their specifications. There’s too much risk. If you’ve ever experienced a field failure and all the effort, time, and costs that occur, you would know it’s worth it.

It’s a nightmare no one wants to go through. In this case, the best part if it’s not cost driven in the same way other things are such as via plugging or very thick copper.

Michael “Mike” Marshall is a field application engineer at NCAB Group. 

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2021

Fresh PCB Concepts: Recommendations for Track Welding and Open Circuit Repair

11-23-2021

Track welding is what some factories may opt for if they find an open circuit. The technique is to attach/stick/weld a thin piece of copper across the broken track. Sounds okay, right? But how reliable is the repair? And how does IPC cover this subject? Well, IPC doesn’t have too much to add on this subject other than mentioning that the customer and supplier should agree whether repairs are acceptable or not. Therefore, if the customer does not advise it is not acceptable, then it is acceptable by default. In my experience, the issue is rarely discussed between the supplier and customer.

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Fresh PCB Concepts: High-tech PCBs from Design to Volume Production

10-25-2021

Today I will talk about producing high-tech PCBs from design to volume production, since it is within this area that customers often do not reach their initial targets regarding time, cost and performance.

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Fresh PCB Concepts: HDI PCBs for New Kids in the Industry

09-30-2021

I have been working with NCAB Group for three years now. When I began I had no experience with PCBs and since have learned so much working with our customers’ PCB designs. I would like to share the basic fundamentals and design features of my favorite type of PCB, high-density interconnect, or HDI.

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Fresh PCB Concepts: Does the Assembly Process Damage a PCB? (Part 2—Time to Delamination)

08-12-2021

In part 1 of this series published back in April, I commented upon the effect the assembly process has upon a printed circuit board. There is another gauge that can be used to help a designer or contract manufacturer understand this point and that is the time to delamination test. These are referred to as either the T260 or T288 tests.

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Fresh PCB Concepts: Auditing a Factory—When Everyone Wins in the PCB Supply Chain

07-25-2021

One of the most important activities when it comes to maintaining the best quality of PCBs is to constantly be evaluating partner factories. An important tool for securing this is auditing those factories on a consistent basis. When the factory develops and the bar gets pushed a little higher each time, we’re in a situation where we all benefit.

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Fresh PCB Concepts: HDI Microvia Features in Illustrations

06-17-2021

Ruben Contreras explains microvias and discusses aspect ratios with microvias. This is important to know when designing an HDI PCB because the different types vary in complexity. And the more complex, the more this affects the cost.

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Fresh PCB Concepts: Does the Assembly Process Damage a PCB? (Part 1—Soldering)

04-14-2021

Every time a printed circuit board is exposed to soldering temperatures it is damaged. This is the case not only for lead-free soldering applications but also for eutectic soldering consisting of tin-lead.

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Fresh PCB Concepts: Mitigating the Increasing Prices of PCBs

03-18-2021

By now, you might have noticed that the cost of PCBs is increasing. What’s worse is that there are also supply chain issues causing additional delays on PCBs. You can’t redesign every board in order to reduce cost. Instead, try these tips to help you reduce manufacturing costs.

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Fresh PCB Concepts: UL Certification for the Safety of PCBs

02-18-2021

Security is essential in the electronics industry. It is vital that users can rely on the finished products when considering factors such as fire and electrical safety, which means that both the PCB and the materials they contain must measure up to the highest standards. To ensure that the boards do conform, it has become common practice to UL certify the constituent materials or the PCB itself. In this column I am going to discuss UL certification, what’s involved and why you need it.

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Fresh PCB Concepts: RF PCB Designs–Challenges, Solutions and Tips

01-14-2021

Today, RF circuitry is crammed into a large variety of commercial products. Most of these are handheld wireless devices for medical, industrial, and communications applications. There are also applications in a variety of fields that are migrating from desktop models to become portable communications units.

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2020

Fresh PCB Concepts: How 5G is Influencing PCB Technology Trends

12-17-2020

We have all heard about the Internet of Things (IoT) and artificial intelligence (AI). In combination with the increased data transfer rates available through 5G, they can open up a whole new level of connectivity and communication between devices and things.

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Fresh PCB Concepts: Finding and Qualifying a Long-Term Partner

11-05-2020

Finding the right factories is not an easy task. Anyone can take customers’ files and send them to whichever factory is available. But what guarantees does the customer have that the factory used is reliable in producing the design? Ruben Contreras details how to find and qualify a long-term partner.

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Fresh PCB Concepts: 4 Characteristics to Consider When Selecting PCB Base Materials

10-08-2020

Selecting the correct material is critical if you want your circuit board to survive the assembly process or come out of the assembly process in good condition. Jeffrey Beauchamp explains the four main characteristics from the IPC-4101 material specification that are critical in finding the performance of your base material.

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Fresh PCB Concepts: Advantages of Application-Engineered PCBs

09-17-2020

When working with your PCB supplier, do you have a dedicated engineering resource to help with the design of your PCB before fabrication? How about a resource that has experience and knowledge about the different applications for PCBs? Jeffrey Beauchamp explains how this is one of the most important and valuable factors when producing high-reliability PCBs, as well as what—or who—this resource could be.

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Fresh PCB Concepts: How Do You Calculate Finished Copper?

08-13-2020

How do you calculate finished copper on a PCB? This may sound simple, but Ruben Contreras has seen copper thickness called out either on the drawing or the specification, which can lead to additional EQs and, in some cases, additional costs. In this column, he explains the unintentional results that can come from misunderstanding what was requested.

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Fresh PCB Concepts: Pros and Cons of the 6 Most Common Surface Finishes

07-23-2020

There are only two different types of surface finishes for PCBs: organic and metal. Harry Kennedy describes the pros and cons of the six most common finishes on the market.

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Fresh PCB Concepts: 7 Options for Via Treatment

06-18-2020

In some cases, it's acceptable to have via holes that are completely exposed in a PCB design. But there are many others where the hole should either be covered and/or tented, or in most cases, plugged. Jeffrey Beauchamp shares seven different via hole protection types based on IPC-4761.

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Fresh PCB Concepts: Why Design and Produce PCBs Beyond Industry Specification?

05-07-2020

While questions may be an annoyance, especially when you finally have a board designed and are ready to have it built for a product, Ruben Contreras explains the importance of asking these questions and requiring specifications.

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Fresh PCB Concepts: What You Should Know About Your Board’s Solder Mask

04-09-2020

It’s a weird time we’re all in, and for most designers, work has slowed down or even stopped. While work might have slowed, now is a good time to review some of your past PCB projects to see if you can improve functionality and reduce field failures. Harry Kennedy explains how one of the simplest ways to do that is to start from the top: solder mask.

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Fresh PCB Concepts: The Benefits of Being a PCB Producer Without Owning Any Factories

03-19-2020

With NCAB's infrastructure and factory management team based in China, many customers ask why they don’t own any factories. Jeffrey Beauchamp explains how it's part of the company's long-term strategy and an advantage to our customers that they don’t own any factories. Instead, they “own” what is most important: the relationship with the factory.

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2019

Fresh PCB Concepts: Designing a PCB for Telecom Applications

12-12-2019

Jeff Beauchamp and Harry Kennedy discuss PCBs for telecommunication applications, including key factors to consider, such as design and material considerations. They also recommend involving your PCB supplier at the time of design to help ensure manufacturability at the lowest possible cost.

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Fresh PCB Concepts: The Current Material Situation

11-11-2019

We have all heard about the component crisis in the circuit board industry, and maybe you heard about the CCL shortage, but how many are aware of the bare board material shortage? Ruben Contreras explains the current material situation and tips to address this issue.

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Fresh PCB Concepts: Getting It Right From the Start

10-23-2019

When faced with critical time-to-market situations, it is all too easy to say, “It doesn’t matter because this is just the prototype; we can fix this later.” However, if the design is perfected from the beginning, cost savings can be applied, and manufacturability can be ensured. Perhaps most importantly, the design can be adapted with reliability in mind, leaving a seamless transition from prototype to production. How do we get it right from the start?

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Fresh PCB Concepts: Why Material Selection Matters

10-02-2019

When you’re designing a PCB, it’s standard to call out FR-4 material, but you could be holding yourself back or even exposing your board to risk by not knowing more about PCB materials. Let’s take a small look into why. What Is FR-4, exactly? Harry Kennedy of NCAB explains.

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Fresh PCB Concepts: Qualities of Medically Applied PCBs

08-26-2019

In this inaugural column from NCAB Group, Alifiya Arastu discusses details of PCBs used in medical applications, highlighting some of the differences in terms of demands and how the design must be handled.

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