X-Rayted Files: A Century of X-Rays in the Automotive Industry, Part 2

In Part 1 of this column series, we explored the intimate relationship between the evolution of the X-ray and automotive industries. As one of the main users of X-ray inspection, the automotive industry has been one of the main drivers for the development of higher power and higher resolution X-ray imaging systems. Keep in mind that cars today are nothing but highly sophisticated computers. The simple analog dashboards with a speedometer and odometer have been replaced by complex entertainment centers.

While demands for ever-smaller electronics have dominated PCB design, and surface-mount components emerged in response to such demand, industries like automotive and aerospace still rely on through-hole components for their reliability in the harshest environments. The strength of the connection of surface-mount components is limited by their thin solder joints, and are thus less reliable under stresses such as vibration, shock, and high temperatures.

Through-hole components are mechanically stronger because their leads run through the board, and the solder joints are much more substantial and less susceptible to an array of environmental stresses. These properties make through-holes the ideal choice for larger components, as well as those with high-power demands, especially in extreme environments that involve rapid acceleration/deceleration, vibration, and thermal expansion/contraction.

Through-hole via (THV) solder filling plays an important role in the long-term reliability of through-hole components. The inadequate filling of THV can, over time, cause mechanical stresses that can result in traces connected to the THV to break. Insufficient THV filling also causes damage to the via itself, causing cracks and splits on the via. These effects are especially present in applications that subject boards to mechanical and thermal stresses, such as equipment in the military, automotive, and aerospace industries.

The diagnostic of THV filling must be done using an X-ray inspection system, preferably with an angled view. The need for an angled view X-ray inspection lies in the nature of the THV. A top view of the view will not produce an adequate perspective of how much solder the THV has.

Figure 1 shows the cross-section representation of an empty, partially filled, and completely filled THV. Due to capillarity, the solder wave flows from the solder source side to the component side. In so doing, it wets the connecting surface of the solder side, surrounds the pin, and forms a solder meniscus on account of the protrusion of the pin on the solder side.

Cardoso_Fig1_1020.jpg

Figure 2 shows the X-ray image of a similar assembly, where partially and completely filled vias are shown. This X-ray displays the importance of an angular inspection to determine the via solder fill in a THV assembly.

Cardoso_Fig2_1020.jpg

The yellow, green, and red lines in Figure 3 illustrate how the THV filling software measures the amount of solder inside the barrel or via. Figure 3 shows an X-ray image of empty, partially filled, and filled THV. The colored ovals in the figure match the color representation, shown in Figure 1, so that you can visualize the location of the solder inside the via. To measure via fill, the software determines the relative distances between the yellow-to-green and yellow-to-red makers to measure the percentage of via fill.

Cardoso_Fig3_1020.jpg

Other than solder penetration problems, IPC-A610E also accounts for issues related to the partial filling of the THV around the component lead. Table 1 summarizes the pass criteria for THV:

  1. Class 1, General Electronic Products: Includes products suitable for applications where the major requirement is function of the completed assembly.
  2. Class 2, Dedicated Service Electronic Products: Includes products where continued performance and extended life is required, and for which uninterrupted service is desired but not critical. Typically, the end-use environment would not cause failures.
  3. Class 3, High-Performance/Harsh Environment Electronic Products: Includes products where continued high performance or performance-on-demand is critical, equipment downtime cannot be tolerated, end-use environment may be uncommonly harsh, and the equipment must function when required, such as life support or other critical systems.

Cardoso_Table1_1020.jpg

Figure 4 shows examples of how to use your X-ray inspection system to diagnose these problems. In this case, contrary to the X-ray images in Figure 2, the X-ray sensor was positioned right above the THV for a top-down view of the whole THV column.

Cardoso_Fig4_1020.jpg

When troubleshooting THV issues, here are some of the things you can take a look at to improve your process:

  • Adequate solder quantity deposited
  • Proper solder to guarantee wetting
  • Proper surface cleaning of PCB to eliminate contamination that will block the proper flow of solder
  • Inadequate temperature of solder so that it doesn’t complete the reflow process properly; it is important to consider the thermal mass of the component and the board (e.g., heavy copper planes require longer times or higher temperatures for proper solder flow)
  • Inadequate time of the soldering process; it’s possible the components and THV are not reaching the right temperature (thus, the solder is not flowing up to the other end of the THV)

Dr. Bill Cardoso is CEO of Creative Electron.

Back

2020

X-Rayted Files: A Century of X-Rays in the Automotive Industry, Part 2

10-28-2020

As one of the main users of X-ray inspection, the automotive industry has been one of the main drivers for the development of higher power and higher resolution X-ray imaging systems. Dr. Bill Cardoso continues with Part 2 of this column series.

View Story

X-Rayted Files: A Century of X-Rays in the Automotive Industry, Part 1

09-29-2020

If you have read any of Bill Cardoso's previous columns, you know that he is passionate about X-rays, cars, and electronics. In this column series, he talks about some of his idols, including Curie, Roentgen, Marconi, Galvin, and Ford.

View Story

X-Rayted Files: Is Quality Really Priceless?

08-19-2020

In a day and age when we can learn virtually anything online, manufacturers still manage to be opaque about pricing, especially when it comes to specialty equipment. Some may say, “Quality is priceless,” but Bill Cardoso explains how it isn't.

View Story

X-Rayted Files: Marching Toward 2021, 20 Miles at a Time

07-29-2020

We’re only at the halfway mark, and 2020 has been a real challenge. Our best-laid plans have been cast in doubt by the COVID-19 pandemic. During this transformational time, Dr. Bill Cardoso looks back a century for a bit of inspiration from Norwegian explorer Roald Amundsen.

View Story

X-Rayted Files: E-Commerce Boom Fraught With Risk—X-Rays to the Rescue

06-17-2020

It’s not news that online sales are increasing dramatically during this global pandemic. However, with increased sales comes the increased risk of return fraud and abuse. Dr. Bill Cardoso explains how X-ray can help detect dummy and counterfeit merchandise.

View Story

X-Rayted Files: Why Do We Break Stuff? Intelligence From Teardowns

05-20-2020

The impulse to break a new gadget to "see what's inside" and to “learn how it works” is often the first sign someone will become an engineer. We’ve learned a lot in over a decade of teardowns, which have helped us to understand how the SMT industry has changed over these years. Bill Cardoso investigates.

View Story

X-Rayted Inspection: Manufacturing in the Eye of a Pandemic

04-08-2020

Dr. Bill Cardoso usually writes about X-ray inspection, artificial intelligence, machine learning, and how it all connects to Industry 4.0. This month, however, he shifts gears and shares some of the things Creative Electron has been doing during the COVID-19 outbreak.

View Story

X-rayted Files: X-ray and AI—A Match Made In Heaven, Part 2

03-18-2020

In Part 1, Dr. Bill Cardoso covered the basics of the relationship between X-ray inspection and artificial intelligence (AI). In Part 2, Cardoso takes a step forward to cover some of the practical ways we use AI to improve the efficiency of our X-ray inspections.

View Story

X-Rayted Files: X-Ray and AI—A Match Made In Heaven, Part 1

02-05-2020

Dr. Bill Cardoso has been working with AI for a while now and seen real application and success in X-ray inspection, as well as failures. In Part 1 of this column series, he shares how AI is changing the way we think about X-ray inspection.

View Story

X-Rayted Files: When SMT Lines Develop Line Conscience

01-22-2020

Bill Cardoso explores the history of Henry Ford's assembly line, how this may be the end of the automation era, and the future of autonomous systems, AI, machine learning, etc.

View Story
Back

2019

X-Rayted Files: Will Radiation Damage My Electronic Component?

12-17-2019

Before I start talking about radiation damage on electronic components, let me warn you: if you are looking for a simple “yes” or “no” answer to the question, "Will radiation damage my electronic component?" stop reading now. Things will get complicated. You may feel like I did not answer the question at all, and you would be correct. There are whole conferences dedicated to this question (check IEEE’s Nuclear and Space Radiation Effects Conference), so the goal of this column is to give you some background to guide you to the right answer for your specific situation. Ultimately, the best way is to ask an expert.

View Story

X-Rayted Files: The Currency of Technology

11-11-2019

In the ever-moving tide of technology, the need to innovate requires a constant shift in vision, and this need has never been more evident than in PCB manufacturing. In fact, innovation has become so valuable that PCBs are quickly becoming the currency of technology. Dr. Bill Cardoso explains.

View Story

X-Rayted Files: The Risk of Installing Counterfeit Parts

10-02-2019

In high-tech manufacturing, the use of sub-standard components can be catastrophic. There is no greater need for quality control than in PCBs, as they are only as good as the components installed on them; therein lies the problem. Some components shipped to manufacturers are counterfeit!

View Story

X-Rayted Files: Just Because You Can't See the Problem Doesn't Mean It's Not There!

08-20-2019

In this new column, Dr. Bill Cardoso will cover everything related to X-rays from cool historical facts to the latest in technological advancements, starting with the discovery of X-rays in 1895.

View Story
Copyright © 2020 I-Connect007. All rights reserved.