The Bare (Board) Truth: ‘The Want of a Nail’ and the Butterfly Effect

Last Sunday, I woke up at 4 AM with a song in my head that I had never heard before—at least not that I could remember! The lyrics had me so perplexed that I had to jump out of bed and check it out. Two things came up on my word search when I looked up “the want of a nail:” the first was the song I had just heard in my head, and the second was something about “the butterfly effect” from a number of chaos theory texts. 

First, I re-played the song titled “The Want of a Nail” by Todd Rundgren and listened to the lyrics I had heard in my head just 20 minutes before in my sleep. 

“For the want of a nail, the shoe was lost,
For the want of a shoe, the horse was lost,
For the want of a horse, the rider was lost,
For the want of a rider, the message was lost,
For the want of a message, the battle was lost,
For the want of a battle, the war was lost,
For the want of a war, the kingdom was lost,
For the want of a nail, the world was lost.”

Then I read the blogs on the butterfly effect. In the example I found, a butterfly flapping its wings can lead to a tornado weeks later, meaning that small events can lead to larger consequences. I believe this wholly. I see that small changes to the initial design or information gleaned at the start of a project lead to much larger issues all the time.

After I digested as much as I could about the butterfly effect, I chanced upon a TV show about bridge failures that focused on a device used to check for voids in the concrete-to-steel wire construction. It was very much like a time domain reflectometer (TDR). Whereas a TDR is mainly used to determine the characteristics of a given electrical line by observing reflected waveforms, they can also be used to locate discontinuities in a connector. In the case being shown regarding a large braid of steel cable encased in concrete, some of the back-filling of the concrete did not fully encapsulate the wire bundle, leading to areas of moisture entrapment and, therefore, oxidation of the wire strand, causing a failure of the bridge.

So, why the Sunday morning revelation? I began to think about how small changes in design characteristics at the PCB fabrication level can have larger consequences for the final product. Some of these include changes in trace geometry, dielectric, material type, copper weights, etc. Let’s go through a basic list of them and discuss each one.

To read this entire column, which appeared in the December 2019 issue of Design007 Magazine, click here.

 

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2020

The Bare (Board) Truth: ‘The Want of a Nail’ and the Butterfly Effect

02-17-2020

After exploring the Todd Rundgren song "The Want of a Nail" and the butterfly effect, Mark Thompson explains how small changes in design characteristics that happen at a PCB fabrication level can have larger consequences for the final product.

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2019

The Bare (Board) Truth: Teaching the Next Generation—An Overview of Today’s University Courses

09-05-2019

In this column, Mark Thompson focuses on the University of Washington, where he counted approximately 163 programs in their catalog of electronics courses. He shares the top 19 courses he thinks are the most valuable for emerging electronic engineers if he were to start his electronics career over again.

View Story

The Bare (Board) Truth: Fabrication Starts With Solid Design Practices

06-20-2019

It’s a fact: Great board design is the key to a great PCB. I’m even more certain of this after spending two days in a wonderful class presented by Rick Hartley titled “Control of Noise, EMI, and Signal Integrity in High-speed Circuits and PCBs.” Several times during Rick’s presentation, I wanted to slap myself in the forehead and say, “I should have had a V-8!”

View Story

Board Negotiations: Design Rules and Tolerances

06-03-2019

Here are several examples of how a PCB fabricator can deal with various tolerances. Let’s look at “press fit” applications for tool sizes. Typically, a given plated hole or slot is ±0.003” and a typical non-plated hole or slot is ±0.002”. So, what does the fabricator do when a plated hole is called out as ±0.002”? The simple answer is to calculate how much plating there will be in the hole barrel, and then over-drill to accommodate the ±0.002 tolerance.

View Story

The Bare (Board) Truth: Eliminate Confusion

03-18-2019

This column will address eliminating confusion that creates remakes both from the end-user/designer and the fabrication house. Let’s say you’ve asked for a material type on your drawing that is not either readily available or used by your fabricator. Here, you should expect the fabrication house to respond quickly and have all the deviations at once for you to review. This includes any impedance width changes, material types, or copper weights to produce the part. Any deviations regarding drawing notes such as wrap plate requirements that cannot be incorporated due to insufficient space or the extra etch compensation to meet the wrap plate requirement should also be addressed.

View Story
Back

2018

The Bare (Board) Truth: Teaching the Next Generation—An Overview of Today’s University Courses

09-05-2019

In this column, Mark Thompson focuses on the University of Washington, where he counted approximately 163 programs in their catalog of electronics courses. He shares the top 19 courses he thinks are the most valuable for emerging electronic engineers if he were to start his electronics career over again.

View Story

The Bare (Board) Truth: Fabrication Starts With Solid Design Practices

06-20-2019

It’s a fact: Great board design is the key to a great PCB. I’m even more certain of this after spending two days in a wonderful class presented by Rick Hartley titled “Control of Noise, EMI, and Signal Integrity in High-speed Circuits and PCBs.” Several times during Rick’s presentation, I wanted to slap myself in the forehead and say, “I should have had a V-8!”

View Story

Board Negotiations: Design Rules and Tolerances

06-03-2019

Here are several examples of how a PCB fabricator can deal with various tolerances. Let’s look at “press fit” applications for tool sizes. Typically, a given plated hole or slot is ±0.003” and a typical non-plated hole or slot is ±0.002”. So, what does the fabricator do when a plated hole is called out as ±0.002”? The simple answer is to calculate how much plating there will be in the hole barrel, and then over-drill to accommodate the ±0.002 tolerance.

View Story

The Bare (Board) Truth: Eliminate Confusion

03-18-2019

This column will address eliminating confusion that creates remakes both from the end-user/designer and the fabrication house. Let’s say you’ve asked for a material type on your drawing that is not either readily available or used by your fabricator. Here, you should expect the fabrication house to respond quickly and have all the deviations at once for you to review. This includes any impedance width changes, material types, or copper weights to produce the part. Any deviations regarding drawing notes such as wrap plate requirements that cannot be incorporated due to insufficient space or the extra etch compensation to meet the wrap plate requirement should also be addressed.

View Story
Back

2017

The Bare (Board) Truth: Teaching the Next Generation—An Overview of Today’s University Courses

09-05-2019

In this column, Mark Thompson focuses on the University of Washington, where he counted approximately 163 programs in their catalog of electronics courses. He shares the top 19 courses he thinks are the most valuable for emerging electronic engineers if he were to start his electronics career over again.

View Story

The Bare (Board) Truth: Fabrication Starts With Solid Design Practices

06-20-2019

It’s a fact: Great board design is the key to a great PCB. I’m even more certain of this after spending two days in a wonderful class presented by Rick Hartley titled “Control of Noise, EMI, and Signal Integrity in High-speed Circuits and PCBs.” Several times during Rick’s presentation, I wanted to slap myself in the forehead and say, “I should have had a V-8!”

View Story

Board Negotiations: Design Rules and Tolerances

06-03-2019

Here are several examples of how a PCB fabricator can deal with various tolerances. Let’s look at “press fit” applications for tool sizes. Typically, a given plated hole or slot is ±0.003” and a typical non-plated hole or slot is ±0.002”. So, what does the fabricator do when a plated hole is called out as ±0.002”? The simple answer is to calculate how much plating there will be in the hole barrel, and then over-drill to accommodate the ±0.002 tolerance.

View Story

The Bare (Board) Truth: Eliminate Confusion

03-18-2019

This column will address eliminating confusion that creates remakes both from the end-user/designer and the fabrication house. Let’s say you’ve asked for a material type on your drawing that is not either readily available or used by your fabricator. Here, you should expect the fabrication house to respond quickly and have all the deviations at once for you to review. This includes any impedance width changes, material types, or copper weights to produce the part. Any deviations regarding drawing notes such as wrap plate requirements that cannot be incorporated due to insufficient space or the extra etch compensation to meet the wrap plate requirement should also be addressed.

View Story
Back

2016

The Bare (Board) Truth: Teaching the Next Generation—An Overview of Today’s University Courses

09-05-2019

In this column, Mark Thompson focuses on the University of Washington, where he counted approximately 163 programs in their catalog of electronics courses. He shares the top 19 courses he thinks are the most valuable for emerging electronic engineers if he were to start his electronics career over again.

View Story

The Bare (Board) Truth: Fabrication Starts With Solid Design Practices

06-20-2019

It’s a fact: Great board design is the key to a great PCB. I’m even more certain of this after spending two days in a wonderful class presented by Rick Hartley titled “Control of Noise, EMI, and Signal Integrity in High-speed Circuits and PCBs.” Several times during Rick’s presentation, I wanted to slap myself in the forehead and say, “I should have had a V-8!”

View Story

Board Negotiations: Design Rules and Tolerances

06-03-2019

Here are several examples of how a PCB fabricator can deal with various tolerances. Let’s look at “press fit” applications for tool sizes. Typically, a given plated hole or slot is ±0.003” and a typical non-plated hole or slot is ±0.002”. So, what does the fabricator do when a plated hole is called out as ±0.002”? The simple answer is to calculate how much plating there will be in the hole barrel, and then over-drill to accommodate the ±0.002 tolerance.

View Story

The Bare (Board) Truth: Eliminate Confusion

03-18-2019

This column will address eliminating confusion that creates remakes both from the end-user/designer and the fabrication house. Let’s say you’ve asked for a material type on your drawing that is not either readily available or used by your fabricator. Here, you should expect the fabrication house to respond quickly and have all the deviations at once for you to review. This includes any impedance width changes, material types, or copper weights to produce the part. Any deviations regarding drawing notes such as wrap plate requirements that cannot be incorporated due to insufficient space or the extra etch compensation to meet the wrap plate requirement should also be addressed.

View Story
Back

2015

The Do’s and Don’ts of Signal Routing for Controlled Impedance

06-10-2015

In this column, we will once again be focusing on controlled impedance structures, both from the layout side and the simulation side. I will break them down into the sub-categories of the models they represent and the important points to remember when using the various models. I will also be asking questions such as, “Why would a fabricator ask for a larger impedance tolerance?” and “Where does the fabricator draw the line for controlling various structures?”

View Story

The Bare (Board) Truth: Tips for Getting the Boards You Need

05-22-2015

This column is about meeting each customer's needs. Some customers' requirements are as simple as a specific definition for a fiducial size, rail tooling, or orientation feature, while other customers may require special processes. Mark Thompson offers fabricator tips that can help designers get the boards they need.

View Story

What Will 2015 Bring?

02-25-2015

I’ve been thinking over what 2015 might look like, from my point of view at a PCB fabrication company. Let me first start out with some broad overviews of trends from 2014 that I see continuing. On my end, I certainly expect to see more RF work, more hybrid analog-digital PCBs, and more surface finishes for lead-free assemblies. And that’s just the tip of the iceberg.

View Story
Back

2014

The Do’s and Don’ts of Signal Routing for Controlled Impedance

06-10-2015

In this column, we will once again be focusing on controlled impedance structures, both from the layout side and the simulation side. I will break them down into the sub-categories of the models they represent and the important points to remember when using the various models. I will also be asking questions such as, “Why would a fabricator ask for a larger impedance tolerance?” and “Where does the fabricator draw the line for controlling various structures?”

View Story

The Bare (Board) Truth: Tips for Getting the Boards You Need

05-22-2015

This column is about meeting each customer's needs. Some customers' requirements are as simple as a specific definition for a fiducial size, rail tooling, or orientation feature, while other customers may require special processes. Mark Thompson offers fabricator tips that can help designers get the boards they need.

View Story

What Will 2015 Bring?

02-25-2015

I’ve been thinking over what 2015 might look like, from my point of view at a PCB fabrication company. Let me first start out with some broad overviews of trends from 2014 that I see continuing. On my end, I certainly expect to see more RF work, more hybrid analog-digital PCBs, and more surface finishes for lead-free assemblies. And that’s just the tip of the iceberg.

View Story
Back

2013

The Do’s and Don’ts of Signal Routing for Controlled Impedance

06-10-2015

In this column, we will once again be focusing on controlled impedance structures, both from the layout side and the simulation side. I will break them down into the sub-categories of the models they represent and the important points to remember when using the various models. I will also be asking questions such as, “Why would a fabricator ask for a larger impedance tolerance?” and “Where does the fabricator draw the line for controlling various structures?”

View Story

The Bare (Board) Truth: Tips for Getting the Boards You Need

05-22-2015

This column is about meeting each customer's needs. Some customers' requirements are as simple as a specific definition for a fiducial size, rail tooling, or orientation feature, while other customers may require special processes. Mark Thompson offers fabricator tips that can help designers get the boards they need.

View Story

What Will 2015 Bring?

02-25-2015

I’ve been thinking over what 2015 might look like, from my point of view at a PCB fabrication company. Let me first start out with some broad overviews of trends from 2014 that I see continuing. On my end, I certainly expect to see more RF work, more hybrid analog-digital PCBs, and more surface finishes for lead-free assemblies. And that’s just the tip of the iceberg.

View Story
Back

2012

The Bare (Board) Truth: I'm From CAM and I'm Here to Help

12-12-2012

In this column, Mark Thompson shows that fabricators are not necessarily meddling in your design; some of them really do want to help make your board right the first time. And he also demonstrates how patience and perseverance can go a long way with a customer!

View Story

The Bare (Board) Truth: Tales From the Fab Shop

05-16-2012

Designers continue to create the same-net spacing violations when relying on autorouters. Surface features connected elsewhere on an internal plane may have copper pour too close to other metal features. Electrically it doesn't matter whether these features bridge, but for most fabricators, any sliver thinner than 0.003" has the potential to flake off and redeposit elsewhere. By Mark Thompson.

View Story

Design to Fab: Making it Work

03-30-2012

A very large customer sent us two 4-layer boards riddled with differential pairs, with no information about any controlled impedances or specific dielectrics. When we asked if these were to be controlled, the customer was most appreciative and realized that some mention of the impedances, threshold and tolerance should have been made initially. When in doubt, talk to the customer!

View Story

Mark Thompson: IPC APEX EXPO Wrap-Up

03-07-2012

It was a mostly sunny week in San Diego, where IPC APEX EXPO returned after a long absence. I thought the San Diego Convention Center was a great choice for a venue. And this year, the engineers and designers on the show floor were looking at new processes and technologies like kids in a candy store.

View Story
Back

2011

The Bare (Board) Truth: I'm From CAM and I'm Here to Help

12-12-2012

In this column, Mark Thompson shows that fabricators are not necessarily meddling in your design; some of them really do want to help make your board right the first time. And he also demonstrates how patience and perseverance can go a long way with a customer!

View Story

The Bare (Board) Truth: Tales From the Fab Shop

05-16-2012

Designers continue to create the same-net spacing violations when relying on autorouters. Surface features connected elsewhere on an internal plane may have copper pour too close to other metal features. Electrically it doesn't matter whether these features bridge, but for most fabricators, any sliver thinner than 0.003" has the potential to flake off and redeposit elsewhere. By Mark Thompson.

View Story

Design to Fab: Making it Work

03-30-2012

A very large customer sent us two 4-layer boards riddled with differential pairs, with no information about any controlled impedances or specific dielectrics. When we asked if these were to be controlled, the customer was most appreciative and realized that some mention of the impedances, threshold and tolerance should have been made initially. When in doubt, talk to the customer!

View Story

Mark Thompson: IPC APEX EXPO Wrap-Up

03-07-2012

It was a mostly sunny week in San Diego, where IPC APEX EXPO returned after a long absence. I thought the San Diego Convention Center was a great choice for a venue. And this year, the engineers and designers on the show floor were looking at new processes and technologies like kids in a candy store.

View Story
Back

2010

The Bare (Board) Truth: I'm From CAM and I'm Here to Help

12-12-2012

In this column, Mark Thompson shows that fabricators are not necessarily meddling in your design; some of them really do want to help make your board right the first time. And he also demonstrates how patience and perseverance can go a long way with a customer!

View Story

The Bare (Board) Truth: Tales From the Fab Shop

05-16-2012

Designers continue to create the same-net spacing violations when relying on autorouters. Surface features connected elsewhere on an internal plane may have copper pour too close to other metal features. Electrically it doesn't matter whether these features bridge, but for most fabricators, any sliver thinner than 0.003" has the potential to flake off and redeposit elsewhere. By Mark Thompson.

View Story

Design to Fab: Making it Work

03-30-2012

A very large customer sent us two 4-layer boards riddled with differential pairs, with no information about any controlled impedances or specific dielectrics. When we asked if these were to be controlled, the customer was most appreciative and realized that some mention of the impedances, threshold and tolerance should have been made initially. When in doubt, talk to the customer!

View Story

Mark Thompson: IPC APEX EXPO Wrap-Up

03-07-2012

It was a mostly sunny week in San Diego, where IPC APEX EXPO returned after a long absence. I thought the San Diego Convention Center was a great choice for a venue. And this year, the engineers and designers on the show floor were looking at new processes and technologies like kids in a candy store.

View Story
Back

2009

The Bare (Board) Truth: I'm From CAM and I'm Here to Help

12-12-2012

In this column, Mark Thompson shows that fabricators are not necessarily meddling in your design; some of them really do want to help make your board right the first time. And he also demonstrates how patience and perseverance can go a long way with a customer!

View Story

The Bare (Board) Truth: Tales From the Fab Shop

05-16-2012

Designers continue to create the same-net spacing violations when relying on autorouters. Surface features connected elsewhere on an internal plane may have copper pour too close to other metal features. Electrically it doesn't matter whether these features bridge, but for most fabricators, any sliver thinner than 0.003" has the potential to flake off and redeposit elsewhere. By Mark Thompson.

View Story

Design to Fab: Making it Work

03-30-2012

A very large customer sent us two 4-layer boards riddled with differential pairs, with no information about any controlled impedances or specific dielectrics. When we asked if these were to be controlled, the customer was most appreciative and realized that some mention of the impedances, threshold and tolerance should have been made initially. When in doubt, talk to the customer!

View Story

Mark Thompson: IPC APEX EXPO Wrap-Up

03-07-2012

It was a mostly sunny week in San Diego, where IPC APEX EXPO returned after a long absence. I thought the San Diego Convention Center was a great choice for a venue. And this year, the engineers and designers on the show floor were looking at new processes and technologies like kids in a candy store.

View Story
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