Testing Todd: Understanding the Fine Print

New technologies are emerging each day with more stringent requirements than the past. Also, reversals in obsolescence programs bring products back to the market for which the original documentation and/or requirements are ancient compared to today’s standards; in some cases, this documentation is even lost. Further, it is not uncommon to find that original artwork isn’t available or that the part must be recreated from a finished circuit board sample. This involves learning a netlist profile and then scanning layer by layer to recreate the actual film layers, but that is a whole different subject that I’ll discuss in a future column.

Specifications and Drawings

With specifications and drawings, it gets complicated very quickly. When printed circuits are procured, the purchase order (PO) is sent along with the master drawing and other deliverable requirements. In most cases, this is a straightforward process. The PO states what is being purchased, and the master drawing outlines the specifics and instructions on what is required for the build. Usually, the master drawing will specify industry specifications and requirements, which may include a special OEM specification. This is where it can get tricky, especially for historic or obsolete rebuilds. These old specifications may not be available. Now what? For the fabrication house, this often requires consulting with the OEM and either obtaining the lost document or acquiring a deviation or waiver for the lost document.

Even though the product may be a new build, there’s a chance that the master drawing calls out for an older specification. Diligence is required by the fabrication house to make sure that the proper specification is used. It cannot be assumed that the latest specification and/or methods are to be used. This becomes increasingly important when processing military products. One cannot assume the latest build specification is to be used. Older designs by OEM military contractors may call for older revisions of say MIL-PRF-31032, 55110, and 50884. For electrical test (ET), this can be especially significant.

Advances in test technology have brought new methodologies that were not allowed or even known in the older revisions of specifications. Just because the latest revision of a specification allows the use of these technologies, one cannot assume the new options apply. If an older specification is called, the requirements of that specification shall be used. This can be challenging for a third-party ET contractor.

Many times, the ET contractor may have access to the master drawing only when the order is being processed. Job-specific notes may be added to the ET database for future reference, but special notes may be lost when the job returns to the fabrication house. This is where it is crucial to save the notes or retain a copy of the master drawing. Most ET contractors will have NDAs with their fabrication houses, so this isn’t usually a problem. However, this becomes extremely important when the fabrication house or ET contractor is audited and allows absolute traceability and assurance that the product was built and tested as originally designed.

Certificate of Compliance Documents

This brings up another item that comes up quite frequently on the certificate of compliance (C of C) documents for ET. What specification should appear on the C of C for ET is a confusing topic. A master drawing may state, “Build to IPC-6012D.” Should the ET C of C state IPC-6012D? The answer is no. If the C of C were to say IPC-6012D, it could be interpreted that the ET C of C is certifying the entire build, which it is not; it is only certifying the product was tested.

To read the full article, which appeared in the September 2019 issue of PCB007 Magazine, click here.

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2019

Testing Todd: Understanding the Fine Print

10-08-2019

New technologies are emerging each day with more stringent requirements than the past. Also, reversals in obsolescence programs bring products back to the market for which the original documentation and/or requirements are ancient compared to today’s standards; in some cases, this documentation is even lost. Further, it is not uncommon to find that original artwork isn’t available or that the part must be recreated from a finished circuit board sample.

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Testing Todd: What Do You Mean 'Passed' Isn't Enough?

08-05-2019

From a reliability standpoint, we need to quickly assess what risk we may have uncovered when faults are detected during electrical test (ET). "Passed" is not always passed. We must be diligent to scrutinize the failures found during routine ET as a high yield may not indicate high reliability.

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Testing Todd: The Evolution of Probers and Fixture Testers: Blinded by Science

06-26-2019

The evolution of the PCB has come a long way in the last 30 years. The science of electrical test has had to travel that road as well. It's not just a question of screening for opens and shorts. Today, the library extends to interrogating passive components, efficiently and cost-effectively evaluating dielectrics with multiple planes and pairs involved, and adhering to strict requirements from the military, export regulations, and OEMs alike.

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Confidence in Inspection

04-12-2019

The job of third-party inspection is to provide an unbiased review of the customer requirements versus the final product manufactured. This inspection can include both physical and functional criteria. Read on to understand the growing acceptance and requirement of third-party inspection in many areas of the manufacturing industry, including military, aerospace, and medical.

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2018

Testing Todd: What’s in your ET?

07-13-2018

With all the buzz around automation, paperless operation, and integrated processes, it’s time to think about how the connected systems work within an electrical test department. We are all familiar with computer-aided design (CAD) and computer-aided manufacturing (CAM), but with electrical test we can also add computer-aided test (CAT) and computer-aided repair (CAR).

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Testing Todd: How are the Ratings?

05-24-2018

Hello, readers! Thank you for stopping by again. Let’s talk about ratings. No, I’m not talking about the latest Facebook likes or Twitter retweets, but a topic that confuses many final QA technicians the world over. I’m talking PCB voltage ratings.

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Testing Todd: AVI—Your Tireless Friend in Final Inspection

05-01-2018

The “automation vs. human” debate continues. There are experts with many years of experience -performing final inspection with precise detail. This is not debated. However, in the course of human events, circumstances change with unpredictable results. This presents challenges to manufacturers striving to deliver product on-time and within specification guidelines.

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2017

Testing Todd: No Missed Steps—5S Methodology

08-22-2017

In today’s work environment, a company should strive to produce quality product, maximize margins and reduce cost as much as possible. At times, this can be very difficult. Work ethics and methodologies of “how to do things” have developed over many years and can be deeply rooted in many manufacturing theatres. We find at times the “way we have always done it” may not be the most practical way today. This is apparent with the advances in automation, labor force reduction and shifting market demands.

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Flying Probe Testing vs IPC-9252B

05-30-2017

Flying probe testing is extremely popular in today’s manufacturing theatres. The main factor is cost reduction in contrast to dedicated fixtures and fixture testing. However, there are some limitations in flying probe testing when gauged against industry specifications—specifically, the use of indirect vs direct testing in Test Level C.

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Testing Todd: Go With the Flow

04-18-2017

In today’s testing theatre, the flow of information from the OEMs and manufacturers to the independent contractors is mission-critical. Missing information can cause delays, incorrect processing and ultimately scrap or end user rejection of the product. The buzz term being used a lot today is “flow-down.” It pretty much describes itself: It is the flow of information down the supply chain.

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Testing Todd: Plating and Surface Finish—The Challenges to Electrical Test

01-23-2017

Plating and surface finish applications are not without their own set of challenges but these manufacturing processes also affect the electrical test theatre. Microvias, high-aspect ratio plate quality, and surface finish all have their own challenges in ET.

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2016

Testing Todd: Are You a Leader or a Manager?

10-21-2016

The question can be asked, are you a manager or a leader? Can you be both? Is there even a difference? The answer to this latter question is, yes. In a successful organization there are many people performing different tasks all in harmony to make the business successful. Some individuals can be phenomenal leaders while others can be excellent managers. Some can actually be both. How do we define a leader from a manager?

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Test & Measurement—The Case for Validation

07-15-2016

Test and measurement (T&M) are terms that can strike fear into the most robust of minds. Many engineers create designs and products of the future with specific results predicted for performance.

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Testing Todd: Quality Management and the Hidden 'I' in Team

05-24-2016

Today, businesses of all types are jumping on the quality bandwagon. The more critical the product, the more the consumer/customer wishes the highest possible quality in the goods or services requested.

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Quality Management and the Hidden 'I' in Team

05-06-2016

Today, businesses of all types are jumping on the quality bandwagon. The more critical the product, the more the consumer/customer wishes the highest possible quality in the goods or services requested. Customers send surveys with buzzwords like ISO, QMS, and AVL for their suppliers to complete so they have confidence that what they receive is of the highest quality.

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Testing Todd: Process Management: Doing It Right

04-27-2016

Simply put, process management is the idea of figuring out how to do something, documenting it and then monitoring the effectiveness of the steps you created for the end result. Simple, right? Unfortunately, many who take on this endeavor fall short due to missing some key attributes to creating and maintaining a robust process. This article features eight steps in building and maintaining a robust process.

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2015

Flex and Rigid-Flex Circuit Testing: Challenges & Solutions

06-24-2015

Although flex circuits are nothing new in today’s technology roadmap, the testing of unpopulated flexible circuits can be challenging. In this article, columnist Todd Kolmodin writes about the different methods available to test these circuits.

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Electrical Test: Surface Finish vs. Water Marks

05-20-2015

New finishes have come to market; some allow better conductivity, while others reduce the overall cost of precious materials. Regardless of the finish, electrical test must be performed on these circuits. With that comes the caveat of how much of a witness mark can be left on any given landing pad and still be acceptable to the CM or the final OEM user. Todd Kolmodin explains.

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Challenges of Electrical Test

01-28-2015

In our arena today, we can solve pitch and density with flying probe machines, and volume with our grid testers, but the catalyst that is in the mix is that pesky soldermask! Here's why I bring up that necessary process as a problem for electrical test.

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2014

What is 4-Wire Kelvin?

12-05-2014

"I've been asked many times, 'What is 4-Wire Kelvin?' So, this month I will explain the 4-Wire Kelvin Test and how it can help uncover defects that normally would go undetected in standard electrical test methodology," writes Columnist Todd Kolmodin.

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Where Do We Go From Here?

12-01-2014

In this installment of "Testing Todd," Gardien's resident expert Todd Kolmodin answers questions from Dan Beaulieu concerning the future of electrical test. His focus is on the future of testing technologies, testing equipment, and E-test.

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Testing Todd: Where Do We Go From Here?

12-01-2014

In this installment of "Testing Todd," Gardien's resident expert Todd Kolmodin answers questions from Dan Beaulieu concerning the future of electrical test. His focus is on the future of testing technologies, testing equipment, and E-test.

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Flying Probe - Indirect Testing vs. Military

08-19-2014

The use of flying probe testers has become increasingly popular in recent times, mainly due to the affordability of the equipment and also the reduced cost of testing, as no dedicated or "bed of nails" fixture is required. When using flying probes to test military product, one must be diligent to make sure the test method is allowable.

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Testing Todd: Flying Probe - Indirect Testing vs. Military

08-19-2014

The use of flying probe testers has become increasingly popular in recent times, mainly due to the affordability of the equipment and also the reduced cost of testing, as no dedicated or "bed of nails" fixture is required. When using flying probes to test military product, one must be diligent to make sure the test method is allowable.

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Everything You Wanted to Know, But Were Afraid to Ask

07-30-2014

This month, "Testing Todd" author Todd Kolmodin of Gardien Services USA presents readers' questions about the basics of electrical test, including the different types of testing available today.

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Testing Todd: Everything You Wanted to Know, But Were Afraid to Ask

07-30-2014

This month, "Testing Todd" author Todd Kolmodin of Gardien Services USA presents readers' questions about the basics of electrical test, including the different types of testing available today.

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Seven Tips for Choosing the Right Test Service

06-12-2014

Do you need to go outside your company for your testing service? Maybe you have capacity issues, maybe your equipment is down, or maybe you just want an established back-up plan? Whatever the reason, it is very important to choose the right outside testing service because, ultimately, you're not just choosing an objective service provider; you're choosing a partner.

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A Summary of Various Test Requirements

06-03-2014

The PCB industry has advanced significantly in the recent millennium. OEM specifications and requirements have also advanced due to the maturing of technologies, which has caused the requirements of electrical test of these higher technology products to advance and increase in intensity.

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Testing Todd: A Summary of Various Test Requirements

06-03-2014

The PCB industry has advanced significantly in the recent millennium. OEM specifications and requirements have also advanced due to the maturing of technologies, which has caused the requirements of electrical test of these higher technology products to advance and increase in intensity.

View Story
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