Testing Todd: Go With the Flow

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. So let’s go with the flow, shall we? We will break it down in the flow required for correct electrical testing of an unpopulated printed wiring board.

1. The OEM designs the latest must-have innovation for the market. Time is critical to get this product built, tested and on the shelves so that little Johnny will not be disappointed on his upcoming birthday. Now, the design engineers have painstakingly designed in all the impedance, IC footprints, material requirements, impedance/inductance and resistive components, and have written it in their design specification document. Since this is a new product and top secret the document is then saved at their top secret secure location (along with the notorious 11 herbs and spices).

2. The OEM procurement department now receives the build request from the engineers and proceeds to shop vendors for manufacturing. They may send out many RFQs and each time they need to be specific on what they want manufactured. Here is the first major flow-down example: When the RFQ goes out they must be very specific on what they wish to receive. Information here are the general manufacturing requirements (IPC-6011, IPC-6012) but also the specifics that may be outlined in the top-secret design specification document the engineers created in section 1. What are the special requirements for characteristic impedance, dielectric breakdown, continuity and isolation? What is the performance class expectation? Does this  board need to pass military performance specifications?

(Mil-PRF-31032, 55110 or 50884 as examples.) These all need to be specified up front for the proper quotation to be generated.

3. Now that a suitable manufacturer has been selected the OEM issues a procurement document (PO) and the final design package. This now goes through the tooling process at the manufacturer. It is critical here that all specific information outlined in steps 1 and 2 are flowed down in the manufacturing order that will run the course of the manufacturing floor. It is important to remember it is difficult as the flow-down increases in steps that it will be more difficult and time-consuming to retrace steps to find important information that is missing in your current area. This can lead to delays and mistakes. So the information from the PO design specification and industry/military specifications need to be flowed-down.

4. Now that the flow-down has worked as it should, the product reaches electrical test and is ready for screening. If proper flow-down has been achieved the technicians will have the important information available for processing:

A. Part number

B. PO number

C. Order number

D. Date code

E. Performance class requirement

F. Voltage, continuity and isolation  requirement

G. Indirect vs direct testing directive

H. Serialization requirement

I. Military requirement (if applicable)

J. Dielectric breakdown requirement

5. When ET is complete and the product goes to final inspection prior to shipping the flow-down information can be reconciled to the original PO and design specifications. The requirements have been flowed-down through the entire process so no required information is lacking. The product ships on time and little Johnny from step 1 (remember him?) receives his birthday gift on time and in perfect condition and working order.

Todd Kolmodin is the vice president of quality for Gardien Services USA, and an expert in electrical test and reliability issues. To read past columns, or to contact Kolmodin, click here


Editor's Note: This article originally appeared in the April 2017 issue of The PCB Magazine, click here.

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2017

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.

View Story

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.

View Story

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.

View Story

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.

View Story

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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