Testing Todd: Test & Measurement—The Case for Validation

Reading time ( words)

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. Guaranteeing those predicted results requires specific tests and measurements. Although breadboards with ICs, jumpers and handheld meters still exist, the products of today require much more validation than any of the preceding examples can provide. Validating characteristics such as inductance, capacitance, buried passives, high voltage, dielectric breakdown, and Z-axis isolation (IR) are examples of electrical validation required. Along with that come validations of board thickness, plating quality across many aspect ratios, line width and space, hole diameters, surface finish, screening and even packaging. Whew! That is a lot to take into consideration in the market of today.

So how do the experts guarantee that your product will meet or exceed the expectations you have put forth? Through test and measurement of course. (Well along with a bit of fairy dust, mad skills and voodoo magic!) In all seriousness, test and measurement tools and equipment gets the job done efficiently, accurately and as expeditiously as possible.


This term can be used to define processes that mechanically change the state of the PCB. These are processes such as drilling, routing, lamination, milling, and beveling. Test and measurement play a large part in these processes as well. This is sometimes overlooked when thinking of T&M. Much of the inspection in these processes remains manual but there are automated alternatives available. Automated visual inspection (AVI) technology has advanced quite a bit in recent years. This is not to be confused with historic AOI, which is used for scanning cores or innerlayers. AVI in the current world can scan the finished board and validate a wide variety of variables. Missing silk screen or legend, metal inclusions, exposed copper, dishdowns, contamination, and soldermask violations are just a few.

Wet Process/Plating

Another variety of tests and measurements is required during these processes. Chemistry validation, material inspections and hole plating validation are all common here. Although required, the standard cross section of the plated hole is not the only validation for copper in the barrels. The electrical 4-wire Kelvin test is becoming a more common requirement in todays’ builds. This test will detect finite changes in the resistive value of the copper in the barrel.

Read the full column here.

Editor's Note: This article originally appeared in the July 2016 issue of The PCB Magazine.


Suggested Items

ICAPE: Staying on Top During ‘Interesting’ Times

12/05/2022 | Nolan Johnson, PCB007 Magazine
Recently, we met with Nathan Martin, group purchasing director; Jean-Christophe Miralles, supply chain director for Europe and U.S., and Lea Maurel, Americas marketing manager. This wide-ranging conversation dug into market drivers, supply chain challenges and how ICAPE creates consistency on its manufacturing floor. Complementing the supply chain control is ICAPE’s engineering experise, which it uses to increase customer yields and quality. Corporate sustainability is a key strategic initiative for ICAPE, and it was enlightening to learn just how holistic ICAPE’s approach to sustainability is.

Optimize Your Etcher for Best Image Quality

11/03/2022 | Christopher Bonsell, Chemcut
When it comes to obtaining high-quality images, many different factors come into play. Typically, most of these factors come down to your imaging equipment and cleanroom; however, there are factors involved in the etching process that can affect the quality of your image. Here are five steps to ensure your etching process is optimized for the best image quality.

Millennium Circuits on The Move

10/31/2022 | Andy Shaughnessy, Design007 Magazine
I recently met with Daniel Thau, CEO of Millennium Circuits Limited, at PCB West. This Pennsylvania-based PCB distributor has been on an expansion path lately, so I asked Daniel to introduce us to MCL and explain where the company is headed. As Daniel says, it’s all about impacting the world in a positive way.

Copyright © 2022 I-Connect007 | IPC Publishing Group Inc. All rights reserved.