-
- News
- Books
Featured Books
- smt007 Magazine
Latest Issues
Current IssueWhat's Your Sweet Spot?
Are you in a niche that’s growing or shrinking? Is it time to reassess and refocus? We spotlight companies thriving by redefining or reinforcing their niche. What are their insights?
Moving Forward With Confidence
In this issue, we focus on sales and quoting, workforce training, new IPC leadership in the U.S. and Canada, the effects of tariffs, CFX standards, and much more—all designed to provide perspective as you move through the cloud bank of today's shifting economic market.
Intelligent Test and Inspection
Are you ready to explore the cutting-edge advancements shaping the electronics manufacturing industry? The May 2025 issue of SMT007 Magazine is packed with insights, innovations, and expert perspectives that you won’t want to miss.
- Articles
- Columns
- Links
- Media kit
||| MENU - smt007 Magazine
Design to Production Flow: DFT and Test Coverage Using Industry 4.0 Principles to Produce Good Products
December 1, 2021 | William Webb, ASTER TechnologiesEstimated reading time: 2 minutes

Achieving design for test (DFT) can be challenging for both design and test groups, as sometimes both expect that the other will be the one to manage DFT. The design and test groups might be in the same organization, or they could be an OEM vs. an EMS company. It works best if both the design and test groups are engaged in the process of DFT and trying to achieve the goal of the best test coverage and lowest rate of field returns.
Traditionally, design and test have operated in silos where there was not always the best communication, and at some point, the design was given to the test department to perform DFT. Often, due to project timelines and people working in different geographic regions, this means if some DFT concern was found, it may have been too late to address and resolve the issue. It is too late to wait until a board has gone through layout to begin DFT, as this needs to happen at the time of schematic capture, when the logic design is taking place, and before the board has gone for routing and layout. There are critical items that can be examined at the schematic capture phase to ensure that the board will be as testable as possible. A continuous feedback loop into DFT and test coverage understanding is key to producing defect free products at a minimum cost.
Companies must deliver good products to their customers, defect-free and at minimum cost. The challenge is how to detect or prevent defects from occurring so that only good products are shipped to the customer. Traditional DFT tools usually work only from the layout stage, which is too late in the whole process. Design data must be analyzed at the earliest stage possible in the product life cycle by importing schematic design data.
Electrical DFT rules violations should be identified and rectified prior to commitment to board layout, to prevent costly design re-spins. These rules can include standard and customer-specific checks relating to company requirements. With a centralized knowledge database, the same problems will never be repeated.
Test point requirements must also be identified pre-layout, during the schematic capture stage. This reduces the need for unnecessary test access, saving on PCB real estate, particularly on high density boards. The test strategy needs to be simulated, including any combination of inspection and test machines, delivering the highest test coverage. This unique combination provides electrical rules analysis, test point analysis, test strategy optimization, and test cost modeling based purely on schematic information. This, in turn, provides valuable layout guidelines that can be used to optimize the printed circuit board layout.
Once the PCBA layout is completed, a mechanical DFT analysis must be conducted to confirm the nets that require test access are not compromised by solder mask, component outline, adjacent probes constraints, etc.
To read this entire article, which appeared in the November 2021 issue of PCB007 Magazine, click here.
Suggested Items
Driving Innovation: Direct Imaging vs. Conventional Exposure
07/01/2025 | Simon Khesin -- Column: Driving InnovationMy first camera used Kodak film. I even experimented with developing photos in the bathroom, though I usually dropped the film off at a Kodak center and received the prints two weeks later, only to discover that some images were out of focus or poorly framed. Today, every smartphone contains a high-quality camera capable of producing stunning images instantly.
Hands-On Demos Now Available for Apollo Seiko’s EF and AF Selective Soldering Lines
06/30/2025 | Apollo SeikoApollo Seiko, a leading innovator in soldering technology, is excited to spotlight its expanded lineup of EF and AF Series Selective Soldering Systems, now available for live demonstrations in its newly dedicated demo room.
Indium Corporation Expert to Present on Automotive and Industrial Solder Bonding Solutions at Global Electronics Association Workshop
06/26/2025 | IndiumIndium Corporation Principal Engineer, Advanced Materials, Andy Mackie, Ph.D., MSc, will deliver a technical presentation on innovative solder bonding solutions for automotive and industrial applications at the Global Electronics A
Fresh PCB Concepts: Assembly Challenges with Micro Components and Standard Solder Mask Practices
06/26/2025 | Team NCAB -- Column: Fresh PCB ConceptsMicro components have redefined what is possible in PCB design. With package sizes like 01005 and 0201 becoming more common in high-density layouts, designers are now expected to pack more performance into smaller spaces than ever before. While these advancements support miniaturization and functionality, they introduce new assembly challenges, particularly with traditional solder mask and legend application processes.
Knocking Down the Bone Pile: Tin Whisker Mitigation in Aerospace Applications, Part 3
06/25/2025 | Nash Bell -- Column: Knocking Down the Bone PileTin whiskers are slender, hair-like metallic growths that can develop on the surface of tin-plated electronic components. Typically measuring a few micrometers in diameter and growing several millimeters in length, they form through an electrochemical process influenced by environmental factors such as temperature variations, mechanical or compressive stress, and the aging of solder alloys.