Keysight is best known for its bench-top test equipment, but it also offers in-circuit testing (ICT) solutions. To gain a deeper understanding of ICT, and its technological advancements, EFY editorial team interviewed Jun Balangue, Business Development and Product Manager, Keysight Technologies.
and Product Manager, Keysight Technologies
Q. Why do we need to test a PCBA when there is a functional test at the end of the line or during the box assembly?
A. ICT (in-circuit testing) has evolved alongside sophisticated technologies, with significant changes in components along the way. A single integrated circuit (IC) functions as a computer, posing challenges in comprehensively testing all its functions. Fortunately, we have developed our testing equipment in adherence to IEEE standards. We have created a test capable of assessing the structural integrity of components from a manufacturing line. In an electronics manufacturing line, every component undergoes testing to ensure proper soldering and correct placement onto the printed circuit board assembly (PCBA). Detecting defects through our in-circuit test (ICT) significantly reduces the cost of product testing. Without ICT, reliance shifts solely to functional testing, which could lead to product failure as functional tests provide limited information; they do not reveal whether the issue lies with a resistor or if there is an open or short circuit.
Q. Complex boards have thousands of test points. How do modern ICT systems manage such complexity?
A. Consider a motherboard of a server, specifically a high-speed board structured in a 3-by-3 or 2-by-2 configuration. Achieving 100% test coverage for such a board necessitates placing test points, but this is impractical as many sites reside in the middle of the PCB, which are unreachable for testing. Our software introduces a concept termed ‘design for test.’ The software is utilised to analyse and combine all test features through this process. Leveraging IEEE 1149.1 on the scan, which is a standard in around 80-90% of large application-specific integrated circuits (ASICs) and central processing units (CPUs), allows for comprehensive testing without needing 100% test points on the board.
Essentially, this standard embeds the boundary scan cell like a test point inside the IC, resembling an in-circuit test within the IC itself. The 1149.1 boundary scan software assesses the IC for interconnectivity, eliminating the need for 100% test points on PCBA to achieve high test coverage during ICT testing. With this capability, designers can focus on strategically placing test points at critical locations, reducing the need for unnecessary points. By the time the product reaches mass production, 80-90% of test points have already been covered. This benefits larger boards with up to 10,000 nodes, where the cost of testing can escalate to $1 million per system. Additionally, using fewer test points minimises the risk of false results and mechanical failures, showcasing the evolution of technology to strike a balance in testing processes.
Q. How does that translate into RoI?
A. The electronics manufacturing test is run with cost sensitivity in mind. By reducing the number of test points, you reduce the cost of the system and almost 50% of the cost of the ICT fixture.
Q. What percentage of test points on a board must be tested—to consider it as a ‘tested’ board?
A. Test coverage measures the efficiency, reliability, and quality of an electronics manufacturing test. A test guaranteeing 90% test coverage is a good electronics manufacturing test. However, if it is 50% or less, the board will surely have problems in the end-of-line testing, functional tests, or even when assembled into the product. That’s why it’s important during prototype or NPI (new product introduction) runs to re-evaluate test coverage to ensure that you have at least 80 to 90%. While you will not be able to achieve 100% test coverage, achieving 80-90% coverage is optimal.
Q. How do ICT systems relate to the optical Inspection machines?
A. Inspection systems are typically used to identify missing components or ensure proper soldering. In contrast, our system captures defects early in the manufacturing process, allowing for the prompt removal of faulty components. Traditional optical inspection systems may overlook certain defects, especially if the faulty component is positioned at a specific angle or if there are volume-related issues. Additionally, these systems cannot discern whether a component is a 100-ohm or 100-kilo-ohm component.
Q. Can’t the latest AOI machines tell if the part is compliant to the specifications?
A. Technology in inspection is evolving to an extent where it can discern whether a component is smaller but cannot determine whether its value is correct. Suppose a 100-ohm resistance component, which is supposed to be 100 kilo-ohms, is under observation. The AOI will pass the component, and it will become functional. Such products might fail in real-world applications, especially the mission-critical ones. This is why global companies prefer 100% ICT.
Q. What kind of innovations have you brought about in electronics manufacturing tests?
A. We have many examples to cite. The first 3070 Series 1, Keysight Technologies (HP at that time) introduced the short wire measurement, which became very popular among our customers in global manufacturing companies due to its transportability, repeatability, and stability (TRS). Next came the 3070 Series 2 launched in 1989, Series 3 in 1998, Series 4 and 5 followed, and the latest generation, the 3070 Series 6, was introduced in 2019. We continue to offer compatibility with our old products, allowing our customers to continue using our ICT system as we offer upgrades from the old series to the new 3070 Series 6. Instead of obsoleting the existing manufacturing tests, we are innovating and translating them to test new technologies that our customers are putting in their PCBs.
Q. What is an ‘end-to-end electronics manufacturing’ test?
A. For the past two decades, electronics manufacturing tests have predominantly focused on compliance at the end of the line, leaving a significant unexplored space at the beginning. Despite this hardware-centric approach, which involves early-stage component detection and subsequent electrical measurements, a gap exists. Now, with the implementation of end-to-end manufacturing analysis, specifically using of pathway manufacturing analysis (PMA) software, a solution has emerged.
PMA allows us to correlate failures at the end of the line with issues at the beginning, bridging the previously overlooked gap. By detecting early signs of component failure or a sudden increase in failures, the software enables immediate notification to the beginning of the line, preventing the completion of an entire defective production run for the day, saving valuable time and resources. Additionally, predictive analysis within the software assesses whether a component is degrading in value, considering factors like system-related issues or oven temperature. PMA informs operators of anomalies that require prompt attention.
Q. Where does your PMA software get all its data from, for it to analyse?
A. For PMA deployment, the customer needs to provide a small server (with the configuration of a desktop/laptop), called a data collection agent (DCA), which can communicate with the PMA server and collect logs from all production machines. For Keysight ICT machines, ICT software is pre-installed with the utility that sends test logs to the DCA. The utility needs to be configured so that it starts sending data to the DCA. Once the DCA receives the logs, it sends them to the PMA server for analysis. For non-Keysight ICTs and FCTs, all test logs need to be shared in a common folder that can be accessed by the DCA server. The DCA will pick up the logs and send them to the PMA server for analysis. Initially, the PMA platform was designed to support Keysight ICTs since it had the default utility to communicate with the PMA server. Later, we expanded to include the whole manufacturing line by implementing the approach to read logs (generated by other machines) from the shared directory.
Q. What are your thoughts on increasing automation of electronics manufacturing?
A. Not every aspect of a product necessitates automation. The degree of automation depends on the specific product. In the automotive sector, certain companies, particularly original equipment manufacturers (OEMs), insist on complete automation, driven by safety concerns and the desire to minimise human handling. Also, given the high cost of these products, such as high-end servers with a single printed circuit board assembly (PCBA) ranging from $10,000 to $20,000, OEMs advocate for full automation to reduce costs, lower the risk of accidental failures, and decrease the need for manpower. Even after 30 years, a blend of human and automated processes on surface mount technology (SMT) lines and automated optical inspection (AOI) is required. Despite advancements, complete eradication of human intervention from manufacturing seems unlikely. Some critical PCBA types may undergo full automation. While technically proficient individuals in India are prepared to support such automation, there will always be products that don’t need full automation.
Q. Which industry segments are driving maximum demand for your ICT solutions?
A. We see customers in the automotive, computing and netcomm business, along with aerospace, military, and medical segments, driving the demand. Since these are mission-critical applications, our PMA Analytics can immediately provide the history of the fault, reducing the time it would have otherwise taken if done manually.
Q. Who are your target customers in India?
A. We are primarily focused on electronic manufacturing services (EMS) companies and original design manufacturers (ODM). Big companies like Google, Meta, Amazon, and Tesla are outsourcing their manufacturing to these companies. The bulk of our business comes from this set of manufacturers. In India, we are targeting local manufacturers. Regardless of size, we are committed to contributing to the success of everyone in the manufacturing industry.
Q. Who is driving the demand in India – local manufacturers or foreign players setting up bases in India?
A. Right now, there are a lot of global companies coming in. The growth is there because they are bringing in the investment and have a lot of resources and money to put into operation. But I’m also seeing that local manufacturing companies have started to adapt and want to be global players in manufacturing. I have seen what happened in China before it became a global player in manufacturing, and I am witnessing the same scenario in India, with the government spending money on infrastructure, logistics, education, and resources for manufacturing.
Q. How many team members does your manufacturing division have in India?
A. At Keysight, for electronic manufacturing test solutions, we have a global operation of 100+ resources, including local resources in India who have 10+ years of experience in ICT. We have also partnered with DJK. This partnership with DJK enables us to support most of our customers who are spread out in India.
Q. In India, many electronics manufacturers are remotely placed. How do you ensure prompt support in such a vast geographic market?
A. We have designed our ICT system, 3070, to last and work 24×7 for many years. We have 20-year-old systems in manufacturing and operating, highlighting the reliability of the system. When it’s down, we have a ready support network that can be activated immediately and respond to customers for assistance if they are under the support contract. If there is a deeper defect, we have a local support person who can fly to any location to help the customer resolve the system failure.
Q. How do you see the growth of electronics manufacturing ecosystem in India? How does Keysight intend to contribute?
A. The Indian government has set huge targets to become a global manufacturing destination. Luring all the big companies into India is a big task, but we are witnessing it happen gradually. We have been associated with major global technological companies for over 40 years, including OEMs and EMS players. We intend to help them start off their manufacturing lines in India, duplicating what they have in other countries. At the same time, we are strengthening the capabilities of local manufacturers. For India to grow, they must grow the local manufacturing sector.
