SMT007 Magazine

SMT007-Feb2025

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also forces lower yields and poorer reliability on new packages due to the pressure to assem- ble them in volume before a robust production process is fully developed. is pinch point can spawn economic effects across the entire supply chain. e original SMTA Miniaturization Test Vehicle designed for solder paste testing has been upgraded to focus on UHDI assembly challenges. e new design removed some larger packages, and added more smaller pack- ages at tighter spacing, and more off-axis ori- entations, rework challenges, and designed experiments for some of the expected pitfalls of increasing population density. e DOEs test for the effects of copper imbalance on tombstoning and skewing of 0201 and 01005 components, mixed mask- and copper-defined pads with mask registration errors, decoupling capacitors within the keepout courtyards of ICs, insufficient solder deposits on the lead- ing edge of the print stroke, and 30- 45- and 60-degree placements. It is currently undergoing another revision to include 006003 capacitors, more wafer level packages and surface insulation resistance (SIR) testing, based on inputs from users. e newer version should be on display at IPC APEX EXPO 2025. As with the original SMTA test board, all the components are daisy-chained and wired out to gold finger connectors to enable reli- ups, wear and tear, and other issues like inade- quate maintenance histories. Do all SMT machines have soft adjustments? Yes and no. In addition to printers and placers, we also work on SPI, AOI, reflow ovens, dis- pensers, die bonders, and other SMT robotic systems. Global offset capability is built into the soware of most high-end automation to enable fine-tuning. Does this apply to new machines or used machines? Both. Some of our users include initial machine measurement in their capital equipment expen- ditures to ensure that their systems are in top shape when they install them, and then perform periodic measurements to maintain high levels of process control. Others find that by correcting an older, sloppy machine's wear-and-tear, they can extend the life of it and save money. Some request us to check used machines before purchasing them to validate their capability and operability. Why do new machines fail their specifica- tions? Don't they have self-calibration rou- tines when they initialize? A machine that measures itself is only accurate to its own resolution. To obtain statistically significant information, a measurement device should have a much finer resolution than the item it is measuring. We use highly accurate, NIST-traceable tools and take appropriate sample sizes to ensure statistical certainty. Can every machine be corrected? No. Some have been so neglected, mis- treated, or crashed that the cost of bring- ing them back into spec is greater than their value. Our data shows that over the past 10 years and nearly 2,000 printers, 84% were able to be corrected to a Six Sigma specifi- cation. Similarly, 90% of the nearly 10,000 placers we have worked on were able to meet their OEM spec, even after being grossly out of tolerance upon initial measurement. Essentially, about 15% of printers and 10% of placers can't be returned to spec, which is why measuring used equipment prior to investing in it can be so beneficial. Mike Sivigny is owner and general manager of CeTaQ Americas. FEBRUARY 2025 I SMT007 MAGAZINE 27

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