Author Archives: Dr. Ron
Measuring Void Content
A reader writes: Dear Dr. Ron, I need to measure the void content of an alloy. Is there an easy way to do it? After a little thought, it occurred to me that the densities of the voided and unvoided … Continue reading
Cool on Global Warming Idea
Folks, I am a global warming skeptic. This term, however, requires some explanation. I believe in climate change. The climate is always changing. However, I don’t think it is clear that the world has been getting warmer in the last … Continue reading
Wet Gold II: Measuring Gold Content in an Ore With Only a Scale
Folks, In my last post we saw how you could measure density with only a scale. In this post, we will expand on that technique and learn how to measure metal content in gold/quartz ore. In principle, this technique could be … Continue reading
RoHS, Six Years After
Folks, I was at IPC Apex Expo the other week. San Diego is a great venue for the show, but I always forget how cold it can be (55°-65°F) this time of year. While at the show, I was interviewed … Continue reading
Posted in Dr. Ron
Tagged Apex, cost, Dartmouth, Expo, IPC, lead-free soldering, Reliability, Rockwell Collins, RoHS
Leave a comment
Measuring Alloy Density
Folks, In the category of interesting requests, Ron, a gold worker, from Guyana, sent me the following note: Dr. Ron, My colleagues use a “wet” gold technique to measure gold alloy density. Is this valid? Where does the formula come … Continue reading
Weibull Part III
Folks, Our discussion of Weibull Analysis continues…. Let’s say you have worked hard and assembled some SMT lead-free PCBs for thermal cycle testing. You used the best lead-free solder paste and some lead-free solder preforms as you assembled several through-hole … Continue reading
Posted in Dr. Ron
Tagged figure skating, pin-in-paste, solder paste, thermal cycling, Weibull distribution
Leave a comment
Weibull Analysis II: The Curse of the Early First Failure
Folks, In continuing our discussion on Weibull Analysis, let’s assume we assembled some SMT and through-hole PCBs with lead-free solder paste. On this board are also some bottom-side terminated (BTC) components (often called QFNs), that are also assembled with solder … Continue reading
Posted in Dr. Ron
Tagged failure, shape factor, slope, solder alloy, solder spread, Weibull distribution
2 Comments
Interpreting Weibull Plots: I
Folks, A while ago I discussed the Weibull Distribution and its importance in electronics reliability analysis. This distribution has been used to evaluate the life of solder joints whether formed in SMT, wave, or even using solder preforms. In the … Continue reading
Pondering the Past, Present and Future
Folks, Let’s step away from electronics assembly challenges, and deep considerations of solder paste, solder preforms and wave soldering, to ponder where electronics have gone in the past decade or so. The mobile phone of the early 2000s was just … Continue reading
Pete Rides the Wave
Let’s see how Pete is handling the wave solder crisis. Pete had to admit that he was surprised by the positive outcome of his meeting with Fred Castle. He had sent Patty a text the day before, after he took … Continue reading