标签: solder

I just read Max the Magnificent's blog: What? EEs who do not know how to solder? Sadly, unlike Max, I was not "shocked" or "flabbergasted" to learn that some engineers can't or don't solder. Like so many things in the modern world, hand-soldering is no longer a required skill. It's useful, and I personally think that everyone in the industry should have the skill, but it's not a requirement anymore. Years ago, I would draw a schematic on paper, acquire the requisite parts, and test the design using solderless breadboards. Once I was confident enough to create a more durable prototype, I would get out my wire-wrap tools or soldering iron. Even when wire-wrapping, I would often need to solder a few parts down. Soldering was inevitable and it wasn't really possible to be involved in electronics without the skill. Today, however, the situation is a quite a bit different. It is very possible, perhaps even common, for an engineer to go from idea to finished product without ever putting iron to solder. This is not to say that problems don't crop up in the process. Some of these problems could be fixed with a hot iron, but not always. The only choice may be to re-spin the PC board and have it built by someone else. Sometimes the problems simply can't be resolved by hand and—in those cases—soldering skills will help about as much as sewing skills. Take a common problem in the prototyping domain: an incorrect footprint on the PCB. This is probably the most frequent design issue to pop up in my world. It can have a couple of different causes: 1. Metric vs. SAE measurements: It's not just Mars Probes that have this problem. Connectors see this one a lot. If you have only four positions on a 0.1" (2.54mm) pitch header strip and you try to use a metric 2.50mm pitch header strip... no one will care. However, if you try that with 25 positions, even good soldering skills likely won't help make it fit. You'll need a new PCB. 2. QFN vs. QFP footprints: Many newer chips, especially in these form factors, don't have pre-made land patterns in CAD software. Either a footprint has to be custom made or a similar one has to be borrowed from a pattern that's close enough. QFP (quad flatpack) land patterns look very similar to QFN (quad flatpack, no lead) land patterns, but are typically larger. Swap the two and, again, hand soldering skills may not get you anywhere. Not long ago, I was designing in a Microchip MCP72833-AMI/MF. It's a compact LiPoly charger, requiring no more than a few resistors and capacitors. It comes in two form-factors: a 3 mm x 3 mm DFN (dual inline flatpack no leads) and a slightly larger MSOP. I picked the DFN to save PCB real estate. It wasn't until after I had PC boards in hand that I discovered the DFN isn't available in the small quantities I need. This was a bad time to discover such an issue. Had I checked and discovered that information early in the design cycle, I would have designed in the MSOP. The land patterns are close, but not close enough that I could place the MSOP on the DFN land. Some people might turn the chip upside down and run individual 24 gage wire from the chip legs to the PCB footprint, but with 0.5mm pitch leads, I just can't do that—despite 30 years of hand soldering experience. 3. Form factors not available: You may have designed in a BGA only to find that particular package unavailable and purchase time. Part availability in a different package won't help, nor will hand soldering skills. Take the NXP LPC11U14 ARM processor. It comes in a 4.5mm x 4.5mm BGA, a 7mm x 7mm QFP, and a 5mm x 5mm QFN. There are two other parts in the family: LPC11U13 and LPC11U12. All three are virtually identical except for the amount of Flash memory. The BGA would be idea for keeping things small. After completing the firmware, however, I might decide that I don't need all 32K of the Flash. The LPC11U12 only has 16K and costs less. That's fine, except the LPC11U12 doesn't come in the BGA form factor. Hand soldering won't help in any of the three scenarios described above. Of course, there are always a few exceptions to everything. I once met a guy who has hand-soldered 01005 passive components. He's a wizard though, so that doesn't really count. So, in summary, my personal opinion is that electronics engineers should know how to solder, but I do know that not all need to. What do you think? Duane Benson Marketing Manager Screaming Circuits  

In the late 1970s when I was still in college, I worked for a while as a broadcast engineer at a local TV station. Working a weekend sign-off shift allowed me to still go to classes during the day. Election night at a TV station is a true mad-house, with every scrap of equipment in use (and many personal bits and pieces in use, too), as they want to have as many remotes as possible. I'd drawn the assignment of "studio" (being physically handicapped sometimes has its own rewards). Of our four big studio cameras, two were out on location, leaving two at the studio. A little after 7:00 p.m., I noticed a problem with Camera 1, and after several attempts to adjust it failed, I told the directors that "Camera 1 just died"—not a welcome message, but they had to live with it. The chief engineer was "floating," and at the time he was at the studio, so he went out to the sound stage to see if it might be a quick fix, then shoved the camera over into the corner and forgot about it. A few days later, the engineer who normally worked on cameras started in on it, and after about two weeks, he gave up on it. The guy who normally worked on transmitters then spent about a week on it, with no more results. The chief engineer then spent about four days on it, with the same results. Then the guy who had the weeknight sign-off shift spent more than a week on it and still couldn't find the problem. Just before Christmas, I was getting a bit bored, since the only thing to do on a Saturday night shift was to take the hourly readings on the transmitter and record them. I figured since I (a) had nothing better to do and (b) had nothing to lose as I could do no worse than everybody else, I'd go ahead and take a shot at it. I did have two clues: First, by swapping heads between cameras, it had been proven that the problem was in the camera head (these cameras had a card case with a number of cards in the head, and about 30 inches or so of a 19-inch rack space of electronics back in the control room). Second, if the camera was left turned off for several hours, it would work for a couple of minutes when first turned on. So, I reckoned that it was some sort of thermal problem in the camera head. I dragged the camera out onto the newsroom floor, punched up so I could see the resulting picture from the camera on one of the newsroom monitors, went into the lab, and gathered up the board extenders for all of the boards in the camera head. I also armed myself with several cans of freeze mist and a heat gun. I started from one end of the card cage, putting one board at a time on the extender, then turning on the camera (fortunately, there was a circuit breaker on the camera head that could be used as a power switch), then waited for the camera to quit working. I then used the freeze mist to cool the board down to the point of it starting to get frosty, and observed the picture (or lack thereof). When there was no change, I powered down, returned the board to the card cage without the extender, and went to the next card. Eventually, I found one where cooling it did cause the picture to come back! AHA! The first real progress in many weeks! So I used the heat gun to get the board warm again, and the picture went away. Repeating the cycle, I was sure that I knew which board actually had the problem. I mentally divided the board in half, and by freezing only part of it, determined which half had the problem. I repeated the "divide and conquer" technique until I'd isolated it to about one square inch, whereupon I changed tactics. I brought out my trusty magnifying glass and carefully inspected that square inch. I discovered a cracked solder joint on a 5 watt resistor. Taking the board back into the lab, I broke out the soldering iron, and repaired the solder joint. Back in the newsroom, with the card still on its extender and power applied, the camera made a (sort of) nice picture even when the board was heated to "can't touch it" (maybe around 150 F). So, the basic problem was solved. I then spent the rest of that evening, and the next, having to readjust almost every setting in the camera, and finally had a really nice picture out of it. Clark Jones earned a BS in computer science in 1980 and worked in the semiconductor industry for 23 years. He worked as a principal design engineer for a start-up doing both hardware and software. He submitted this article as part of Frankenstein's Fix, a design contest hosted by EE Times (US).  

I am upset and bothered. I am shocked and horrified. In short, I am flabbergasted (I think it fair to say that rarely has my "flabber" been quite so "gasted"). And what is the reason for my current state of discombobulation? Well, I'm glad you asked... A few days ago, my chum Adam Taylor said something like: "Max, you'd be surprised how many new electronics engineers don't know how to solder." Well, I must admit that I really didn't give much credence to this statement, and I sort of shrugged it off at the time, but now I'm starting to wonder... The thing is that I just observed a young engineer making the most appalling botch-up of a very simple soldering task. Once I'd fought my way through the smoke, I was staggered to discover what he'd been doing—the board was burned, the excessive heat was causing traces to pull away, a bunch of pins were shorted together, and the component in question had gone to meet its maker. The sight of that poor board brought tears to my eyes (or maybe it was all the smoke and solder fumes). What do they teach electronics students at college these days? Isn't soldering one of the core skills one is expected to know? In my day—when dinosaurs roamed the Earth—all the students on my university course already knew how to solder before they'd even set foot on the campus (I don't know about the others, but I taught myself by reading hobbyist magazines like Practical Electronics). On the bright side, I am heartened to see that companies like SparkFun actually offer hands-on classes in soldering. Also, I just heard from my old friend, Alan Winstanley, who is the online editor for the electronics hobbyist magazine EPE (EPEmag.com). Way back in the mists of time, Alan created an incredibly useful online soldering (and de-soldering) guide featuring oodles of high-quality, close-up photographs. The great news is that Alan has just published a new e-book, which he describes as: "A much expanded and updated version of my original online work, with 80 all-new colour photos showing everything a trainee or hobbyist needs to know to get started in electronics soldering." Alan kindly send me low-resolution versions of two of these images:       I just bounced over to Amazon to take a peek at the Kindle edition of Alan's Magnum Opus, which he's modestly dubbed " The Basic Soldering Guide ." In addition to teaching you how to solder and de-solder, this tome also explains the correct choice of soldering irons, solder, fluxes, and various tools. I think it's safe to say that I know at least one young engineer to whom I shall be recommending this little beauty.

I am sad and troubled. I am revolted and appalled. In short, I am flabbergasted (I think it fair to say that rarely has my "flabber" been quite so "gasted"). And what is the reason for my current state of discombobulation? Well, I'm glad you asked... A few days ago, my chum Adam Taylor said something like: "Max, you'd be surprised how many new electronics engineers don't know how to solder." Well, I must admit that I really didn't give much credence to this statement, and I sort of shrugged it off at the time, but now I'm starting to wonder... The thing is that I just observed a young engineer making the most appalling botch-up of a very simple soldering task. Once I'd fought my way through the smoke, I was staggered to discover what he'd been doing—the board was burned, the excessive heat was causing traces to pull away, a bunch of pins were shorted together, and the component in question had gone to meet its maker. The sight of that poor board brought tears to my eyes (or maybe it was all the smoke and solder fumes). What do they teach electronics students at college these days? Isn't soldering one of the core skills one is expected to know? In my day—when dinosaurs roamed the Earth—all the students on my university course already knew how to solder before they'd even set foot on the campus (I don't know about the others, but I taught myself by reading hobbyist magazines like Practical Electronics). On the bright side, I am heartened to see that companies like SparkFun actually offer hands-on classes in soldering. Also, I just heard from my old friend, Alan Winstanley, who is the online editor for the electronics hobbyist magazine EPE (EPEmag.com). Way back in the mists of time, Alan created an incredibly useful online soldering (and de-soldering) guide featuring oodles of high-quality, close-up photographs. The great news is that Alan has just published a new e-book, which he describes as: "A much expanded and updated version of my original online work, with 80 all-new colour photos showing everything a trainee or hobbyist needs to know to get started in electronics soldering." Alan kindly send me low-resolution versions of two of these images:       I just bounced over to Amazon to take a peek at the Kindle edition of Alan's Magnum Opus, which he's modestly dubbed " The Basic Soldering Guide ." In addition to teaching you how to solder and de-solder, this tome also explains the correct choice of soldering irons, solder, fluxes, and various tools. I think it's safe to say that I know at least one young engineer to whom I shall be recommending this little beauty.  

As a "newbie" electrical engineer at an aerospace design company in Louisville, Colo., I have been learning the flight hardware design techniques, testing procedures and the rules that go along with troubleshooting a problem. It usually involves some extreme amount of paperwork, three signatures and highly skilled technicians trying to read through a rework or troubleshoot steps that somehow always come under scrutiny, thus making me feel like ... well.... a newbie. In the past 14 years of my career, I served as a communications repair technician in the U.S. Marine Corps, and, after I was honourably discharged, I worked at other small companies as an experienced technician using the skills I had gained in the Marine Corps. During this time, I worked part-time and used my GI bill to obtain my EE degree from the University of Nevada, Reno. While earning my degree, I spent many hours working in the aerospace field of study. Teaching old dogs old tricks When I moved on to the avionics group with my current employer, I was a semi-expert on sensors for micro satellites. I was proud to find my niche and felt like I could show a bit more of my knowledge without getting myself in a bind or be made fun of by my peers. And, until a few weeks ago, I never really had the right moment to "show them what I got!" While we were working a failure on a circuit board, management wanted to conduct a destructive analysis to determine a root cause for the failure in the flight board...doing this would take time and cost a bit more than our group wanted to spend. And, at the time, the board and component failure had become the "long pole" (the biggest issue of concern) in our program and was given the highest priority. I quietly said to my boss, "Why don't we 'Huntron track it?'" Based on a name-brand piece of test equipment called a Huntron Tracker, this was a term we had used a lot in my days at a fourth-echelon electronic repair facility in the Marines. Of course, my boss didn't know about any of this, so to him I must have sounded like a "goof." And, my "whisper" was a little louder than I had planned and resulted in everyone at the table looking up at me in total confusion. I said quickly, "You guys know what I am talking about right? Using a curve tracer to compare a component to a known good component to look for a difference in the 'signature'.." (Insert sound of crickets here). Still nothing was changing their looks, so I started over with a detailed account of how I used this test equipment while a tech and how it saved us many hours trying to troubleshoot down to the root cause of the failure. Once they all were on the same page, they pointed to me to conduct the test and prepare the procedure, and since they knew no one person would have a clue what I was describing, it would be up to me to conduct the test first-hand. For a split seconded I realised that all my years of training and experience hadn't been for not, and that I would now be able to call on my "bag o' tricks" without having to feel like I was talking nonsense in the aerospace world. Solder issues I troubleshot the circuit to a compare-and-hold IC that had inductive shorts to the 5V reference on the wrong pins—in fact it was TWO pins that had been damaged or shorted—looking closer, I realised that, during the QA inspection, the true problem was missed. On a metal can-integrated circuit, the soldering had bubbled up to the can and thus created a semi-inductive short once the board and IC were operating in a hot environment. It was so hard to see and required that the board be tilted and reviewed under a microscope, but I was able to show that the quality of the solder on this component had caused the failure. A review and circuit analysis was also conducted, and it showed that the type of intermittent problem could be traced back to this component. (Figure 1, below, the IC with shorted pins). Figure 1: Solder Blobs! Yikes! After I gave my full report and provided my findings, I felt like I had really come through for my team. I had several people give me a pat on the back, which motivated me to continue speaking from my experiences and show that, just because I was new to the company, I still had some area of expertise that no one else on the team had... and I felt proud to help on a problem that was given the highest priority to solve. - William Davison William Davison recently moved from Northern Nevada to the Denver area to work in the aerospace industry after obtaining his electrical engineering degree from University of Nevada, Reno. He keeps busy with his hobbies (old BMW car restorations, LEGO Robotics and Halloween effects/costumes) and continuing his education. He is currently going to Colorado State University with a focus on obtaining his Systems Engineering Masters.