PCB Assembly Services - Screaming Circuits: Sometimes, I just want to build it myself

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Sometimes, I just want to build it myself

It should (and does) stand to reason that I'm a big fan of professional assembly. When you need it done right, or need a bunch built, there's no better way to get working PC boards than a solid professional assembly house. Good thing I work for one.

Here's a Freescale KL03 microcontroller in 2 mm x 1.6 mm wafer level chip scale (WLCSP) micro BGA form, soldered by our folks on the manufacturing floor.

KL03 Prof solder closeup

I'm also a big fan of the underlying skills. I like having the practical context of being able to design and build my own boards. I'm personally no where near as good at it as the folks out on our factory floor, nor do I have the same quality of equipment at home. But I do build things, even attempting some of the super small parts. So, today, I thought I'd speculate a bit on how to home-build some of the more complex chips available.

I tried out a Schmartboard with a small QFN, and the same micro BGA pictured above with a home-toaster (reflowster?) oven. I've got a few pictures to show the results.

The Schmartboard is an interesting concept. The boards have channels filled with solder that connect up to the leads on, in this example, a QFN. The idea is that you put the tip of a fine point soldering iron in the channel, and slide it toward the chip,melting the solder and pushing it up to part.

Schmart unpopulated

I tried it out, with some level of success. I got a good fillets on one side of the chip, broke two of the traces, and ended up with a number unconnected.

Schmart soldered

Good fillets here:

Schmart good fillets

Those are some nice fillets and would pass IPC inspection. I need a bit more practices (see earlier photo), but I could see this as a viable way to make a breakout board for a QFN. This particular part has some of the metal connection on the side of the chip. The Schmart board also works on QFNs without that side metal exposure.

Home BGA processing

Getting a bit more ambitions, I designed my own board for a 20 ball 2 mm X 1.6 mm micro BGA. This is one of the parts that just has solder bumps on a piece of the silicon dice.

The professionally soldered image is at the start of this article. Here's my attempt at using a home reflow toaster oven:

KL03 home solder closeup

I hand positioned the parts and ran them through my toaster oven. Not bad, really. Just messy with all of those solder balls. And, the BGA balls didn't really mix with the solder paste all that well. It would likely be serviceable as a hobby project.

All of the little solder balls scattered around show up because I put down too much solder paste. As the paste melts, the flux will out gass a bit, spitting off the little balls of solder. We do see some of those in our shop sometimes, but we remove them when we do.

With more time at home, I could dial my skills in a bit and get somewhat better results, but for anything I hand out at a tradeshow or other event, I'll stick with factory built.

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Duane Benson
Spider bites man
Man turns into werewolf
No other spiders on spider island
No one seems to care

Comments


There being a boom in the overall PCB industry in China


The hot August has witnessed an extraordinary boom in the PCB market of China.
With half a year gone, there is appearing a wave in the PCB industry to show their own performance report. According to The Sixteenth Ranking List of the PCB industry released by CPCA which can be called a list of weight, among which 137 PCB enterprises, 12 copper-clad enterprises, 15 material for special use enterprises, 9 special chemicals enterprises, 9 facility and instrument enterprises for PCB special use and 4 environmental protection and cleaning enterprises were enlisted with an honor of enterprise with over RMB 1000 million. As You Li, the president of CPCA, said, the year 2016 was a year full of challenges as well as pains for the manufacturing industry in China. Faced with the complex and varied economic conditions, people in the PCB industry fought their way and made great achievements. The total business revenue of the PCB industry in the list amounts to RMB 164.216 billion, an increase of 2.76% compared with that of 2015, among which domestic-funded enterprises maintain a high increase rate of double digits. Of all enterprises on the list, 94 enterprises maintain a positive growth rate and 67 enterprises are domestic-funded ones, and many star-level quality PCB enterprises are at the top of the list.
Nevertheless, achievement is only a matter of the past and many domestic enterprises are actively adjusting transformation and improving themselves. It is firmly believed that the overall industry will turn over a new leaf in a couple of years. It’s no exaggerating to say that this July is destined to be a month of “burning hot”.
A wave of cooperation is blowing in China in terms of both domestic cooperation and cooperation with overseas enterprises. There is no doubt that these newly built factories are not a matter of copying the old ones but is an upgrading and improvement of technology and equipment. Faced with new challenges, enterprises need new ways to cope with them. They are trying to get rid of the traditional path of “investment – expanding production – growth - investment” and break through the old thinking patterns to rebuild the business pattern and pursue a road of growth with innovation and great inner strength.
As the old saying goes, one will rise abruptly based on its accumulated strength. In 2016, the PCB industry in China has made the best achievement among the overall global PCB industry with not only the largest scale but also good economic efficiency, and the overall industry chain is making fundamental changes. As long as grasping the opportunity of industrial upgrading well, in the future, China’s PCB industry is certain to enjoy a stable and rapid development and actively expand the market under the driving force of the overall industry. http://www.pcbindex.com

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