Blog - Screaming Circuits


Possible Weather Caused Delays

Sign on 2-6-14UPDATE Feb 11, 2014

We are back to our usual 40 degrees and drizzling - so business as usual. No more weather delays from this storm. Just dampness. Never... ending... dampness...

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Yes, we here in the Portland area can get snow too. I know it's not as deep as everywhere else, but it still gets in the way. That means that some parts shipments in to our plant may be late and some finished board shipments going out may be late.

Unfortunately, I have to pop up a reminder that  weather related days do not count toward your turn-time. I'll let you know as soon as I can if anything changes. Unless it gets worse, Bob the cat will attempt to keep on delivering, but may be late.

Duane Benson
Eli The Ice Man says "What?"

 

UPDATE Feb 7, 2014:

We're here. We're working. But we still may have some weather caused delays. I know, Minnesota has ten more feet of snow than we do, but they also have things like snow plows and mittens.

Here's proof positive that Bob the Cat is attempting to get parts in and out of here.

Bob the cat prints

Old and New: 60 Years at Milwaukee Electronics

In 1954, one of my favorite movies, "THEM!", premiered in U.S. theatres. An even more significant (to us, anyway) event took place in Milwaukee, Wisconsin: The founding of Milwaukee Electronics.

We are excited to announce that our parent company, Milwaukee Electronics has been in business for 60 years! After six decades of dedicated service to customers, and several name and logo changes, Milwaukee Electronics is updating it's image. Click here to view more details.

Without Milwaukee Electronics, Screaming Circuits would not be possible. 60 years of expertise, plus our unique perspective, gives us the ability to offer something that no one else can: real-time, on-line turn-key quote and order of quick-turn prototype and small-lot production assembly.

Duane Benson

Open The Pod Bay Doors, HASL

Does anyone use HASL (Hot Air Surface Leveling) anymore? It's also known as HAL.

Prior to the RoHS days, HASL was probably the most common surface finish. You can get it lead free, but most boards seem to use immersion silver or ENIG (Electroless Nickel Immersion Gold). HASL has traditionally come at a lower cost than those other two finishes, but immersion silver can generally be found at the same price now.

Our friends at Sunstone.com, for example, charge the same for silver and tin/lead HASL. ENIG is still more BGA on HASL closeexpensive no matter where you go though.

One of the chief disadvantages of HASL these days, is the lack of planarity on the surface. (Note the bumps on the BGA land pattern in the image on the right.) With thru-hole or large components, an uneven surface doesn't matter so much. With the increasingly smaller BGAs and QFNs, however, surface irregularities can cause big problems.

Both Immersion silver and ENIG have nice flat surfaces. OSP (Organic Surface Preservative) has a pretty flat surface too, but it's not used much except in high volume consumer goods or specialized applications.

By Duane Benson
Oh, the pain! Save me, William.

ODB++ plus, plus, plus

I wrote a bit about ODB++ back in October. Nothing has really changed much since then. I'm just clarifying a few things.

First, I want to put more emphasis on the use of ODB++. In addition to being beneficial to the manufacturing process, it can make your job a little easier. If you send us ODB++, you do not need to send either the Centroid or Gerber files. The ODB++ replaces both.

Eagle CAD does not have an ODB++ export. However, the Eagle .brd file will work too. You can send us the .brd instead of the Centroid and Gerber files.

If you can't send either of those formats, we still need the Centroid and Gerbers (top copper, bottom copper, solder paste stencil, silkscreen and solder mask layers).

Number Six
I am not a number, I am a free man!

Corporate Cats

Here at Screaming CIrcuits, we're all busy making sure to get everyone's assembly orders shipped off on time so here's a picture of one of our corporate kitty cats.

COrporate kitty

We have a pair that live on campus here. They seem to be quite content to buzz about the parking lot and surrounding hedges all day while we build things. That's for the best because we do keep them off our production floor. Cats can cause static electricity and that would be bad.

Duane Benson
Make sure the dip with your chips is lead free before eating it

VLV - Very Large Vias

I recently received a question over on Twitter. Tomaž Šolc, AKA avian2 asked:

"@pcbassembly What is your opinion on the "one big plated drill in QFN ground pad" pattern? pic.twitter.com/M9ZLftpuo0"

From Avian2 Ban_N62IEAAm3acI answered back: "Bad for machine assembly, okay for hand assembly." That's definitely true, but it's worthy of a bit more explanation. Here's the photo avian2 included along with the question. We're looking at the side opposite of where the QFNs are mounted. The two big openings in the square gold pads are the big vias (plated drill).

This is often done when hand soldering QFNs. Somehow you get the little pins on the outside edge of the QFN soldered down. Then you turn the board over and poke your soldering iron into the big opening to solder the pad down.

Generally, there wouldn't be any reason to do this with machine assembly, as we do here in our plant. You put a number of small vias, cap them, and segment the solder paste layer (refer to this post and this post). Thus, we would never recommend using big vias like this for machine assembly.

However, I can envision some situations that might call for this. First, there's the hand solder method I mentioned above. Next, there may be some very specific need to expose a lot of the pad to open air for cooling. In general, this is not the best way to get cooling, but maybe in some special case. Third, perhaps you need access to the pad as a test point and don't have enough room to get access any other way.

You wouldn't do any of those three things in a production environment, but in a prototype world, sometimes things happen differently.

Duane Benson
Hurray! Only one day until Mitten Tree Day!

Surface Mount, But Not Really

Sometimes parts labeled as surface mount aren't quite ready for prime time. I've written about this subject before (read here), and I'm going to write about it again - whether you like it or not. This time, however, I'm not talking about components that aren't up to thermal par. Today, it's about components that can take the heat, but aren't set up to be machine assembled.

Surface mount machines need a flat surface to pick on. They use small vacuum nozzles that need to seat on that flat spot. Chips, of course, are flat on top, as are most other components. Connectors, however, are often not flat on top. That doesn't leave any place for the "pick and place" machine to pick.

Single row header with pick and place padGenerally, manufacturers will place a small tab of Kapton® tape or a small snap-in plastic pad on top of the connector, giving the machine a surface to work with. You can see that in the photo on the left. Once the board has been fully assembled, the tape or plastic pad is simply removed.

Every now and then, we'll see connectors come in without that flat pick and place surface (like on the right). That means the machine can't place it, so it will have to be placed by hand. 1.25mm-Wafer-SMT-Connector

When buying your surface mount connectors, if you have a choice between a part with the tape and one without, you're better off picking the one with the tape. No offence intended to all of you humans, but machine assembly is generally preferred over human assembly.

Duane Benson
Only three more days until Mitten Tree Day!

How Do You Know?

This isn't a Thanksgiving blog. It is Thanksgiving day, and if it were a Thanksgiving blog, I would have to be working today, but we're shut down for the holiday, so I'm not working. I just woke up pondering what it would be like to do business with us (or anyone like us) and decided that I wanted to hear myself speak (metaphorically) for a bit. A word of warning though; I'm in a long-winded rambling mood today.

Take an example; the Beagleboard. I use that because it's a complex board that's open source, so I can freely talk about it. It was originally put together by Gerald Coley and Jason Kridner. I don't know how Beagleboard face onlong they spent designing it, but according to a UBM study, a typical product design cycle is about a year.

So, what we're really talking about is a year of a couple of engineer's lives. It can be a lot of cash money too. When ordered in large quantities, the Beagleboard and it's progeny are inexpensive enough to be sold for quite a decent price. However, when purchased in small quantities - say five - it can cost several thousand dollars.

When the Beagleboard was new, we built a few just to kind of show off. We took the open source files and ordered all of the parts. We tried to get some PCBs fabbed, but in that quantity, they would have cost us $1,200. Instead, I posted a request on the Beagleboard.org forum and found someone with some bare Beagleboard fabs.

I got those boards and the parts and ran them through our system. Had a customer quoted the build, it would have cost somewhere (if my memory serves correctly) around $800 per board for assembly. That would be $10,000 for a set of prototypes. That may seem like a lot for a board that retails for $150.00, but that's the difference between ordering hundreds of thousands and ordering five.

That cost comparison isn't the point. If you're in this business you know that getting small quantities of complex stuff in short notice is expensive in direct dollars, but more than worth it in time and effort saved. The point is that, while we build a lot of sub-$1,000 orders, we are frequently given orders that are valued at $10,000 or more. Sometimes CONSIDERABLY more. We've seen projects where parts alone are tens of thousands of dollars. I've seen a single FPGA cost several thousand dollars alone. Yikes!

You've spent a year of hard labor on a design. You hit "Save" for the last time. If you're like me, you want nothing more than to get a working board into your hands. The gap between that save and a fully built board is painful for me. But the prospect of shelling out $20,000 to some unknown company for the purpose of turning that year of my life into a physical product is positively terrifying.

Well, if you don't already do business with us, we are that "some unknown company." That makes me wonder how this all happens. I design boards myself - not the big ones, but I do design a fair number of them. Right now, I have four boards I'm actively working on and about that many that I've shelved for a few months. I understand a bit of the fear of handing a design off. Of course, I have an unfair advantage. I can just send some boards through our shop and get them done just about any time.

It's easy for me to trust us. I got a job here and I know that I take the stewardship of that big check and year of your life very seriously. I treat it like it were my own. I also know that I don't work for companies that don't share that philosophy. I've tried, out of necessity, twice in my career, working for companies that didn't treat customers they way I would and I ended up pushing my agenda so hard that I got fired. It wasn't pretty.

I've established that I (as in me) trust us. How do you get to the point that you can give us (or anyone else) the same trust? The Beagleboard guys didn't know us enough to do so. We built some of their boards on our own. Plenty of people do know us well or are somehow willing to make that leap. We quite literally* have built things that have gone up into space, down into the ocean and everywhere in between. It's pretty fun to look through our customer list and see so many names of companies doing really cool stuff.

All of the marketing mumbo-jumbo I spit out is designed to somehow convince you to let us take care of your design. But those are just words. Words are meaningless without the deeds. It's what all of the other people in my company do that really counts. I spill out glurge. They do their best to treat your project with the same respect and care that you do. I'm thankful for that, because if they didn't do that, I wouldn't want to work here. If they didn't do that, my job would be meaningless and stupid. Hey - this did turn out to be a Thanksgiving post!

Happy Thanksgiving!

Duane Benson
* The word "literally" is terribly misused these days, but I'm actually using it by the correct definition. Well, okay, the "everything in between" isn't quite literal, but "space" and "under water" are. And it's comprehensive a representative sample that I'm in the spirit of "literal."

Boo

Nosferatu-le-vampire-05-gGooood evening (said with my best vampire accent)

Turn out the lights. Hide your Mosfets. Keep your phase-locked loops locked. Calm your Verilog.

Your simulation is useless against the terrors of the infinite state machine. Your impedance is no longer matched and your bypass caps have stopped bypassing. Your RF signals will not stop reflecting.

Beware

Beware

But, do not fear the evil lectroids

  

More Fun File Facts: ODB++

In my last post, I wrote about the up and coming IPC-2581 PCB manufacturing file format. While IPC-2581 may be looked at by PCB fabricators and assemblers as a holy grail of sorts, it's not yet widely adopted by CAD software. But, that doesn't mean that Gerbers are the only option.

ODB++ was developed by Valor in the waning years of the last century as an improved method for getting manufacturing data into their CAM systems. Valor and, hence, ODB++ was purchased by Mentor Graphics in 2010. ODB++ is still widely available, however there's concern in some circles that it's not truly open. That concern is where IPC-2581 came from. In fact, IPC-2581 is somewhat derivative of ODB++.

I can see how a CAD software developer might fear the use of something owned by a rival. However, my understanding is that Mentor does it's best to treat it like an open standard and has made it available more or less as though it is open.

The history isn't really important. What is important is that ODB++ is a more complete format than the Gerber and is widely supported. Pretty much everything good that I said about IPC-2581 in my prior post also applies to ODB++.

The bottom line is that, regardless of whether Screaming Circuits is your fab (through our partner Sunstone) and assembly (through our factory right here) provider, ODB++ is a good thing. It makes the job easier and more accurate than does use of Gerber files. Both "easier" and "more accurate" help keep costs down and keep ambiguities to a minimum. As you know, ambiguity is the bitter enemy of both accuracy and quality.

Unfortunately, for all of you Eagle users, Eagle does not yet support ODB++. If anyone out there is really good with Eagle ULP scripting, you might want to create a on ODB++ and/or IPC-2581 creation ULP.

Duane Benson
I was ionized, but I'm better now.