From CES, get a first-hand video look at emerging technologies that are pushing boundaries of innovation in vehicle technology. https://vimeo.com/383851852
CES Updates
Dispelling The ‘Five Ball Rule’
Michel writes:
Dr. Ron, when if comes to SMT printing of solder paste, why do some people use the five-ball rule for rectangular apertures and the eight-ball rule for circular apertures?
Michel:
The “Five Ball Rule” is another metric that SMT assembly industry leaders believe, but it is difficult to find its origin. It states that when selecting a solder paste, five of the largest solder balls should be able to fit across the width of the smallest rectangular stencil aperture. See Figure 1a for a 0.2mm wide rectangular aperture.
Typically, the largest solder ball diameter is assumed at the 90th percentile. See Figure 2. So, in this example, a type 4 solder paste would fit the five ball rule as the largest solder ball is 0.038mm. Five times 0.038 is 0.190mm, just a little less than the aperture width of 0.2mm. It should be remembered that this is a “rule.” not a “law.” So let’s say you had 4.5 balls across the aperture with instead of 5, it would most likely be OK.
Figure 1. A comparison of the Five and Eight Ball Rules
Figure 2. Solder Powder Sizes
A generation ago, the advent of circular apertures to support BGA and CSP packages necessitated a new “rule.” Figure 1b shows why the five-ball rule is inadequate for circular apertures. Although five type 3 solder balls fit along the 0.275 diameter, off the diameter, there is not enough room for many solder balls. Hence, an insufficient amount of solder paste would be printed.
For the same aperture, if a type 4 paste is used, 7 or 8 solder balls span the diameter and the amount of paste printed would be much closer to the volume of the aperture.
For a little more on this topic, see a past post.
Cheers,
Dr. Ron
At AltiumLive, Lots of Sun (and One Big Cloud)
by Brooke Anglin
One of the first things I heard when I arrive at AltiumLive last week was was how much they loved the recap of the event my colleague Chelsey Drysdale wrote last year. They added that Chelsey truly captured what AltiumLive is about. Talk about pressure!
Let’s start at the beginning.
Drinks are on Them. The week (well, three days, but they really pack a lot in!) kicked off with a great reception on an outside terrace at the Loews Coronado Bay Resort. Dave Starkey, the engineer who designed and built the Piano Arc — the circular piano used by Lady Gaga’s pianist, among others — was there. So was the pianist. They displayed the unit, a 360-degree custom keyboard, with one of the panels removed, exposing the PCBs. Altium director of community engagement Judy Warner met Dave at a user group meeting in San Diego, heard his story and recruited him for the event. In case anyone wants to know the piano has 288 keys, a total of 12 circuit boards and only cost $57,000.
I saw our customary PCB West speakers Suzy Webb, Rick Hartley, Gary Ferrari and Eric Bogatin and met a lot of engineers.
Getting Younger. One of the things you note about AltiumLive is the demographics. It’s a younger crowd than you typically see at industry events. Eric Bogatin noted this in the first keynote (AltiumLive had not one, not two but three keynotes). He brought some of his students, had them stand up for recognition and encouraged hiring companies to talk to them. That drew a good laugh from the crowd. In his talk, he pointed out that while many designers will be retiring in the next 10 years, AltiumLive gives us reason to think a new generation is coming on strong.
Keynote #2 featured a celebrity from outside our industry. Jor Grand of Grand Idea Studio has a short-lived TV show called Prototype This! on the Discovery channel. The concept, which was similar to Mythbusters, was about the viability of gadgets and technology and how engineers feel a since of winning when a product doesn’t work the first time, but they don’t give up until their creation finally works successfully. While the show lasted only one season, Grand shared several clips and generated lots of laughs.
Finally, the main event: Altium rolled out its much-anticipated Altium Designer 20 ECAD. VP of marketing Lawrence Romine detailed the new “push and shove” capabilities that enable routing of complex HDI boards and ramp up design times over 20%. (For more on the tool, click here.)
Cloud in their Eyes. This was the third year of AltiumLive, and the multi-city event (another is being held in Frankfurt this week) draws 500 designers. The company grow is equally impressive. Last year 2018 Altium saw over 8,000 new users for its Designer PCB CAD tool, and on average Altium users do over 10 designs a year.
Looking ahead, Altium wants to move toward the cloud, something the industry has been avoiding for years. Its has added real-time collaboration, and hopes to bridge the gap between manufacturers and designers.
Not surprisingly then, AltiumLive focused as much on tomorrow as on today. The highlight of the event was the Robot Build and Battle. Attendees split into teams of six or more. Ours had nine; eight engineers, from all of the country, and me. I was cheerleader, motivator and general handyperson. (They said I sounded like each of their bosses … I beg to differ!) Team Sierra beat last year’s record, but we weren’t far behind. Amit Bahl of Sierra Circuits told me he didn’t realize just how geeky our industry was until the robot build. Such a fun and educational event!
Brooke Anglin is senior sales associate with PCD&F/CIRCUITS ASSEMBLY.
What a Waste
I like articles like this one from Forbes — even if they are out of date, because they cast attention on the intrinsic complexities of manufacturing.
But, while Forbes may think manufacturing inefficiencies cost the industry $8 trillion a year (no idea where that figure comes from, by the way), it points to the need for tools like the digital twin.
Submit an Abstract to SMTA Pan Pac
Folks,
This coming February will be my third SMTA Pan Pac. Pan Pac is a very enjoyable and rewarding conference. It is small enough that you can get to know all of the speakers, yet large enough that there is a full venue. For those of us in the northern part of the US, it is also a nice break from the winter weather. The first time I went I was surprised that it wasn’t very expensive. For this coming conference, air tickets from Boston are as low as $600 and the hotel is about $200 per night.
The conference will be held on the “Big island” of Hawaii. If you come early or stay late there are many interesting attractions, including the active volcanoes and the Mauna Kea Observatories. So for sure come to the conference, but why not submit an abstract to be a speaker? If interested in submitting an abstract go to this site.
Cheers,
Dr. Ron
The Disruptors
In his most recent monthly column my friend Gene Weiner pointed out the irony of calling a printed circuit board a commodity. “When did printed circuits become mass-produced unspecialized products?” he asks.
As I told Gene, it’s true PCBs are custom, but in some (many?) instances they are highly mass-produced. Think residential LED lighting, or game consoles or the most popular phones, etc. My sense is that calling them “commodity” or “custom” is a bit of a red herring. Large OEMs call PCBs commodities even though they know each is specific to a particular program. I think to most its a catchall word for “volume procurement.”
There is real tension on costs between customers and suppliers, and without artificial price bottoms I can see no reason that won’t continue. I think it’s highly unlikely sellers will be able to change the pricing model as long as the process technology remains essentially the same. It’s too entrenched, and often the buyers (which more and more often are EMS companies) have lower margins than the fabricators, so there’s no incentive for them to switch to a pricing model that will cost them more. A move to a different process technology (3-D/additive manufacturing) might well change the pricing curve.
It’s not that simple, of course. As double-Ph.D. and former CTO of Multek Craig Davidson once said, “Never underestimate the tenacity of incumbent technology.” It’s perhaps the best quote on technology adoption I’ve ever heard.
I used to think that with the many brilliant minds in our industry, we would successfully disrupt ourselves — in other words, the ideas that obsolete our current ways of doing things would be conceived and implemented by one of our own — maybe some genius in the basement of Apple or Intel or IBM. I’m less confident of that now.
I now lean toward the notion that the true disruptive change will come from someone outside our industry who has knowledge of both hardware and software and who uses a truly novel process to develop a widget that the public embraces. The mass appeal of the product (not the process, to which the general public is ambivalent) will be the proof of concept. And the investment money will follow.
Selecting Reflow Oven Length
Folks,
You are putting in a new assembly line to assemble some large boards for which your company just received a three-year contract. The boards are 45cm long and you expect the cycle time from the component placement machines to be 40 seconds per board. Your boss is pressuring you to get another 5-zone oven, as they are cheaper and take up much less space than a 7- or 10-zone oven. But, you are concerned that a 5-zone oven may not have the capacity that is needed to keep up with the component placement machines. Let’s make some calculations and see if your concerns are justified.
Table 1 shows some typical reflow oven metrics:
Let’s assume that you will be using a typical modern SAC solder paste. By studying the reflow profile above, we see that the amount of time needed in the heated zone is about 4.5 min. or 270 sec.
So if we choose the 5-zone oven the belt speed will be:
Belt Speed = BS= Heat Tunnel Length/Time in Heated Tunnel = HTL/Time = 180 cm/270 sec. or 0.66 cm/sec
The component placers will be presenting a 45cm board every 40 sec., so the belt speed needs to be:
BS = Board Length/Cycle Time = BL/CT = 45cm/40 sec = 1.125cm/sec
So clearly a 5-zone oven won’t work. What about a 7-zone oven? Let’s calculate the belt speed for this oven.
BS = HTL/Time = 250cm/270 sec. or 0.926cm/sec
Now we can see that the 7-zone oven won’t do the job either.
How about the 10-zone oven? Let’s see if the belt speed is greater than the 1.125 cm/sec needed.
BS = HTL/Time = 360cm/270 sec. or 1.33cm/sec
Success! Since 1.33cm/sec is greater than 1.1125cm/sec, this 10-zone oven will work. The extra belt speed will permit a small amount of spacing between the boards. Let’s calculate what it will be:
BS = (BL + Spacing)/CT = 1.33cm/sec => BL+ Spacing = BS x CT => Spacing = BS x CT – BL
Spacing = 1.33cm/sec. x 40 sec – 45cm = 53.2cm – 45cm = 8.2cm
To summarize: For our 45cm board that has a cycle time of 40 sec., we need a 10-zone oven with a heated tunnel length of 360cm. There will be an 8.32cm spacing between the boards in the oven.
If you would like an Excel spreadsheet to make these calculations send me an email at [email protected].
Cheers,
Dr. Ron
Not with a Bang …
Cemtrex’s run in EMS ended today with a decided whimper. The New York-based company sold its remaining contract assembly assets to a German private equity group for about $7 million.
It brings to a close one of the stranger stories in recent EMS memory. Cemtrex grew through acquisition, buying up a German EMS company, and later another, and green-fielded plants in Romania and India.
Focus was not its strong suit. Along the way, it became involved in virtual reality software and proprietary IoT device design and manfuacturing. It set a goal of $500 million in revenue, but its most recent quarterly results, released this week, put it on a run rate of about $90 million annually, which is behind its pace of just a year ago.
Then there was bewildering and lame hostile takeover attempt of Key Tronic, at the time a Top 50 EMS in terms of revenue. In offering a 1:1 stock swap, Cemtrex called out the larger EMS for its seemingly underwhelming profitability. Key Tronic’s response — at once clinical and dismissive — was one for the ages: “Our initial research shows [Cemtrex] reports approximately $45 million of EMS revenue. In our opinion, this does not qualify [Cemtrex] to make any statements as to how it might operate an EMS business like KeyTronic which is over 10 times [its] current size in terms of revenue.”
Cemtrex never filed the paperwork for a potential acquisition and the proposal quietly vaporized. And today, so did its aspirations of EMS supremacy.
Ralph Morrison, RIP
I don’t have all the details, but the industry icon Ralph Morrison passed away Aug. 2.
Ralph spent more than 50 years in the electronics industry. He was responsible for teaching thousands of engineers all about the fundamentals of how voltage and currents work. Up until about eight years ago, he was a constant presence at the PCB West design conferences.
He wrote several books, including Solving Interference Problems in Electronics, Grounding and Shielding Techniques in Instrumentation, and The Fields of Electronics: Understanding Electronics Using Basic Physics.
I didn’t know Ralph in his prime, but we developed an amiable relationship over the past 18 months as he did some writing for us. I truly enjoyed him — he had an economy with words that I will always strain to achieve.
Last year, he put together a series of articles for PCD&F: Voltage in the GHz World, Limiting Radiation from Logic Circuit Boards, Maxwell and Transmission Lines, and The Layout of Fast Logic on Printed Circuit Boards.
According to longtime friend Dan Beeker, a memorial service will take place in October. I will miss his emails and occasional phone calls, and most of all, his kind words about the role we editors play in helping designers and engineers better understand their craft.
Silicon Valley Not Paved with Gold
Is the bloom off the rose in the Silicon Valley?
For years, manufacturers have insisted on putting factories in the greater San Jose area. The CIRCUITS ASSEMBLY Directory of EMS Companies lists hundreds of entries with Silicon Valley zip codes. Damn the costs — siting near customers — actual or desired — takes precedence!
In the first quarter, the most up-to-date data available, industrial space vacancy rates were 2.7%, near an 18-year low. That’s despite more than 200,000 sq. ft. of new industrial space coming online in the period, on top of about 3 million sq. ft. of new industrial space that came online last year.
Ironically, industrial space rents, while climbing, are a relative bargain. The average rent was $1.27 per sq. ft. in the March period, more than twice that in 2010 ($0.60 per sq. ft.), but well below the national average. That comes to more than $381,000 in rent a year for a modest 25,000 sq. ft. factory. But tack on energy, and labor costs — unemployment rates are not only lower than the national average, but workers earn a small fortune — and it all adds up to a very expensive enterprise.
Today the pendulum is shifting, if only bit by bit. We are seeing furloughs, layoffs and even some big names starting to blink. Jabil, Creation Technologies,
and this week, Benchmark are among those closing factories in Silicon Valley.
Will more follow? In an industry where margin and cash flow often make all the difference, it won’t be a surprise if more players head for lower-cost pastures.