Lyle Johnson wrote:

All,

The Zephyrtronics BGA/CSP placement tools arrived here today. A couple of minor shortages were found and the supplier has promised to send the missing parts tomorrow.

We are now in a position to be able to place these packages in small qty for prototype and flight.

As someone who makes his living selling circuit boards, I don't understand this purchase. I mean, I'm all for the "let's do it all ourselves thing", but BGA placement equipment seems a bit over the top. Many of the chips this will be used to place will cost hundreds, if not thousands, of dollars. Isn't it wise to pay someone else to do the placement, someone who does it all day long and knows how to do it?

Besides, I wouldn't send out a single BGA-containing board to my TERRESTRIAL customers without having it X-Ray scanned first to check the connections. I certainly wouldn't send one into space without a scan. Are you planning on purchasing an XRay machine as well?

Matt

Lyle Johnson wrote:

...

Besides, I wouldn't send out a single BGA-containing board to my TERRESTRIAL customers without having it X-Ray scanned first to check the connections. I certainly wouldn't send one into space without a scan. Are you planning on purchasing an XRay machine as well?

No, no plans on an X-ray machine, Matt. High-volume manufacturers of boards with BGAs dont; X-Raythem either.

Not true at all. EVERY SINGLE board with a BGA on it from ANY of the contract manufacturers I use is XRayed. Even the bargain-basement guys who I wouldn't trust with a valuable BGA do it. It isn't even optional. You don't have to request it, you don't have to pay extra for it, they automatically XRay EVERY SINGLE BGA board, no matter what. The cost is negligible.

Once you get the thermal profiles worked out, it makes reliable connections.

The equipment comes with a test board for 4 positions, and 4 BGA devices that contain a pattern of jumpers so that you can determine when it is in fact properly soldered down. This helps to calibrate the thermal profiles.

There is a very big difference between making electrical contact and making a good solid physical joint. And calibration means that most chips will be properly placed the first time. It doesn't mean ALL will be placed properly.

This is the same machine JPL used to place the BGAs in the Spirit and Opportunity rovers. Not sure if they X-rayed these or not, but it is the same exact placement tool set. In fact, Zephyrtronics includes a NASA report on how to use the machine for reliable placements.

I'd bet my life that JPL XRayed them. In fact, I'd bet they XRayed them several times -- once after assembly, once after thermal vac tests, once after a shake test, and then once again for good measure.

To repeat, I wouldn't send a single BGA-containing board out to a customer without an XRay, and the only risk to me would be roundtrip UPS charges.

I know you've sent a lot more satellites into orbit than I have, so you have a lot of experience with this. But I have to say that anybody sending a BGA into space without XRaying it first is absolutely nuts. I don't care if Werner von Braun himself said otherwise.

Matt

Eagle is not the only project this will serve. We are officially supporting HPSDR. HPSDR is mostly terrestrial in nature and I am convinced this will help us, convinced enough to have requested budget for it and to have authorized its purchase. We still need to be able to do some work on BGA and we have found that we often have to do our own thing. As these things go, this was inexpensive in the big picture if it allows us to continue to do our business and support our new joint ventures.

Bob

Lyle Johnson wrote:

Going into space, I'd want to X-ray it, too. For prototype construction, I'm not so sure.

Guess we'll find out...

73,

Lyle KK7P

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