Airbus big secret

community

circuit boar

management

I understand that the lead solder directive specifically excludes Aerospace 'and other high criticality' applications, which rather gives the game away that they know it fractures and don't care about the consumer !

AWEM (who has a cache of reels of 60/40 that probably will last him out)

Aerospace applications are exempt from RoHS solder requirements.

Conveniently.

From Electronic Design magazine, August 3, 2007

"The defense and aerospace industries are exempt from the European Union's RoHS directive, so they haven't had to shift to lead-free parts. The exemption was granted based on the need for the high reliability of leaded solder in the high-stress environment and long shelf life of defense and aerospace equipment. Lead helps mitigate the growth of tin whiskers, which can grow on pure-tin solder, then break off, potentially causing shorts."

So what clues do we have about the wire harness problem other than this ghost?

Anyone else remember the (only a decade ago) problems that arose when gold plated SIMM's were placed in tin plated sockets and vice versa?

Mark Rand RTFM

Wayne, The Europeans used the lead-free solder on the aircraft boards as a demonstration that it could be done and would result in boards equal to or better than leaded solder. We knew several years ago that Boeing was doing the same thing. Last year we were told by a component distributor from Seattle that Boeing was having a terrible time getting their boards to pass the environmental tests which include vibration testing, but they were able to solve their problems and are now using all lead-free solder on their circuit boards. About the same time we read that the new Airbus was being delayed for all sorts of strange reasons, including the faulty wiring.

Several of our customers are now requiring us to build their products using lead-free solder, including paste and wire solder. The smoke from the flux used with the solder must be kept away from the assemblers. It's pretty bad smelling and makes their nose and throat sore. Other than the flux, the only real change is about 5 - 10 degrees higher temperature on the irons and convection oven.

This week we had a rework job on a bunch of lead-free boards. Remove and replace a capacitor that was physically too large. We had to cut the cap leads because the 20 watt and 40 watt irons wouldn't melt the solder on the big copper pads. Today I got a 60 watt iron for next time.

So lead-free solder is here, it works and we had better get used to it. I think next year, all electronic devices from and to China have to be lead-free and their requirements are more strict than the EU. Japan and the rest of Asia will soon follow.

Bottom line, the EU will never admit their real problem and I don't think they should. Only in America would we find whistle blowers and blog writers that would reveal our problems.

Paul Drahn, President Jodeco, Inc.

How much actual electronics does Boeing build? I assumed that they purchased most of their avionics, engine controls and entertainment systems from other venders.

Thank you Paul, a real eye opener!

They may need "thermal reliefs" or "wagon wheels" in the artwork around the leads. Large through hole leads into large plane areas of copper would also do this will tin-lead solder. I assume the higher melting poit of lead free solders will make this worse.

Carl Boyd

The Boeing company probably builds none, but are farmed out to companies like mine to build to their specifications. I am sure they thoroughly inspect each board, just like our customers do. We do no work for Boeing, but are doing work for other aviation related companies. Their boards are still using 63/37 solder.

Paul

Well now, just becase they are exempt from the lead free regulations does not mean that they don't have to deal with lead free parts. The aerospace and defense industries make up a small part of the electronics market. Many of the componet suppliers are going lead free on everything they make so they can sell in the global market. If you know where I can buy tin-lead finish chip resistors or capacitors please let me know. Some of the manufacturers are changing lead finish without prior notice. We received some BGA packages with lead free balls labeled as tin-lead (some manufactures don't even re-identify the parts when they o lead free) put them on the boards with the standard process. We had big problems with fractured soldered joints.

We are 5 to 10 years away from understanding all the ramifications of RoHS.

Carl Boyd

Worse than falling off, they bridge between circuits. Most critical in IC's and thick and thin film circuits. But bulk head connection points can be a problem.

Martin

Mart> Wayne Lundberg wrote:

fact: Lead free solder is here. fact: It works in some applications. fact: it's long term reliability impacts are unknown. fact: It's higher reflow temperature prevents the use of some of the better high reliability PWB materials. fact Lead is effectively just being replaced with other heavy metals with no real proof that they are less hazzardous.

Not thinking of Purple ... :-)

Yep - and then the tant cap issue out of Taiwan.. Mart> >

wayne - others have pointed out that the assumption below about tin/lead solder is incorrect - to find out more about the airbus, I'd encourage you to read the trade press, including aerospace america, the AIAA magazine, Spectrum (for electronics), and of course Aerospace and Devense Weekly and Aviation Week - most of these will be at your local library and will provide far more authoritative information

The first Tandy/ Radio Shack computers had the same problem long before their were SIMMs. Tin plated PCB fingers, and gold flashed IDC ribbon connectors. The problem was so bad that a company sold sets of gold plated adapters to solder to the PCB fingers.

Thanks. This has been an eye opener thread for me.

OUCH! I hate BGA at the best of times, but that really sucks!

Years ago I had a supplier that sent us AgPd plated chip caps. We trashed an entire run of boards becuase of it. You CAN adjust the thermal profile of the process to allow for it, but >> "The defense and aerospace industries are exempt from the European

It just does not work quite as well as "real" solder.