August 5th, 2006
Folks:
Oliver writes;
Dr. Lasky,
Your statements sound rather strange to me.
1. It makes no sense to compare the increased energy and tin demand to the total numbers to justify leadfree. If it's worse, it's worse. Else you also had to consider that lead usage in electronic solder is near to insignificant compared to the total lead usage.
2. I really wonder who told you that you can use finer pitch packages with lead free, because it wets worse! Tin whiskers will kill your fine pitch after a short time.
Again, I get the impression that you are an advocate of short-lived "equipment" (or should I write junk?).
Although I also need to sell new stuff, I feel responsible to make it as good as possible.
Oliver
My Response:
1. a. I calculated the increase electrical power usage for RoHS compliant assembly as 0.0002% of the total world usage. This amount is "in the noise" and it is not possible to measure an increase this small. It is statistically insignificant, hundreds of other factors that fluctuate naturally have thousands of times more effect than RoHS compliant assembly. It is so small, it is meaningless.
b. I agree electronic use of lead is insignificant, lead is banned from electronics by the EU to make recycling easier.
2. Motorola has manufactured well over 100 million, fine lead spacing, lead-free cell phones since 2001 with equal or better reliability to leaded solder phones. Studies are emerging that show that RoHS compliant assembly with SAC solder minimizes tin whiskers. Is more work needed in this regard.....absolutely. Is the "sky falling" Re reliability for SAC assembly electronics, absolutely not.
I don't like junk and I buy a lot of electronics. I strongly support more work to establish long term reliability of RoHS compliant assembly, but with all of the earnestness I possess I will tell you that I don't beleive I will ever be a victim of a reliability fail due to RoHS compliant (read lead-free) assembly. (But I think every laptop I have had has lost a hard drive!)
Cheers,
Dr. Ron
Oliver Betz:
Ron,
the cited study doesn't compare SnPb finish to LF finish, it compares different processing of components with LF finish.
Regarding (Motorola) cell phones: ours are all pre-2001 and shall last some more years. Cell phones are usually not operated at elevated temperatures. BTW: did you know that most Freescale (formerly Motorola) ICs were available with LF not before 2005? They seem to have different strategies for industrial and (greenwashed, SCNR) consumer products.
Given that you are "surrounded by electronics that are all < 3 years old" it's indeed unlikely that you will "ever be a victim of a reliability fail due to RoHS compliant (read lead-free) assembly". BTW: my 8 year old notebook PC runs still with the first HDD. Our ten years old PBX and telephones don't lack any feature and won't be replaced in the near future - to be continued...
Oliver
John Anderson:
Not to be a party pooper, but the fact us that I have to repair industrial control equipment, and so far there has been a really poor track record with lead-free solder. Mind you, the products I repair and design are almost always wet, cold, hot and vibrating and tin-lead solder is far superior to the lead-free assembly processes in every respect for extreme applications. Not only are tin whiskers a headache, but embrittlement problems cause thousands of hours of troubleshooting time searching for intermittant, hairline-cracked joints that we just don't see, or very rarely see with tin-lead solder.
At this point, several industrial clients of mine are insisting on non-RoHS assembly (RoHS parts are OK, just not the assembly process) of all componentry used on assembly equipment and control systems.
And by the way, my new Moto phone died in 6 weeks, and has been replaced twice and I'm wondering how long the third unit will last. I'll bet the recurring problems can be traced to RoHS assembly, just because I am biased that way from experience in the real world.
RoHS just isn't a good idea, and point me to the sign-up sheet to start the revolt...
-John Anderson, Professional Electrical Engineer