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Lead free contamination at reflow

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Can lead free components/assemblies be contaminated if reflo... - May 15, 2006 by smtspecialist  

#41536

Lead free contamination at reflow | 15 May, 2006

Can lead free components/assemblies be contaminated if reflowed in a reflow oven for leaded process?

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aj

#41550

Lead free contamination at reflow | 16 May, 2006

Hi,

I might have misunderstood your question but as far as I am aware a Leadfree Reflow Oven is exactly the same other than the adjustments required for your Profile...

aj...

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#41551

Lead free contamination at reflow | 16 May, 2006

I have only one reflow oven can I use it for both processes (leaded and lead-free)? If I do use it, one run for leaded and the next run for lead-free will that contaminate my lead-free process?

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aj

#41552

Lead free contamination at reflow | 16 May, 2006

Contaminate your Leadfree Process with WHAT?

What contamination are you concerned about?

Its an oven - it doesnt care what you put in it...

Your main concern is that you can achieve the desired Leadfree Profile...dont be confused or concerned when you see the "Advertisements " for LEADFREE Reflow Oven(this is a marketing Camouflage)- as far as Im concerned all Reflow ovens are Leadfree...

Are you sure your concern lies with Reflow and not Wave Machine?

aj...

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Chunks

#41553

Lead free contamination at reflow | 16 May, 2006

Hi smtspecialist (man I gotta get me a name soon),

NO! Your oven cannot contaminate your process. Unless you have flux residues dripping on your board, there is nothing to worry about.

Now having your operators switch from leaded to lead-free smocks may be a challenge! (just kidding).

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#41554

Lead free contamination at reflow | 16 May, 2006

Thanks Chunks, I do have a very good maintenance done on a monthly basis to clean the accumulation of flux and I never saw nothing dripping, the operators says sometimes that I'm a bit too picky on the cleaning but that's the key to impress customers. The vapors were my concern. There is no way I'll get sucked in the sales bullshit since I have a great Vitronics soltec convection oven 8 zone. Thanks again!

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#41555

Lead free contamination at reflow | 16 May, 2006

Should you be "Master Chunks" or maybe "Master Dr. Chunks"

Jerry

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Rob

#41556

Lead free contamination at reflow | 16 May, 2006

Surely that would be Mistress Chunks?

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Chunks

#41560

Lead free contamination at reflow | 16 May, 2006

Good for you smtspecialist and your clean oven. It's always better to be too picky, cause once the goo starts dripping, they'll only blame it on your paste.

Mistress? No, gotta keep gender out of the work place. How about "Connoisseur Chunks"? Sounds like a good dog food or a bad red-neck steak house!

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#41616

Lead free contamination at reflow | 17 May, 2006

The question to ask is not so much in contamination of this mixed technology metallurgies, but rather, will this metallurgy successfully coalesce into a reliable interconnect? I find in my consulting travels worldwide that many of my clients do not ask the "correct questions." It is not a question of contamination but rather, synergy. Ask yourself, what is being achieved with the metallurgy of choice? In fact, my firm chooses to think outside the box.

Our soldering division is currently in the process of mining alternative metals and other composite materials.

I urge all to stay tuned for our discoveries that will one day revolutionize electronic interconnect technology as we know it.

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marc

#41621

Lead free contamination at reflow | 18 May, 2006

smt

You should have no issue using your exsisting oven for both leaded and lead free materials if the machine is capable of delivering the desired profiles.

One aspect that makes a "lead free" oven is the design of the system. Ability to reach the higher temperature setpoints is easily achieved with the offerings out there today, even many older systems.

The more important factor in my mind is reliability. The higher temperatures increases strain on all aspects of the tool. Conveyor rails should be designed properly grow and reduce sag with the increased temp, chain lubrication requirements should increase. Width adjust mechanisms, etc.. Flux residues tend to "bake" on the system, more difficult to clean so to combat, more frequent cleanings. Internal temperatures of the blowers are higher, bearing life can be shortened.

If you use N2 for lead free, seals will be a factor, higher temps dry them out and cause leaks.

With your attention to maintence AND regular profile verification for process control you should have no issue.

Thanks marc

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#41622

Lead free contamination at reflow | 18 May, 2006

Dear Guru,

Dude, are you on drugs?

Seriously, I really would love to know. I want some of them. I have dreamed for years to enter the state of mind you have attained.

Your going to mine alternative metals? What stuff that's not on the periodic table? Going to solder with a composite material?

Where did you come from, and did you get a return ticket?

Grant

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RDR

#41631

Lead free contamination at reflow | 18 May, 2006

Guru, you are nothing but a liar, any respectable consulting firm would not use a name as Guru Expert. Also would not change from a contamination thread to all the BS you just threw out trying to impress with your vocabulary. One does not need to question the joint, that has been done. most consulants know this already. ever see an SEM or a cross section or anything like that?

Please either go away or post your company and your name and provide a reference list of those comapanies you have "consulted". I would write this to mumtaz and WML but we all know that you're one and the same.

Russ

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Rob

#41639

Lead free contamination at reflow | 18 May, 2006

Looks like early experiments using lithium as a lead replacement in a nitrous oxide atmosphere may have had some side effects.......

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#41640

Lead free contamination at reflow | 18 May, 2006

I don't think so.

But I want to point out the amount of lead needed to contaminate a joint is microscopic.

You won't have lead vapour in your oven and with a clean oven there probably isn't any other way for even a microscopic amount of lead to contaminate the lead-free assemblies.

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#41663

Lead free contamination at reflow | 18 May, 2006

Now THAT'S some good stuff right there.

Earl just comes here to release his inner comedian because it's frowned upon by his upper crust IPC crones.

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Loco

#41690

Lead free contamination at reflow | 19 May, 2006

I think Mr Guru likes to smoke his joints leaded.

Seriously, Soltec offers 'leadfree upgrade kits'. You should be fine with 8 zones, but if you don't have bottom heating, you might want to consider inserting some in your reflow (peak) zones. Gives you less delta T, something that's more critical in a lead free evironment.

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Ola

#41697

Lead free contamination at reflow | 20 May, 2006

Interesting... We had visitors from (maybe out of space) that claims that the fumes!!! from whithin the reflow leadead solder process in an oven can get caught inside the oven during time and later on when we fire up the beast to the lead free temp-profile, that the lead later on will in a strange crazy way fall down on the pcba!!! Our question was: If this is the truth; how about the % of contamination that is allowed by the RoHS directive? No answer!! Belief this!!!! Seriously they got a point but hey, are we talking about ppm:s here...

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#41702

Lead free contamination at reflow | 21 May, 2006

Hi,

I think you should be ok, as the contamination in a reflow oven is generally flux from what I have seen. I have never heard to the solder metals itself being inside the oven apart from some paste in hole we did that sometimes dropped a bit of solder on the bottom of the oven.

But that's easy to clean up, and even if we did not clean it, it would not contaminate. Don't know of any other ways there could be contamination.

Grant

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#41733

Lead free contamination at reflow | 23 May, 2006

I worked for a company that had an industrial nurse come in and talk to us about lead and saftey.

Basically she told us in no uncertain terms that we had nothing in the facility that would come close to producing the temperature required to have lead vapours anywhere. I've never indepently confirmed this but do believe her.

If true then there is no lead in any fumes in the oven.

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#41737

Lead free contamination at reflow | 23 May, 2006

Stephen, you better believe the nurse she's right If it would be possible to produce lead vapors you would see lead vapor condensation in the hood or in the ducts. Never seen any lead deposits anywhere. There is no reason for concern

The absence of lead in the alloy might be a concern but that�s an other story

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