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changing from no-clean to clean

Yngwie

#19955

changing from no-clean to clean | 17 May, 2002

I'm trying to convince my customer to change to the clean process. They are asking me what is the benefit of going to clean process from no-clean. does anybody have any input or reference/article that I could refer to include in my report ?

Appreciate your prompt feedback and tahnk you in advance.

rgds.

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Hussman69

#19959

changing from no-clean to clean | 17 May, 2002

It primarily has to do with your product. Water wash does produce a much cleaner board from an ionic standpoint. I know products that are sensitive to ion leaking need to be cleaned. So you may want to use the customers own product as a point in switching over to cleaning. Although, if you're charging more money to do so, it may be a hard to sell.

Hope this helps.

Oh yeah, I almost forgot the general answer everyone gives - "Check the archives for all your wondrous answers."

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Dason C

#19965

changing from no-clean to clean | 17 May, 2002

I will convinced to change to the no clean process by environmental safe even though clean process is water soluble but it still produce the waste. Also, the BGA is not recommend to clean, if the flux is not completed removed from the board and electromigration may happen....

I assume that you are not building any RF product.

I can send you one of the presentation and we are succssful to convince our customer to change to no-clean.

Good Luck

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#19967

changing from no-clean to clean | 17 May, 2002

Now that�s a switch. Most are moving or properly have moved in the polar opposite direction. Dano, has someone been drilling your teeth lately?

We use water washable flux to: * Remove solder balls. [Or put another way, we don�t have to screw-down the process to prevent solder balls.] * Lower concerns about contaminating the board should we decide to over-apply WS flux. * Improve pin testability of soldered pads. * Provide better appearance. * Broaden the choice of coating and encapsulation products. * Allow routine process monitoring of process residues.

We believe we can clean under high pitch BGA, but know we can not clean under lower pitch BGA.

I don�t know your customer, but the thing that gets our customers� attention when we try to talk them into accepting our proposed process or part change is: * �Money, get away / get a good job with more pay and you're O.K. / money, it's a gas / grab that cash with both hands and make a stash / new car, caviar, four star daydream / think I'll buy me a football team.� * �The best things in life are free / But you can tell me 'bout the birds and bees. / Now gimme money THAT'S WHAT I WANT / That's what I want THAT'S WHAT I WANT / That's what I want, ye-ye-yeh, / That's what I want.� * Good evening, and welcome to The Money Programme. Tonight on The Money Programme, we're going to look at money. Lots of it. On film, and in the studio. Some of it in nice piles, others in lovely clanky bits of loose change. Some of it neatly counted into fat little hundreds, delicate fivers stuffed into bulging wallets, nice crisp clean checks, pert pieces of copper coinage thrust deep into trouser pockets, romantic foreign money rolling against the thigh with rough familiarity, beautiful wayward curlicued banknotes, filigreed copper plating cheek by jowl with tumbly ( ? ) rubbing gently against the terse leather of beautifully balanced bank books!!

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Yngwie

#19975

changing from no-clean to clean | 18 May, 2002

First of all, my Customers can be described as a real "Jack-Ass" or at least the SQE does. They don't treat us as their partners OR more like "do what I said...When I started to use solder paste you probably weren't borned yet and/or probably still on your wet stink diapers. Do what I say..or I give it to some other folks who can do it".

My factory is only a Small-Medium industry with only 3 lines. Their product is a real HMLV, say volume of 1 - 4 brds a months with about 300-1000 products codes a month and all of them are clean process. Same customer with a diff. division runs on the same line. This is their first RF product & all other products were running on clean. We only have one Wave soldering machines and I can't be flushing the flux tank every now and then. ( you guys sure know the risk I'm in ). Imagine, all products in my factory running clean except for this one, and the customer aspects clean board with no residue ( due to the RF requirement, & that is why I said they are a real jack-ass ). we have quite a number of RMA due to touch-up residue from no-clean flux pen ( they don't accept cosmetic defect). Tell me what is the best solution for this one. I know I'm going reverse way i.e. fr no-clean to clean, but, the economy is bad enough for us to kick this customer out of our way.

What the heck, they are willing to pay...but before that I need to justify as to why I want to do this before I decided to do selective wave with 2 flux tanks & 2 spray nozzles.

Thanx for your helps guys....

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Hussman69

#19979

changing from no-clean to clean | 20 May, 2002

I actually built a dual tank fluxer for my Econo-Pak once to handle the same thing. Not all that difficult if you're mechanically inclined. BUT, for your application I'd recommend just hand spraying the 1 to 4 boards a month with any flux they recommend. I mean, their volumes are so low that even at 4 boards a day, it wouldn't be worth the effort to switch fluxes in your tank. Plus, with water wash fluxes, a little excess can be tolerated and washed off.

I'd hand spray em', unless the customer is willing to pay big bucks for complete wave solder changeover. Even then, just hand spray em' and ask the boss for a raise.

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ianchan

#19990

changing from no-clean to clean | 21 May, 2002

yngwie, Hi mate,

and Holy Crap! what a blooming pile of 7 feet dung you have sitting on your front lawn!

ok, we had a customer SQE like that before, fortunately she was promoted from SQE to purchasing officer. and in the name of universal sharing, in addition to all the wonderous points listed by our friendly experts, run this trhough em customer :

" some PCB due to "not up to scratch" process control, will have plating chemical residue lying dormant in the Au/Ni(?) pads. the advantage of WS flux paste is that post-reflow Aqueous Cleaning is mandatory. this helps perform a DI water rinse of the mentioned plating chemicals. "

PS :got this out of a photo-copy of a book.

PSS: worked b4 in a RFID lab, think WS process is reasonable from your customer.

Good Luck!

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#19998

changing from no-clean to clean | 21 May, 2002

Dave, I hear ya on the WS perks. The one thing that got me thinkin' is the BGAs. I've been doing the normal higher stuff with no issues, but sales is starting to get orders for them little buggers. I'm thinking under .8mm, I'm gonna have to think about switching to no clean :( Whats your take on this? I thought about running the boards with WS, then manually soldering the BGA on later with no clean, but really don't like that thought either

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#20001

changing from no-clean to clean | 21 May, 2002

Larry,

Yes, no matter how much you�d like to avoid using NC, you probably will have to start using the stuff, if the design [sales, in your case] types have their way.

We can clean WS under 1mm and 1.25mm pitch BGA. For 0.8mm pitch BGA, we use NC. We cannot remove the WS flux residue from under 0.8mm pitch efficiently.

Recognize that the effectiveness of your cleaning depends on a variety of factors [ie, flux res materials and stubbornness, stand-off height, flood characteristic of your cleaner, slipperiness of your water, etc.]. Consider: * Getting some sample boards [or thermal glass] and parts from a dummy component supplier. * Soldering [or glue] the components with WS paste. * Cleaning the boards. * Evaluating the cleanliness of the board under the BGA.

Words from the weary are: * Don�t contaminate the primary side BGA with WS flux that�s applied to the secondary side and is allowed to flow to the primary side through via. * Don�t underestimate the cost of running NC. [Search the fine SMTnet Archives for previous commented about this.]

On your idea of soldering only the 0.8mm BGA with NC and using WS on the rest of the board: If you solder with the NC after cleaning, it's probably OK. Washing NC in a standard wash probably is not a good idea. Our thinking is, either: * Don't wash NC ... OR * Wash NC to clean all NC res.

It would be difficult for your NC paste supplier NOT to be more conversant on cleaning NC res than we are. [Although we would like to know more on this topic.]

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#20010

changing from no-clean to clean | 22 May, 2002

I have experience cleaning NC for military boards. The reason for cleaning the NC is due to conformal coating requirements. Zestron Vigon A200 and Atron AC 100, as well as Petroferm Hydrex DX have both been effective at cleaning Alpha UP78 NC paste. This was done at 15-20% chemical concentration in the wash tank on an in-line system with a chemical isolation stage. As far as density we were able to remove the residues from under devices that have a 0.1mm gap - PCB surface to component bottom. As far as ionic contamination, there is no issue since the NC boards pass Ionograph testing prior to cleaning. It is important to note that cleanliness testing with Ionographs, Omegameters and similar instruments can only measure contamination where their solution can penetrate and dissolve residues. Ion-chromatography is a more effective testing method. There is equipment that can clean boards with high-density, low profile components. This equipment is a centrifuge cleaner. The main company that makes those is Accel, a Cookson company. The MicroCel for non-aqueous solvents and HydroCel for aqueous solvents, are batch type systems and but are not well suited for real high volume. http://www.speedlinetechnologies.com/about_us/accel.htm

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