Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Cleaner device for PCB

rick

#27051

Cleaner device for PCB | 29 January, 2004

What kind of cleaning method you recommend for PCB - double side SMD (fine pitch and BGA components) and THT elements (PCB are for microwave application!!). Process technology no-clean.We have to remove grease-fingerprints, dust etc. It is low volume production. We are thinking about ultrasonics and spray devices so: - do you recommend 3-chamber machine (cleaning, rinsing, drying) or one chamber is enough effectiveness?? - what is your opinion about ultrasonics machine for fine pitch application in microwave application should i be concerned about damage solder joint or elements? - i have proposal to buy professional cleaner machine which is similar to dish wash machine - do you have any experience with this kind of stuff?

-i have heard about new technology in cleaning system for PCB. it is cleaning in vapourus hydrocarbons so you don't have to immerse PCB. does anyone know this technology and have experience?

Any help will be appreciate

Rick.

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#27052

Cleaner device for PCB | 29 January, 2004

Rick,

As I understand your comments, you do not need to clean off the flux residues? Then hot water and a little cleaning chemistry should do. However, there may be some reaction by the residual flux if not enough cleaning chemistry is used. There are many out there cleaning no-clean flux residues. Its best to use a chemistry such as supplied by Zestron, Kyzen and Petroferm. www.zestron.com www.kyzen.com www.petroferm.com Consult your solderpaste mfg. and the cleaning vendors for best chemistry match for your application. There are batch type and in-line cleaning equipment that can do the job on fine-pitch leaded and BGA components. I would not consider ultrasonics as it may damage some components such as ICs and clock types. When using chemistry you need to rinse with DI water after. You do not want any of the chemistry remaining on your assemblies after cleaning. Any machine you look at should have some sort of chemical isolation or have a final DI rinse. Some of the leading cleaning equipment companies that offer both batch and in-line systems are: Aqueous Technologies www.aqueoustech.com Austin American Technologies www.aat-corp.com Speedline Technologies- Electrovert http://www.speedlinetech.com/electrovert/index.aspx

I have not heard of that vaporous hydrocarbon cleaning technology.

Hope this helps.

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blnorman

#27053

Cleaner device for PCB | 29 January, 2004

Another equipment manufacturer is Smart Sonic.

Most equipment manufacturers have their own chemistries, but they are also willing to use other cleaners. What we have done is to send boards that need to be cleaned to the equipment manufacturer. We tell them what cleaner we want to be used. They clean the boards and tell us what parameters we used to clean them. We take the boards back, finish populating them, and put them in test. If you're concerned with the microwave application - send test boards get them back and test them in the end use configuration. If you use a one chamber cleaning system, I would be afraid of cross contamination. One of our potential vendors hawked his one chamber machine, but we went with the 3 chamber for this reason.

The vaporous hydrocarbon cleaning sounds like vapor degreasing. Problem with that is extensive system with condensers to condense any vapors so they are not released into the atmosphere - air permitting problems potentially.

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rick

#27073

Cleaner device for PCB | 1 February, 2004

Pete C

Thank you for answer.

Yes we have to remove solder flux so we need chemistry for no-clean flux residue. What kind of damage can i expact from ultrasonics device? you said damage IC and clock types?. We have all components in solid encapsulation so is it realy problem for ultrasonic I am thinking about 40kHz frequency.

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Dean

#27074

Cleaner device for PCB | 1 February, 2004

Ok, maybe I'm missing something here:

It's a no clean flux type AND your going to wash it? Why not migrate to OA Flux and just run DI water with Ion-Exchange beds? Benefits: No need for ultrasonics No need for chemical isolation No need for cleaning chemistry (expensive) No waste stream (100% closed loop)

Microwave and RF applications (typically) are excluded from no-clean flux types; As-well-as Hi-reliability assemblies.

Save yourself the trouble. It's easier to implement an OA flux and wash process than semi-aqueous was process.

Do you currently omega-meter, ionograph or SIR test?

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#27078

Cleaner device for PCB | 2 February, 2004

Rick,

Ultrasonics can damage some components that react to the mechanical action of the ultrasonics inside the device. Some component mfr data sheets will comment on ultrasonics.

Better safe than sorry.

Dean makes a good point if you can change solderpaste to water soluable. Because WS solderpaste is much stronger for de-oxidation, ionic contamination monitoring is essential.

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Mark

#27079

Cleaner device for PCB | 2 February, 2004

Just something we have done with our low volume cleaning of boards. Go buy a cheap steamer and a slow cooker. Let the boards submerge in the cooker at 160 degrees on a grate for about 30 mins than spray away. Don't forget the DI-water to put in it and away you go. The main reason we do this is for one particular board is a medical casing. And there can not be one spec of flux or anything on the board. This may sound ghetto but hey it works and people are happy with it cause the quality of the board is grade A.

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Larry

#27099

Cleaner device for PCB | 2 February, 2004

Do you bake the boards after 30 minute submersion? Parts and boards are netoriously hydroscopic. What do you do to combat organcis in solution? How do you know your boards are "clean"? Clean is differnet things to different people. Just currious.

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#27101

Cleaner device for PCB | 2 February, 2004

Hello Rick, There have been several papers published on the benefits and safety of using ultrasonics for cleaning PCBs. The following are just a few:

*B.P. Richards, P. Burton, et. al. "Does Ultrasonic Cleaning of PCBs Cause Component Problems: An Appraisal" IPC Technical Review, June 1990

*Bill Vuono and Tim Crawford "Ultrasonic Cleaning of Military PWAs" Electronics Manufacturing Productivity Facility, Indianapolis, IN (TS0040) April 1991

*Les Hymes "Defluxing with Ultrasonic" Circuits Assembly September 1999

*William Kenyon "Ultrasonic Cleaning Acceptance Accelerates" SMT magazine May 1995

I have not had much success e-mailing these articles via the SMTnet e-mail system, so if you (or anyone) would like a copy, just send your e-mail address to: bill@smartsonic.com

Regards, Bill Smart Sonic Corporation Tel: 1(818) 610-7900 www.smartsonic.com bill@smartsonic.com

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Debbie

#27128

Cleaner device for PCB | 4 February, 2004

Hi Rick,

Cleaning No Cleans is becoming more of a norm. It is true that changing to a OA flux/paste would be a easier process to control from a cleaning standpoint. A water soluble process will cost a great deal less as well. However, if your process does not allow you to change from a no clean, cleaning in either a batch or inline with a chemistry is possible. A batch system may require a bake process after a batch system. I would recommend sending samples to several cleaner companies (both batch, inline and vapor degreasers) to have testing completed.

You may also want to contact American Competitiveness Institute. They have several different cleaning system in house and can provide testing on boards. Their website is http://www.aci-usa.org In addition to the companies listed by Pete, you may also want to visit Technical Devices website at http://www.technicaldev.com,

Hope this helps. Debbie

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