Well put Doug !!
James Hofer
Director of Operations
Accurate Circuit Engineering
3019 S. Kilson Dr.
Santa Ana Ca. 92707-4202
714-546-2162 work
714-473-6127 cell
[log in to unmask]
----- Original Message -----
From: "Douglas O. Pauls" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, September 01, 2004 9:22 AM
Subject: Re: [TN] Cleaning populated boards with Isopropyl
> Grand Wazoo? <snort> Kinda gives "out tha wazoo" a whole new
perspective.
>
> As to your recommendation for cleaning machines, I would agree. Both
> companies make some good cleaners.
>
> Let's dissect Paul's situation:
>
> I currently clean SMT stencils in a sink with hot deionized water.
>
> **So you are putting lead down the drain?. Might be some local effluent
> laws waiting to bite you. Might want to check on that with your local
POTW
> or EPA folks.
>
> I would like to automate this process (and eliminate the DI water) and
have
> been looking at cleaners that can do the job.
>
> **Automation is good. Automation is consistent. And DI water is your
> friend, not your enemy. Tap water is the Darth Vader of materials.
> Remember that.
>
> One of them uses Isopropyl Alcohol with no rinsing.
>
> **Which means you have a cloud of flammable vapor inside the machine. Is
> it explosion-proof? What does your local fire marshall have to say? Does
> the machine empty the workspace of fumes before you open it. Having spent
> the last 20 years cleaning the insides of humidity chambers with
> isopropanol, I can say you get some wonderful hallucinations from the
> fumes, but not something you want to do on a regular basis. Also, the use
> of IPA may also affect your VOC emissions for EPA compliance. In terms of
> the material, does your paste manufacturer indicate that pure IPA will
> remove all of the paste residues? Does the machine capture the lead in a
> trap somewhere? If yes, does it get recycled? If not, you have a
> hazardous waste situation. DI water is cheaper than isopropanol,
> especially when you start counting the cost of handling flammable
> materials, storage, fire suppressions, Aunt Gladys going home with fume
> headaches each day....
>
> This should work fine for the stencils but occasionally I also have to
> clean misprinted boards that may already be populated on one side, using
> no-clean solder paste. If I were to use this Isopropyl process on the
> misprints, would I be risking reliability of the board?
>
> **Arrghhhhhhhhhhhhhhhhh! Burn the Heretic!!!!! Ummm, not a practice you
> want to use. First, IPA is a lousy cleaner of flux residue, reflowed or
> not. DI water alone is not much better. One advantage with either is
> that paste residues that are not reflowed are easier to clean, but you
> would have to get used to seeing a white haze on your boards. The only
> advantage I see from IPA only is that the stencil comes out dry. What I
> suggest is that you use DI water, with a small amount of a cleaning agent
> that works with your paste. We use a lot of Kyzen products at Rockwell
and
> I have found their technical staff to be very good in matching the right
> material to the right soil. Many products can go to drain as long as you
> capture the lead. In the products we use, the micro-critters at the waste
> treatment site love the Aquanox chemical. To them, Rockwell is Delmonico.
>
> In terms of reliability, I would never take the chance with our products
of
> getting those iddy biddy spheres of solder somewhere they don't belong or
> places where you cannot remove them. They will see reflow conditions
> before they see another mass cleaning. So relays, connectors, under fine
> pitch devices, BGAs, air wound coils and transformers, etc., all become
> compromised if those solder balls reflow in place. Bare boards,
> maaaaaaaybe, but assemblies, no way.
>
> OK, beaming back up to the mother ship.
>
> Doug Pauls
>
>
>
>
> Phil Nutting
> <PNutting@KAISERS To: [log in to unmask]
> YSTEMS.COM> cc:
> Sent by: TechNet Subject: Re: [TN] Cleaning
populated boards with Isopropyl
> <[log in to unmask]>
>
>
> 09/01/2004 10:17
> AM
> Please respond to
> TechNet E-Mail
> Forum; Please
> respond to Phil
> Nutting
>
>
>
>
>
>
> I'm interested in what the "Grand Wazoo" Doug Pauls and Brian Ellis have
to
> say about this. If I've read their musings correctly alcohol does a nice
> job of spreading the ionic schmootz where DI water cleans it very well.
>
> If my research is correct, there are several automated DI water stencil
> cleaning systems readily available on the market (www.aqueoustech.com
> www.aat-corp.com to name just two) and these suppliers also make batch
> style board cleaners. Austin American (aat-corp) has a new unit on the
> market for under $10k.
>
> Oops, was that too close to a sales pitch?
>
> Why would you want to "eliminate DI water"?
>
> Phil
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Black, Paul
> Sent: Wednesday, September 01, 2004 10:58 AM
> To: [log in to unmask]
> Subject: [TN] Cleaning populated boards with Isopropyl
>
>
> Hi Everyone,
>
> I currently clean SMT stencils in a sink with hot deionized water. I would
> like to automate this process (and eliminate the DI water) and have been
> looking at cleaners that can do the job. One of them uses Isopropyl
Alcohol
> with no rinsing. This should work fine for the stencils but occasionally I
> also have to clean misprinted boards that may already be populated on one
> side, using no-clean solder paste. If I were to use this Isopropyl process
> on the misprints, would I be risking reliability of the board?
>
> Any help would be appreciated.
>
> Thank you,
> Paul Black
> Manufacturing Engineer
> Kronos
> E-mail: [log in to unmask]
> Voice: (978) 947-1520
>
>
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