Another option could be to add a coupon to the PCB panel that is
representative of the component types on the assembly, but less the
magnetics. Run that with the assembly and then perform the ionic test on
the coupon. Costs a little more in components, but you get valid data.
Kevin Glidden
Manufacturing Engineer
Astronics Luminescent Systems Inc.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bloomquist, Ken
Sent: Thursday, November 30, 2006 4:58 PM
To: [log in to unmask]
Subject: Re: [TN] Question about J-STD-001 cleanliness designator C-22
Hi Kevin,
I'm just asking the question. I have heard that a good benign no-clean flux
can give you some bogus readings using a ROSE test.
Assume that it's not a big deal for a qualified no-clean to be on a solder
joint within a wound magnetic device. If you submerged the assembly into the
75%/25% IPA/DI ROSE tester you could get a strange reading from the magnetic
device. You may get an abnormally high reading that I don't believe would
give you the ability to tell if the board itself is really clean. Not only
that but you really don't want to be contaminating the filters in the ROSE
tester with flux. It would shorten their life and those puppies are
expensive.
You could submerge the portion of the board that does not have the magnetic
device on it but that would get to be a pain in the butt also.
I'm just exploring options. Thanks for the suggestions and comments.
Anybody else?
KennyB
-----Original Message-----
From: Kevin Glidden [mailto:[log in to unmask]]
Sent: Thursday, November 30, 2006 12:56 PM
To: 'TechNet E-Mail Forum'; Bloomquist, Ken
Subject: RE: [TN] Question about J-STD-001 cleanliness designator C-22
I guess I don't fully understand. If you need to pass ionic cleanliness
testing, than you need to pass. That includes the components used, not just
the joints you made. Ionics are detrimental on the PCB and on the
components- no discrimination there. I would either pre-clean the
components or find different supplier. If neither are feasible, you would
need to do some sort of investigation with IC testing and/or SIR testing to
prove the residues are not detrimental, wherever they may lie. Then if
validated by that testing, you could put in the documentation that the P/F
limit is higher, just so long as you have the data behind it. The Rockwell
Gang or P.A.L pals might have a valid opinion here...
Kevin Glidden
Manufacturing Engineer
Astronics Luminescent Systems Inc.
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