Answer below:

Bev Christian wrote:
> Brian, Ingemar, Greg, George, Dave, Graham and others,
>
> Brian's first sentence contains a very important word - "carefully".
> Most dip tests I have seen are certainly not that.  Certainly people are
> generally not using a wetting balance as the dipping apparatus!  And
> Brian's dip test replaces forces measurements with distance
> measurements, if I read one of your previous e-mails correctly, Brian.

Yes, but under perfectly repeatable conditions (see the description of
the apparatus I "invented" nearly 40 years ago, which does automatically
ensure repeatability between fluxing and dipping AND a freshly-skimmed bath.
>
> If there is variation in the time between fluxing and dipping then your
> procedure is not tight enough.  And wouldn't this also affect a dip and
> look test, if it really were critical enough?

This is difficult to automate with many WBs, but easy with dipping.
>
> I wish I had a dictionary and the time to debate the philosophy of
> "subjective" vs. "objective", but I will only say I am a little
> uncomfortable in how you use those words in this context, Brian.
>
> I do not understand why you say the test piece from a wetting balance is
> useless for archiving.  You still have the piece that was being tested.
> You can see if the solder wetted.  You can see how far the solder front
> advanced. You can see if dewetting took place.  How is this any
> different from a piece that was tested using a dip and look test? I am
> confused.

Because, in the dip test I described, you can see the reaction of the
solder on the test piece for times from 0 to 10 seconds, clearly
defined, with no equivocation because of the buoyancy of the insulation.
I should perhaps say that my machine was developed when I was studying
wetting of PCBs. A WB will give different answers depending on the
conductor widths: a dip test won't.
>
> I agree both serve a purpose.
> I would say both do not give a completely correct answer - to avoid the
> use of subjective or objective.

Let's not get into semantics.
>
> And, Brian, you make a very important statement at the last I completely
> agree with "the dip test is useless for SMDs" - certainly for the small
> sized parts we are dealing with.  In our company we only have one
> through hole component! 0402's are the size of choice for chip
> components.

Agreed 100%

  I defy any supplier to tell me that their workers can meet
> IPC or MIL Spec parameters for dipping by doing it by hand.

I NEVER mentioned hand dipping.

And I defy a supplier and a client to get the same results with a
globule test on a 0402 component!!!!! (even if they each have identical
apparati)

Brian

Please note new e-mail address [log in to unmask]

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------