Brian,
Why would it be any easier to automate times for dipping vs. WB?
Certainly on the old Kester WB system the times for flux dipping were
fixed.
You never mentioned hand dipping, but I maintain most suppliers are not
using a controlled dip, but are doing it by hand.
Dave Hillman has already pointed out that a newer batch of WB passed a G
R&R test. And trying to get a supplier and customer to agree on
anything with regards to solderability - unless it is 100% good or 100%
can't solder better than wood is pretty difficult, irrespective of
equipment.
Bev
RIM
-----Original Message-----
From: Brian Ellis [mailto:[log in to unmask]]
Sent: June 8, 2005 8:46 AM
To: TechNet E-Mail Forum; Bev Christian
Subject: Re: [TN] Wetting balance
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]
---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.
---------------------------------------------------
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
-----------------------------------------------------
|
