Hi Kathie & All,
I have an in-line aqueous cleaner and hand cleaning processes and haven't
implemented SPC on either.
Is it feasible? Anything is feasible. How much money do you want to spend
and do you need a staff to go with that? :->
(I just flew into BWI last week, nice area . . . But seriously.)
On occasion, we have run our assemblies through the Omegameter (for ionic)
and FTIR (for nonionic). This is more of a troubleshooting effort.
We only do this when we have a problem otherwise we leave it at a visual
inspection by either the Assembly folks or somebody on the Engineering
staff. I'm sure you could do some kind of gradual response, sampling
program along the same lines. Not necessarily simple, inexpensive or
something the assembly folks can track themselves, I'm afraid.
I second Franklin's question, what's the goal here, other than keeping the
boss happy? (Nice boss . . . Boss Stay!)
My two guesses for why anyone would do this is:
1. you have a cleanliness problem or
2. you are looking to reduce cleaning costs (along the lines of Joseph's
post).
The best way I see, but haven't tried, SPC in cleaning would include warning
and action levels. This might include a tiered cleaning approach or
establish a reason for dumping a bath instead of it being 'operator'
dependant. This might be especially useful on the hand cleaning procedures
where there are already plenty of other variables.
I use Kyzen Aquanox XJN in an in-line aqueous cleaner. They have an
analysis service to check the wash bath for contamination and chemistry
strength. (We have Kester doing the same thing for our tin-lead solder
bath.) The one time we used the Kyzen service, the bath came back fine and
eliminated it from my list of potential causes to our problem. (Again, not
simple, cheap or something done in-house). I also have a log for people to
fill out while they wait for their parts to be cleaned. My goal is to
determine how long or how many pieces we can clean before making adds or
dumping it. More technical sounding, track No. Parts Cleaned/Gallons of
Cleaner. Hand Cleaning operations include Isopropyl Alcohol, DeOxIt, Flux
Off Rosin, and Trans LC using stainless steel trays and nonabrasive brushes.
Quantitative SPC for Cleaning . . . let me sleep on it.
Hans
~~~~~~~~
Hans M. Hinners WR-ALC/LYPME Bldg. 640
Materials Engineer 380 Second Street,
Suite 104
Manufacturing Eng. Sec. Robins AFB GA 31098-1638
912-926-1970 (Voice) 468 - 1970 (DSN) 912-926-7974 (Fax)
[log in to unmask]
> -----Original Message-----
> From: Lambert, Katherine A. [SMTP:[log in to unmask]]
> Sent: Friday, October 22, 1999 03:21
> To: [log in to unmask]
> Subject: [TN] SPC applications for cleaning
>
> Hi folks,
>
> I have 3 cleaning processes for cleaning assembled printed circuit
> assemblies - in-line semi-aqueous, batch vapor degreasing, and good old
> hand
> cleaning with various solvents.
>
> My management is requiring me to develop an SPC application for cleaning.
> This application should include the use of variable data (actual
> measurement
> of a parameter rather than pass/fail, good/bad). The measurement should
> be
> something the average assembler can measure and chart with a minimum of
> fuss
> and muss - in other words, keep it simple and inexpensive.
>
> Right now, the only measurement we can do fairly quickly, is an ionic
> contamination test (old Alpha Omegameter). I realize that this test is
> really more qualitative than quantitative even though it produces a
> number.
>
> I have a few questions of my esteemed colleagues out there in the virtual
> factory:
> 1. Do any of you have SPC applications on your cleaning systems? If
> so, what are you measuring and how often?
> 2. Is this even feasible?
>
> Thank you for any help you can provide.
>
> Kathie Lambert
> Process Development Engineer
> Northrop Grumman
> Baltimore, MD
> 410-765-9746
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################
|
