Stacy,
check ECD's website, first for the interesting point of view on robust
profiles, http://www.ecd.com/emfg/instruments/papers/rookspaper.htm, then to
download their profile planner at
http://www.ecd.com/emfg/instruments/download.asp?action=form&file=ProfilePla
nner1_07b.EXE.
Then I would go for a group technology approach, that is:
- group your 8000 boards according to their thermal masses, and be tough,
don't make more than 5 groups
- try to see if you can't transfer the boards from a certain group to others
by having a DFM (panelizing, redesign, etc) input that would alter the
thermall masses enough to make them transferrable
- develop your robust profile according to the paste you use and tweak it a
little so that the boards from your medium thermal mass group come out OK
- use the previously profile for all the groups with inferior thermal mass,
watch for exceptions
- develop another profile by bumping up the robust profile, so that your
highest thermal mass boards solder well
Like this, ideally you have 2 reference profiles that should cover 90% of
your needs.
Keep in mind that you must assess each assembly according to the IPC-610,
judging the joints that you obtain. If they are OK, don't bother profiling
each board, because you will never get the perfect distribution you get with
your 8000 custom profiles. However, keep a keen eye on the first batches of
each assembly. If they have touchy components, profile them and try to be
under 225 celsius in the spike zone on the top of the BGAs.
Then, be ready for the exceptions, but there shouldn't be too many.
This is my point of view as 100% no-clean user. But, if it can be done on
no-clean, WS should be easier, isn't it?
Regards,
Ioan
> -----Original Message-----
> From: My Nguyen [SMTP:[log in to unmask]]
> Sent: Wednesday, January 16, 2002 2:33 PM
> To: [log in to unmask]
> Subject: Re: [TN] Way too many Product Oven Profiles
>
> Technetters,
>
> Firstly, thanks so much for your input!
>
> We use:
>
> - Heller Oven Profiles, most of them are 8-9 zones.
> - Solder Paste Type: Water Soluble, Sn63Pb37 - P3
> type.
> - Board: 6 layers; thickness is equal or less than
> 0.05"
>
> I agree with Mr. Krug that we should look for a
> nominal oven profile that would satisfy about 80% of
> the product profiles. However, to short through 7000
> of them, it would be A LOT.
>
> Also, there will be so much resistance to this change,
> Q.A. will blame on different outcome, Production would
> do the same thing until ... they reach a comfortable
> zone. By having a scientific method, I may be able to
> convince them and have them cooperated much easier
> than shorting through 7000 to find the commonalities
> among them.
>
> A typical profile at here is:
> 100 - 140 - 160 - 175 - 170 - 190 -235 -255
> where process windows are:
> 30-150 degree: 50 - 140 sec.
> 150-183: 50-120 sec
> above 183: 40-80 sec
>
> Depending on the products and panel layout (maximum
> panel size: 7" x 12")the temperature for each zone can
> be changed +/-20.
>
> Again, I am looking for a scientific way that will not
> only satisfy the product quality requirement (all
> class 2) but also acceptable from strict people base
> on what they called: Logical/scientific thinking.
>
> Thanks,
>
> Stacy
>
>
> --- "Krug, Dick" <[log in to unmask]> wrote:
> > I have seen the same issues and have reduced the
> > number of different
> > profiles dramatically. When working for an OEM
> > which had similar PWB layer
> > counts, similar component densities and only one
> > solder paste, we got down
> > to 1 profile per oven model. Now in the contract
> > world, we are up to only 7
> > oven profiles after over a year of our reduced
> > profile initiative; RMA
> > Standard, RMA Heavy, RMA Light, RMA Standard
> > Nitrogen, RMA Heavy Nitrogen,
> > RMA Medium Heavy and Cure. We use the same profile
> > on RMA paste and WS
> > paste, and both the Sn63Pb37 and Sn62Pb36Ag2 alloys.
> >
> >
> > Using our paste suppliers' "nominal" profiles and a
> > "typical" (obviously a
> > judgment call) assembly, we defined the profile we
> > wanted to match. After
> > several iterations (because we wanted an "exact"
> > match) we had our RMA
> > Standard profile which is used on ~80% of all
> > assemblies. All other
> > profiles are variations because RMA Standard is not
> > acceptable.
> >
> > Each oven model has different zone settings and
> > speeds, but the same profile
> > name.
> >
> > The profile we "matched" is as follows:
> > Time Temp
> > (sec) (deg C)
> > 0 25
> > 30 49
> > 60 73
> > 90 97
> > 120 121
> > 150 145
> > 180 169
> > 210 184
> > 240 215
> > 270 183
> > 300 120
> > 330 60
> >
> > Dick Krug
> > Sypris Electronics
> >
> > -----Original Message-----
> > From: My Nguyen [mailto:[log in to unmask]]
> > Sent: Wednesday, January 16, 2002 1:17 PM
> > To: [log in to unmask]
> > Subject: [TN] Way too many Product Oven Profiles
> >
> >
> > Good morning Techneters,
> >
> > I am working on oven profiler consolidation project.
> > Currently, we have 540 Product Profile for each
> > oven.
> > For 13 oven machine, we have 7020 profiles. That is
> > way too many for a memory manufacture!
> >
> > We currently use water-soluble solder and no clean
> > solder. We know that for each product, the pre-heat
> > zone, soak-zone, re-flow zone, and temperature could
> > be a bit different from one Solder Paste Manufacture
> > to other, or from one Solder Paste type to others,
> > or
> > even from single side, to double side.
> >
> > HOWEVER, for memory, the width, length, thickness,
> > and
> > number of ICs, resisters, capacitors, and others are
> > limited to a certain number, i.e, PCB height is less
> > than 1.7 inches; PCB thickness is equal or less than
> > 0.05 inch; PCB length follow the spec. of 5.25" for
> > DIMM, DDR, RIMM, 2.66" for SODIMM, 4.25" for 72 Pin
> > SIMM, etc.
> >
> > I have heard that out there, there is a way to
> > reduce
> > from 1000s down to 10-100 oven profiles based on
> > Mass/Density. And of course, there are many other
> > scientific ways that I have not heard of. Please
> > help
> > me! What would be the best method you recommend or
> > you
> > have successfully tried to reduce the number of oven
> > profiles down to a control/reasonable numbers?
> >
> > Your advice and suggestion are greatly appreciated.
> >
> > Stacy
> >
> >
> > __________________________________________________
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> >
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