I recently participated in troubleshooting a process for a difficult mixed
technology assembly (minimum pitch 1.27mm, or .050"). After optimizing flux
deposition, preheat profile, etc., we ran over 30 panels without a defect (I
do not know how many opportunities per panel exactly, but certainly there
were over 1000). Even at 1 defect per 10 panels, this would be <=100ppm. I
believe this is achievable in a high-mix environment, given reasonably good
designs.
Fritz Byle
Rockwell Automation/Allen-Bradley
At 01:17 PM 6/17/97 -0700, you wrote:
>
>
>This post caught my eye because it's implied that "around 400 to 600ppm" is
>considered a good solder defect rate coming directly off a wave solder machine.
>
>I would like to know how others feel about this. What do you consider an
>acceptably "good" wave solder defect rate (before any touch-up, of course!) on
>mixed technology boards? With what minimum lead pitch?
>
>I have read benchmarking studies which say that there are people out there
>getting very close to ZERO ppm.... if so, someone out there ought to have
direct
>knowledge of this!
>
>
>On Mon, 16 Jun 1997 11:28:57 -0700 Ron Hollandsworth wrote:
>
>> From: Ron Hollandsworth <[log in to unmask]>
>> Date: Mon, 16 Jun 1997 11:28:57 -0700
>> Subject: Re: Hot Air Knife after solder pot?? Anyone use this?
>> To: [log in to unmask]
>>
>>
>> Hi ED:
>> I have some experience with Hollis GBS machines with Hot Air Knives.
>> The machines are good. Let me say that right out of the gate. The
>> Hot Air Knife will work as well as you make it work. I have used the
>> HAKs and have redesigned the internal parts to the HAK for a more even
>> air flow (Three have been redesigned). Back in "93" we bought a used
>> GBS machine and completely rebuilt the machine incorporating a
>> separate control console using PID controllers, Hollis' high mass
>> preheat system, with a chip wave, and the redesigned HAK. This
>> machine was built as a backup to Hollis One our main machine. Hollis
>> one was a GBS machine controlled by a GE FANUC computer. Both
>> machines One and Two could produce product of mixed technology (SMT &
>> PTH). Setup for the machine to operate well, around 400 to 600 PPM,
>> takes experience in wave setup (solder pot). Both machines were
>> equipped with wave fluxers and conveyors that incorporate finger
>> styles so fixtures could be used to process product.
>>
>> We are getting rid of the machines for a new Dover Soltec Delta
>> System. I worked and built those Hollis's machines. We made a lot of
>> changes so the machines would do what we wanted them to do quality
>> wise with our product. We are high mix semi-high volumn.
>>
>> If you have more questions I can be reached at:
>>
>>
>> [log in to unmask] (home)
>> [log in to unmask] (WORK)
>>
>> My name is Ron Hollandsworth, I am a IR&D Operations Task Leader for
>> ITT Aerospace/Communication Division.
>>
>>
>> ______________________________ Reply Separator
>_________________________________
>> Subject: Hot Air Knife after solder pot?? Anyone use this?
>> Author: <[log in to unmask]> at INTERNET
>> Date: 6/16/97 12:23 PM
>>
>>
>> Hi there Technetters!
>>
>> Hollis used to make a machine called the GBS that utilized a hot
>> airknife after the solder pot. I believe they have a patent on it,
>> however, they were bought by Cookson (Electrovert) a few years ago and
>> might not be enforcing it nor building it.
>>
>> The customers I've had contact with are split 50-50 (approx) as to it's
>> usefulness. It does a fine job debridging, however the parameters
>> (temp, angle, force, distance) are somewhat critical. There is a
>> significant drawback as well: If an assembly which would normally have
>> "a few" blowholes visible were to be processed using the hot air knife,
>> ALL blowholes (a majority of the holes on that assy) would be exposed.
>> Some people believe in touching up blowholes and this makes the process
>> counter productive. Those who feel blowholes are a fatal defect are
>> delighted at the revelation... I guess it's a matter of philosophy?
>>
>> To Tony: (originator of the topic)
>>
>> I'd lost your email addy in an unfortunate digital-snafu... I'd like to
>> discuss this further with you, including developing retrofits for your
>> equipment. Please contact me directly at this addy or by phone, if you
>> are interested.
>>
>> Regards,
>>
>> Ed Popielarski
>> QTA Machine
>> 714-364-6614
>>
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