In a previous life I used Hollis GBS and Future 1 machines with a hot air knife.
The original GBS knife worked better than the newer design on the future 1
series.
Electrovert and Sensby (and others) offer a hot air knife now.
Note 1: It works well once the setup is correct (up to 1 hour)
Note 2: Incorrect setup causes voids, solder splash and solder balling
Note 3: Setups using Hollis' designs are not necessarily repeatable and take a
long time
Note 4: It works better with water wash flux than with a burn off no clean (no
flux left to assist the air knife
Note 5: In a previous life, we removed the air knife from 4 of 5 machines after
designing out the solder shorts
conclusion: don't need one with proper PCB design, solderability and process
control and low solids flux. If you run low mix, poor designs or solderability
issues regularly occur, it can help.
______________________________ Reply Separator _________________________________
Subject: Re: Hot Air Knife after solder pot?? Anyone use this?
Author: "Ron Hollandsworth"<[log in to unmask]> at INTERNET
Date: 6/16/97 1:28 PM
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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