Sometime ago I posted an e-mail regarding DEK Proflow issues which we were
having here at Viking Components. After DEK had corrected these issues I
posted a follow-up memo stating these resolutions. I posted this to the
Tech-Net as an attachment. The attachment was not readable by many of the
subscribers. I am posting below the following up memo again for those who
would like to know these resolutions.
MEMORANDUM
TO: Scott Riegle
FROM: Kathy S. Palumbo, Bruce Spencer, John Wilson and Yogesh Doshi
SUBJECT: Update to DEK Proflow Issues
Cc: Jason Kim, Michael Jogan, Simon Clasper
<<...>> Listed below are the issues Viking has been experiencing since the
installation of the Proflow Head:
1. After installing new 350mm Wiper foil with metal
strip glued on it, It worked for about a week and suddenly metal
strip started peeling off from wiper foil.
2. End retainers (SKIS) has hard plastic piece glued on
rubber piece. That plastic piece comes off from End retainer. So far,
we have changed 4 End retainers.
3. In transfer head you have removable grid between
paste cassette and conditioning chamber. This removable grid has `O' Ring .
This O ring is larger than it's slot on removable grid. After placing O
ring on the grid, when you invert the grid to fit on conditioning chamber O
ring comes off. We had to glue the O ring in slot.
4. Removable grid on transfer head doesn't stay flat on
conditioning chamber. After you tighten the screws, it becomes
convex.
5. Holes on removable grid and holes on metal grid do
not match.
6. Solder paste come out from ski area on stencil.
7. After print, it leaves streak of solder on stencil.
8. Lots of solder paste oozes out from gap between
paste cassette and conditioning chamber. Making transfer head very
messy.
9. After printing about 10 panels, next panel has
insufficient solder. We prime 3 times solder paste at this time. But
half of the time it still has insufficient
solder on panel, at time we increase pneumatic pressure and it comes
out O.K.
10. We do not have sensor for `Paste cassette empty.' The
one we had was bad and service man took it with him saying they will mail
us new one. It's about 3 weeks now, and we haven't heard anything
about it from any one at DEK.
11. Paste cassette has 1.2kg solder paste in it and we
can use only half of it, other half goes to waste.
12. We spent about $ 30,000.00 for Proflow compare to
$300.00 for squeegee blades expecting much better print results, no solder
paste waste, cutting down on stencil cleaning time and worry free printing .
But that's not the case.
The DEK USA Field Service and Support in Milpitas,
California was not able to provide timely and accurate support on these
issues. However, this was not because of their incompetence or inability to
provide proper support, but more a result of DEK Management not providing
their Field Service personnel timely training on the Proflow system. We
understand this is currently being rectified, and should no longer be an
issue.
As a result of all the issues stated above Scott Riegle, an
Applications Engineer, was finally sent out to Viking to assist in finding
adequate resolutions. The results of his visit are shown below:
1. We now have the new improved full metal wipes and
composites. Wiper blade foils will have a fixed position from now on due to
a predetermined thickness. This will aid in eliminating variations in its'
installation. As of yet this has not been verified by Viking. This has now
been verified by Viking and is no longer an issue.
2. We now have the new improved black PDFE End
retainers (SKIS). As of yet this has not been verified by Viking. This has
now been verified by Viking and is no longer an issue.
3. We were informed that the O-Rings can not withstand
solvents, and we should be careful when cleaning. However, we used pure DI
water when cleaning the O-Ring and there was still a stretching problem
(approximately 1"). Scott stated he would recommend a change in the O-Ring
composition to rectify this problem. We were informed to use Parker O-Ring
grease to hold the O-Ring in place so you can turn the unit upside down when
putting the grid in place. As of yet this has not been completely resolved
by DEK.
4. It is suppose to move a little so it can make a
tighter seal.
5. We now have the new improved grid holes which now
match. All sizes will have the new improved grids which will match one to
one.
6. One of the End retainers (SKIS) was reversed. There
is a vent hole on one side of the End retainer (SKI) which must be facing
outward (not pointing into the paste area). As of yet this has not been
verified by Viking. This has now been verified by Viking and is no longer an
issue.
7. The Paste Pressure setting was too high. The new
improved black PDFE End retainers (SKIS) will eliminate this as well. As of
yet this has not been verified by Viking. This has now been verified by
Viking and is no longer an issue.
8. The Thumb Wheels were being tightened in the wrong
direction. The correct direction is now scribed onto the unit. As of yet
this has not been verified by Viking. This has now been verified by Viking
and is no longer an issue.
9. We were informed that the insufficient prints are
directly correlated to "change of force". The Proflow head must be
supported across the entire length of the head or you will have air gaps in
the roll of paste and this air gap will move all across the roll of solder
paste. DEK has mushroom supports (at an additional cost of $300 each) they
can supply which should eliminate this issue. In addition, it was
discovered that the pressure regulator for the plunger was not staying
constant. Initially, it was thought there was an air leak. However, after
adding Teflon tape to the regulator the pressure still does not remain
constant. Scott recommended that this regulator be replaced. Scott also
recommended we evaluate the rechargeable 350mm unit Transfer Head when it is
available. As of yet this has not been completely resolved by DEK or
verified by Viking. This has now been verified by Viking and is no longer an
issue.
We were also informed that the Proflow head should not be
stored in an open environment. The cover should be put on the head
and the entire head should be stored in a ZIP LOCK baggy in a
refrigerator. As of yet this has not been verified by Viking. This has now
been verified by Viking and is no longer an issue.
10. A new `Paste cassette empty' sensor was finally sent
to us, but it was not the new design. The new sensor has been installed. As
of yet this has not this has not been verified by Viking. This has now been
verified by Viking and is no longer an issue.
11. We were informed that there is a new improved 'Paste
cassette empty' sensor (not shipped/installed yet) which will allow us to
use 85% of our cartridge. This has now been installed and verified by Viking
and is no longer an issue.
We were also informed that there is a new improved design in
the works which will allow us to use 100% of the solder paste in the
cartridge. In the new improved design the plunger size will be
improved by increasing its' size, as well as the bladder walls will be made
more rigid. As of yet this has not been completely resolved by DEK.
12. DEK agrees.
At the conclusion of our meeting we were informed that the
outstanding issues would be handled promptly, and Viking agreed to verify
all resolutions which as of yet have not been verified. We also agreed to
keep one another informed on the progress of all unverified and unresolved
issues.
Viking would like to thank Scott Riegle in his outstanding
application support and service which he provided Viking. Viking would also
like to thank Michael Jogan in providing the necessary Field Service Support
personnel so that we may complete the verification process of all unverified
resolutions.
Sincerely,
The Viking Manufacturing Engineering Team
In addition to the above memo, I a would also like to inform
everyone that the Proflow head is working so well for us that we have since
added two more high speed lines which include two DEK GSX265 systems with
the Proflow head option. Using the proflow head we are able to run the
stroke of the head about 2.5 (40mm/sec to 100mm/sec) times faster than when
using the conventional squeegee blade printing method. This enables our
screen print machine to keep up with our chip shooters speed, thereby
eliminating a bottleneck at screen print.
In addition we have performed some 3D analysis with a solder
paste scanning system and have found that the solder paste deposits made by
the proflow head system are perfectly flat and even. When working with fine
pitch product this has proven to be extrememly helpful in reducing the most
common defects. We have compared these deposits with deposits made by
regular metal squeege blades and found a significant difference in the shape
of these deposits. We have found that this difference in shape eventually
leads to some of the more common defects found in SMT fine pitch
manufacturing.
If you have any questions regarding any of the above, feel
free to contact me at (949) 643-7255 ext. 352 and I will be happy to share
any analysis data with you.
Kathy Palumbo
Manufacturing Engineer
Viking Components, Inc.
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