Phil, first of all, my experience has been that solution impingment doesn't
really address plating surface uniformity issues; it helps a lot in improving
surface-to-hole uniformity and I have seen improvements in
panel-to-panel uniformity. I have had much better success with a system
where the eductors are mounted on the bottom of the tank, rather than
the sides of the tank - however, this means that the tank depth must be
14"-16" deeper than the maximum panel depth and this frequently makes it
difficult to retrofit an existing tank.
Shielding can affect surface distribution on a particular panel, but should
theoretically not affect panel-to-panel distribution. Perhaps you could
elaborate a bit on what types of distribution problems you are seeing -
from the top to the bottom of the panel, from front-to-back, or from the
outside panels to the inside panels on a cathode bar of flight bar. More
often than not, these problems are associated with the anodes, which
may not be drawing equal current for a variety of reason, or with the
racks themselves, which may be in need of attention. I would highly
recommend acquiring a tong tester where you can check the current
draw for each cable, anode hook, and rack.
I did have a former customer who I assisted in converting to a airless
solution sparging system. They have long copper tanks and saw large
differences in plating uniformity from the outside panels to the inside
panels; this made it necessary to move the panels around in the tank
during the plating cycle to equalize the plating. Improving the anode
maintenance schedule and using the solution sparging eliminated this
problem, as well as reducing the plating load time by about 10%.
You may wish to contact Baker Technology about their plating systems
and how to retrofit your existing process to an airless system. PAL also
has some experience with this technology, but Baker seems a lot more
interested. Call 310/458-1752.
Regards,
Fred J.
>>> Phil Dam <[log in to unmask]> 01/14/98 03:19pm >>>
Presently we have an automatic vertical pattern plating line (acid copper
and
tin resist). Original manufacturer- Napco. Cathode sizing up to 36" x 72".
Plating thickness variation from panel to panel has become an issue and
we
are looking for ways to improve. We presently use top anode shields,
incorporate plating thieves on panel designs to help improve distribution.
Has anyone had experience retrofitting solution impingement equipment,
sparger systems, floating shields on a similar process line for the copper
buildup process? If so, were results positive, was cycle time reduced?
Thanks.
##############################################################
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.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or
847-509-9700 ext.311
##############################################################
##############################################################
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.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################
|
