Adam,

In addition to the ideas presented in the 2 parallel responses to your
post that have been posted so far, I have 3 initial thoughts, all of
which may be totally worthless, since I have no experience in this area,
but nonetheless I offer them as food for thought.

1. ) At each nozzle location (in a row of nozzles), have a second nozzle
nearby (in a second row of nozzles), that will cover the same area at a
right angle to the first nozzle, such that as the nozzle assembly
"oscillates back and forth", it will allow the area to be covered by
both nozzles at right angles to each other. These nozzle pairs could be
arranges such that the "fan" of the nozzles forms an "x" or a "+".

2. ) Have adjacent nozzles (in a row) spaced such that their spray
patterns overlap a full 50 percent. Additionally, have the nozzle
assembly "oscillate" a distance that will equal 50 percent (or more) of
the width of the spray pattern. This will insure that as the nozzle
assembly "oscillates back and forth", each area of the board will be
sprayed by 2 nozzles in a pattern that will insure that each area of the
board receives uniform coverage with uniform pressure delivered at a
uniform angle.

3. ) In a vertical row of nozzles, have each nozzle (or group of 2 and
possibly 3 or more nozzles) fed by a separate hose or pipe with its own
"flow" / "pressure" adjustment valve, such that at each "lower" nozzle
(or nozzle group) location, the etchant "flow" / "pressure" can be
adjusted and lessened slightly to compensate for the additional flow of
etchant "runoff" from nozzles above a given nozzle location. In other
words, have the nozzles that cover the lower areas of the board deliver
slightly less etchant than the nozzles that cover the upper areas of the
board, to compensate for the etchant "runoff" that occurs in the lower
areas of the board. This effect could also possibly be effected by
nozzle placement, such that the nozzles are spaced closer at the top of
the row then at the bottom, or possibly by variations on nozzle type,
such that the nozzles at the bottom of a row of nozzles have a slightly
different spray pattern (angle) or spray volume.

As a side note, or actually more of a question of my own, and certainly
something that will affect the issues raised above, and any other final
configuration that you may ultimately come up with; do the nozzles have
a uniform distribution of etchant over the full width of their spray,
both in terms of volume and also pressure?

Hopefully the issues above be helpful in determining your final nozzle
configuration.

JaMi Smith


----- Original Message -----
From: "Adam Seychell" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, September 30, 2003 10:10 PM
Subject: [TN] spray nozzle configuration for etching


Hello,
I am constructing a vertical spray etching machine for processing
single panels. A series of nozzles will periodically oscillate
back and forth across the panel in a vertical motion. The nozzles
will be the fan type as opposed to cones. I am in need of a
little help choosing the appropriate nozzle. I was hoping someone
here might have some knowledge on typical nozzle configurations
used in spray etching equipment.
The nozzles (NF series by BETE) are available in fan angles of
15,30,50,65,80,90,110 and 120 degrees and I don't have the
experience to choose the right one.

My initial calculations say to use 65° fan nozzles with a
spraying distance of about 120 mm from the panel, and then
experimentally determine the needed jet overlapping for a uniform
etch.

regards,
Adam Seychell,
Australia.

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