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Date: | Fri, 19 Apr 1996 11:10:11 +600 CDT |
Content-Type: | text/plain |
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Address,
We are currently using a Chemical Clean line to prep inner layers
for lamination resist. For the most part, the chemicals are being
maintained and the only operator variable is the conveyor speed.
We have had good success with this process.
For external images we are using a mechanical scrub (Sommer&Maca)
prior to external image. Unlike the chemical clean line, most
of our operators are not insuring the brushes make a light to
medium contact to the copper surface. What usually happens is a
63mil panel is scrubbed and behind it follows a 125mil panel. The
brush distance is not compensated for the increase in panel thickness
which in turn removes needed copper and deep copper valleys. It
has been a difficult task in monitering operators.
Q. Is there an alternative to mechnical scrubbing for external
layers?
NOTE: We will continue using the mechanical scrub for deburr.
Q. Are other PCB shops using Chemical Clean lines for external
layers? And is so, does your resist hold up in the
Electrolytic bath, Nickel bath and Gold bath. No resist
breakdown.
Q. Do other PCB shops experience resist breakdown that is result
of improper mechanical scrub. In this case, deep copper
scratches that interrupt the image and polymerization process.
Please advise. Thank you.
John Gulley
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