Walter Siegenthaler, Daetwyler, gave an update on the laser engraving process. Laser
engraver has no mechanical moving parts. It operates off a light beam, which will engrave
approximately 35,000 cells per second verses a conventional engraver, which engraves 4,000
per second. The cells are round with flat bottoms with a similar look to an etched cell.
Different cell shapes are possible.
We are testing some alternatives for de-plating. Currently we are de-plating chrome and zinc
down to the copper base. We do no longer have to polish, we simply go into a standard degreaser.
We have increased the efficiency by using a 1 00 percent immersion. Only adding a
special exhaust to remove the zinc fumes we can use a standard polishmaster.
Before chroming, we clean with a paste. We are not totally happy with that and are working to
improve that process. The chrome itself-we was unable to achieve the results with cold
chrome that we desired so we have now switched to conventional hot chrome. There are
some modifications to the process we have to make for this to happen. Chrome polishing
Laser Engraving update We currently have three installations. The first is in Belgium, a packaging
printer. To date they have produced over I 0,000 cylinders with laser. They went straight
from a etching process to laser. They were using cold chrome with acceptable results. We did
change them over in late September to hot chrome. The second installation is MDC, which is
a publication printer. They were the first to have the hot chrome installed. We are testing a
dual head system
for them which should produce a 140,000 cells per second. The third installation is at Keating
Gravure. We experienced problems with the cold chrome there so we have switched to hot
Question – You cannot repair the zinc-plated cylinder because when you de- chrome the zinc
comes off. Are there any plans to find a way to fix this problem?
Answer – Yes, we are looking into ways to be able to de-chrome cylinders.
Question – At the installation in Belgium, are they still doing some chemical etch?
Answer – They are still using some chemical etching.
Question – Is it possible to chemical etch zinc?
Answer – Walter – He’s unsure and has no intentions of going in that direction.
Question – Do you have any way of measuring cells, mainly in depth?
Answer – Walter – Of course you can measure the depth but the way we do the test cut we
don’t measure the depth. We need to be able to measure the power it needs to melt the surface.
Once we know that, we adjust the power accordingly.
Question – Can you engrave the zinc?
Answer – Walter says, we are testing now and the results look pretty nice. The hardness can
vary in the zinc by 20 to 30 Vickers with no problems.
Laser Engraving Update (cont.)
Question – How many cylinders have been engraved on the laser engravers?
Answer – Walter said, I 0,000 plus.
Question – What effect does hardness have on the durability of the cylinder?
Answer – Hardness is about 140 to 150 Vickers. The hardness is not the durability of the
Eliminating the Proof Press
Gary Wiff – Here, we have two of the publication people. I would appreciate it if you would
come up. Bob Hopp from Quebecor and Mark Herraid from RR Donnelley. I would like to talk
to you a little bit about the elimination of the proof press. Why do we proof? Sometimes we
have customer contracts that require it. Certain ob mixes require the proof press. We look at
the quality assurance. It’s a process check to make sure everything to that point has been
done properly. Sometimes prints are used to make color corrections. Sometimes we get different
paper styles that could influence the way a proof is marked up. We want to make sure
we have cylinders that will run in the process (runnability). We want to eliminate the lays and
get the ink formulations that we want to work with. Check the ribbon imbalance. Sometimes
Helio tends to have a ribbon imbalance in the process. Make sure we have the proper color
and proper text. One of the main things we want to do is to eliminate the press down time. A
proof readers job is affected down the line. This will give them something to do. Its time consuming
and job deadlines are getting shorter and shorter. Speed differences from most of the
proof presses run a lot slower. These presses don’t have the capability the production presses
have at running higher speed. Sometimes there is a difference in humidity and temperature
throughout the year from one area of the room to the proof press. Many times, we put on corrections
that have to be taken off the production press. I think that is a problem. The setup
can be hectic to change if only you have only one proof press.
A question is are you proofing in copper or chrome? Which way do you go? If you do proof in
copper, sometimes you end up with cylinder damage. Sometimes different cylinder circumferences
can be a challenge. Light conditions make a difference depending where you look at
the proofs. There is a lot of paper and ink waste associated with proofing. What happens is it
ends up blowing up with you because it cannot match the press?
Some of the steps of eliminating the proof press are that we can use standard inks. We have
done that in RR Donnelley by setting up the Bureau of Standard Specifications. We try to
setup and recommend ink varnish ratios that we can all work with. We have a standard digital
proof that we have adopted from our Kodak approval. I think it is a big step in involving the
customer. We want to make sure they understand what we are doing. There is a learning
cycle. We want to get everyone educated in the process.
We recommend using SPC (Statistical Process Control) to implement process checks. Driving
corrections back to Graphics is a big step. Instead of doing corrections on the cylinder now
we do them back in Photo Prep. That allows us to gain confidence in the process. L*a*b* factors
are instant checks.