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Electrograining

I have problem with the electrograining process that produce a uniform matte surface for lithographic plate. The corners and the sides are not uniform with heavy pits. Thank you.

Wailok Yee
- Hong Kong
1999

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Electrograining sounds interesting, but I know nothing about it. If a reader does, please fill us in. Lithographic plates are normally made of aluminum, aren't they? Is there a reason that the usual caustic etch for aluminum does not produce a sufficiently uniform matt surface?

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999

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First, I would like to answer Ted's question. Electrochemical acid etching or electrograining process has been used in industry to replace mechanical process for preparing lithographic plates since earlier 1950s. This process is operated in a dilute hydrochloric acid electrolyte with sodium chloride and other additives generally at room temperature and 15-40 asf of current density with an AC voltage 8-15V. This process produces a heavily pitted but very uniform matte surface. As far as Wailok's problem is concerned, it is apparent that current distribution is not very good. Increasing the distance between two plates is certainly helpful. Since no detailed technical information was provided in his request, it is hard to give more specific suggestions. Anyway, the problem can be solved by adjusting solution composition, AC voltage, temperature, agitation, and adding organic additives. Good luck! Ling

Ling Hao
- Grand Rapids, Michigan
1999

I don't know much about electrograining, except from what I have read above. I would like to know where I can get a detailed description of the process. I am quite interested in the topic.

Terry Concepcion
- Manila, Philippines
1999

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I just happened to stumble upon "On the Mechanism of the A.C. Electrolytic Graining of Rolled Aluminum Substrates" by Laevers, Hubin, Terryn and Vereecken--a major 8-page article on the subject, published in Transactions of the Institute of Metal Finishing, vol. 75, part 5, September 1996.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999

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I am a 4th year Chemical Engineering student working on a non-profit project for Queen's University at Kingston, Ontario, Canada. I am in need of start up information for the electrochemical graining of aluminum for use in Intaglio printing. I am not particularly well versed in electrochemistry and am looking for useful references/people to aid in the design of some test equipment.

Any help anyone could lend would be greatly appreciated! Thanks,

Jamie Allen
- Kingston, Ontario, Canada
2000