Web 8 ink key zero setting

[rugerred]

I am looking for the proper way to mechanicly zero the ink keys on a mid "80"s Heidelberg web 8. I know how to set the newer Harris presses but cant find any information for the older Web 8.

[Erik Nikkanen]

I am looking for the proper way to mechanicly zero the ink keys on a mid "80"s Heidelberg web 8. I know how to set the newer Harris presses but cant find any information for the older Web 8.

Does this press have a ductor roller or a continuous (ductor) metering roller?

[rugerred]

It has a ductor. Im looking to zero set the keys to the fountain ball and cpc readout.

[rugerred]

Any thoughts Erik?

[Erik Nikkanen]

Any thoughts Erik?

If you had the continuous metering roller system, there is a method that I would have sent to you. Not perfect but quite good.

I don't have a method for the conventional ductor system. Even though there are methods based on measuring the ink film on the ink fountain roller, determining the actual point of zero transfer into the press is a problems since it changes as conditions change on the press.

Sorry I can't be of more help.

[rugerred]

Thanks anyway. I think I can do it by setting the electronic zero / discontect motor and then mech zero the key to an ink film / reinstall. I just wanted some ideas beyond that.

[blazini]

... Even though there are methods based on measuring the ink film on the ink fountain roller, determining the actual point of zero transfer into the press is a problems since it changes as conditions change on the press.

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theere is no "zero transfer" setting on a ductor fed press. There will always be some ink transfer from the ball to the ductor. At the point where there is "zero transfer" the fountain blade is touching the ink wall. Zero transfer can only be achieved with a continuous feed system. Any point at which ink does not tought the metering roller is zero.

I'm sure there's some scientific method for setting them precisely but it's hardly worth the effort. Blade wear and warpage will never allow you to maintain precise settings.

I don't know anything about the specific ink keys on your press, but on ductor presses I have always set the console at zero, then set each blade segment until is tapped the ink ball then backed the key off a hair, just until it doesn't touch. Run the keys up to 20% and look for consistant film. Then to 50% and back down to zero. if a key touches the ink ball it needs to be opened up. I usually never have to pull a servo out to set a key. Most setups use a double threaded shaft from servo to ink key. You can usually adjust the manual adjustment without turning the servo. I only pull the servo out if the manual side of the shaft isn't even with the rest of the keys. Of course your press may differ.

[Erik Nikkanen]

theere is no "zero transfer" setting on a ductor fed press. There will always be some ink transfer from the ball to the ductor. At the point where there is "zero transfer" the fountain blade is touching the ink wall. Zero transfer can only be achieved with a continuous feed system. Any point at which ink does not tought the metering roller is zero.

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Normally I would go into a long explanation to correct your view but no point doing it these days.

I will say that you probably don't observe what your press actually does. As an example, if you have some of the ink keys closed so it does touch or almost touches the ink fountain roller, I would expect that you would see clean steel when the ductor has not touched the ink fountain roller and then inked steel when the ductor has touched the ink fountain roller. That says to me that your are actually having ink feed back from the press to the ink fountain.

[rugerred]

Blazini is correct in that you always have a very thin film of ink on the ball. If you did not you would wear the keys in very short time. The film is actually thin enough that it doesnt transfer. I was looking for the mech way of setting the Web 8 keys. They have an odd servo setup

[Erik Nikkanen]

Blazini is correct in that you always have a very thin film of ink on the ball. If you did not you would wear the keys in very short time. The film is actually thin enough that it doesnt transfer. I was looking for the mech way of setting the Web 8 keys. They have an odd servo setup

Yes he is correct in that a thin ink film is required but in that situation, when the ductor hits the ink fountain roller, it applies a thicker ink film to the ink fountain roller, meaning ink is coming form the press and back to the ink fountain.

The zero set point is a point where there is no "net" transfer of ink from the ink fountain roller to the press. It is a "net" ink transfer of ink because ink is actually being transferred in both directions at the same time even at non zero set point conditions. This can be seen when backtrapped ink goes back to the ink fountain.

Lack of accurate zero setting is related to the lack of control of ink feed.