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Screen Printing Column (49)

~Explaining with actual angle of attack~

The column " How far can you print the attack angle of the squeegee?" discussed how the ink film thickness is affected by
the angle at which the plate and the squeegee are actually in contact (actual attack angle).
The angle was less than 15°.
The squeegee head of the screen printing machine is generally designed so that the angle can be adjusted from 60° to 90°.
We call this the "attack angle" and use it as a printing condition.
However, this controls the actual angle of attack,
I don't think this angle directly controls ink ejection.

Conditions for screen printing include "rubber hardness", "printing pressure", and "printing speed".
I can't quite explain how this parameter is related to ink ejection.
For example, it is said that printing with a squeegee with low rubber hardness results in a thicker print film.
Why···?
If the rubber hardness is low, the printing pressure should be weak when printing with downstop,
I feel that it is correct to think that the force for ejecting ink will be reduced and the film thickness will be thinner.

It will be very refreshing to explain the effect on the film thickness of the ink with the theme of this time "Actual attack angle".
Various conditions for screen printing are explained below using "Actual Attack Angle".
 
If the rubber hardness is low, the print film thickness will be thick.
If the hardness of the rubber is low, the deflection of the rubber will increase, and the "actual angle of attack will decrease".

Increasing the printing pressure increases the thickness of the printed film.
Increasing the printing pressure increases the deflection of the rubber, and "the actual angle of attack becomes smaller".

As the printing speed increases, the printed film thickness increases.
As the printing speed increases, the frictional force between the squeegee and the plate increases, causing the rubber to flex more.
"Actual attack angle becomes smaller"

If the left-right balance of the squeegee is poor, the printed film thickness will vary.
The balance is bad and the amount of rubber deflection changes on the left and right, resulting in a "difference in the actual attack angle".
How about that···.

Don't you think you can explain it clearly?
If you are having trouble with variations in printing film thickness,
How about reviewing the current printing conditions from this point of view?

Now, how to measure the deflection of this squeegee?I'm looking forward to this next time.
NEWLONG SEIMITSU KOGYO CO.,LTD.
〒141-0022
3-21-5 Higashi-Gotanda, Shinagawa-ku, Tokyo-to
TEL.03-3473-1155
FAX: 03-3473-5055
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