Ink transfer is most often described as interface, variable, center pressure, pressure differential, and fluid pressure drop, but even so, these precise quantities are inconspicuous. Here are 12 terms to keep in mind when dialing in automatic press calibration.
1. Line or input pressure from the compressed air is metered by and gauged at the regulator.
2. Air pressure at a lower rate feeds into sealed pneumatic cylinders, which delivers force to the piston.
3. Force from the piston causes a change in the motion of the blade. This is sometimes mistermed as “pressure.”
4. Interface pressure on the mesh is equal to force, divided by the area at the first platen contact.
5. Variable pressure in stroke or perpendicular axes occurs with poor press calibration.
6. Center pressure is a lesser form of interface pressure due to traditional blades and bowed beams.
7. Pressure differential occurs at the blade and forms a tight seal on the mesh to form a “pump.”
8. Mechanical position adjustments don’t add or subtract pressure; they only limit piston travel.
9. Net pressure on the platen equals resistance of the mesh, minus the pressure from the blade.
10. Fluid pressure causes ink to thin and flow and is exerted by compressive and shearing force of the blade.
11. Fluid pressure drop happens every time the ink reaches the mesh opening.
12. Financial pressure is a result of one’s misunderstanding of the previous 11 definitions.