How to clean the face milling machine layout?

Layout cleaning refers to the process of scrubbing the plate after positioning and positioning. The face milling machine is also referred to as open plate. Its purpose is mainly to improve the activity of the layout, enhance the water absorption of the blank parts and the ink receptivity of the graphic part. The method of scrubbing is to wipe off the protective film on the plate surface with a damp cloth first, and then draw the graphic ink on the plate surface with gasoline. If the plate surface still has dirty spots that cannot be washed out, the dirt removing agent can be used to dissolve and remove.

One, dampening ink

1, dampening

For lithographic proofing, the dampening must be performed before the printing on the surface of the plate, so that the blank part of the plate is evenly adsorbed by a layer of fountain solution, and the plate is always kept in this wetting state during the proofing process to prevent the occurrence of ink absorption. phenomenon.

(1) The way of dampening

The proofing dampening method includes the automatic dampening of the water supply device, the manual water dampening version, and the low-temperature version of the condensing dampening version. Proofing can be flexibly applied according to the specific circumstances. In general, the automatic dampening of the water proofing device is mainly used in the proofing technique. The manual dampening dampening version is supplemented, and the dampening dampening version of the low-temperature version stabilizes the dampening state, reducing the evaporation of the dampening solution.

When the dampening is started, the face milling machine can use the water delivery device for multiple times of water and hand rubbing to accelerate the dampening speed and improve the wetness of the plate.

(2) Inspection of dampening water volume

The methods for checking the size of layout water mainly include visual inspection and instrument detection. The visual observation method is to judge the size of the layout water by the operator by observing the strength of the reflected light of the layout. The reflected light of the layout is stronger and the gloss is larger, indicating a larger amount of water on the layout; on the contrary, the reflected light of the layout is weaker and the gloss is lower. When the layout is dark, it indicates that the amount of water is small. The observation method is simple and easy, but the accuracy is poor. It is influenced by factors such as the angle of observation, the thickness of the layout of the sand, and the size of the layout text. It has higher experience and technical requirements for the inspectors.

Under normal circumstances, the surface is darkened, there is no obvious reflection of light and watermark, and the amount of water can be controlled by using the standard of dirty.

The instrument detection method is to detect the amount of reflected light on the plate surface, and the end face milling machine converts this reflected light quantity into a water film thickness value. The accuracy of this detection method is high, but the monitoring equipment is more expensive and is rarely used at present.

(3) Factors Affecting the Size of Dampening Water

The following factors affect the size of layout water:

1 proofing temperature, when the proofing temperature is high, the amount of water is large.

2 layout sand fineness. Large amount of water is used when the layout is rough.

3 ink thickness. When the ink layer is thick, it should increase the amount of water.

4 ink performance. When the ink is easy to emulsify, reduce the amount of water.

5 fountain solution performance. Face Milling When the surface tension of the fountain solution is small, reduce the amount of water.