The focus search is used to determine the optimum focus setting. For this, the number of lines is set in the field “tracks” and are ablated using different focus unit positions.
Mount a plate on the drum and move the laser head to the correct starting position (50mm).
Select Options > Focus Search.
Select the correct Plate Material Type and Thickness.
Click the Advanced button to preview and change to the settings below. Make a note of the current settings.
Speed /Laser Power 4260 CDI=400 RPM/10 watt
5080 CDI= 200 RPM/5 watt
Axial advance = 0.05 mm (how far the laser head moves across the drum per track)
Focus advance = 0.1mm (max) 0.05 (min) (how far the laser head moves in to the drum per line.)
Run the focus test either on a partial plate or in an available spot on a production plate. To make the handling of focus target image more convenient you may want to make a tape transfer of it. To do so, follow these steps:
Press a piece of clear tape on to the focus test image.
Carefully peel the tape off, taking black mask LAMS layer with it.
Place the tape image side up over the transmission light source on the Betaflex PR.
Double click the Beta Flex3Pro software icon on the desktop to launch the software.
Click the Transmission tab, select Plate type. Mask Flexo Plates and center the focus search tape transfer or partial plate in the center of light aperture.
Click the PREVIEW Icon or press F2 and make sure the focus target image is centered (Fig1)
Click the Capture Icon or press F3 to capture the image. The Focus Icon will then become active. (Fig 2)
Click the Focus icon (Fig 3).
13:11.9 The first number displayed in red is the track number and the second number is the width of the line in microns (µm). The software will highlight in red the thinnest track. You want track 10 highlighted and to be the thinnest line. The above example shows that track 13 has a width of 11.9 microns.
After the CDI has engraved these tracks, a dialog box will prompt you to enter the track number of the thinnest line, track 13 in the example above. Track 10 is displayed by default, in this example you would enter track 13 and reimage the focus search. Focus search reimaged and measured. (Fig 4)
10:16.4 Track 10 is now highlighted, which is correct. On the Esko CDI Focus dialog box, click OK.
If the focus is changed, it is recommended that you perform the focus search again to verify that the best track is obtained.