Product

• ThermoFlex^® Mid
• ThermoFlex Narrow

Background

The Width Factor or LD is the actual diameter of the ThermoFlex drum after the calculated correction has been accounted for.

Requirements

Note: Before beginning these procedures, make sure that the width factor (LD) = 1

To calculate the width factor, you will require the following:

• Light table
• Ruler
• Microscope or CCD camera for measuring
• File on the system disc. (Solid color in H = 500 mm, W = 10 mm)
• Digital plate with approved thickness (measured with a micrometer).

Procedure

These calibration procedures describe how to calculate the width factor (LD) using the following example:

Digital plate with a 1.7 mm (0.067") thickness - after it has been measured and the SF has been calculated.

1. Load a plate with the following dimensions:
   H=550 mm x 30 mm
2. On the Brisque, open the expose dialog box.
3. Enter the calculated scale factor (SF) in the Scale window, located beneath the Around Drum Position.
4. Expose the file.
5. Unload the plate.
6. On a light table, measure with precision, the image length size.
7. If the length size measures exactly 500 mm, the calibration is complete and the width factor will = 1.
   However, if for example,the length of the imaged file is 449.20, you will need to calculate the width factor (LD) as shown below:

   
   LD = DF / EF
   LD = Width factor
   DF = File length (on disc)
   EF = Image file length
   LD = 500 / 499.20 or LD = 1.0016025

8. On the Lotem controller, open the machine database and change the default Width Factor from 1 to 1.0016024.
9. Save the changes. The adjusted width default value will be acceptable for plates with a different thickness.

Test

Do the following to test to ensure that the adjusted width factor is correct:
Expose plates with a different thickness, for example 1.14 mm, using the same file as the ones used in the above procedures.

Technical contact

Moshe Arviv

Date submitted

30 Jun 2003