Flexographic Printing Process

Flexographic Plates:

Engraving, Clishe or Iron are photopolymers, plastic materials sensitive to ultraviolet light (UV rays) is used as the main raw material for the flexographic process.

These are done through a direct process. It is laser engraved on the charcoal mask that comes with the photopolymer, exposed to ultraviolet light penetrating the areas removed by the laser commonly called image areas. The exposed parts are polymerized, bone harden and become insoluble, however the areas that the mask was not removed, remains unseverk being soluble in the action of washing with brushes and solvent and thus be removed. The exposed area (polymerized) is left as a high-relief image and is defined as the printing surface of the plate.

STEPS FOR THE ELABORATION OF AN IRON:

  1. Define thickness and type of plate

It is reviewed in the production order to select the thickness and type of plate required for the job to be processed.

  1. Back exposure:

Once step 1 is defined, the iron is carried to the display and placed on the display unit table, with the transparent polyester backrest facing up. The thickness and type of plate defined to create the hardened polymer layer that will be the base or floor of the plate is selected on the control panel of the display unit.

  1. Engraving of the iron:

The iron with the defined floor is carried to the CDI engraving unit (Cyrel Digital Image), the gate is opened and grimped with the starting staples, the vacuum is activated so that the plate has the best adhesion to the cylinder, then the other end of the plate is attached to the end staples. Then we go to the monitor and with the help of the Mouse we define the recording conditions (recording start position, dimensions, autocross, image distance, cutting lines, thickness and type of iron), we proceed to start recording.

  1. Front exposure:

Once the plate is engraved it is placed on the display unit table with the engraved areas facing up, the time defined to be exposed is selected, then the exposure cycle for polymerization or hardening of the image areas engraved on the plate is activated.

  1. Washing:

The already exposed iron is carried to the puncher to make the drilling and place it in the ruler that will serve as transport during the process of brushing, rinsing and cleaning the liquids, the washing speed is selected according to the thickness and type of plates and then the process begins.

  1. Drying:

Once removed from the washing machine it is taken to the oven, which must be selected the drying time according to the thickness and type of iron, since the temperature is constant between 60oC – 65oC, and this process is started.

  1. Rest:

After the drying time is removed from the oven and placed on a tray at room temperature for 6 hours so that the iron manages to migrate all the solvent and reach its dimensional stability.

  1. Final finish

After the resting time the iron is ready for the final finish which consists of removing the stickiness and giving more resistance to the iron by exposing two different types of radiation lights that can be given together or separately, and as the above processes before initial we must select the thickness and type of iron and then start the process in the display unit.

  1. Backup Cleaning:

The iron is placed on a cardboard surface with the embossed image facing down and the transparent polyester backrest facing up, with a cloth moistened with solvent is cleaned then dried with another dry cloth.

  1. Refile and Packaging:

The surpluses or waste are cut to the iron and then proceed with the packaging with cardboard, protective sheets and brown adhesive tape to prevent the plates from being exposed to the radiations of the UV Light, then the identification of the customer who will receive our product will be placed.