Common Problems In Film Flexo Printing, All At Once

- Mar 30, 2021-

Common problems in film flexo printing, all at once


Film flexo printing is not particularly mature for domestic flexible packaging manufacturers. But in the long run, there is a lot of room for the development of flexo printing technology in the future. This article summarizes twelve common problems and solutions in film flexo printing. for reference. Web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   1. The imprinting on the film has poor adhesion fastness, and is not resistant to rubbing and rubbing


   Reasons and treatment suggestions: Web printing machine, flexo printing machine, envelope bag making machine, medical paper printing machine, roll cutting machine


   (1) PE or PP film has no surface treatment or the surface treatment effect is not ideal, and the surface tension of the film is lower than (3.6~3.8)×10-2N/m. Use the surface tension test liquid to detect the surface tension of the film. If it fails to meet the requirements, it should be surface treated again. Web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   (2) The ink is over-diluted, the adhesive is destroyed, or the thinner is wrongly used. Choose the diluent correctly, and the viscosity of the ink should be controlled within 25 to 35 seconds during dilution.


   (3) The ink itself has poor adhesion to the film. Change the ink type, or negotiate with the ink manufacturer.


  2. Stacked web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   Reasons and treatment suggestions: Web printing machine, flexo printing machine, envelope bag making machine, medical paper printing machine, roll cutting machine


   (1) There are impurities in the ink, the ink should be filtered or replaced with a new one.


   (2) The ink is thicker, and a certain amount of thinner can be added to adjust the viscosity of the ink to a suitable value for 25 to 35 seconds.


   (3) The ink dries too fast. Add a proper amount of slow-drying diluent to reduce the ink drying speed.


  3, the pattern color is changed, the web printing machine, the flexo printing machine, the envelope bag making machine, the medical paper printing machine, the roll cutting machine


   Reasons and treatment opinions:


   (1) The viscosity of the ink changes. When diluting the ink, stir while adding to make the ink fully dissolve in the solvent and control to the ideal viscosity. If possible, mechanical circulation pump can be added for better effect.


   (2) After the ink has been used for a period of time, add diluent to reduce the ink density. The diluent should be added every 30 minutes or so. After adding the diluent 2 to 3 times, part of the original ink should be added at the same time and stirred evenly to avoid the ink concentration drop.


  4. Mixed color web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   Color mixing means that the ink of the next color is contaminated by the color of the ink of the previous color, or the color is diffused and migrated.


   Reasons and treatment suggestions: Web printing machine, flexo printing machine, envelope bag making machine, medical paper printing machine, roll cutting machine


   (1) The ink of the previous color dries too slowly, or the ink of the next color dries too fast. According to the specific situation, use the appropriate solvent (the previous color ink must be dried thoroughly), or adjust the temperature of the heating system of each part.


   (2) The ink viscosity is too high. Appropriately reduce the ink viscosity. Web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   (3) Affected by the plasticizer in the substrate film. Understand the types and precautions of film plasticizers, and replace the film if it is not suitable.


   (4) Improper use of pigments and dyes in the ink causes migration. Should try to avoid using dyes as raw materials to produce inks.


   5. Printed matter rewinding adhesion


   Reasons and treatment suggestions: Web printing machine, flexo printing machine, envelope bag making machine, medical paper printing machine, roll cutting machine


   (1) The ink drying speed is slow, and there are more residual solvents in the printed matter. Adjust the drying speed of the ink, add a fast-drying diluent or appropriately increase the drying temperature to minimize the residual amount of solvent. Web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   (2) If the rewinding tension is too high, the rewinding tension should be appropriately reduced.


   (3) The temperature and humidity of the air during rewinding are relatively high. Web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


   (4) The drying temperature is too high, resulting in the film surface temperature being too high, the accumulated heat cannot be diffused in time during rewinding, or the cooling process is short, and the film cooling is insufficient. The drying temperature should not be set too high, or the cooling time should be lengthened. Web printing machine Flexo printing machine Envelope bag making machine Medical paper printing machine Roll cutting machine


  6. The edge of the pattern is hairy, and there are irregular flashes around the mark


   Reasons and treatment opinions:


   (1) The pressure between the ink transfer roller and the printing plate is not appropriate, generally the pressure is too large. The pressure between the two should be adjusted appropriately.


   (2) The ink has dried on the printing plate or anilox roller. Add slow-drying diluent to the ink, or cover the ink tank to reduce the volatilization of the solvent in the ink.


   (3) The ink is too thick. Control the ink viscosity within 25-35 seconds, or flexibly control the ink viscosity according to the printing conditions.


   (4) There are burrs and flashes on the edge of the print due to the influence of static electricity. Install a static elimination device, or add an appropriate amount of antistatic agent to the ink.