Common problems and causes in screen printing of cosmetic packaging

As a company that has been producing cosmetic hoses and cosmetic packaging for many years, we have specially summarized the common problems and causes in screen printing of cosmetic packaging for your reference. If you need a professional solution, you can contact us.

What is screen printing? Screen printing is actually screen printing. In the process of screen printing, the following problems often occur, and we summarize the reasons as follows.

Screen printing

1. There is no ink on the surface of the substrate (uneven ink leakage). The reasons are:

1. The mesh count of the screen is too high and the ink permeability is poor.

2. The photosensitive film is too thick and the ink permeability is poor.

3. There are scars on the edge of the squeegee.

4. The pressure of the squeegee is not enough or the pressure is uneven.

5. The gap between the screen printing plate and the substrate is too large.

6. The viscosity of the ink is too high and the permeability is low.

7. The ink is not evenly fed when the ink returns to the squeegee.

8. The printing speed is too fast, resulting in uneven ink supply.

9. Too little ink on the screen.

10. The printing table is not flat.

2. The ink and the substrate are not firmly bonded after screen printing. The reasons are:

1. The surface of the substrate is dirty with oil, dust, etc., or the plastic products are not treated sufficiently before printing.

2. The ink itself has weak adhesion. In this case, other types of ink should be replaced.

3. Improper selection of dilution solvent.

4. The ink is expired.

5. The mesh distance is too large.

6. Improper addition of additives.

3. Causes of screen blocking:

1. The substrate is not smooth or has low strength, and powder and hair loss cause screen blocking.

2. The pigments and other solid particles in the ink are large, which are easy to block the mesh during screen printing.

3. High temperature, low temperature, fast evaporation of solvent in ink, high viscosity, causing screen blockage, or long downtime, which can also easily cause screen blockage. Low temperature and poor ink fluidity can also easily cause screen blockage.

4. The screen printing plate is placed for a long time, cleaned before printing, and adheres to dust, causing screen blockage.

5. The pressure is too high during scraping, and the curvature of the squeegee is large, causing contact with the ground during scraping. The ink is not scraped clean by the squeegee every time, and residual ink is left on the printing plate, which causes conjunctiva and screen blockage after a certain period of time.

6. The screen spacing is small, the screen cannot be separated from the substrate after scraping, and the printing surface of the printing plate adheres to ink when it is lifted, which can easily cause screen blockage.

7. There are ghost images in the pattern part of the plate making.

4. Burrs and jagged edges of the image and text are caused by:

1. The resolution of the photosensitive glue is not high, resulting in broken or incomplete fine lines.

2. If the screen printing plate is underexposed or overexposed, burrs (serrations) will appear during development.

3. The printing surface of the screen printing plate is uneven and has gaps. The ink overflows during scraping, causing burrs.

4. The original film is bad.

5. The angle of the screen is improper.

6. The mesh count of the screen is too low, and burrs appear during plate making.

5. After printing, the ink seeps oil, resulting in edge shadows or virtual shadows, and blurred images and texts. The reasons are:

1. The edges and corners of the squeegee blade are worn, and the ink wire breakage effect in the squeegee is poor.

2. The scraping angle of the squeegee is too small, resulting in excessive ink supply.

3. The viscosity of the ink is too low, and the ink flows and seeps after printing.

4. The ink and solvent are not stirred evenly, and the ink with more solvent produces penetration after printing.

5. After the screen printing plate is cleaned, there is residual solvent.

6. The screen printing plate and the printing substrate are misaligned.

7. Improper selection of ink and screen mesh, the ink is fine and the screen mesh is too low.

8. Pause or repeat brushing in the middle of screen printing.

9. The squeegee is too strong when returning ink, and a small amount of printing material has been squeezed out of the mesh before scraping.

VI. Reasons for bubbles on the surface of the finished screen ink:

1. The squeegee scraping speed is too fast or the drying is too fast.

2. The ink itself has bubbles or is not stirred evenly.

3. The screen is contaminated.

4. The surface of the substrate is not clean or has oil stains.

VII. Reasons for the screen ink layer to be too thick:

1. The screen mesh is too low.

2. The squeegee is too soft or the blade is too round.

3. The squeegee scraping angle is too small.

4. Too much ink is placed on the screen.

5. The pushing pressure of the squeegee is inappropriate.

6. The screen printing plate is too thick.

7. The squeegee speed is too slow.

8. Reasons for the enlargement of the size of the image and text of the screen printing product:

1. The viscosity of the ink is too low.

2. The fluidity of the ink is large.

3. The tension of the screen is too low.

4. The pressure of the squeegee is too high.

9. The reason for the net marks on the print is:

1. The ink has low fluidity and dries too quickly. Choose ink with greater fluidity.

2.  Use ink with a slower drying speed. You can also add some high-efficiency slow-drying agents to the ink.

3.  When making the screen, try to use a single-filament screen with a thinner wire diameter.

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