What Problems Might Occur During The Coating Process of The Meyer Rods?

The Mayer rod may encounter the following problems during the coating process and the corresponding solutions are as follows:

1. Uneven coating thickness

Causes:

· The gap between the Meyer rod and the substrate surface is inconsistent, which may be due to the unevenness of the substrate, improper installation of the Meyer rod, or uneven pressure distribution.

· The coating speed is unstable, either too fast or too slow will affect the transfer amount of the coating and the thickness of the coating film.

· Changes in coating viscosity: If the viscosity is too high or too low, it may cause uneven flow of the coating between the Meyer rod and the substrate.

· Solution:

· Ensure that the base material surface is flat. Use a level gauge to check and adjust the placement position of the base material; check if the installation of the Meyer rod is level and calibrate it if necessary.

· Use an automatic coating equipment and set a constant coating speed to avoid speed fluctuations during manual operation.

· Adjust the viscosity of the coating according to the characteristics of the paint. This can be achieved by adding thinner or adjusting the temperature.

2. Scratches or streaks appear on the coating film

· Causes:

· There are impurities, particles or damages on the surface of the Meyer rod, which cause scratches on the coating film during the coating process.

· There are particle impurities in the coating, blocking the winding gap of the Meyer rod and affecting the uniform transfer of the coating.

· The coating speed is too fast, and the coating cannot fully level out in time, resulting in streak-like marks.

· Solutions:

· Regularly clean the Meyer rod, wipe it with a clean solvent to remove the impurities and residual coating on the surface; check if the Meyer rod is damaged, and replace it immediately if necessary.

· Filter the coating to remove the particle impurities, and use a filter screen or filter for filtration.

· Appropriately reduce the coating speed and give the coating sufficient time to level out to avoid the formation of streaks.

3. Edge accumulation or overflow of coating film

· Causes:

· The distance between the Meyer bar and the edge of the substrate is too close, resulting in the accumulation of coating at the edge.

· Excessive pressure causes the coating to be overly squeezed at the edge, leading to accumulation or overflow.

· The edge of the substrate is not smooth or has burrs, which affects the uniform distribution of the coating.

· Solutions:

· Adjust the distance between the Meyer bar and the edge of the substrate to ensure there is a certain gap, to prevent the coating from accumulating at the edge.

· Appropriately reduce the coating application pressure to avoid excessive pressure causing the coating to overflow.

· Check if the edge of the substrate is smooth. If there are burrs or uneven areas, perform grinding or repair.

4. Poor coating adhesion

· Reasons:

· The cleanliness of the substrate surface is insufficient, with oil stains, dust or other contaminants present, which affects the adhesion between the coating and the substrate.

· The compatibility between the coating and the substrate is poor, resulting in insufficient adhesion.

· The drying conditions after coating are improper, such as too low drying temperature or too short drying time, causing the coating not to fully cure.

· Solutions:

· Before coating, clean the surface of the substrate. Use solvents for wiping or other cleaning methods to remove contaminants on the surface.

· Select coatings with good compatibility with the substrate, or pre-treat the substrate surface, such as corona treatment, plasma treatment, etc., to increase the surface energy of the substrate and enhance adhesion.

· Optimize the drying conditions. Adjust the drying temperature and time according to the characteristics of the coating to ensure full curing of the coating.

5. Bubbles or pits appear on the coating surface

· Causes:

· Before coating, the bubbles in the paint were not fully eliminated, and the remaining bubbles formed bubbles or pits on the coating surface.

· During coating, air was introduced into the paint, resulting in bubbles.

· The substrate surface has pores or unevenness, causing the paint to form pits during the filling process.

· Solutions:

· Before coating, the paint should be treated for defoaming, using defoaming agents or vacuum defoaming methods.

· During coating, avoid excessive contact between the paint and air, and use closed-coating equipment or cover protective films during coating.

· Treat the substrate surface to fill in the pores or smooth the surface, reducing the formation of pits.

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