Defect factors and measures for melamine resin impregnated paper veneer

Warping of the veneer: There are many reasons for the warpage of the veneer. The main ones are: 1 The base paper is impregnated unevenly and has different volatiles.

2 hot pressing without thickness gauge;

3 The temperature difference between the hot plate and the lower plate is too large, so that the curing speed of the two sides of the veneer is inconsistent, causing the plate to bend toward the fast curing side.

Take measures: 1 adjust the impregnation speed of the base paper, and prepare the impregnated resin as required;

2 increase the hot pressing thickness gauge to control the compression thickness;

3Adjust the temperature difference between the upper and lower platens so that the adjustment does not exceed 4 degrees Celsius

. Adhesive plate of polished plate: melamine resin partially adheres to the polishing plate during curing, causing cracking of the surface of the veneer

The reasons are:

1 curing time is too long or the hot pressing temperature is too high;

3 no melamine resin in the melamine resin;

3 The quality of the polished plate is degraded.

Overcoming the above shortcomings can adjust the hot pressing temperature, increase the release agent when adjusting the glue, and better the polishing plate, such as chrome plated polishing plate.

. The surface of the veneer is porous: the surface of the plate is mainly porous due to insufficient flow of the resin at high temperature or low pressure, and the surface structure of the particle board also has an influence on the veneer. Therefore, the pressure can be increased to the maximum, and the volatile content of the paper can be increased. Resin content; increase the content of the modifier to 0.5% . In addition, check whether the impregnated paper is stored too long or improper.

. The layering and bubbling of the veneer, the delamination of the veneer mainly has the following aspects:

1 resin waterproof paraffin, oil or paraffin coating on the surface of particle board;

2 The impregnated paper has a small resin content, and the resin fluidity is too low, so that the resin on the surface of the particle board is insufficient;

3 The moisture content of the particleboard is too low or the volatile content of the impregnated paper is too low.

The reason for the bubbling of the cloth is that the water is vaporized when the substrate is too thin or the water content is too high, when the press is turned on.

Causes bubbling.

. Plywood board edge damage when the cutting edge, which edge damage due to tearing down the wood chips and the like, may be the cause of defects: an edge strength of the substrate is insufficient; shear strength of the substrate surface layer is insufficient, or the tool shape, serrate Need to adjust, sawing speed is too low or the plate feed speed is too fast is also one of the reasons. Therefore, in addition to purchasing high quality substrates, the tools should be inspected regularly.

. Dip paper folding during hot pressing: There are many reasons for the folding of impregnated paper during hot pressing. Generally, the following measures are taken to overcome:

1 slow down the closing speed of the press;

2 Check whether the pressing strip of the upper polishing plate is warped or whether the polishing plate needs to be updated;

3 Check the electrostatic device and clean or switch the power supply;

4 Check the climatic conditions of the impregnated paper in the storage compartment and the rigidity of the wet paper.

. Paper wrinkles immersed in a dry box: the measures taken are:

1 relax the friction brake on the relaxation device to reduce the tension of the paper;

2 reduce the tension between the active roller and the driven roller;

3 The base paper passes through the first dipping tank to relax the driving blade.

. The surface water stain (wet flower) is caused by: 1 the moisture content of the substrate is too high; 2 the impregnated paper moisture content measuring instrument is not properly installed; 3 the residual moisture of the impregnated paper is excessive; 4 the edge temperature of the panel is too low and the impregnation during storage Paper resurgence, etc., take measures: 1 adjust the moisture content of the substrate; 2 adjust the moisture content measuring instrument; 3 adjust the drying process conditions of the impregnated paper; 4 increase the temperature of the hot pressing plate to increase 5 Â° C, in addition, pay attention to the storage of the impregnated paper.

. This type of emulsion speckles defect occurred in hot coating swatch, main reasons are: â‘ pressure is too low; â‘¡ large thickness tolerance of the substrate; â‘¢ Contaminated polishing pad. The main measures are: 1 increase the pressure of the hot plate; 2 adjust the sanding amount of the substrate or increase the thickness of the substrate; 3 clean the plate or replace it.

In short, the defects in the production process of melamine resin impregnated veneered wood-based panels are constantly discovered, and the reasons are overcome. As long as we strictly follow the process requirements and check the quality, we will be able to produce more and better products and improve Enterprise economic benefits.

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