Pulp molded products of this type of packaging materials, because of its environmental protection, has gradually replaced the foam plastic, access to steady development, the current larger amount of export electrical parts and ceramic protective liner, food packaging trays and so on.
In the process of pulp molding, one of the inevitable problems encountered is the deformation of pulp molded articles. In order to reduce the volume of the packaging, in use, the paper sheets are often overlapped by layers, that is, the bottom of the upper paper mold For the lower cover of the paper mold, which is not only required to die with the shape of its packaging products match, but also requires the upper and lower paper mold at the mouth must also be consistent with each other. However, due to the deformation of the paper during the drying process to meet the above requirements caused a lot of waste, I think the main reason for two.
1. The paper pattern is too thick
Due to improper mold design, resulting in the local excessive thickness of the paper mold, causing uneven drying of paper deformation occurs, the countermeasure is to not affect the function of the paper packaging conditions, improve the mold design to eliminate excessive thickness of the paper mold The phenomenon.
2 paper dry too fast or uneven heating
In the mold design under the conditions of the paper is also often deformed. This is due to over-drying or a surface heating temperature higher than the other parties. In particular, manual intermittent drying tunnel drying more prone to the above problems, the solution can be drying tunnel drying tunnel to automatic tunnel hot air drying to extend the drying time and generally uniform heat of the paper. In order to reduce the deformation of the paper mold, the temperature is relatively high at the initial stage of drying. When the temperature approaches the midpoint, the temperature decreases slowly. A long drying tunnel can be established if the conditions permit, and the drying temperature and the drying time can be reduced as much as possible.
In order to reduce the deformation, you can use more free machine wood pulp or pulp waste newspaper, which is because the contraction rate is less than other viscous chemical pulp raw material, while reducing the burr phenomenon of paper.