There are two types of paper trays, one is dry pressed paper trays, and the other is wet pressed paper trays. The distinction between these two types is clearly defined. Wet-pressed paper trays are very common packaging in the market. At present, the most commonly used white wet-pressed paper trays. The surface of wet-pressed paper trays is more smooth and smooth, and the quality is significantly better than that of dry-pressed paper trays.
1. Vacuum suction molding method: It is the most popular method for paper plastic products. According to its different structure, there are three ways: drum type, flip type, and reciprocating lifting type.
Rotary drum type: continuous rotation production, high production efficiency, large investment in mold shells, high mold processing accuracy, high technical requirements for equipment processing accuracy, one set of concave molds with eight sets of punches. Need to use the CNC center to process the mold, the processing cycle is long, and the investment is large. Because it is continuous production, it is suitable for mass production of stereotyped products, such as trays, dinner trays, and egg trays. For industrial molding production, it is not applicable due to non-standard, small quantity, small batch, and large investment in molds.
Flip type: lower production efficiency than drum type, suitable for medium batch and non-standard production of industrial molding, but because it is a set of concave molds with two sets of punches, the mold needs to be processed by a CNC center, and the mold shell investment is large and the cycle time long.
Reciprocating lifting type: The production efficiency is the same as the flipping type, which is the most common production method at present. Because the equipment only needs a set of concave molds to match the punches, and does not need CNC center processing, it is especially suitable for non-standard, small batch, and fast cycle industrial packaging. Product (Industrial packaging product mold production cycle is usually within 10 days)
2. Grouting molding method: The injection molding method calculates the required amount of slurry (material) according to different pulp packaging products, and then quantitatively injects it into the molding cavity for adsorption molding. This kind of molding method adapts little to changes. The finalized standard products are commonly used in tableware molding products. Because the finalization calculation is difficult to grasp, this molding method is not used in non-standard paper-plastic packaging (industrial packaging).
The above content is an introduction to the molding process of wet-pressed paper tray products. In addition, there are stripes on the surface of wet-pressed paper tray products after hot pressing. These lines are mainly caused by uneven slurry absorption of the molding die. The method is to use a smaller drill bit for drilling and increase the pressure of the hot press, which can effectively improve the pattern phenomenon. If feasible, you can also add a few more layers of mesh to the forming mold, so that the vacuum force at the punching area can be well dispersed.
