The production of Pulp molded general includes pulp preparation, molding, drying, hot pressing and other processes.
1. Pulp preparation
Pulping includes the three steps of raw material dredging, pulping and pulping. Firstly, the primary fiber is dredged in the pulper after screening and classification. Then the pulp is beaten, and the fiber is separated by the pulper to improve the binding force between the pulp molded products. Because the size of the ratio, hardness and color are different, generally need to add wet strength agent, sizing agent and other chemical additives, and adjust the size of the concentration and pH value.
At present, our pulp molding process is the vacuum forming method. Vacuum forming is a process in which the lower die is immersed in the slurry pool and the fibers in the slurry pool are uniformly absorbed on the surface by pressure and the upper die is closed. We are equipped with a reciprocating lifting molding machine, more suitable for the production of large size and specification requirements, demoulding height requirements of deeper paper and plastic products.
Dry pressure products need to be dried, generally using drying passage drying and film drying. Our company uses the drying passage for drying. The moisture content of the pulp moulded wet embryo can reach 50%~75%,after the lower mould is absorbed and combined with the upper mould, and then it can be reduced to 10%~12% after drying. Wet pressure products generally do not need to dry.
4. Hot pressing
After the pulp molding products are basically finalized, they are then pressed with high temperature and great pressure to make the pulp molding products more compact, better mechanical properties, and make the shape and size of the product temperature, wall thickness uniform, smooth and flat outer surface. The molding process generally adopts high temperature mold (generally 180~250℃) and high pressure pulp to suppress the pulp molding after drying, and the hot pressing time is generally 30-60s.
5. Trimming and finishing
After the end of hot pressing, the product will be cut to get the finished product. After trimming, some products will be processed in post processing according to customer demand, such as pad printing, grooving and so on.
6. Screening and packaging
After the completion of all production and processing steps, we have professional quality control personnel to screen the products, according to customer requirements, eliminate some unqualified products.Finally to meet the requirements of the production packaging.
Post time: Oct-28-2020