The raw materials of molded pulp products are mainly some natural fiber like sugarcane bagasse, wheat straw, woodchip, bamboo, or recycled paper. Different materials can result in different physical properties (strength, thickness, color…)
These raw materials are put into a giant blender with certain amount of water and turn into slurry. If needed, some additives are added in the slurry to make the products waterproof, flame-retardant, oil-resistant or stronger; or dyes can be mixed with the slurry to make products colorful.
The finished pulp then is conveyed to the forming machine where equipped with a mold in desired shape. The mold is with perforations in either or both sides to absorb the pulp to the mold by suction and/or vacuums. The products are formed in the desired shapes in this process.
1). For dry press process (rougher surface), wet semi-products are dried up naturally or in the heaters, then go into the thermoforming machines to finalize the shape under high temperature and pressure.
2). For wet press process (very smooth surface), the semi-finished products will go to the thermoforming machines directly to finalize the shape when they are still wet.
The dried products can be cut based on the specific requirements in order to make the products more elegant and tidy. The products in need of punching and edge cutting entail more complicated manufacturing process and more precise edge-cutting die.