Pulp molding mold types
Pulp molded products in the forming process to go through several times to enter the mold to finalize the product manufacturing process, as mentioned above, pulp molded products are formed in a single convex or concave mold, molded and then must be in the punch and die after the mold The cavity is transferred and transferred to a shaping die where the wet paper web is pressurized in a shaping die and shaped after heating. Therefore, the pulp molding mold is divided into forming molds, setting molds, plastic molds and die-cutting molds. There are two types of forming process, one is adsorption forming, and the other is press forming, pressing and forming die somewhat similar to rubber and plastic mold, and adsorption forming die is more special and complicated.
(1) adsorption forming mold:
Adsorption molding die structure by the punch, die, mesh mold, the mold base, the mold back cavity and gas chamber and other components. Mesh mold is the main body of the mold, because the mesh mold is made of metal or plastic woven into the wire diameter </ font> 0.15mm, can not be independently formed, must be attached to the mold surface to work. Mold back cavity is maintained with a certain thickness of the mold surface, the shape of the mold is completely synchronized with the back part of the cavity seat relative to the seat, that is convex, concave mold is a shell with a certain thickness. Die face and the back cavity by the uniform hole Unicom.
The mold is installed on the mold of the forming machine through the mold seat. The other side of the mold is equipped with a gas chamber, which is communicated with the back cavity, and at the same time there are two channels of compressed air and vacuum. Adsorption molding mold reserve: adsorption molding mold reserve is the key to mold design.
Pulp molded products from wet paperboard to finished products shrink due to precipitation of water. The same product at different positions shrinking rate is not the same and there is no law, resulting in the product during the forming process to multi-directional and changing shrinkage changes to the mold design to determine the amount of the reservation due to the difficulty, but fortunately the current packaging industry on the pulp mold Plastic products manufacturing precision is not high, with the experience of design can also meet the requirements. In order to obtain a higher manufacturing precision and improve the mold design method, the author through a long period of testing and theoretical derivation concluded a universal value, high precision mold reserve formula (due to understandable reasons can not be announced ) In addition to this formula by the structure, shape constraints, but also added the type of slurry, forming conditions and drying method of the coefficient, so this formula has both theoretical basis, but also experience coefficient.
(2) Pulp molding mold:
Forming dies is a type of mold that has the function of heating, pressurizing and dewatering directly after the forming of the wet paper web.
Stereotypes mold is used to make the wet blank in the mold drying shape, with the shape of the mold manufactured products smooth, accurate size, solid, good rigidity. Disposable fast food are made using this mold. In the industrial packaging, a number of small, sophisticated, large number of small items are stacked layer by layer, each layer is used to package the positioning of packaging products, if the use of pulp molding products will need to use fixed mold To create. The general industrial packaging products are single-sided work, no heat-setting, direct drying can be. The die structure includes a punch, a die, a mesh mold and a heating element. A drainage vent hole is formed on the convex or concave mold attached with the mesh mold. During working, the wet paper blank is first pressed in the mold and some water Squeezed out, then the moisture content of the wet paper blank 50-55% so that the wet paper blank in the mold after the remaining water is vaporized, wet paper blank is dried after forming the product shape.
The mold in the mold will cause the net marks on the surface of the product, and the mold will be damaged quickly in the frequent extrusion. In order to solve this problem, I designed a non-network mode, this network-free mode is made of copper-based spherical powder metallurgy. After several structural improvements over the past two years and the selection of appropriate powder particle sizes, the resulting meshless die has a die life of 10 times that of a mesh die, reducing costs and producing high-precision paper products with smooth inner and outer surfaces.
(3) Pulp molding plastic mold:
Wet blank to be deformed after drying, and some parts of the serious deformation, or the shape of the product requires high precision, the product to go through a plastic surgery process, the use of the mold called plastic mold. This mold also requires heating elements, but no mesh mold is ok. Need to plastic products in the moisture content to be retained in order to facilitate plastic surgery. In production practice because of the water content is not easy to control, making products difficult to achieve quality requirements. I designed a spray plastic mold, the mold corresponding to the need to create plastic parts spray holes. Working products are thoroughly dried into the plastic mold, the mold at the same time mold spray hole spray hot pressing products, this mold and the garment industry is somewhat similar to the spray iron.
(4) die-cutting mold:
Die cutting mold is used to trim the product burr, also known as trimming die.