Rotational molding plastic powder form

Rotational Molding. Large containers and some toys are manufactured with a specialized technique caHed rotational mol ding. A rotational mol ding machine contains several large metal molds that can be rotated in two perpendicular planes. A load of fine LLDPE particles is introduced into each mold, and the mold assembly is transferred into an oven. Inside the oven, heated molds rotate at speeds ranging from 10 to 40 rpm. The polymer powder melts and is uniformly distributed on the internal surface of each mold. After the container is formed, the mold assembly is removed from the oven and cooled at which point the plastic containers are removed. 

Powdered plastic n. A resin or plastic compound in the form of extremely fine particles, for use in fluidized-bed coating, rotational molding, and various sintering techniques. 

Rotational Molding. The process of rotational molding is ideal for creating hollow parts. Polyethylene is the most common polymer used in rotational molding. Powdered plastic is introduced into a clamshell mold. Color and additives, usually a micro-pulverized blend, are added and the mold is closed. The mold is then rotated. The powder is distributed to the mold s surface by the centrifugal force. The mold is heated and a melt skin forms on the mold s surface. Spinning continues as the mold is allowed to cool. The mold is then opened, the part removed, and the process starts again. 

Rotational molding, rotomolding, or roto-casting is a production process to form hollow parts of limitless size wherein powdered resin and glass fibers are charged into a split mold. The mold is then continuously rotated in a biaxial mode, in a high-temperature environment to above the resin melt temperature. When the plastic material has covered the inside of the mold and densified, the mold assembly while still rotating is cooled to room temperature. The rotation is stopped and the part removed. 

Plastics are available in the form of pellets, granules, and powder which can be extruded, blow molded, injection molded or rotational molded, to finished products. Knowledge of plastics to production to their end use properties has become important in view of material development [6-8]. 

Many polymers can be purchased as finely divided powders. These include polyethylene, polycarbonate, nylon, and rigid or lightly plasticized polyvinyl chloride. Highly plasticized polyvinyl chloride comes in a plastisol form. After the material is charged into the mold it is clamped shut prior to heating and rotation. 

Some high-flow plastics, such as nylon, have been used in small pellet form. Ethylene vinyl acetate and PEs are also used in specialized applications as are PVC, PC, TP polyester, nylon, and PP. RM vinyl plastisols produce different products such as beach balls, floating animals, and toys as well as industrial products. The liquid or powdered plastic used in this method flows freely into comers or other deep draws upon the mold s being rotated and is then fused by heat passing through the mold s wall. 

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