Views: 0 Author: Site Editor Publish Time: 2022-04-25 Origin: Site
In our production life, Rotational Moulding is controlled by certain conditions, so what are the conditions under which Rotational Moulding is controlled? Three conditions control Rotational Moulding, let's take a look at them.
This is the content list:
l Resin conditions for Rotational Moulding
l Heating and Influencing Factors
l Control of cooling
The resins used in Rotational Moulding were mostly polyvinyl chloride paste in the early days, but with the development of Rotational Moulding, the variety of resins used has been expanded, and Rotational Moulding mainly includes polyethylene, modified polystyrene, polyamide, polycarbonate, and ABS. Several types of plastics are also used to produce "sandwich-continuous" products.
For Rotational Moulding, parameters such as density of the resin, the particle size of the powder, and melt index have a great influence on the molding process. In the melting process of Rotational Moulding resin, for example, the higher the density, the higher the melting point, and the higher the heating temperature or longer the heating time during Rotational Moulding. Rotational Moulding resins with a large melt index have a relatively low relative molecular mass and are easier to melt and have good melt flow, which is conducive to Rotational Moulding.
Whether the heating process of Rotational Moulding is well controlled or not is one of the most important conditions to obtain good products. The heating process of Rotational Moulding includes the heating of the mold, the heating of all the materials in the Rotational Moulding mold to the melt temperature, and the heating of the molten materials to the melt temperature. The heating process of Rotational Moulding involves heating the mold to a temperature where all the material in the Rotational Moulding mold is heated to molten temperature, the molten material is fused into a three-dimensional mesh structure and the air bubbles and pores in the molten material are removed under the action of heat, making the Rotational Moulding product a dense, homogeneous structure. The heating time is shorter for Rotational Moulding molds with thinner wall thicknesses, and the healing time is significantly different for Rotational Moulding parts with different wall thicknesses because the melting time of the plastic is mainly controlled by the wall thickness of the product.
After all the Rotational Moulding materials have been melted, the Rotational Moulding mold is transferred from the heating station to the cooling station, and reasonable cooling should enable the Rotational Moulding parts to be cured quickly without warping. For polyethylene and other crystalline materials, its crystallization growth rate changes are extremely sensitive to temperature, must be cooled evenly to obtain qualified products. For example, for low-density polyethylene, the mold and its parts can be cooled by spraying water immediately after the heating of Rotational Moulding. In the case of high-density polyethylene roto-molding, it is advisable to use cold air cooling for 1~2min after the heating of Rotational Moulding, and then spray water cooling. For large Rotational Moulding products should also be sprayed by water mist, if necessary, even hot water cooling first, and then cold-water cooling, but the cooling rate should not be too slow to prevent the formation of large spherical crystal polymer Rotational Moulding products impact strength and resistance to stress cracking decline.
Shanghai Jingyao Industrial Co., Ltd. is a modern high-tech enterprise, specializing in the development, production, and sales of Rotational Moulding products. As the first domestic high-tech enterprise with independent research and development of rolled products as the core, the production of Rotational Moulding products is given great technical investment and is committed to the better development of Rotational Moulding products. If you are interested in Rotational Moulding, you can contact us at www.shanghai-rotomolding.com.
