Publish Time: 2022-04-19 Origin: Site
We know that Rotational Moulding has become a necessary choice in our production and life. Rotational Moulding has technological characteristics, so what are the technical characteristics of Rotational Moulding? Let's take a look together next.
This is the content list:
l Hardening characteristics of Rotational Moulding
l Rotational Moulding' moisture and volatile content
Rotational Moulding transforms into a plastic viscous state under heating and pressure during the forming process, and the fluidity increases to fill the cavity. At the same time, a condensation reaction occurs, the crosslinking density continues to increase, the fluidity drops rapidly, and the melt gradually solidifies. When designing a Rotational Moulding mold, the material with a fast-hardening speed and a short flow state should be easy to load, loading and unloading inserts, and selecting reasonable forming conditions and operations to avoid premature hardening or insufficient hardening, resulting in the poor molding of plastic parts. Rotational mold's hardening speed can generally be analyzed from the holding time, which is related to the type of plastic, wall thickness, the shape of the plastic part, and mold temperature. However, it is also affected by other factors, especially related to the preheating state. Rotational Moulding should keep the plastics at proper preheating to maximize the flowability of the plastic, and try to increase its hardening speed. Generally, the preheating temperature is high and the time is long. The hardening speed is increased, especially when the pre-compacted ingot is preheated by high frequency, the hardening speed is significantly increased. In addition, high molding temperature and long-press time increase the hardening speed. Therefore, the hardening speed of Rotational Moulding can also be properly controlled by adjusting the preheating or forming conditions. The hardening speed of Rotational Moulding should also be suitable for the requirements of the forming method. For example, injection and extrusion molding should require slow chemical reaction and slow hardening during plasticization and filling and should maintain a fluid state for a long time, but when the cavity is filled, the temperature should be high. It should harden quickly under high pressure.
Rotational Moulding contains different levels of moisture and volatile content. When it is too much, the fluidity will increase, easy to overflow, long retention time, and shrinkage, and it is prone to corrugation, warping, and other maladies, which affect the electromechanical performance of plastic parts. However, when the Rotational Moulding is too dry, it will cause poor fluidity and difficulty informing. Therefore, the Rotational Moulding should be preheated and dried as required. For materials with strong moisture absorption, especially in the wet season, even the preheated materials should be prevented from reabsorbing moisture. Because Rotational Moulding contains different components of water and volatiles, and at the same time condensation occurs during the condensation reaction, these components need to become gas to be discharged out of the mold during forming. Some gases have a corrosive effect on the mold and are also irritating to the human body. effect. For this reason, in the design of the Rotational Moulding, we should understand the characteristics of various plastics and take corresponding measures, such as preheating, the chrome plating of the mold, opening an exhausted groove, or setting up an exhausting process during forming.
Shanghai Jingyao Industrial Co., Ltd. is a modern high-tech enterprise specializing in the development, production, and sales of roto-molding products. As the first domestic high-tech enterprise with independent research and development of rolling products as the core, the company has passed the CE and ISO9001: 2008 quality system certification, maintaining a good quality reputation in the industry. If you are interested in Rotational Moulding, please contact us, our website is www.shanghai-rotomolding.com/.