Contact: Zhao Fanzhang
Contact: Xiong Jingyu
Official website: www.gdsdzz.com
Address: No. 6, Yongxing Street, Leliu, Shunde District, Foshan City, Guangdong Province
Continuous rotational molding can be divided into two-step, multi-step and one-step methods.
Multi step process is usually used to produce multi-layer products, and its working principle of rotational molding supplier is similar to that of two-step process. If there is a layer of non foaming layer on the foam inner wall, a second input box or a plurality of thermoplastic input bags are used to release non foaming resin on the surface of the formed foam inner core layer to form a non foaming layer.
The two-step and multi-step methods still have some problems, such as complex equipment, a large number of transformation of the old rotational molding equipment, and difficult control of process conditions. In order to maximize the use of the original rotational molding equipment, people have developed a one-step rotational molding foaming technology in Changxing.
The traditional rotational molding equipment can be directly used in one-step rotational molding, and the production process is relatively simple without additional equipment modification. Compared with the traditional rotational molding equipment, the one-step rotational molding foaming equipment does not need large-scale transformation, but puts forward higher requirements for its heating, cooling and other temperature control systems. It requires accurate temperature control and high heat conduction efficiency. At present, due to the obvious advantages of one-step rotational molding technology in equipment, process and product quality, it has developed rapidly in recent years and will become the most important and promising technology in the future.
In order to obtain dense non foaming shell and foam inner core, one-step rotational foaming mainly uses the characteristics of foam resin and non foaming resin with different density, heat capacity and particle size to process products.
Rotational molding is to achieve the heat transfer effect of powder by heating the rotational molding mold, so as to achieve the purpose of plasticization. There are two ways to add rotational molding:
1. Straight fire type
As the name suggests, direct fire is to directly use the flame to heat the mold. In this way, the heat transfer efficiency is high. The flame directly contacts the mold surface. As long as the distance between the flame and the mold is reasonably controlled, the color of the flame is adjusted, and the direction and size of the flame are controlled, the heating effect is generally better. For roto plastic tanks, canoes and other products, the general use of direct fire. However, this heating method also has disadvantages, such as exposure of fire source, temperature is not easy to control and so on.
2. Indirect heating
Using air, hydraulic oil and electric power to complete the heating process of the mold, there are the following methods:
(1) Forced air convection heating in heating chamber
This is the most commonly used heating method, by heating the air in the heating chamber to carry out the heat conduction of the mold.
(2) Heat the mold with a liquid system.
(3) Electric heating system. The advantages of electric heating are clean, no air pollution, fast heating and accurate control of heating temperature. It is an ideal heating method, but this method is still subject to technology.
(4) Infrared heating system
The infrared heating module transmits the heat radiation energy directly to the mold surface, which can effectively project the heat energy, but it will be affected by the projection angle.