The current situation and development trend of rotational molding equipment at home and abroad
Rotational molding, also known as rotational molding or rotational molding, is a plastic molding technology with a long history. It is reported that as the core of the most original process of rotational molding, it may start from the manufacture of Terra Cotta Warriors in the Qin Dynasty. But the rotational molding process, as a plastic, originated in the UK. The first rotational molding patent was issued in 1887, and the first commercial rotational molding machine was manufactured in 1934. In the 1950s, it achieved great development in Europe and gradually spread to places such as the United States and Japan. At first, it was just a supplement to injection molding and blow molding processes. With the maturity of polyethylene powder technology, it has increasingly become a highly competitive molding method in plastic molding processes. Since then, the rotational molding process has been continuously developing worldwide
1. Foreign Situation and Development Trends
In recent years, in developed countries in North America and Europe, the rotational molding industry has developed rapidly, with a development speed higher than the average development speed of the entire plastic industry. The development of the entire rotational molding industry is also relatively complete. In addition to rotational molding machine manufacturing factories and rotational molding product production factories, there are also a considerable number of other professional auxiliary factories, such as rotational molding mold manufacturing factories, release agent production factories, rotational molding specialized pigment production factories, milling machine manufacturing factories, embedded parts manufacturing factories, and mixing equipment manufacturing factories suitable for rotational molding, as well as numerous rotational molding specialized raw material supply factories, and so on. The rotational molding equipment manufactured in developed countries is also becoming increasingly sophisticated, constantly developing towards higher levels of automation control.
At present, using rotary molding equipment can not only produce small products with simple and single-layer structures, but also complex, multi-layer, large and super large products, including various container products, motor tool accessories such as automobiles and airplanes, military supplies, ships, and human organs.
From the perspective of the heating methods of rotary molding machines, there are currently only two main types commonly used, direct fire and hot box heating. Large products are often produced using direct fire heating, that is, direct fire heating swing type rolling molding machines; The production of small and medium-sized products often uses hot box heating, and the most common models are hot box heating swing type rolling plastic machines, hot box heating 2-arm shuttle type rolling plastic machines, 3-4 arm tower type rolling plastic machines, and hot box heating" Mussels; The development of roller molding machines has been rapid in recent years.
Developed countries not only continuously improve the rolling molding machine models, but also vigorously improve the control level of rolling molding machines. Here, a special introduction should be given to the Rotoolog Rotomolding Process Diagnosis System, which was successfully developed in 1991 by Northern Ireland Rotomolding Systems in the UK and Exxon Chemical in Canada. The system has been improved several times and is now very complete. The system includes two main parts: temperature measurement and control display. The temperature measurement part is sealed in an insulated box that can be installed on the mold frame. The temperature inside the mold measured by the thermocouple is transmitted in real-time to the monitoring computer outside the hot box through radio, and the computer displays the temperature/time change curve inside the mold. Compared with the temperature/time variation curve in the hot box, this curve can visually display the real-time status of heat transfer and material heating of the mold and its components during the rolling molding heating process. Operators can optimize the heating and cooling cycles, improve and ensure the plasticization quality of products, maximize product strength, reduce production costs, and accurately evaluate molds and new materials.
Foreign rolling mills generally have multiple rolling machines of different sizes or types. For example, Spincast Company in the United States has 7 roll forming machines with a maximum rotational diameter of 4m for the molds; Dimond Company has 9 rolling molding machines with a maximum rotation diameter of 4.3m for the molds; Amerikart has 10 units with a maximum rotation diameter of 3.3m for molds.
2. Domestic situation and development trend
The rotational molding industry in China started relatively late in the late 1970s. Most rotary molding factories do not have sufficient understanding of the deeper rotary molding technology. Textbooks for plastic processing majors in higher education institutions provide less information.
From the use of domestic rotary molding equipment, most of the rotary molding machines used are swing type, shuttle type, and tower type, with fewer other models; The same is generally true for domestically manufactured rotary molding machine models; The number of rolling machines owned by each domestic rolling mill is not large, with one or two manufacturers having more.
Overall, there is still a significant gap in the development level of China's rotational molding industry compared to developed countries. However, there have been developing production factories for rotational molding machines and rotational molding molds. We have also successfully developed specialized materials for roll forming in China, and the variety of roll forming plastics is constantly increasing. In recent years, the rapid development of the rotational molding industry has attracted more and more attention from foreign countries to China's rotational molding, and international exchanges are also increasing.
The development of China's roll forming industry is inseparable from the continuous development of new products, the continuous expansion of the application field of roll forming products, and the continuous improvement of roll forming machine manufacturing technology and related technologies. The Roll Forming Industry Association will also vigorously accelerate the development of various aspects of China's roll forming industry in the future, and of course, everyone needs to work together and continuously strive. The rotational molding industry in China should have a good development.