Characteristics of Wuhan Handern rotary molding machinery
日期：2021/1/6 8:44:46 / 阅读： / 来源：本站
Characteristics of Wuhan Handern rotary molding machineryRotary molding machine should be equipped with a device to supply peach heating and cooling; a device to rotate the mold as needed; a device to transfer the mold from the feeding station to the heating station, and then to the cooling station: a device to install the mold. The main moving parts of the rotary molding machine are the rotating arm, mold base and driving device. The main molding process components are mold, heating system and cooling system. Air permeable film production line www.handern.com
The mold structure of rotary molding machine is determined by the shape of the product, but it is generally shell structure. In order to facilitate demoulding, the wall thickness of the tool should be as thin as possible, which not only saves power consumption, but also has a direct impact on the wall thickness and performance of the product. In addition, the wall thickness of the mold is also related to the rotary forming method and heating system. The wall of the mold used for hot liquid conduction heating should be thickened, generally 12 ~ 15mm, so as to ensure that the high temperature caused by the rapid heating of the liquid is evenly distributed and hot spots do not occur. For the mold heated by hot air circulation, the wall thickness can be thinner, generally 5 ~ 7mm.
The rotary forming mould shall be provided with an insulating cover for the production of open products or parts with partial openings. The commonly used insulation covers are fluoroplastics, asbestos board, etc. after using this kind of insulation cover, the powdery resin does not melt and adhere to the covered part of the insulation cover. After cooling and demoulding, a complete open mouth product is formed. If local thin wall is needed for rotary molding products, this method can also be used to adjust. In the process of rotary molding, the air in the mold is heated and expanded, which increases the pressure in the mold, and the low molecular compound is decomposed into gas
The gas must be discharged from the cavity. The exhaust port is a thin-walled metal fluoroplastic pipe, which is mostly located in the upper cover or the place with holes and extends to the center of the mold cavity. In order to avoid the powder resin overflowing from the exhaust port when rotating, the hole should be filled with glass fiber, graphite powder and other materials. Figure 11-7 is the schematic diagram of the rotary die.
The mold of rotary molding does not require high material strength, as long as the thermal conductivity, ductility, weldability and heat resistance are good. Cast iron, steel plate, aluminum copper alloy, aluminum, beryllium copper alloy are commonly used materials, among which the most commonly used are steel and aluminum. Air permeable film production line www.handern.com
2. Heating system
(1) Hot air circulation heating method. For the thick arm products with the production capacity less than 1.8mm, the heating furnace temperature range is 205-480c, and s7ec should be selected for HDPE products. The internal hot air flow velocity and internal temperature uniformity of heating are very important. The disadvantage of the movable ring heating is that it has a hot air movable ring, high energy consumption and low number rate.
(2) Open fire heating method this method is directly using liquefied petroleum gas, gas heating calibration, so the efficiency is twice as high as the above method. This method is suitable for large products or products with complex shape and the same thickness. The temperature can be adjusted by controlling the heating time of different posts and the size of large stations. Due to the operation of Linghua by open fire heating method, it has the advantages of low cost, high efficiency and wide adaptability.
(3) This method uses hot liquid injection to heat the mold. The heat transfer medium used in this method is non corrosive and easy to use inorganic salt mixture which is commonly used in all heat treatment. The operating temperature of the liquid injection system is generally controlled at 1330-290c, and it is easy to be equipped with a hot chamber to raise the liquid temperature to the operating temperature, and the liquid Hill nozzle is injected into the mold. This method is especially suitable for thick products and complex color products. Due to the irritation of heating medium to skin and corrosion of mould, it is not widely used at present. Air permeable film production line www.handern.com
(4) Hot oil heating method hot oil heating method is to send hot air to the drain pipe in the oil tank to heat the oil. The hot oil passes through the mold interlayer to plasticize the resin by heating, and then change the cold oil when it is cooled. This method consumes less energy, but the cost of die is high.
(5) Infrared heating is a fast and efficient method, but it is only limited to the mold and single core with simple shape. Such as complex mold shape. The radiant heat can not reach all parts of the mold evenly, and the temperature skin on the shady side of the mold will be far lower than that on the star falling side, so the wall thickness of the product will be difficult to control.