What is the difference between rotary molding and injection molding?

1, Working principle
The working principle of a rotational mold is mainly to heat the plastic raw material to a molten state and then place it into a rotating mold. During the rotation of the mold, the molten plastic evenly covers the inner surface of the mold and gradually cools and solidifies. Finally, by opening the mold, take out the formed plastic product. Injection molds, on the other hand, inject molten plastic into the mold cavity under high pressure, cool and solidify to form products.
2, Forming method
The forming method of rotary molding is rotational molding, which allows plastic to be evenly distributed on the inner surface of the mold, thereby producing products with uniform wall thickness and no seams. Injection molds, on the other hand, are formed through injection molding, which can produce products with complex shapes and high precision.
3, Application field
The application fields of rotational molding and injection molding are also different. Roll forming molds are commonly used to produce large, hollow, and uniformly thick plastic products, such as water tanks, storage tanks, and ship hulls. These products often need to withstand significant pressure and weight, so roll forming molds can meet their strength and stability requirements. Injection molds are more suitable for producing small, complex, and high-precision plastic products, such as mobile phone casings, electronic components, automotive components, etc. These products need to have high precision and quality, and injection molds can meet their precision and detail requirements.
4, Material selection
There are also differences in material selection between rotary molding molds and injection molding molds. Due to the high pressure and weight that roll forming molds need to withstand, they are usually made of high-strength and high toughness materials, such as high-quality alloy steel, stainless steel, etc. These materials have good mechanical properties and wear resistance, which can ensure the long-term use of the mold. Injection molds, on the other hand, need to consider the thermal stability and wear resistance of the materials, usually made of high-temperature alloys, high-quality carbon steel, and other materials. These materials can withstand high temperature and high pressure environments, ensuring the stability and durability of the mold during the injection process.
5, Manufacturing costs
In terms of manufacturing costs, there are also certain differences between rotary molding molds and injection molding molds. Due to the relatively simple molding method of rotary molding molds, the manufacturing cost is usually lower. In addition, roll forming molds can produce large products, thus reducing unit costs during mass production. The manufacturing cost of injection molds is relatively high, as injection molds require more complex processing and higher precision requirements. However, injection molds can produce high-precision and high-quality products, so they have irreplaceable advantages in some high-end application fields.