Popular CMF process tip: Rotational molding
I. Introduction
Rotational molding, also known as rotational molding and rotational casting molding, is a thermoplastic hollow molding method.
It includes three types of rotational molding, such as dry powder molding of PE, PVC paste resin molding of rotational molding and liquid monomer polymerization molding of rotational molding.
The three types of rotomolding have their own characteristics, but the general principle is the same.
It is mainly used in the production of small products such as toys, leather balls, bottles and jars by PVC paste plastic, but recently it has been applied to large products.
Applicable materials
At present, the rotational molding industry relies heavily on polyethylene (PE), and almost 97% of rotational molding products are made of PE series materials, in addition to PA, PP, PVC, EVA, etc.
III. Application fields
Simple, airtight, hollow, thin-walled products, such as: storage tanks, containers, light ladders, transportation facilities, large toys, ship hulls, clothing models, etc. At present, the processing of up to 100,000 liters of containers.
IV. Process flow
Step 1: Pour the polymer particles into the mold cavity
Step 2: Heat the mold to melt the polymer particles inside the cavity into liquid, rotate the mold to force the polymer liquid to mold inside the mold cavity (25 min +)
Step 3: Inject air into the cavity until the mold cools (25 minutes +)
Step 4: Demold and finish
V. Competitive Processes
Heat molding, blow molding method, hand paste molding
Six, design tips
1、It is suitable for manufacturing large and extra-large products. Theoretically, there is almost no upper limit in terms of size for products made by rotational molding process.
2、More selective and adaptable equipment and molds.
3、The products are formed once, no internal stress, not easy to deformation, no seam, high strength.
4、It is suitable for the production of multi-species and small-lot products.
5、It is suitable for forming complex shape hollow products.
6、Saving raw materials, and very easy to change color.
7、The cost of rotomolding mold is low, the cost of rotomolding mold is about 1/3 to 1/4 of the cost of blow molding and injection molding mold for the same size products.
8、The dimensional accuracy of rotational molding products is low, and its dimensional accuracy is usually ±5%.
9、The energy consumption is larger and the molding cycle is longer.
