Rotomoulding

The rotational molding process (English rotationally - molding, rotomoulding ) is a manufacturing process for plastic parts. Other names include rotational molding (English rotationally sintering ) and rotational molding. The procedure was developed in the early 1940s in the U.S. and is one of the oldest methods for shaping of plastics.

Dissemination

Compared to the total production volume of plastic articles is it the rotational molding process is a niche technology. In the U.S., this is very common and, in recent years, the number of users in Europe and Asia is rising. Some plastic products can best be achieved with this method.

Description

Each plastic product requires a separate form. It is made ​​of steel or aluminum. The mold is mounted on a mold carrier. Subsequently, the two-to - multi-part mold is opened and the pulverized material ( eg, polyethylene, polypropylene) filled. The mold carrier is driven together with the mold in the oven. Under controlled heating of 190 ° C up to 320 ° C, the mold is slowly added into biaxial rotation. In the form melts the raw material rolls more and more against the inner wall of the mold and builds the wall thickness of the plastic part on layers. Once this process is completed, the mold carrier is driven together with the mold out of the furnace and into the cooling chamber. After the controlled air or water cooling the mold removal done. The open mold is removed, the finished molded plastic part. A production cycle takes about an hour, which means that each form maximum a piece of plastic part can be produced in one hour. Depending on the size of the form in relation to the size of the boiler room ( oven ), but may have one to several shapes mounted on the mold support and are heated together and cooled.

At present, the development of direct- heated forms is operated.

Benefits

Because of the almost unpressurized production ( low-pressure process ) the products are almost stress- free and thus very tolerant of pressure and shock. The other properties of the products are determined by the raw material. Rotationsgesinterte containers are manufactured primarily from polyethylene. Rotationsgesinterte container made ​​of PE for example are very robust and because of the raw material, resistant to many chemicals. They are used in plant chemicals, water and food, as well as for the storage and transport.

Types of production

The arrangement of the oven / furnace refers to the shape of the production plant, which is called rotational molding plant. The carousel system ( binary system ) in the form of mounting station, the furnace, the cooling chamber and the product removal station are disposed around a central axis.

When shuttle system these workstations are linearly arranged horizontally.

Details of the procedure

The rotational molding process is due to the long production time only for small and medium-sized series of parts useful and economical.

In the rotational molding process is a seamless hollow body is always made. Other body can only be achieved by separation of the completed rotation molding. This must be in the design of rotational molded plastic parts and are included in the preparation of the corresponding rotational molding. It result from the interesting design possibilities, which are increasingly used for new products with groundbreaking design.

Applications for rotation Molten products

  • Industrial container and drip pans
  • Fuel Tanks
  • Equipment housing
  • Canoes, kayaks, boats, float
  • Lamp housing for indoor and outdoor
  • Garden furniture and other furniture made ​​of plastic
  • Mobile toilet cubicles and Kennels
  • Truck wheel aprons and other commercial vehicle parts
  • Sports and play equipment
Aluminium
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