How do you make a one piece seamless plastic tank, or other rotationally molded products?        Amprotec,Inc.-800 537.9444

Rotational Molding Process.

STEP 1: LOADING RESIN IN THE MOLD                                                                    STEP 2: HEATING AND FUSING THE RESIN

 

 

 

 

Step 3: Cooling the mold                                                                  STEP 4: UNLOADING THE MOLD

 

 

 

 

 

 

The process of rotational molding includes these four steps.

• loading the resin in the mold

• heating and fusing the resin

• cooling the mold

• unloading the mold

STEP 1: LOADING RESIN IN THE MOLD

A closeable mold ( looks like the final product but is made of steel with machine interface clamps welded to the exterior) is charged with a plastic resin material in liquid or powder form. A variety of resin materials are available. The most widely used is polyethylene. Other resins materials include nylon, fluoro polymers, polypropylene, polycarbonate, cellulose acetate butyrate, elastomers, ionomer, polyurethane, EVA and specially formulated compounds.

The charged mold is moved into an oven.

STEP 2: HEATING AND FUSING THE RESIN

The mold is continuously rotated on two axes at low speed. As heat penetrates the rotating mold, the resin begins to melt and adheres to the mold’s inner surface until the distribution of materials time line has completed.

STEP 3: COOLING THE MOLD

The mold is then moved ( rotated out of the oven ) to the cooling chamber and cooled by air or water spray or a combination of both while still rotating. The temperature is lowered in a gradual manner to allow the newly molded part to solidify, retaining the shape of the mold.

STEP 4: UNLOADING THE MOLD

The mold is opened, the finished part is removed, and the mold is charged for the next cycle.

Copyright amprotec, inc 2007; extracted from http://www.raventank.com