The rotational molding process starts with a good quality mold that is placed on a molding machine that has a loading, heating, and cooling area.
To rotationally mold parts more than one molds may be placed on the machine at a time. Pre-measured plastic resin is loaded into each mold, the molds are closed then moved into the oven where they are slowly rotated on both the vertical and horizontal axis. The resin melts within the mold as it rotates. The melting resin sticks to the hot mold and coats every surface evenly. The mold continues to rotate during the cooling cycle so the parts retain an even wall thickness.
Once the parts are cooled, they are removed from the mold. The rotational speed, heating and cooling times are controlled throughout the rotational molding process.
We are Roto-Lite, Inc. and for over three decades we have offered only the finest Rotationally Molded parts for our customers. We have a complete in-house facility to handle all your products needs.
Rotational molding offers design advantages over other molding processes. With proper design, parts that are assembled from several pieces can be molded as one part, eliminating expensive fabrication costs.
Inserts, threads, handles, minor undercuts, flat surfaces that eliminate draft angles or fine surface detail can all be part of the design. Designers also have the option of multi-wall molding that can be either hollow or foam filled.
The process also has a number of inherent design strengths, such as consistent wall thickness and strong outside corners that are virtually stress free. If additional strength is required, reinforcing ribs or kiss-offs can be designed into the part.
Rotational molding delivers the product the designer, designed. Designers can select the best material for their application, including materials that meet Food and Drug Administration requirements.
Additives to help make the part weather resistant, flame retardant, or static free can also be added to the process.
If cost is a factor, rotational molding has the advantage over other types of processes as well. Rotational molding can easily produce large and small parts in a cost effective manner compared to injection and blow molding. Tooling is less expensive because there’s no internal core to manufacture. Since there is no internal core, minor changes can be easily made to an existing mold if one is available…
And because parts are formed with heat and rotation, rather than pressure, molds don’t need to be engineered to withstand the high pressure of injection molding.
Production costs for product conversions are reduced because lightweight plastics replace heavier, often more costly materials. Which makes rotational molding as cost effective for one-of-a-kind prototypes as it is for large production runs.
Advantages of Rotational Molding
There are many advantages of rotational molding compared to other plastic processes:
- Wall thickness can be uniform – no thinning in the extremities
- Stress free parts
- Variety of finishes and streamline appearance
- Less expensive molds than other processes
- Design freedom
- Large parts economically manufactured
- Prototypes produced at low cost
- No draft angles required – minor undercuts are possible
- Metal inserts often can be molded as integral parts
- Economical small production runs
- A multitude of colors
- One piece construction
- Totally enclosed parts
Contact us today, we can assist you in a new design or answer any questions relative to the capabilities of the process on existing items!