plastic rotational molding

Rotational molding, also called rotomolding or rotocast, is a closed mold process that is utilized to make hollow parts. Plastic resin in powder form is placed inside a mold. The machine arm holding the molds is engaged and sent into biaxial rotation traveling into the oven for a predetermined time. The plastic begins to melt and stick to the inner walls of the mold. The part is allowed to cool enough to be removed from the mold. There are many advantages to custom rotational molding such as: low cost tooling, robust durable parts, parts can be reinforced with foam in a one-step process, fasteners can be molded in for mounting purposes, buttress threads can be molded in to accept different styles of caps, and graphics can be molded or fused into the parts.

Ego Rotational Molding development


Engineering and Design works with you on your project requirements
Your project idea is drawn with CAD software to make a 3-D model or we can import an existing CAD drawing
A Rapid Prototype can be produced from a 3D solid model
A pattern is produced out of milled high density wood, composite boards, epoxy resin, or other materials.
After the pattern meets your approval the mold is made

Production Recommendations


Parts color matched to your specifications (PMS or supplied sample)
Surface finish and texture
Wall thickness recommendation
Packaging & Shipping

What we can do for you


Eco-friendly & Quality Finish:

The process is eco-friendly, as only the material that needs to be used is used. There's no wasted material in the process. Rotational molding also requires minimal post production part finishing, which also helps separate it from competing plastic production processes.

Effective for short runs:

Many plastic production processes are best for long run part production. That's not the case with rotational molding. That's because the up front tooling costs and molding costs are cheaper than comparable methods, so you don't need to justify larger up front costs with longer part runs to get your money's worth.

Cost effective:

As we hinted at in the opening, rotomolding is a cost-effective production process. Up front costs to create the mold are comparatively lower than other plastic production processes and tooling costs are also affordable. Molds are typically lightweight and no cooling is necessary, either.

No size limitations:

High level of flexibility and freedom in design. Unlike other production process, there's a lot of part flexibility when it comes to rotational molding - both large and small parts can be made. Multiple cavity molds can also be used in production runs, which is advantageous. Containers and barrels are a common application of the process. To give you a better idea on the size range, consider that hollow barrels can be made ranging from 5 gallons to 22,000 gallons. That's a big part range.