Rotational molding technology is expanding the capabilities of polymer product manufacturers by enabling them to create light-weight, seamless, stress-free parts of virtually any size in the most complex shapes. Rotationally molded products represent a wide range of materials, performance characteristics, colors, surface textures and finishes. The products can be custom-designed to meet precise market requirements more economically than by conventional injection or blow molding.

Rotational molding is a three-stage, no-pressure, plastic molding process. During the heating stage, the mold slowly rotates in two planes (bi-axial rotation). Heat transfer causes the plastic charge inside the mold to melt and uniformly coat the interior of the mold. During the second stage, the mold moves to the cooling station,

where it is cooled by air and/or water spray. In the final load/unload stage, the part is removed from the mold and a new charge of material is loaded into the mold.

Ferry's innovative Rotospeed^TM machines enhance this process with design styles that vary the configuration of these three stages. A variety of sizes accommodate most processor needs. Ferry offers over 30 standard models of Rotospeedª rotational molding machines, with mold swings to 218" (5537 mm) and weight capacities to 10,000 pounds (4540 kg). Versatile, dynamic and market-responsive, Ferry Industries is committed to introducing new designs, product refinements, and effective integration of ancillary equipment to advance the technology and value of the Rotospeed product line.

What you can make by rotational molding!

What do you need from me to recommend the best style and size of machine for my needs?
We need the dimensions of your products, projected annual production and the type(s) of resin you plan to mold. Sketches help and any other details.

What other equipment do I need to start producing?
Typically a tow motor, semi-skilled operators, resin, secondary finishing equipment such as router, and of course, a building.

What is the difference between an Independent-Arm and a Fixed-Arm Turret machine?
With Fixed-arm turret machines, 3- or 4-arm, all the arms index at the same time. This means oven, cooling and servicing operation need to be accomplished within same time allotment. The Independent-arm machine, with 5 stations, allows one arm to index while the other arms may remain stationary, providing more process flexibility.

What type of molds are used for rotational molding?
The most common type of molds are cast aluminum, fabricated aluminum, fabricated steel and stainless steel. Other types are available such as machined and electro-formed. Here are links for some of the mold suppliers to rotational molders.

Cole Industries, Inc.
Norstar Aluminum Molds, Inc.
Johndel, Inc.

What types of material are commonly used for rotational molding?
Polyethylene (HDPE, LPDE and LLPDE), PVC, Fluorocarbons, Polypropylene, Nylon and Polycarbonate. Here are links to some of the material suppliers to rotational molders.
A. Schulman
ICO Polymers
Nova Chemicals
Total Petrochemicals

Can you recommend some independent consultant to discuss our needs regarding rotational molding?
Yes, here are some is a highly regarded and very knowledgeable independent consultants to the world-wide rotational molding community.
Paul Nugent
Einar Voldne
Glenn Beall

Are the molds under high-pressure and spin fast?
No, rotational molding is a low/no pressure process where the molds are charged with resin, clamped shut and rotate in two axes at low speeds. Typically the major axis revolves four times to every one time of the minor axis. The speeds are slow enough that no centrifugal force is involved.