Wall thickness defines a molded part’s basic shape, but it also determines the amount of plastic that’s required. In turn, this has a direct effect on part costs, part weight, and cycle times. Thicker walls require more material, which adds costs and weight. Parts with thicker walls also take longer to cool, which extends cycle times. If there are significant differences in wall thicknesses, cooling can occur at different rates and result in part defects.
Uniform wall thicknesses are easier to achieve with rotational molding than other plastics processing methods. In fact, wall thickness uniformity can be held to within ±10%. That’s better than what’s usually possible with blow molding, a plastics process that can also produce hollow parts. Blow molding also uses more expensive molds and is limited to low-strength items such as plastic bottles. By contrast, rotational molding can use less expensive molds and produce high-strength parts like plastic tanks.
Relative to their size, rotomolded parts can have thinner walls. Although it’s rare for walls to have a minimum thickness that’s less than .125”, Gregstrom can mold walls as thin as .080”, depending on the design. But what if your part requires reinforcement? Compared to other plastics processes, rotational molding supports thicker outer corners. Rotomolding also supports reinforcing ribs and kiss-off ribbing for added strength. Rotational molding can even support double-wall construction if you need it.
Gregstrom Corporation of Woburn, Massachusetts (USA) is an experienced rotational molder with over 75 years of plastics manufacturing experience. In addition to rotational molding services, we offer design assistance and help with material selection. If you’re comparing manufacturing methods for hollow plastic parts, we invite you to talk to our experts before making a decision. The benefits of rotational molding are many, and Gregstrom also offers added-value services like testing and assembly.