Articles | Mar 22, 2023
Guide to Rotational Molding
Rotational molding, more commonly called Rotomolding, is a processing method that has been around for many decades. Basically, in Rotomolding a plastic powder is weighed and poured into a mold which then goes into an over. While the mold is in the oven, it is heated and rotated and the plastic powder starts to melt and builds up until the desired thickness is reached. The mold is then removed from the oven and allowed to cool before it is opened and the part is removed. Rotomolding is used to produce hollow parts that can range in size from small to very large.
There are many advantages to Rotomolding compared to other common plastic processing methods. Some of the main ones include:
- Mold and tooling costs are low.
- Good for small volume or short production runs.
- Can make very large parts.
- Able to make hollow parts.
- Low-pressure process so parts are virtually stress-free.
- Little to no resin waste or scrap.
Rotomolded parts can be found in virtually every industry and market. Common rotomolded applications include:
Kayaks
Playground Equipment
Traffic Barriers
Large Trash Cans
Tote Bins
Storage Tanks
Portable Outhouses
While polyethylene is by far the most widely used resin for Rotomolding, other resins such as polypropylene, nylon, acetal and polyester are also used.
If you’re interested to learn more about Rotomolding, then check out our new Guide to Rotational Molding where you’ll learn more about the Rotomolding process, applications, part design, resins used, molds, and equipment. We’ve even included a helpful Rotomolding Troubleshooting section to help you solve any processing problems or part defects.
And if you are looking for more information after reading our Guide to Rotational Molding, then you can contact Entec Polymers and speak with one of our Rotomolding experts.
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Click Here!Other Rotomolding Resources
Rotational Molding Materials Guide
Pulverized resins in powder form specifically formulated for rotational molding. Use this guide to see an overview of densities and melt flows. Contact us for technical support on specific applications.
Venting Molds in Rotational Molding
Do you want to learn more about how properly venting molds in rotational molding can reduce your scrap rate? Learn our tricks and tips on how to properly vent a mold.
Causes and Solutions for Warped Parts
Are you struggling with warpage issues in your roto-molded parts? Let Entec's roto-molding experts provide you with assistance to produce warp-free parts!
Mold Release in Rotational Molding
Would you like to learn more about how to reduce many of your roto-molded part quality issues by simply applying your mold release agents properly? Our tricks-of-the-trade about mold release will benefit you and your team and help reduce your quality costs.
The Importance of Thickness Testing your Rotomolded Parts
Would you like to reduce your internal scrap rate and ensure that the rotational molded parts that you are producing meet your customers’ expectations and requirements? Then please take a few minutes to review why we believe having a robust molded part thickness test program will help you and your company.
The Importance of Parting Line Maintenance in Rotational Molding
Do you want to save time and labor costs and reduce scrap in your Rotational Molding secondary operations? Then take a few minutes to review our critical-to-quality operation of mold parting line maintenance that we truly believe can help improve your quality and bottom line.
Determining Rotomolded Part Cure
Check out our technical document on how you can determine the correct amount of cure in your roto-molded part.
Pulverized Resin Quality
Is your roto resin not flowing the way you need it to? Our Pulverized Resin Quality document can help explain why the quality of the pulverizing operation is critical to successful roto molding.
Monitoring the Internal & Peak Internal Air Temperature during the Rotomolding process
Do you monitor the Peak Internal Air Temperature (PIAT) in your Rotomolding process? If not, you should. And here’s why. Our document on monitoring Peak Internal Air Temperature (PIAT) helps explain the many benefits of this diagnostic tool and how it can improve the quality of your roto-molded parts and why every roto-molder should use it.
Pinking Discoloration in Polyolefins
Pinking discoloration is a well-known phenomenon that occurs in polymers such as HDPE, LLDPE and polyolefin elastomers.
Troubleshooting Guide For Injection Molding
Processing issues and defects organized by causes and solutions. Contact our technical team for engineering and processing support.