Rotational molding — also referred to as rotomolding — is a versatile process used to produce hollow plastic parts. While it’s an extremely dependable solution, any manufacturing method comes with its own set of challenges. Experiencing defects in rotomolded products can lead to increased costs, delays, and quality issues. However, understanding common rotomolding defects and knowing how to prevent them can ensure a high-quality final product. At GVL Poly, we have decades of experience in the rotomolding space. Here are some of the common rotomolding challenges we see — and how we fix them.
Most Common Rotomolding Defects
Warping and Shrinkage
Warping and shrinkage can cause parts to be out of tolerance, which is a considerable problem for most businesses. Without the proper tolerances, you risk your parts not melding with the other components in the final build. Both warping and shrinkage can be caused by uneven cooling, the wrong material choice, and issues with the mold design.
To prevent warping and shrinkage, your design and engineering team must consider a few different things. Adding strategic cooling channels to the mold and ensuring uniform wall thickness are just a few of the ways to avoid these costly challenges. That’s why working with an experienced manufacturer is so important. They’ve spent decades honing their production processes and can quickly get your product back on track once an issue is identified.
Surface Defects
There are a few common surface defects when it comes to rotational molding. Bubbles and pinholes are caused by trapped air or moisture in the resin. This not only messes with the aesthetic quality of the part, but can also lead to weak points in the plastic. These defects can be prevented by improving venting, drying resin properly, and adjusting the heat cycle.
Orange peel texture is also common and is caused by inadequate fusion and improper cooling. As the name suggests, this is a surface defect that resembles the bumpy skin of an orange. To prevent this, the manufacturer must adjust the oven temperature and heating time and optimize the cooling rate.
Incomplete Filling
Incomplete filling refers to when the plastic resin doesn’t fully fill the mold during the process. It may be caused by insufficient material, poor powder flow, and complex mold geometry. To prevent this issue, our team may use finer powder grades and simplify the mold design where possible.
Discoloration and Burning
Discoloration and burning may be caused by overheating, oxidation, or contamination. To prevent this, your rotational molding partner must optimize the heating cycle, use appropriate antioxidants, and ensure a clean production environment.
Work with GVL Poly for Your Rotomolding Needs
If you have questions about rotomolding defects, we can help. For over 30 years, we’ve been creating the best rotomolded parts for our customers, ensuring they meet high expectations. Over the years, we’ve helped countless businesses get the right fit for their organization. We’d be honored to help you, too.
At GVL Poly, we can help you from start to finish. Our in-house team can cover everything from design and rapid prototyping to fabrication and logistics. All of our services are backed by experienced machine operators, engineers, designers, tool builders, and other professionals. When you work with us, you can be sure you’re getting the best products possible.
Let’s Get Started
Are you ready to start your next rotomolding project? We’d love to help and answer any questions you may have. Get in touch with us here.
