Injection Molding Defects: Voids – Understanding the Cause and How to Fix Them

What Are Voids?

Voids are empty pockets or spaces that form inside your molded parts. While they might not always be visible from the outside, they can weaken the structure of your product, potentially causing failure down the road.

What Causes Voids?

Voids are usually the result of material shrinkage during cooling or improper venting in the mold. When the material doesn’t pack properly, it leaves behind these internal gaps, reducing the overall strength and integrity of the part.

Other factors that can cause voids include gating in the thin wall sections that flow into heavier sections or improper intersecting wall sections. These design choices can disrupt the material flow, increasing the risk of voids forming inside the part.

How to Prevent Voids

To prevent voids, it’s important to ensure the mold is well-vented and that the material is packed tightly into every cavity. Increasing the packing pressure and maintaining consistent cooling across the part are also key steps to avoiding this issue.

Additionally, maintaining uniform wall sections, properly sizing intersecting features, and gating in thick sections that flow to thin can help ensure better material flow and reduce the chances of voids forming.

If you’re experiencing voids in your parts and it’s affecting your product’s reliability, contact Aprios. We’ll help you troubleshoot and resolve the issue, so your parts are as strong as they need to be.