Engineers at Johns Hopkins University have turned a major flaw in 3D printing into an exciting new feature.

By solving the problem of weak connections between layers in 3D-printed objects, they’ve created a groundbreaking technique called Voxel Interface 3D Printing (VI3DP).

This innovation, detailed in Advanced Materials, could make 3D printing more versatile than ever.

A common issue in 3D printing is how layers stick together. “The material either sticks too much or too little, leading to weak spots,” said Jochen Mueller, an assistant professor of civil and systems engineering.

“It’s like how cooked spaghetti clumps together but can still fall apart easily.”

These weak spots limit the strength and usefulness of 3D-printed items.

To fix this, the team developed VI3DP, a technique that allows them to precisely control the interfaces between 3D-printed layers. These interfaces, located between tiny building blocks called voxels (3D equivalents of pixels), play a key role in how materials stick and function.

Here’s how it works: The VI3DP system uses a printhead with a standard nozzle surrounded by four smaller nozzles.

While the main nozzle deposits material, the extra nozzles add a thin film of a different material on top. This lets engineers customize how layers bond without needing extra printheads or creating unnecessary gaps.

But VI3DP isn’t just about making stronger prints—it also opens up exciting new possibilities. The researchers showed they could add optical, mechanical, or electrical properties to the interfaces, all in a single print. This method doesn’t add extra weight, time, or cost, making it efficient for creating advanced designs.

Doctoral candidate Daniel Ames explained that while adding these properties is possible with other 3D printing methods, they usually require the entire voxel to be modified, which reduces quality and speed. With VI3DP, these features are added as thin layers around the voxels, enabling greater precision and flexibility.

According to the researchers, this new approach could lead to incredible advancements, such as 3D circuits, electromechanical devices, and complex structures that integrate different materials. “Interfaces are incredibly important because of what they enable,” said Mueller.

“With VI3DP, we can create thinner, smarter layers and combine materials in ways we’ve never done before.”

Looking ahead, the team plans to explore how this technique can improve 3D printing even further. “This is just the beginning,” said Ames. “VI3DP gives us a strong foundation to build on. We’re excited about what’s next.”

The research team included doctoral candidate Sarah Propst and visiting high school student Aadarsh Shah, showcasing how collaboration across different levels can drive innovation.