Medical Device Die Cutting: How Liner Material Affects Part Accuracy

When manufacturing custom die-cut parts, one of the biggest goals is getting the most usable parts out of the least amount of material. For example, these two parts fit into the end application like this. (Hold up parts in a circle.) But if we cut them like this, we end up creating a large amount of wasted material in the middle. If we change the orientation and nest the parts together like this, (hold parts up inside each other) we can use that space much more efficiently and, in this example, produce about 60% more parts from the same amount of material. This is called nesting, and it’s one of the ways a converter can improve material yield, reduce waste, and potentially lower the cost of your parts.

What do you need to consider when nesting your parts?

Nesting sounds like a no-brainer. Just cram the parts as close together as possible and start producing them, right? Not quite. There needs to be enough space between parts for the tooling and press to cut them consistently. The amount of space required depends on several factors, including the material, part geometry, thickness, tolerances, and the converting process being used.

For example, a thin film may allow parts to be nested much closer together than a thick foam. As the blade cuts thicker or softer materials, the material can compress and deform, which can affect the cut or damage nearby parts. Our engineering team looks at these factors when setting up a job, along with the material width, web direction, press speed, and how the finished parts will be stripped, wound, or packaged.

And nesting isn’t always about getting the absolute smallest gap possible. Sometimes a slightly larger gap can improve manufacturing consistency enough to reduce scrap and make the overall process more efficient. For complex parts, we can also run trials on press to compare different layouts and confirm which nesting pattern provides the best combination of material yield and manufacturability.

Even if you nest your parts there will always be material waste. So it's a good idea to talk to a converter before locking in your material needs because the amount of material you need may change based on how we are able to nest your part.

What are the benefits of nesting?

The most obvious benefit is material savings. If you can fit more usable parts into each roll or sheet, you can reduce the amount of material required for the job, which can lower your cost per part. Nesting can also increase production efficiency. More parts in less material means fewer material changes and potentially less setup and handling time. The nesting process can also reveal other opportunities to optimize the part itself. Sometimes a small change to the geometry, tolerance, material, or orientation can make a significant difference in how efficiently the part can be produced.

What makes a part optimized for nesting?

Parts with open areas are often good candidates for nesting because one part can fit inside the unused space of another. We have cut gaskets before inside of other gaskets allowing for use of other wised scrapped material. Another important factor that affects if your part can be nested properly is how you plan to use the part. Certain nesting applications can be hard for automated systems to register and pick up, making complex nested parts better for hand application. Another form of nesting is creating segmented gaskets. For example, instead of manufacturing a square gasket as one continuous piece, you could potentially use four separate perpendicular sections and assemble the gasket during the application process. This can improve material utilization because the individual sections can be nested more efficiently. However, there is a tradeoff: because the corners are created during assembly rather than being one continuous piece, the finished gasket may have different sealing characteristics at those joints.

So, good nesting is about more than simply putting parts as close together as possible. It’s about finding the right balance between material utilization, part quality, production speed, and manufacturability. If you’re working on a complex die cut part and want to learn how nesting could improve your material yield, or you want to explore other ways to optimize your part for production, visit our Learning Center or reach out to us directly. Thanks for watching!