When you are not using a shredder, turbo, or delamination mill in your processing system, the right granulator screen to use can vary a lot. In this case, where you are just using a granulator straight into an air table, there will be more variation in your screen size needs.

Depending on the recycling equipment, some screen dimensions use the imperial system while others use the metric system. This is why you may see something like a 1/16″ unit of measure by some manufacturers and a 2mm unit of measure by others.

If you are using a granulator directly into an air table, you are going to want to use a 1/16” screen for the best separation of Telco or low-grade wire. For THHN processing, a 1/8” screen would be best and for Romex®, 3/16” would work best.

Now, if you are using a turbo mill, granulator screen size is less critical, since the turbo handles the final processing. In this case, you just want the material to be broken down enough before it hits the turbo, so you might use a 3/16″, 3/8″, or even a 5/16″ screen, depending on which material you are running and the size of your granulator. When using a turbo, you can adjust screen sizes based on the material flow.

One important thing to note when you are not using a turbo mill: if you use a 3/16″ screen for Romex®, you can run THHN through the same screen. However, if you are using a 3/16″ screen for THHN, you may encounter long strands of wire that clog the air table. But, if you try to run Romex® through a 1/8″ screen, the larger Romex® pieces will have a harder time passing through, which generates excess heat and copper dust. To avoid this, keep the screen size appropriate for each type of wire—1/8″ for THHN and 3/16″ for Romex®. Running them together? Stick with a 3/16″ screen.

Now, time to talk about plastics. When chopping plastics, the screen size depends on what the plastic will be used for. If your end customer is turning it into pellets or a product directly, you need to select the screen size accordingly. The smaller the screen, the more dust you will generate, so you may want a de-duster after the granulator to manage that. For example, when processing 55-gallon plastic drums, we use a screener and de-duster to remove the lightweight plastic particles that clients do not want mixed in with the granules.

The same principles apply to many other materials. Whether it is textiles, pharmaceuticals, food-grade materials, or hemp, you always need to consider what the end goal is. For example, with hemp, the goal is often to extract fibers, so the screen size will affect how fine those fibers are.

In short, the key is to go as large as possible for the screen size while still achieving the desired result. For materials like copper, where you are trying to separate two materials, screen size becomes especially important. You do not want to go too big and fail to separate the materials properly, but you also do not want to go too small and turn everything into dust.

We hope this helps shed light on the right granulator screen size to use for your non-ferrous recycling. If you need more information or are looking to discuss, please reach out to us!