How It's Made: U-HIPS Filament

Ever wondered how Closed Loop Plastics is able to take bottom-of-the-barrel garbage and transform it into beautiful, performant filament?

No, it isn’t magic (though wouldn’t that be nice?); it’s a multi-step, finely honed, patent pending process that our team has developed over the span of numerous years to make you filament that’s so great, you’d never even know it had a whole other life before it reached your hands.

So we wanted to take this post to break down our process just for you!

Intake of Material and Initial Sorting

When we first receive the material, we hand-sort it to remove large contaminants, like bike parts or glass bottles. Over 10% of the waste we receive is not actually plastic.


The cups are then granulated into a flake about 4mm in size and vacuum conveyed into a bulk bag.


Our secondary decontamination step removes further impurities like paper and rocks and accumulates it into similar sized particles. The plastic is then transferred to proprietary wash bags that ensure the flake is retrievable and still allows dirt and other small contaminants to be removed.


Wet flake is then sucked into the drying hopper, where we can ensure no moisture escapes and causes sticky issues in the extrusion process. The inside of this drying chamber will get down to a dew point of -70F, literally stripping the flake of any moisture.


Our extrusion system is flood fed, simply by gravity, and the flake is then passed through multiple heat zones to achieve just the right amount of heat pressure to form it into a consistent monofilament.

The filament diameter is then measured 4800 times per second to ensure that the final product meets quality standards.

While the extrusion process pushes filament, the puller allows that pasta-like strand to be stretched into the right diameter.


The filament is wound through an accumulator that dynamically responds to the output pace and onto a spindle and packaged for your enjoyment at home, work, or wherever else you’re printing.

Check out the video below to see how CLP’s process in action!