Filling the Filament: How 3D Printers Get Their Base Materials

How 3D Printers Get Their Base Materials

We’ve marveled at 3D printers and how they seem to create objects out of thin air, but there’s a lot more going on behind the scenes. Most casual fans of 3D printing know about filaments — the spooled, raw materials that feed into a machine’s extruder and print a finished piece — but they have no idea what goes into their creation.

People tend to think that filaments are squirted out of a nozzle, like candy or cake frosting, and then wound on a spool like yarn, but that isn’t accurate. The process begins with raw material, which is usually in a granulated or flaky form and doesn’t have pigmentation yet. Two of the most popular plastic varieties, ABS and PLA, have unique properties that lend themselves to certain projects. ABS (or Acrylonitrile Butadiene Styrene) is great for printing quick ideas because it has a reputation for not jamming or clogging an extruder, but also tends to shrink when cooling down and it smells like plastic fumes. PLA (or Polylactic Acid), however, smells delicious when you print. The material is a little more brittle and difficult to extrude, but it’s also biodegradable. That means you can recycle or compost an object when you’re done with it.

Once you’ve decided which raw material to use, you might want to add colors or additives to the mix. First, they pour the plastic into an industrial blender with some pigment and start the machine. Other additives can infuse special characteristics into the material — from magnetism to high-impact strength — so choose additives that fit your project’s goals. From there, they dry the raw material at temperatures around 150 degrees Fahrenheit for about two hours, or there’s a risk of creating a volatile filament that doesn’t cooperate when extruded.

After drying, the mixed material is heated and blended in a machine called a single-screw extruder, which produces a monofilament that can be rounded off with warm water. Once the filament string has gone through water baths at different temperatures, it achieves a perfectly round shape and is ready to be spooled. In addition, a filament’s diameter can change depending on how fast it travels through the machine.

Creating filament involves a lot of moving parts and variables that need to be perfect for it to work well. Most hobbyists obtain their filament from large production facilities in China, since they have devices that produce the spooled material on a gigantic scale. However, a few small businesses have obtained a single-screw extruder and figured out how to properly treat the plastic at each stage. Even for these companies, though, the process isn’t easy. It requires passion, dedication, and a willingness to experiment. Eventually, filament will be as simple to make as a plastic bottle, but for now, it feels a little more like alchemy than exact science.