The Differences Between PET and PETG Filaments


PET and PETG aren’t as similar as you might think. These two filaments are related by their monomers, strength, and durability in manufacturing applications. However, the biggest difference is the extra monomer in PETG. Learning the differences between PET and PETG filaments is essential for knowing what to expect when printing with either fiber.

PETG Has an Extra Monomer

PET and PETG are phenomenal filaments, but PETG has the upper hand. PETG contains another monomer: glycol. The glycol compound is a translucent organic liquid used in manufacturing processes, primarily for polyester fibers and antifreeze formulas.

Why Is PET Inferior?

PET causes a hazing effect, meaning it gives off a cloud-like appearance after processing a print. Adding glycol to the fibers diminishes the hazing effect, making PET less useful in most applications.

PET Has a Tough Surface and Rigid Edges

Without glycol, PET remains in a rigid state. Printing with PET produces tougher surfaces and more rigid edges than PETG, making the prototype weak and prone to breaking if it’s not processed at higher temperatures.

PETG Doesn’t Break Easily

Although PETG filaments contain glycol to bring the prototypes to a brittle state, it resists breaking. Raw PET fibers are tough but break easily because of their purpose, leading to longer production times for duplicates. After weighing the differences between PET and PETG filaments, you can understand what fiber could work best for your project.

PET Is Hygroscopic

Any 3D printing specialist should know that PET is a hygroscopic filament. The spool cannot resist moisture in the air. Prepping the work area is the best way to contain your project and reduce moisture buildup. Switch to a PETG filament if you have no time to prepare, as it’s more resilient than PET when printing in humid climates.

PETG Isn’t Completely Recyclable

Most businesses considering 3D printing for their applications want something recyclable. Some filaments aren’t recyclable because of the chemicals in the design of the spool. Unfortunately, PETG is not entirely recyclable, but PET is.

Even though PETG is safe for food storage, it requires rigorous processes to break down the material. Both are fine fibers to use, but PET is the best choice for applications without too many steps for recycling.

Companies using large equipment in factories and warehouses need the best 3D printing fiber to produce replacement parts. PETG 3D printer filament is the most durable and flexible material to use. You can find an assortment of this material and more at Filamatrix, a USA-branded 3D printing fiber manufacturer.

Check out our great selection of 3D printer filaments and our tips and tricks for utilizing them in your business applications.

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