PETG (Glycol-Modified Polyethylene Terephthalate) is a thermoplastic material commonly used in 3D printers due to its combination of strength, ease of printing and transparency. It is particularly suitable for printing functional parts, prototypes, transparent containers and other applications requiring robustness and optical transparency. With the right print settings and printbed preparation, it is possible to achieve high-quality printing results with PETG on your 3D printer.
The production of PETG
Raw materials : PETG is mainly derived from PET (Polyethylene Terephthalate), which is a type of plastic commonly used in plastic beverage bottles, food containers and other packaging. PET is made up of monomers of ethylene glycol and terephthalic acid.
Polymer modification : The PETG manufacturing process involves modifying the PET polymer by adding glycol (usually ethylene glycol). This chemical modification makes the material more flexible and impact-resistant than traditional PET, while still maintaining many of its other desirable properties, such as transparency and chemical resistance.
Polymerization : The polymerization process involves the chemical reaction between PET and glycol. This reaction leads to the formation of more flexible bonds in the polymer structure, giving the material the desired properties of PETG.
Extrusion : Once polymerization is complete, the PETG material is extruded through a spinneret to create filaments or granules. During this process, molten material is pushed through a nozzle to form a continuous form of PETG filament or granule.
Cooling and Processing : After extrusion, the PETG material is cooled and solidified. The solidified filaments or granules can then be cut and further processed to achieve the desired size and shape.
Technical and mechanical characteristics of PETG
Strength and Durability : PETG is known for its high strength and durability. It is more resistant to impact and bending than PLA and ABS, making it suitable for printing functional parts and prototypes that require greater robustness.
Transparency : PETG has good transparency, making it ideal for printing objects that require optical clarity, such as containers, display cases and transparent parts.
Ease of printing : Despite its strength, PETG is relatively easy to print. It has a higher melting temperature than PLA, usually between 220°C and 250°C, but requires lower print bed temperatures than ABS. Additionally, it has a lower tendency to warp than ABS, making it easier to print without the use of a heated chamber.
Adhesion to the print bed : PETG requires good adhesion to the print bed to avoid peeling during printing. Solutions such as using blue tape or a sticky-coated print surface can help improve adhesion.
Chemical Resistance : PETG offers good chemical resistance, making it suitable for applications requiring resistance to chemicals such as oils, solvents and detergents.
Biocompatibility : PETG is considered biocompatible and safe for use in medical and food applications. However, it is important to note that 3D printing with PETG does not guarantee sterilization of the printed parts, and is therefore not suitable for applications requiring sterilization.
Recyclability : PETG is recyclable and can be melted down and reused to print new objects, making it a sustainable choice for 3D printing.
Printing Tips for PETG
Extrusion Temperature : The optimal extrusion temperature for PETG is usually around 220-250°C, but this can vary depending on the brand and color of the filament. Follow the filament manufacturer's recommendations or experiment with different temperatures to find the one that works best for you.
Heated bed temperature : it is advisable to set the temperature between 70°C and 80°C. However, some printers may not require a heated bed to print PETG.
Printing Speed : PETG can be printed at moderate speeds, but it is best to avoid printing too quickly, especially on fine details or complex models. A print speed of 50-80 mm/s is often a good starting point.
Ventilation : Unlike PLA, PETG does not require a lot of ventilation for cooling during printing. It is advisable to reduce or completely disable the cooling of the layer fan or nozzle cooling fan, as cooling too quickly can cause warping and layer adhesion problems.
Post-processing : After printing, allow the model to cool completely before removing it from the build bed. You can use tools such as scrapers or spatulas to help remove the pattern. If necessary, you can also refine the surfaces using fine sandpaper or other finishing tools.
Brands I recommend
Since PETG is one of the most used filaments in 3D printing, all brands have thrown themselves into its production. Quality of the raw materials, precision in the diameter and winding of the spool are essential to have excellent results, which is why my advice always falls on the Prusament filament produced by Prusa Research. Prusament filaments have extremely pure and high quality raw materials, dimensional precision of ±0.02mm with constant breakfast. Prusa, not happy, brands each reel with a QR code which shows a complete identikit of the specific reel in terms of dimensional precision.
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