All About PETG 3D Printing Filament
Learn more about PETG 3D printint filament and the different ways it can be used in 3D printing. Subject to availability. Xometry doesn't guarantee that we can provide this material at any given time.
PETG (Polyethylene Terephthalate Glycol) is highly sought after for its excellent mechanical strength and resistance to water intrusion and chemical attack. PETG combines some of the good qualities of two other well-known thermoplastic materials used for 3D printing: ABS (acrylonitrile butadiene styrene) and PLA (Polylactic Acid). ABS is known for its durability and PLA for its printability.
PETG, short for polyethylene terephthalate glycol, is an adaptation of PET (Polyethylene Terephthalate). The ethylene glycol in PET is partially replaced with another molecular group, cyclohexanedimethanol (CHDM). The origin of PETG can be traced back to work done by two British scientists, James Dickson and John Whinfield, in the year 1941. PETG is a food-safe material. As a result, it is in demand as a packaging product in the food and beverage industry. PETG is also widely used for retail signage. PETG is cost-effective and less prone to warping compared to materials such as ABS. This article will discuss PETG’s characteristics, composition, recommended printer settings, and comparisons with other 3D printing filaments.
What Is PETG 3D Printing?
PETG 3D printing is the use of PETG (Polyethylene Terephthalate Glycol) (a thermoplastic material) as a build material for 3D printing, especially in FDM (Fused Deposition Modeling) printers. The “G” in PETG indicates that the glycol molecule in PET, a familiar material used in the production of plastic bottles, has been modified. PETG is one of the most popular 3D printing filaments thanks to its high impact strength, low haze, and good printability. For more information, see our guide to 3d printers.
Figure 1 below shows an example of PETG filaments:
Five PETG filaments illustrations.
Image Credit: Shutterstock.com/petrroudny43
Composition of PETG Filament
The composition of PETG is derived from the composition of polyethylene terephthalate (PET). They are similar in their chemical composition except for the fact that PETG has been enhanced by modifying its glycol content. PETG is formed by replacing ethylene glycol in PET with cyclohexanedimethanol (CHDM). This is what the “G” in PETG indicates. It is clearer, less brittle, and prints more easily compared to PET.
Properties of PETG Filament
A PETG filament has certain properties that make it distinguishable from other filament materials, namely:
- High chemical and impact resistance.
- Good thermal stability.
- It is a food-safe material.
- Its extrusion temperature falls in the range of 220-260 °C.
- It can be printed at a rate of about 40-60 mm/s.
- The print bed must be heated to about 80 °C. Anything above this will lead to the warping of the print.
Comparison of PETG Filament Properties
Table 1 below highlights some common properties of PETG filament compared to other filament types:
| Property | PETG | ABS | TPU | PLA |
|---|---|---|---|---|
Property Fumes | PETG Non-toxic (proper ventilation is still required) | ABS Toxic | TPU Non-toxic (proper ventilation is still required) | PLA Non-toxic (proper ventilation is still required) |
Property Hygroscopic | PETG Yes | ABS Yes | TPU Yes | PLA Yes |
Property Heated bed temperature | PETG 70-80 °C | ABS 80-110 °C | TPU 60-90 °C | PLA 20-60 °C |
Property Melting/Extruder temperature | PETG 220-260 °C | ABS 210-250 °C | TPU 190-245 °C | PLA 180-230 °C |
Property Biodegradable | PETG No | ABS No | TPU No | PLA Yes (but will take quite some time – about 80 years) |
Property Strength/Impact resistance | PETG Very good (but prone to scratches) | ABS Good | TPU Very good | PLA Medium |
Property Recyclable | PETG Yes | ABS Yes | TPU Yes | PLA Yes |
Limitations of 3D Printing with PETG
PETG has a number of advantages that makes it good for 3D printing, including its high impact resistance, odorless fumes, and good thermal stability. There are still some disadvantages associated with PETG compared to ABS, however. PETG cannot be easily stored because of its high hygroscopicity. Another limitation of PETG is that it is difficult, if not impossible, to paint. ABS, on the other hand, is far more forgiving in this area: in fact, post-processing of ABS is relatively easy.
How To Use PETG in 3D Printing
Just like PLA, PETG is known for its ease of printability. If PETG filament is printed according to the manufacturer's and printer's recommendations, the resulting prints should meet the customer’s requirements. Here are some tips and tricks for 3D printing with PETG:
- The temperature of the heated bed should be around 80-90 °C.
- The melting or extrusion temperature should be anywhere from 220-260 °C.
- The hot end (the device responsible for melting the thermoplastic) does not have to be fully metallic. Hot ends with PTFE inner tubes can also be used.
- Part quality can be improved by using layer fans. A layer fan is a small fan placed at the 3D printer head that cools the plastic once it is deposited.
- To achieve good layer adhesion when printing with PETG, glass surfaces and adhesives such as hairspray should be used. If the PETG print is placed directly on glass, it is most likely going to stick too firmly to the glass surface – making it difficult to separate. Using adhesives ensures good adhesion while facilitating the easy separation of the print from the build surface.
Configuration Settings for PETG 3D Printing
Getting the PETG print settings right is fundamental to achieving a high-quality print. The retraction speed, for instance, determines how fast the melted filament is extruded from the hot end and nozzle. Getting the filament out of the nozzle as quickly as possible without compromising on the quality of the filament is important. Listed below in Table 2 are the recommended printer settings for PETG:
| Printer Settings | Value |
|---|---|
Printer Settings Extruder temperature | Value 220-260 °C |
Printer Settings Bed temperature | Value 80-90 °C |
Printer Settings Print speed | Value 40-60mm/s |
Printer Settings Retraction speed | Value 35-40mm/s |
Printer Settings Retraction distance (direct drive extruders) | Value 2-4mm |
Printer Settings Retraction distance (Bowden extruders) | Value 5-7mm |
Printer Settings Flow of filament or flow rate | Value 95-100% |
Printer Settings Layer height | Value 0.28mm |
Printer Settings Bed material | Value PEI (Polyetherimide) surface |
Wall Thickness for 3D Printing With PETG
Generally speaking, thermoplastic materials with moderately strong materials, such as PETG, can be printed at wall thicknesses that fall in the range of 0.8-1.6mm. Nonetheless, it is possible to print thicker walls using a nozzle with a larger diameter. Thicker walls, in the range of 2-3 mm, can create parts with higher strength.
Wall Density
A suitable infill density for PETG is 20%. The infill density determines how much of the filament material will be consumed in the entire printing process. A 20% infill is sufficient for non-functional parts such as prototypes and display models. The infill density can be increased but this would have a considerable impact on the printing cost and time. Infill density values range from 0%-100%. 0% will produce a hollow model while 100% will produce a totally solid model.
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