PETG (Polyethylene Terephthalate Glycol)

polymer

amorphous/semi-crystalline copolyester thermoplastic

Polyethylene terephthalate glycolPET-GPETG+eSUN PETGPrusament PETGColorFabb PETGGlycol-modified PET

PETG (Polyethylene Terephthalate Glycol) 3D printed component

Density

1.27 g/cm³

UTS (FDM as-built (XY))

44–56 MPa

Elongation (FDM as-built (XY))

20.0–50.0 %

Elastic modulus

2–3 GPa

Glass transition (Tg)

75–85 °C

Mechanical & thermal properties — 2 conditions

Property	FDM as-built (XY)	FDM as-built (Z — upright)
Elastic modulus	2–3 GPa	—
Ultimate tensile strength	44–56 MPa	25–38 MPa
Elongation at break	20.0–50.0 %	5.0–18.0 %
Density	1.25–1.29 g/cm³	—
Glass transition (Tg)	75–85 °C	—
As-built surface Ra	7.0–18.0 µm	—

Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.

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Engineering considerations

Material selection vs PLA: choose PETG over PLA when any of these apply: (1) temperatures above 50°C, (2) impact or dynamic loading, (3) snap-fits or clips, (4) chemical exposure, (5) food/water contact. Use PLA when stiffness is paramount and temperature is controlled.
Material selection vs ABS: choose PETG over ABS when: (1) no heated chamber available, (2) food contact required, (3) odour is a concern, (4) chemical resistance needed. Use ABS when: (1) acetone smoothing is needed, (2) maximum heat resistance within FDM polymers is required, (3) painting/plating finishes are planned.
Moisture management: dry PETG filament at 65–70°C for 4–8h before printing if stored without desiccant for more than a few days. Wet PETG shows stringing, blobbing, and reduced mechanical properties. Vacuum-seal with silica gel for long-term storage.
Print settings sensitivity: PETG is highly print-settings-sensitive. UTS can vary ±20% with nozzle temperature and speed changes. Run characterisation samples before structural applications. Higher nozzle temperature (245–250°C) generally improves layer adhesion and Z-direction strength.
Wall design: PETG's ductility means thick walls increase toughness disproportionately. For impact-prone enclosures, prefer 2–3 wall perimeters over high infill. The outer walls carry most impact load.
Chemical resistance caveat: while PETG resists dilute acids and bases well, it is attacked by concentrated acids and esters. Verify chemical compatibility with specific reagents for laboratory or industrial applications before deployment.
Transparency: for optical parts, use transparent PETG with 0% infill (single-wall vase mode) or near-100% infill and minimal layers. Annealing can increase haze. XY-oriented specimens have better clarity than Z-oriented due to layer line visibility.

Advantages

Significantly better impact resistance than PLA: ductile failure mode (20–50% elongation vs. PLA 3–6%) means PETG bends rather than shatters
Higher temperature resistance than PLA: HDT ~72°C vs ~55°C — survives hot cars and warm environments
Better chemical resistance than PLA and ABS: resistant to dilute acids, bases, and many alcohols. Not attacked by water-based solutions
Food-safe in appropriate grades: PETG is the same polymer family as PET used in food bottles — food-contact certified grades widely available
Good optical clarity: PETG can be printed in transparent grades with good light transmission — useful for light diffusers and display parts
Semi-flexible without being rubbery: slight flex on impact prevents catastrophic failure while maintaining dimensional stability
Easier to print than ABS: no heated chamber required, minimal warping, good bed adhesion, lower odour
Recyclable: PETG (like PET) can be recycled via standard plastics recycling streams

Limitations

No solvent smoothing: unlike ABS, PETG cannot be smoothed with acetone. Surface finishing requires sanding, priming, or chemical treatments (specific to grade). Finish quality is harder to achieve than with ABS
Lower stiffness than PLA (2.2 vs 3.5 GPa): PETG parts flex slightly under load — not ideal for high-rigidity applications
Moisture sensitivity: PETG is hygroscopic. Wet filament causes stringing, bubbles, and poor surface quality. Dry at 65–70°C for 4–8h if stored unsealed
Stringing tendency: PETG has higher tendency to string between features compared to PLA — requires careful retraction settings
Not suitable for prolonged UV exposure without UV-stabilised grades: standard PETG yellows over time outdoors
Over-adhesion to print beds: PETG sticks extremely well to glass and smooth surfaces — use PEI, glue stick, or release agent to allow part removal without damage
Density penalty: heavier than ABS (1.27 vs 1.05 g/cm³) for equivalent geometry — matters in weight-critical applications

Typical applications

Mechanical parts requiring toughness and some heat resistance: brackets, mounts, enclosuresWater bottles, food contact containers, and fluid handling components (food-safe grades)Medical device housings and instrument casings requiring chemical resistanceElectronic enclosures where occasional heat exposure is possibleSnap-fit and clip mechanisms where ductility prevents brittle fractureTransparent or translucent parts — PETG has excellent optical clarityAquarium equipment and wet-environment applications (better hydrolysis resistance than PLA)Consumer product casings and display componentsProtective covers and guards for machinery

PETG (Polyethylene Terephthalate Glycol)

Mechanical & thermal properties — 2 conditions

Engineering considerations

Advantages

Limitations

Typical applications

Industries

Standards & certifications

Compatible AM processes (1)

Other polymer materials

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