PETG filament: The complete guide to a versatile 3D printing material

All about PETG filament - benefits, options, applications and problem solving. Learn how to get perfect 3D prints with this versatile material and see how Lab3D can help with your next prototype.

In the world of 3D printing, there are a myriad of materials, each with their own unique properties and applications. Among these, PETG filament has established itself as one of the most versatile and reliable materials, combining the best of several worlds. In this comprehensive guide, we explore everything you need to know about PETG filament - from its basic properties and benefits to tips for optimal printing and finishing. Whether you're new to 3D printing or experienced, this guide will give you valuable insights into a material often described as the "golden compromise" in the 3D printing world.

What is PETG filament?

PETG (Polyethylene Terephthalate Glycol-modified) is a thermoplastic created by modifying the well-known PET plastic (the same material used in water bottles) with glycol. This modification gives the material improved properties, especially when it comes to clarity, strength and chemical resistance. The addition of glycol also prevents the material from crystallizing, making it less brittle and easier to print with.

PETG has become incredibly popular in 3D printing for several reasons. It combines many of the user-friendly properties of PLA with the strength and durability of ABS, but without the significant drawbacks of these materials. It's this compromise that has placed PETG as a favorite among hobbyist and professional printers alike.

PETG vs. other 3D printing materials

To understand PETG's position in the 3D printing world's material hierarchy, it's useful to compare it to other popular filaments:

PETG vs. PLA

PLA (Polylactic Acid) is often the first material newcomers are introduced to:

Printability: PLA is generally slightly easier to print with than PETG, requires lower temperatures (180-220°C vs PETG's 230-250°C) and can be printed without a heated bed (although a bed temperature of 50-60°C is recommended for both).
Strength: PETG is significantly more impact resistant and has better layer adhesion than PLA, which is more brittle.
Temperature resistance: PETG can withstand higher temperatures (80-85°C) before it starts to soften compared to PLA (around 60°C).
Flexibility: PETG has some flexibility, while PLA is stiffer and breaks more easily under load.
Environmental friendliness: PLA is bio-based and biodegradable under industrial composting conditions, while PETG is oil-based and non-biodegradable, but is 100% recyclable.
Odor and fumes: Both materials have minimal odor during printing and do not release harmful fumes like ABS.

PETG vs. ABS

ABS (Acrylonitrile Butadiene Styrene) has long been the industry standard for functional parts:

Printability: PETG is significantly easier to print with than ABS, with less warping and no need for a closed chamber.
Strength: ABS has slightly better impact resistance, while PETG has better layer adhesion.
Temperature resistance: ABS can withstand higher temperatures (around 105°C) than PETG.
Chemical resistance: Both materials have good chemical resistance, but react differently to different solvents.
Finishing: ABS can be smoothed with acetone vapors, which is not possible with PETG.
Environmental impact: PETG does not release the potentially harmful fumes that ABS does during printing.

PETG vs. TPU

TPU (Thermoplastic Polyurethane) is a flexible filament:

Flexibility: TPU is extremely flexible and rubbery, while PETG has moderate flexibility.
Printability: PETG is easier to print with than TPU, which can be challenging to extrude evenly.
Applications: TPU is ideal for parts that require extreme flexibility, while PETG is better for semi-flexible applications that also require strength.
Abrasion resistance: TPU has superior abrasion resistance, while PETG has good but less impressive abrasion resistance.

PETG vs. Nylon

Nylon is a high-performance technical filament:

Strength: Nylon typically has higher tensile strength and is more durable than PETG.
Flexibility: Nylon is more flexible and has better fatigue strength.
Moisture sensitivity: Nylon is extremely hygroscopic (absorbs moisture) and requires careful drying, while PETG is less sensitive to moisture.
Printability: PETG is easier to print with, requires lower temperatures, and has less warping issues.
Price: PETG is generally cheaper than most nylon filaments.

Advantages of PETG filament

PETG's popularity is due to its impressive combination of properties that make it suitable for a wide range of applications:

1. excellent mechanical properties

PETG is known for its robustness and durability:

Good impact resistance: Resistant to shock and impact, less prone to cracking than PLA
Strong layer adhesion: Layers bond well together resulting in stronger vertical prints
Semi-flexibility: Has some flexibility without breaking, making it suitable for snap-fit parts
Abrasion resistance: Good resistance to repeated use and wear and tear

2. User-friendly printing

Compared to many other high-performance filaments, PETG is relatively easy to work with:

Minimal warping: Significantly less tendency to warp compared to ABS
Wide temperature windows: Works well within a wider range of temperature settings
Good adhesion: Adheres well to the print bed but is still relatively easy to remove
Moisture tolerant: Less sensitive to moisture than materials such as nylon and PVA

3. Visual and aesthetic qualities

PETG offers excellent visual properties:

High transparency: Can be printed in clear or translucent versions with excellent transparency
Smooth surface: Results in aesthetically pleasing prints with minimal layer visibility
Glossy finish: Natural shiny surface without the need for finishing
Color stability: Retains color well over time, even with UV exposure

4. Chemical and temperature resistance

PETG is characterized by its resistance to various conditions:

Waterproof: Absorbs minimal water, suitable for waterproof applications
Chemical resistance: Resistant to many acids, bases and solvents
Temperature stability: retains its shape and strength at temperatures up to 80-85°C
UV resistance: Good resistance to degradation from sunlight

5. Food safety

PETG is often a preferred choice for food-related applications:

Food approved: Many PETG filaments are certified as food safe
No BPA: Does not contain bisphenol A, which is found in some other plastics
Low migration: Minimal leakage of chemicals into food
Easy to clean: Can be washed repeatedly without degradation

Limitations of PETG filament

Despite its many benefits, PETG also has some limitations that are important to be aware of:

1. Stringing and oozing

PETG is known for its tendency to stringing (formation of thin strands between separate parts):

Sticky texture: PETG is stickier in the molten state than PLA
Challenges with retraction: Requires careful adjustment of retraction settings
Oozing during travel movements: May drip during movements where no extrusion is required

2. Surface and finishing

Some aspects of PETG surface quality and finishing can be challenging:

No acetone smoothing: Cannot be smoothed with acetone vapors like ABS
Stickiness to metal: Can be difficult to work with metal tools due to stickiness
Surface tension: Can show tension marks on the surface of complex prints
Difficult to paint: Requires special primers for good paint adhesion

3. Temperature limitations

Although PETG is more heat resistant than PLA, it still has temperature limitations:

Softening point: Begins to soften at around 80-85°C
Not suitable for high-temperature applications: Not suitable for parts exposed to temperatures above 80°C
Crystallization: Can become more brittle with repeated heating and cooling

4. Material properties

Some specific material properties can be a disadvantage in certain applications:

Non-biodegradable: Unlike PLA, PETG does not biodegrade naturally
Less stiffness: For applications requiring high stiffness, PETG may be less suitable than PLA
Moderate UV resistance: Although better than many alternatives, prolonged UV exposure can still lead to degradation

Types of PETG filament

The PETG market has evolved and there are now several specialized variants available:

Standard PETG

The classic PETG filament:

Features: Good balance between strength, flexibility and printability
Applications: General 3D printing projects, functional prototypes, holders and brackets
Availability: Wide range of colors and diameters (typically 1.75mm and 2.85mm)

High Impact PETG

Improved version with increased impact resistance:

Features: Increased resistance to impact and shock
Applications: Parts subject to mechanical stress or potential impact
Compromises: Often slightly less transparent and may require higher print temperatures

Carbon Fiber PETG

PETG reinforced with carbon fiber particles:

Features: Increased stiffness and dimensional stability, less weight
Applications: Structural parts requiring high stiffness and low weight
Challenges: Abrasive on standard nozzles, requires hardened nozzles

Transparent PETG

Specialized for maximum transparency:

Features: Extra high clarity and transparency
Applications: Visual prototypes, display items, functional transparent parts
Printing: Requires specific settings for optimal clarity, including 100% infill

Flexible PETG

Softer variants with increased flexibility:

Properties: More pliable and elastic than standard PETG
Applications: Parts that require flexibility but still some structural strength
Comparison: Less flexible than TPU but more flexible than standard PETG

Food grade PETG

Specifically certified for food contact:

Properties: Meets regulatory requirements for food contact materials
Applications: Food containers, kitchen utensils, measuring cups
Certification: Typically meets FDA or equivalent European standards

Optimal print settings for PETG filament

For best results with PETG printing, here are some recommended settings:

Temperature settings

Correct temperatures are crucial for successful PETG printing:

Extruder temperature: 230-250°C (start at 240°C and adjust as needed)
Bed temperature: 70-90°C (80°C is often ideal)
First layer temperature: 5-10°C higher than subsequent layers for better adhesion

Print speed

PETG thrives at moderate print speeds:

General print speed: 40-60mm/s
First layer: 20-30mm/s for optimal adhesion
Outer perimeter: 30-40mm/s for better surface quality
Infill: 50-70mm/s may be acceptable

Cooling and fan speed

Proper cooling is critical for PETG:

First layer: 0% fan speed to ensure good adhesion
Subsequent layers: 30-50% fan speed (higher for small details, lower for larger layers)
Bridges and overhangs: Temporary increase to 70-100% can help
Small parts: Higher cooling may be needed to allow enough time for cooling

Retraction settings

To minimize stringing:

Retraction distance: 4-6mm for Bowden systems, 1-2mm for direct-drive extruders
Retraction speed: 25-45mm/s (not too fast as it can lead to filament degradation)
Z-hop: Minimal or no Z-hop as this can worsen stringing with PETG
Coasting/Wiping: Activate these features to reduce oozing during travel movements

Bed adhesion

PETG can have strong (sometimes too strong) adhesion:

Surface: PEI, glass with glue or BuildTak-like surfaces work well
First layer height: Lightly squished first layer (90-95% of normal layer height)
Separation: Allow the print to cool completely before removal to avoid damage to both print and bed
Brim/Raft: Often unnecessary for larger models, but can be useful for small contact surfaces

Flow and extrusion

Flow adjustment may be required for optimal printing:

Flow rate: Start with 95-100%, adjust as needed
Extrusion width: Set to 100-105% of the die width for better layer adhesion
Slicer-specific settings: Experiment with extrusion multiplier to find the optimal point between under- and over-extrusion

Handling and storage of PETG filament

PETG is less moisture sensitive than many other filaments, but proper handling and storage is still important:

Moisture absorption

PETG absorbs moisture from the air, albeit to a lesser extent than materials like nylon:

Signs of damp filament: Bubbles, spattering during extrusion, degraded surface quality
Relative moisture absorption: Moderate - less than nylon and TPU, but more than PLA
Moist filament printability: Moist PETG can still be printed, but with reduced quality and strength

Optimal storage

To keep PETG filament in optimal condition:

Airtight storage: Store in airtight containers or vacuum sealed bags
Desiccant: Include silica gel or other desiccants in the storage container
Temperature: Store at stable room temperature, away from direct sunlight and extreme temperatures
Rotating use: Follow the "first in, first out" principle for your filament storage

Drying moist filament

If your PETG filament has become damp:

Oven drying: 4-6 hours at 65-70°C in a convection oven (be careful not to exceed the PETG glass transition temperature)
Filament dryers: Dedicated dryers designed specifically for filament are ideal
Food dehydrator: A food dehydrator at 65-70°C for 4-6 hours
Drying length: Thicker filaments (2.85mm) may require longer drying time than thinner (1.75mm)

Finishing PETG prints

PETG prints can be finished in several ways to improve their appearance and functionality:

Mechanical finishing

Physical methods for finishing:

Sanding: Start with 150-220 grit and work up to finer grits for a smoother finish
Filling: Effective for removing stringing and small irregularities
Polishing: After fine grinding, PETG can be polished to a high gloss finish
Vibratory grinding: Can be effective for smoothing surfaces without manual effort

Chemical post-treatment

Chemical methods are more limited for PETG than for ABS, for example:

Chemical resistance: PETG is resistant to most solvents, so acetone steam treatment does not work
Dichloromethane: Can affect the surface of PETG but is highly toxic and generally not recommended
Alternative: Mechanical polishing and coatings are typically better solutions for PETG

Paint and coating

Improving aesthetics and surface protection:

Primer: Use a plastic-specific primer for best adhesion
Sanding before painting: Light sanding with fine sandpaper improves paint adhesion
Acrylic paint: Generally works well on PETG after priming
Epoxy coating: Can provide a very smooth, hard surface and increased strength
UV protective coating: Protects against yellowing and degradation in outdoor use

Assembly of PETG parts

Methods to assemble PETG components:

Cyanoacrylate (secondary adhesive): Works well on PETG, especially after light sanding
Epoxy: Provides strong joints but takes longer to cure
Heat welding: Can be done with a 3D pen or dedicated tool
Mechanical assembly: PETG is ideal for snap-fit and screw joints due to its strength and semi-flexibility

Application areas for PETG printing

PETG's versatility makes it suitable for a wide range of applications:

Functional prototypes and end-use parts

PETG is excellent for functional components:

Mechanical parts: Gears, holders, brackets and functional components
Electronics enclosures: Protective housings for electronics that utilize PETG's electrical insulation properties
Clips and fastening mechanisms: utilizes the flexibility and strength of the material
Structural components: Parts that must be able to bear weight or withstand mechanical stress

Waterproof applications

PETG's properties make it ideal for water management:

Water-carrying components: Pipes, fittings, nozzles and water distribution systems
Containers for liquids: Watertight boxes, tanks and storage containers
Marine applications: Parts for boats and water activities that can withstand constant moisture exposure
Waterproof enclosures: Protective casings for electronics or other water-sensitive equipment

Visual prototypes and displays

PETG's visual qualities make it ideal for:

Transparent models: Parts that require transparency, like displays or windows
Presentation models: Prototypes to show both form and function
Illuminated design: Objects designed to diffuse or transmit light
Colorful presentation objects: Take advantage of PETG's brilliance and excellent color reproduction

Food related applications

With food approved flavors:

Kitchen utensils: Spoons, spatulas, measuring tools and other kitchen tools
Food containers: Storage boxes, mugs and bowls
Cake rings and molds: For baking and food presentation
Coffee filters and brewing equipment: Utilizing PETG's heat and water resistance

Outdoor and environmentally exposed applications

PETG's resistance properties are useful for:

Outdoor signs: Resistant to wind, weather and UV exposure
Garden furniture components: Parts that need to withstand wind and weather
Sensor housings: Protective enclosures for outdoor sensors and electronics
Automotive parts: Components that can withstand temperature fluctuations and chemicals

Lab3D and PETG filament

As leading specialists in 3D printing solutions in Denmark, Lab3D offers extensive expertise in PETG filament printing. Our dedicated team has built solid professional knowledge through collaboration with over 100 Danish companies and educational institutions.

PETG printing services for businesses

At Lab3D, we understand that different projects require different material properties. Our PETG printing service offers:

Professional advice: Our technical experts will help you assess whether PETG is the right material for your project and guide you in design optimization for PETG printing.

Quality PETG printing: We use industry-standard printers and high-quality PETG filament to ensure reliable, strong and accurate results every time.

Finishing: We offer professional finishing of your PETG parts, including mechanical finishing, surface finish and assembly to your specifications.

Fast delivery: We know that time is precious. That's why we ship over 70% of our orders within 24 hours.

How the process works with Lab3D

Our PETG printing process is designed to be simple and efficient:

1. Development

Let your imagination develop and see if your ideas work in reality. Before you spend $100,000 on a mold, you should test your ideas in smaller quantities with us. PETG is ideal for functional testing as its mechanical properties make it suitable for prototypes that need to be tested under realistic conditions.

2. Uploading a 3D file

A 3D file is needed before we can print your ideas. You can either upload your own 3D file directly via our online platform or we can help you develop one. Our technical designers can assist in turning your idea into a printable 3D model optimized for PETG printing. Of course, everything you pay for belongs to you.

3. print

After uploading your file and creating a user, you can receive a price for your PETG print instantly. You can also see your estimated delivery time when ordering. We print your model with the highest quality to ensure it meets all your criteria.

4. Delivery

We prioritize fast delivery because we know it's crucial to the success of your projects. When you order through our ordering system, your order goes into production within minutes and we ship the majority of our prototypes within 24 hours.

PETG for education and schools

PETG filament has particular advantages in educational environments, and Lab3D offers specialized solutions for schools and educational institutions:

Secure PETG printing in educational environments: We understand the special requirements for security and usability in educational environments. PETG is ideal for schools as it combines the security and ease of printability of PLA with better mechanical properties. Our school packages include printers configured for safe and reliable PETG printing.

Balancing ease of use and performance: For technical schools, technical colleges and higher education, PETG offers the perfect balance between easy handling and professional results. It allows students to work with a more advanced material without the challenges that come with more technically demanding filaments.

Support for STEM projects: We support schools' STEM initiatives with PETG printing solutions that allow students to create robust, functional projects with a material that has real industry applications.

Why choose Lab3D for your PETG printing needs?

Solid professional skills

We have built up extensive experience in PETG printing through many years of working on various projects. Our experts know the material, its strengths and how to overcome potential challenges to ensure optimal results.

High quality materials

We only use quality PETG filament from leading manufacturers, ensuring consistent properties from print to print. For specialized applications, such as food-grade parts or extreme strength, we have access to specialized PETG variants.

All-in-one solution

With our combination of design assistance, print service, finishing and professional advice, we act as your one-stop partner for all your PETG printing needs, whether it's a one-off project or an ongoing production job.

Focus on sustainability

We are committed to making 3D printing more sustainable. PETG is 100% recyclable and we have implemented processes to minimize waste and reuse misprints where possible.

Design guidelines for PETG printing

To ensure successful PETG prints, there are some design principles that are particularly important to consider:

Wall thicknesses and structural integrity

Optimal design parameters for PETG:

Minimum wall thickness: 1.0-1.2mm recommended for structural integrity
Maximum overhang angle: PETG can print overhangs up to 45-50° without support structures
Rounding: Use rounded corners (minimum 0.8-1mm radius) to reduce stress concentration
Reinforcements: Add ribs or gussets (triangle reinforcements) at structural joints for added strength

Design for minimal stringing

Strategies to reduce PETG's tendency to stringing:

Minimize travel movements: Design parts so the print head can move continuously without crossing open spaces
Group similar features: Place features to be printed together close to each other
Optimize orientation: Orient the model to minimize the number and length of travel movements
Seam placement design: Place seams in non-visible or functionally irrelevant areas
Consider slicer settings: Design with commutation control and wiping features in your slicer in mind

Tolerances for joints

Correct tolerances for PETG parts:

Press-fit connections: 0.1-0.3mm tolerance for parts to be pressed together (tighter than PLA)
Loose joints: 0.3-0.5mm tolerance for parts that need to slide or rotate
Snap-fit design: utilize PETG's flexibility with tighter tolerances than other materials
Thread: Design pre-threaded with 0.1-0.3mm tolerance for good screw assembly
Expansion: Consider PETG's small expansion in humid environments

Design for transparency

For maximum transparency in transparent PETG parts:

Uniform wall thickness: Keep wall thickness consistent for even light transmission
100% infill: Use 100% infill for fully transparent parts
Infill pattern: If 100% infill is not possible, use rectilinear or cubic infill
Slower printing: Design parts that can be printed slower for better clarity
Minimize perimeter counting: Fewer perimeters for better transparency in thin walls

Design for water resistance

For waterproof PETG applications:

Increase perimeter count: Minimum 3-4 perimeters for water tightness
Overlap settings: Design for high overlap percentage between infill and perimeters
Height-to-width ratio: Pay attention to height-to-width ratio to avoid leaks
Sealing systems: Incorporate O-rings or gaskets into the design for critical waterproof applications‍
Post-processing: Integrate epoxy sealing option in critical areas