PETG vs. PLA: Which Filament is Right for Your 3D Printing Projects

As a seasoned manufacturer well-versed in the intricacies of 3D printing materials and techniques, I’ve often been asked which filament is better: PETG or PLA.

Both have their unique properties and applications, making them popular choices among 3D printing enthusiasts. In this blog post, I’ll share my insights on the key differences between PETG and PLA, their respective advantages and disadvantages, and how to determine which filament is best suited for your specific 3D printing projects.

Whether you’re a hobbyist or a professional, understanding the nuances of these materials can significantly impact the quality and performance of your prints.


PETG vs. PLA 3D

What is PETG?

PETG, or Polyethylene Terephthalate Glycol-Modified, is a type of thermoplastic polyester. It is derived from the base polymer PET (Polyethylene Terephthalate) with the addition of glycol during the polymerization process. This modification enhances the material’s properties, making it more suitable for 3D printing applications. The glycol prevents the material from crystallizing and becoming brittle, resulting in a more durable and flexible filament.

Key Properties and Characteristics

  1. Strength and Durability: PETG offers excellent strength and durability, with high impact resistance and tensile strength. It combines the robustness of ABS with the ease of use of PLA.
  2. Flexibility: Unlike brittle materials, PETG has a degree of flexibility, which makes it resistant to cracking and breaking under stress.
  3. Clarity: PETG can be printed with a clear, glossy finish, making it ideal for applications where transparency is desired.
  4. Chemical Resistance: It is resistant to a wide range of chemicals, including acids and alkalis, which makes it suitable for functional parts exposed to harsh environments.
  5. Moisture Resistance: PETG does not absorb water as readily as PLA, which helps in maintaining the integrity of the printed object over time.
  6. Ease of Printing: PETG is relatively easy to print, with good bed adhesion and minimal warping compared to other filaments like ABS. It prints at moderate temperatures (typically between 220°C and 250°C) and adheres well to heated print beds.

Common Applications and Use Cases

  1. Functional Prototypes: Due to its strength and durability, PETG is often used for creating functional prototypes that need to withstand mechanical stress and wear.
  2. Mechanical Parts: Its resistance to impact and flexibility make PETG suitable for mechanical parts, such as gears, brackets, and enclosures.
  3. Medical and Food Containers: PETG’s chemical resistance and ease of sterilization make it a good choice for medical applications and food-safe containers.
  4. Transparent Components: Its ability to print with clarity is beneficial for creating transparent components like light covers, display cases, and protective screens.
  5. Outdoor Applications: The material’s UV and weather resistance make it suitable for outdoor use, where exposure to the elements is a concern.
  6. Custom Tools and Fixtures: PETG’s durability and chemical resistance make it ideal for custom tools and fixtures used in various industrial processes.

    PETG vs. PLA

What is PLA?

PLA, or Polylactic Acid, is a thermoplastic polymer derived from renewable resources such as cornstarch or sugarcane. Unlike petroleum-based plastics, PLA is biodegradable under industrial composting conditions, making it an environmentally friendly option for 3D printing. The polymerization of lactic acid produces PLA, resulting in a material that is both easy to print and versatile in its applications.

Key Properties and Characteristics

  1. Ease of Use: PLA is one of the easiest materials to print with, making it ideal for beginners and educational purposes. It has a low printing temperature, typically between 180°C and 220°C, and good bed adhesion with minimal warping.
  2. Biodegradability: As a bioplastic, PLA is biodegradable under industrial composting conditions, reducing its environmental impact compared to conventional plastics.
  3. Surface Finish: PLA can produce high-quality prints with a smooth surface finish and excellent detail resolution, making it suitable for aesthetic applications.
  4. Stiffness and Rigidity: PLA is relatively stiff and rigid, which is beneficial for parts that do not require flexibility. However, this also means it can be more brittle compared to other materials like PETG or ABS.
  5. Odor: During printing, PLA emits a mild, sweet odor, which is generally considered more pleasant and less harmful than the fumes produced by other plastics like ABS.
  6. Variety of Colors: PLA is available in a wide range of colors and effects, including translucent, glow-in-the-dark, and metallic finishes, providing versatility for creative projects.

Common Applications and Use Cases

  1. Prototyping and Model Making: PLA is widely used for creating prototypes, architectural models, and scale models due to its ease of printing and ability to capture fine details.
  2. Educational Projects: Its user-friendly nature makes PLA ideal for educational purposes, including school projects and introductory 3D printing courses.
  3. Decorative Items: The excellent surface finish and variety of colors available make PLA perfect for printing decorative objects, such as vases, figurines, and art pieces.
  4. Consumer Products: PLA is often used for making consumer goods like phone cases, toys, and household items where biodegradability is a desirable feature.
  5. Packaging: Due to its biodegradability, PLA is used in the production of biodegradable packaging materials, such as compostable cups, containers, and disposable cutlery.
  6. Medical Models: PLA’s ease of use and ability to produce detailed prints make it suitable for creating medical models for educational and pre-surgical planning purposes.

Rapid Prototyping Industry

Comparison of PETG and PLA

Ease of Printing

Printing Temperature

  • PLA: Prints at lower temperatures, typically between 180°C and 220°C, which makes it accessible for most 3D printers.
  • PETG: Requires higher temperatures, usually between 220°C and 250°C. Some printers may need upgrades to handle these temperatures consistently.

Bed Adhesion

  • PLA: Excellent bed adhesion, especially with blue painter’s tape or a glue stick. Little to no heated bed is needed, though it helps.
  • PETG: Good bed adhesion but may require a heated bed (70°C to 80°C) and a special adhesive like a glue stick or PEI sheet to prevent sticking too well, which can damage the print bed.

Warping and Stringing

  • PLA: Minimal warping, making it ideal for detailed prints and large parts without deformation. Stringing can be controlled with proper retraction settings.
  • PETG: More prone to stringing due to its higher viscosity, but adjusting retraction settings can mitigate this. Warping is less of an issue compared to ABS but can occur if bed adhesion isn’t optimal.

Practical Examples

  • PLA: Ideal for printing intricate models and educational projects. For instance, when printing a detailed architectural model, PLA’s low warping ensures precise, clean lines and stable structures without the need for a heated bed.
  • PETG: Suitable for functional parts that need durability and flexibility. For example, printing a mechanical part like a custom bracket, PETG’s higher impact resistance and slight flexibility outperform PLA, making the part more durable under stress.

Strength and Durability

Impact Resistance

PLA: PLA is relatively rigid and has lower impact resistance compared to PETG. While it can withstand light impacts, it may crack or shatter under heavy stress.

PETG: PETG offers excellent impact resistance, making it more suitable for parts subjected to mechanical stress or potential impacts. It is less likely to crack or break compared to PLA.

Flexibility

PLA: PLA is relatively stiff and lacks flexibility. It is prone to snapping under bending or torsional forces.

PETG: PETG has a degree of flexibility, allowing it to bend without breaking. This makes it more resilient to deformation and better suited for parts that require some give.

Longevity

PLA: PLA prints can degrade over time, especially when exposed to high temperatures or UV light. However, PLA can remain stable for several years under normal indoor conditions.

PETG: PETG is more resistant to degradation from UV light and heat compared to PLA, making it suitable for outdoor applications or parts exposed to harsh environmental conditions.

Practical Examples

  • PLA: Ideal for printing decorative items or prototypes that don’t require high durability. For example, printing a figurine or a model for display purposes can be done effectively with PLA due to its ease of printing and good surface finish.
  • PETG: Better suited for functional parts subjected to mechanical stress. For instance, printing a custom tool handle or a protective casing for electronic components benefits from PETG’s superior impact resistance and longevity, ensuring the part remains intact and functional over time.

Understanding the differences in strength and durability between PLA and PETG helps in selecting the appropriate material for your specific 3D printing applications, ensuring the longevity and performance of your printed parts.

Visual Quality

Surface Finish

PLA: PLA typically produces prints with a smooth surface finish, showcasing fine details and sharp edges. It is relatively easy to achieve a polished appearance with PLA prints, making it ideal for aesthetic projects.

PETG: PETG prints also exhibit a smooth surface finish, but they may require more post-processing to achieve the same level of polish as PLA. However, PETG prints can still achieve high-quality surface finishes with proper printing settings and techniques.

Clarity and Color Options

PLA: PLA offers a wide range of vibrant colors and translucent options, allowing for versatile and visually appealing prints. Translucent PLA variants provide a semi-transparent appearance, allowing light to pass through, which can be desirable for certain applications.

PETG: While PETG is available in various colors, including translucent options, it typically offers less color variety compared to PLA. However, PETG’s inherent clarity is superior to PLA, making it an excellent choice for transparent or translucent prints where optical clarity is crucial.

Practical Examples

  • PLA: Well-suited for printing decorative items or models that require vivid colors and a polished finish. For example, printing a colorful vase or a figurine with intricate details benefits from PLA’s vibrant color options and smooth surface finish.
  • PETG: Ideal for printing transparent or translucent objects that require optical clarity and durability. For instance, printing a protective cover for LED lights or a display case for collectibles benefits from PETG’s clarity, ensuring the contents are visible while being adequately protected.

    Environmental Impact

    Biodegradability

    PLA: PLA is derived from renewable resources such as cornstarch or sugarcane and is biodegradable under industrial composting conditions. It breaks down into carbon dioxide and water within a few months to years, depending on composting conditions.

    PETG: PETG is not biodegradable and does not decompose easily in natural environments. It requires recycling or proper disposal methods to minimize environmental impact.

    Recyclability

    PLA: PLA is recyclable but requires specialized facilities for processing. It can be broken down and reprocessed into new PLA filament or other products.

    PETG: PETG is recyclable and widely accepted by recycling facilities. It can be recycled multiple times without significant loss of quality, making it a sustainable choice for 3D printing.

    Emissions and Odors During Printing

    PLA: PLA emits minimal odors during printing, typically described as a mild, sweet smell. It produces fewer harmful emissions compared to ABS or other petroleum-based plastics.

    PETG: PETG may emit a slight odor during printing, but it is generally less noticeable than ABS. PETG emits fewer volatile organic compounds (VOCs) and does not release toxic fumes, making it a safer option for indoor use.

    Practical Examples

    • PLA: Suitable for environmentally conscious users or projects where biodegradability is a priority. For instance, printing disposable utensils or packaging materials with PLA ensures they can be composted after use, reducing environmental impact.
    • PETG: Ideal for durable, long-lasting prints that can be recycled at the end of their lifecycle. For example, printing reusable containers or functional parts with PETG ensures they can be recycled and repurposed, minimizing waste.

Pros and Cons of PETG

Advantages

  1. High Impact Resistance: PETG offers excellent impact resistance, making it suitable for parts subjected to mechanical stress or potential impacts.
  2. Flexibility: PETG has a degree of flexibility, allowing it to bend without breaking. This makes it more resilient to deformation and better suited for parts that require some give.
  3. Chemical Resistance: PETG is resistant to a wide range of chemicals, including acids and alkalis, making it suitable for applications where exposure to harsh substances is a concern.
  4. Moisture Resistance: PETG has low moisture absorption, ensuring the integrity of the printed object over time, even in humid environments.
  5. Easy to Print: PETG is relatively easy to print compared to other engineering-grade filaments like ABS or Nylon. It has good bed adhesion and minimal warping, making it accessible to users of all skill levels.

Disadvantages

  1. Stringing: PETG is more prone to stringing compared to PLA, especially if printing settings are not properly optimized. Adjustments to retraction settings may be necessary to minimize stringing.
  2. Higher Printing Temperature: PETG requires higher printing temperatures, typically between 220°C and 250°C. Some printers may need upgrades to handle these temperatures consistently.
  3. Less Clarity: PETG is less transparent compared to PLA, which may affect the visual appearance of transparent or translucent prints.
  4. Limited Color Options: While PETG is available in various colors, it typically offers less color variety compared to PLA or ABS.

Rapid Prototyping Solutions

Pros and Cons of PLA

Advantages

  1. Ease of Printing: PLA is one of the easiest materials to print with, making it ideal for beginners and educational purposes. It has a low printing temperature, typically between 180°C and 220°C, and good bed adhesion with minimal warping.
  2. Biodegradability: PLA is derived from renewable resources such as cornstarch or sugarcane and is biodegradable under industrial composting conditions. This makes it an environmentally friendly option for 3D printing.
  3. Surface Finish: PLA produces prints with a smooth surface finish and excellent detail resolution, making it suitable for aesthetic projects that require high-quality visual appearance.
  4. Variety of Colors: PLA is available in a wide range of vibrant colors and effects, including translucent and metallic finishes, providing versatility for creative projects.
  5. Low Odor: PLA emits a mild, sweet odor during printing, which is generally considered more pleasant and less harmful than the fumes produced by other plastics like ABS.

Disadvantages

  1. Brittleness: PLA is relatively rigid and lacks flexibility, making it prone to snapping under bending or torsional forces. It may not be suitable for parts that require high durability or impact resistance.
  2. Limited Heat Resistance: PLA has a lower heat resistance compared to materials like ABS or PETG. It softens and deforms at temperatures above 60-70°C, limiting its applicability for functional parts exposed to high temperatures.
  3. Environmental Impact: While PLA is biodegradable, it requires specific composting conditions to break down properly. Improper disposal may result in PLA taking a long time to degrade in natural environments.
  4. Less Chemical Resistance: PLA is less resistant to chemicals compared to engineering-grade filaments like PETG or ABS. It may degrade when exposed to certain solvents or harsh substances.

Pricing Comparison of PETG and PLA

PETG

Cost Range: PETG filament typically ranges from $20 to $40 per kilogram, depending on factors such as brand, quality, and supplier.

Factors Affecting Cost:

  • Brand Reputation: Established brands may have higher prices due to quality assurance and reliability.
  • Filament Quality: Premium-grade PETG with consistent diameter and quality control may be more expensive.
  • Color and Special Effects: Specialty PETG filaments, such as transparent or metallic finishes, may be priced higher than standard colors.

PLA

Cost Range: PLA filament is generally more affordable than PETG, with prices ranging from $15 to $30 per kilogram.

Factors Affecting Cost:

  • Brand Reputation: Similar to PETG, well-known brands may have slightly higher prices.
  • Filament Quality: High-quality PLA with excellent dimensional accuracy and print consistency may be priced slightly higher.
  • Color and Special Effects: Specialty PLA filaments, such as glow-in-the-dark or wood-infused variants, may have premium pricing compared to standard colors.

Considerations

  • Project Requirements: Assess the specific requirements of your 3D printing project and determine if the properties of PETG or PLA better suit your needs.
  • Budget Constraints: Consider your budget constraints and evaluate the cost-effectiveness of each filament option based on your project’s scale and complexity.
  • Supplier Options: Explore different suppliers and compare prices, discounts, and promotions to find the best deal for your filament purchase.

FAQs

Is PETG better than PLA?

Whether PETG is better than PLA depends on your specific needs and preferences. PETG offers advantages such as higher impact resistance and chemical resistance, making it suitable for functional parts. PLA, on the other hand, is biodegradable and easier to print with, making it ideal for aesthetic prints and beginners. Ultimately, the better choice between PETG and PLA depends on the requirements of your 3D printing project.

Why is PETG so hard to print with?


PETG can be challenging to print with for a few reasons:

  1. Higher Printing Temperature: PETG typically requires higher printing temperatures compared to PLA, ranging from 220°C to 250°C. Some 3D printers may struggle to maintain these temperatures consistently, leading to printing issues.
  2. Adhesion to Print Bed: PETG tends to stick very well to the print bed, which can make it challenging to remove prints without damaging the bed surface. Proper bed adhesion techniques, such as using a heated bed and applying adhesives like glue stick or PET tape, are crucial for successful printing.
  3. Stringing and Oozing: PETG has a higher viscosity than PLA, which can result in stringing and oozing between printed layers if retraction settings are not properly tuned. Adjusting retraction settings and print speeds can help minimize these issues.
  4. Warpage: While PETG is less prone to warping compared to ABS, it can still warp if the print bed temperature is not adequately controlled or if there are sudden temperature fluctuations in the printing environment.

Is it safe to print PETG indoors?

Yes, it is generally safe to print PETG indoors, but it’s essential to take proper precautions to minimize any potential risks:

  1. Ventilation: Ensure adequate ventilation in the printing area to reduce the concentration of any emissions or odors released during printing. Open windows or use a ventilation fan to help dissipate any fumes.
  2. Enclosure: Consider using an enclosed 3D printer or an enclosure to contain any emissions and prevent them from spreading throughout the room.
  3. Air Filtration: Use an air purifier or filtration system to remove any particles or fumes from the air, especially if printing in a confined space.
  4. Safety Guidelines: Follow safety guidelines provided by the filament manufacturer and your 3D printer manufacturer. This includes using the recommended printing temperatures and settings and wearing appropriate personal protective equipment if necessary.

Does PETG melt in the sun?

PETG has a relatively high glass transition temperature (Tg) compared to PLA, which means it has better heat resistance. However, PETG can soften and deform when exposed to high temperatures, including direct sunlight on a hot day.

While PETG is more heat-resistant than PLA, it’s still susceptible to deformation under prolonged exposure to high temperatures. Therefore, it’s advisable to avoid leaving PETG prints in direct sunlight for extended periods, especially in hot climates or during peak sunlight hours. If outdoor use or exposure to sunlight is expected, consider choosing a filament with higher temperature resistance or applying a protective coating to minimize the effects of heat on the printed object.

 

At Modo Rapid, we have been specializing in custom product manufacturing since 2005, covering a variety of processes including 3D printing, CNC machining, sheet metal fabrication, injection molding, and more. With our professional team and advanced equipment, we are capable of meeting the needs of various projects. If you have new projects or ideas, we welcome you to discuss with our expert team and provide you with customized solutions. Regardless of the scale of your project, we are committed to delivering high-quality, efficient services to help you achieve your manufacturing goals. We look forward to collaborating with you!