PET or Polyethylene Terephthalate is a transparent thermoplastic polyester material. It is a widely popular material and often used in product packaging, single-use plastic products like glasses, spoons, plates, mineral water bottle applications.
In terms of material properties, PET exhibits good chemical resistance to organic food and water and is the main reason for its application as a product packaging material. As PET is transparent, it is ideal for packaging as the contents of the packaged item can be easily seen. It is shatterproof and also showcases a great strength-to-weight ratio. Additionally, it is easy to recycle and is represented by the Plastic Recycling Symbol #1.
With all its favorable properties, PET also has some glaring drawbacks. One of its major negatives is the fact that it is sensitive to heat. Boiling water can easily deform the material. It is also affected by UV rays. Prolonged exposure to the sun’s rays can result in oxidation and it can release chemicals in the process. If any food product comes in contact with the material then the food material can become toxic. Thus PET is not used for applications requiring extended outdoor use.
Properties of PET Material
- Flexural Strength: 221 MPa (32000 PSI) W/ 30% Glass Fiber
- Tensile Strength: 152 MPa (22000 PSI) W/ 30% Glass Fiber
- Heat Deflection Temperature (HDT): 70 °C (158 °F) at 0.46 MPa (66 PSI)
- Typical Injection Mold Temperature: 74 - 91 °C (165 - 195 °F)
- Melting Temperature: 500°F (260°C)
- Specific Gravity: 1.56
- Shrink Rate: 0.1 - 0.3 % (.001 - .003 in/in)
What is PETG Filament?
PETG or Polyethylene terephthalate glycol is a thermoplastic polyester that is a popular variant formulated with the addition of G – Glycol at a molecular level to offer a different set of material properties. With the addition of Glycol, the new material delivers significantly better chemical resistance, durability, and formability for manufacturing.
Owing to its superior properties, PETG is popularly used in 3D printing. PETG also showcases greater strength and better impact resistance. It can also sustain higher temperatures making it applicable in more applications. While PET is transparent, PETG is translucent and has a glossy finish.
Characteristics of PETG Filament
- In comparison to other 3D printing filaments, PETG is exceptionally strong and exhibits functionality comparable to ABS material and reliability comparable to PLA.
- It is an excellent engineering-grade material and can be used as an alternative to ABS.
- The relative ease of printing also makes it a preferred choice over ABS.
- PETG is odorless making it ideal for household usage.
- Since PETG has a low level of shrinkage it can maintain its original dimensions for longer periods of operation.
- It does not absorb water which ensures that it remains strong even in parts exposed to moisture.
- PETG is an ideal material for medical applications as it showcases strong chemical resistance. PETG parts can also be sterilized easily.
- The material can be easily recycled, including prints and misprints.
- On the flip side, PETG is also prone to scratches.
- PETG is also affected by strong US rays. Prolonged exposure can deteriorate the material and adversely affect its mechanical properties.
Print Settings for 3D Printing PETG Filament
- Melting Temperature: 220oC to 265oC
- Heated Bed: Necessary
- Build Platform Temperature: 70oC to 80oC
- Printing Speed: 50-60mm/sec
- Printer Enclosure: Recommended
Applications of PETG 3D Printing
PETG is widely used as a 3D printing filament in FDM 3D printing. Owing to its superior properties, the material is used in a range of applications. We see some of them here.
Prototyping is a popular application of PETG filament. Designers can take advantage of its unique properties like translucency, moisture, and chemical resistance and ductility, to make strong functional prototypes. Engineers can also use prototypes to conduct product testing.
PETG’s properties are highly attractive to the medical industry. PETG’s durability makes it ideal for 3D printing prosthetics, tools, and medical equipment. Its chemical resistance allows for easy sterilization of the tools. Its translucency also helps the material to be used in dental applications. Braces are often 3D printed with PETG material. Also due to their collective range of properties the braces can be regularly cleaned, they are durable and can be used for months on end without and dimensional deformity.
Food and Beverage
PETG is a food-safe material and this allows it to be used as a product packaging material. Most PETG filaments are FDA approved and so end-users can maintain hygiene standards for specific applications. As the material can be sterilized this adds another safety layer for the material to be used in food applications.
Its strength properties allow the food and beverage packaging to remain intact even on considerable impact. The translucency allows users to look through the packaging to check the inside contents with ease.
(Note: The food safety should be verified by the manufacturer as each manufacturer may not have an FDA approval for its PETG filament)
PETG has considerable flexibility in addition to being strong and durable. This property helps the material to be used to manufacture Point-of-purchase stands like exhibition kiosks, Displays at Malls and events, etc. The material is also available in a wide range of colors and this adds to its demand in the retail application.
As mentioned earlier, the PETG filament is flexible and durable and this makes it ideal for creating fitment parts like snap fits, protective guards, live hinges, etc.
Its excellent heat and chemical resistance properties can be leveraged by designers and engineers to develop durable parts like testing components, robot end-effectors, etc.
Its durability, strength, and ability to retain its dimensions are perfect characteristics for 3D printing the production aids like jigs and fixtures.
Since PETG filament exhibits low water absorption, it can be effectively used in applications exposed to high moisture content or direct water. Some application areas include pumps, water valves, hydroelectric power stations, etc.
Tips to 3D Print with PETG Filament
It is always important to understand the strengths and weaknesses of every material we print with. Only when we understand the material, will we be able to successfully 3D print it to our advantage.
While PETG exhibits superior properties to most FDM 3D printing materials it is a difficult material to print with. In this section, we analyze the issues share the tips to successfully 3D print with PETG filament.
By now you must have noticed that the melting temperature range for PETG is quite big. A typical PETG filament will melt anywhere between 220 to 270° C. It depends on the brand you are using and the ideal temperature recommended by the specific brand. Additionally, PETG requires a heated bed and so the bed temperature also has to be perfect for the specific brand of filament you are using, otherwise the chances of print failure increase.
To print with this material, users will need to have more control over the print settings. Fan settings will play a big role in ensuring a successful print experience with PETG filament. PETG filament exhibits first-layer adhesion and retraction/stringing issues and so while printing, the fan has to be strategically used according to the layer being printed.
At first, the users should switch off the fan for the initial layers (1 to 3 layers) to ensure a strong first layer. The heat is essential to allow for a strong first layer.
Once the initial layers are printed, the fan should be turned ON. The cooling fan will rapidly cool the filament as it is deposited resolving the retraction issues thus eliminating the stringing and oozing issues. This also helps in highlighting the details of the print.
As stated previously, first-layer adhesion is an issue with PETG. For this in addition to using bed adhesion tools and fan settings, a user should also consider calibrating the build surface and ensuring the surface is compatible with PETG.
An automatic bed leveling feature can go a long way in ensuring the bed is always evenly balanced minimizing the risk of failure. Additionally, a PEI sheet is considered the best surface for printing with PETG filament.
It is a fact that the higher the printing speed, the lower the quality of the printed part. So the ideal printing speed has to be achieved. For this, a user has to find the optimum speed through trial and error methodology and also by following the recommended settings provided by the filament manufacturer.
The ideal speed for printing with PETG ranges between 30mm/s to 100mm/s. This can also be varied depending on the type of part you are printing. If the part has detailed sections, then the lowest possible speed is recommended.
PETG filament sometimes sticks to the nozzle and if ignored, this material will either harden on the nozzle itself affecting the flow of the material, or get deposited on the part causing a blob/bump. In a worst-case scenario, this blob on the surface of the print can also result in a layer shift thus leading to complete print failure. So, a user has to ensure that the nozzle stays clean. Using the pause feature, a user can easily pause the print, clean the nozzle and just resume printing from where it has stopped.
One of the newest blends of PETG is the PETG Carbon Fibre. As the name suggests, the blend is formed by combining PETG and Carbon Fibre to form a supremely strong 3D printing filament.
PETG Carbon Fibre by 3D Maker Engineering
3D Maker Engineering took the PETG filament to the next level by blending it with a generous amount of Carbon Fiber.
Features and Specifications of 3D Maker Engineering PETG
- Hotend Temperature: 220-250° C
- Bed Temperature: 75-85° C
- Filament Diameter (mm): 1.75±0.05
- Net Weight: 1kg (2.2 lbs)
- Build Surface: Polypropylene or PEI
Printing Tips for 3D Maker Engineering PETG
- Default Print Speed: 30-60 mm/s (Recommended: 40 mm/s)
- First Layer Height: 0.28 mm*
- First Layer Speed: 15 mm/s
- Extrusion Width: 0.48 for 0.4 Nozzle (1.2X Nozzle Diameter)
- Retraction: Bowden 5mm @ 45 mm/s or Direct 2mm @ 45 mm/s
- Perimeter Print Speed: 70% of Default Print Speed
- Infill and Support Print Speed: 80% of Default Print Speed
- Fan Profile:
- Layer 1: 0%
- Layer 3: 25%
- Layer 5+: 50%
- XY Jerk: 8
- Z Jerk: 0.3
- E Jerk: 5
- Acceleration (Print/Travel): 300
- Retract Acceleration: 1000
- Travel Speed (non-print moves): 120 mm/s
Since the 3D Maker Engineering PETG blend is filled with a good amount of carbon fiber, it is recommended that users should print with a nozzle diameter bigger than 0.6mm, or else the nozzle will clog.
Brands Selling PETG Filament
PETG is a popular material and so is manufactured by a huge number of brands. It is available in both 1.75mm and 2.85mm diameters, multiple colors, at affordable prices, and sold across the globe. Here we see some of the brands selling the PETG filament.
MakerBot’s PETG filament exhibits high chemical resistance making it an excellent choice for food packaging. It is perfect for use in research labs that require chemical resistance in functional parts or containers.
Features and Specifications of MakerBot PETG
- Heat Deflection: 70° C
- Flexural Modulus: 2,000 MPa
- Tensile Strength at Yield: 44 MPa
- Tensile Modulus: 1,900 MPa
- Strain at Yield - Elongation (%): >3.8%
- Notched Impact Strength: 18.7 J/m
Printing Tips for MakerBot PETG
- Extruder Temperature: 220° C to 250° C
- Bed Temperature: 70° C to 80° C
- Printing Speed: 50-60mm/sec
- Heated Bed: Necessary
- Enclosure: Recommended
The eSUN PETG filament is specially created to easily 3D print popular applications like PPE products, Toys, Electric, and electronic products, Stationery, and Cosmetics containers.
Features and Specifications of eSUN PETG
- Odorless and has a low shrinkage rate
- Hydrophobicity (Will not absorb water and as such clog the extruders)
- Outstanding toughness and high impact strength
- Good liquidity (flows smoothly)
- High mechanical strength and excellent flexibility
- High transparency, good gloss, and recyclable
Printing Tips for eSUN PETG
- Best print temperature: 230~250℃
- Bed temperature: 60-80 ℃
With PETG Economy ColorFabb offers a new standard in high-quality PETG filament at an affordable price. It is the choice for users looking for large volume printing of functional parts without breaking the bank.
Features and Specifications of ColorFabb PETG
- Diameter Tolerance: ± 0.1 mm
- Density: 1.28 g/cm3
- Glass Transition Temperature: 70° C
Printing Tips for ColorFabb PETG
- Printing temperature: 235C-255° C
- Print speed: 30 - 50 mm/s
- Heated bed: 70-80° C
- Cooling fan: 75/100%
BCN3D PETG has an excellent balance of tensile strength and elongation at break. It is as easy to print as PLA but better of mechanical, chemical, and thermal properties.
Features and Specifications of BCN3D PETG
- Resistance to corrosive chemicals
- Good balance of strength, impact resistance, and elongation at break
- Great dimensional stability and toughness
- Good glossy surface quality
- Good abrasion resistance
- Water and moisture barrier
- Withstand operating temperatures up to 70° C
- Low rate of ultrafine particles (UFP) and volatile organic compounds (VOC)
- Compatible with PVA supports
Printing Tips for BCN3D PETG
- Extruder temperature: 240° C - 260° C
- Bed temperature: 90° C
- Cooling fan: 0-25%
- Speed: 40-80mm/s
- Minimum layer height: 0.1-0.2mm
PolyLite™ PETG from Polymaker is an affordable PETG filament with balanced mechanical properties and ease of 3D printing.
Features and Specifications of PolyLite™ PETG
- Young’s Modulus: 1472 ± 270 Mpa
- Tensile Strength: 31.9 ± 1.1 Mpa
- Bending Strength: 53.7 ± 2.4 Mpa
- Charpy Impact Strength: 5.1 ± 0.3 kJ/m2
- Drying Settings: 70° C for 8h
Printing Tips for PolyLite™ PETG
- Nozzle Temperature: 230˚C – 240° C
- Printing Speed: 30mm/s – 50mm/s
- Bed Temperature: 70˚C – 80° C
- Bed Surface: Glass with glue, PEI sheet
- Cooling Fan: LOW for better surface quality. OFF for better strength
Taulman’s TECG-G is a PETG filament that is superior to other PETG filaments in the market. It is specifically developed for engineering and architectural use. According to Taulman, this material is ideal for functional testing environments.
Features and Specifications of TECH-G
- High Tensile Strength: 5900+ PSI
- Low Elongation: 3%
- No odors when printing
- FDA approved
- True Diameter: 1.75mm
- Opacity: 90%
Printing Tips for TECH-G
- Printing Temp: 235 - 242° C
- Nozzle Size: Any
- Print Speed: ABS speeds, or slower for higher detail
- Bed Temp: 68° C Max