PETG filament is perhaps the best material for 3D Printing. It’s extremely durable, has a moderate amount of flex, and it’s quite easy to print. Widely used in manufacturing, it can be injection molded, vacuum formed and extruded. As an FDA Approved resin, it’s also considered food safe and recyclable.
This guide looks at what we need to know when getting started. Small adjustments can make a world of difference, from the fan speed to print temperatures. With the proper slicer settings and hardware, it might just replace PLA as your preferred choice.
What is PETG?
PETG is a modified version of Polyethylene Terephthalate (PET), the plastic used for water bottles and food packaging. The addition of Glycol (G) makes this variant far easier to print, increasing the flexibility and impact resistance while reducing brittleness and hazing.
Comparable to PLA’s ease of use, and offering the same strength and durability as ABS, it has the best characteristics of both materials rolled into one. It is however hydroscopic, meaning it will actively absorb moisture from the air that can affect prints.
Proper filament storage is necessary in humid environments. Spools that have already absorbed moisture can be restored with a DIY filament dryer (How to Make a Filament Dryer for $30).
Do I need an All Metal Hotend?
The short answer is no, but it’s strongly recommended.
3D Printer’s comes with a PTFE lined hotend, perfect for PLA and ABS filaments. However, that tube starts to degrade at higher temperatures, becoming soft and no longer able to retain its shape. This deterioration can also release toxic fumes, although at what temperature that occurs, no one can say for sure. To be on the safe side, it’s best to avoid prolonged use above 240° Celsius.
For occasional PETG prints, the stock hotend should be fine. Some recommend replacing the white PTFE tube with Capricorn Tubing, also known as Luke’s Hotend Fix. This may slow the speed at which the tube breaks down, but it’s not a permanent solution.
The best choice long term is an all metal hotend. Designed to eliminate the PTFE tube, they are safe to use at much hotter temperatures. Creality 3D Printers like the Ender 3 and CR10 will find the Micro Swiss All Metal Hotend to be a simple drop-in upgrade. Other 3D Printer models will generally be better suited with a universal option like the V6 All Metal Hotend.
Best Filament Brands
Shopping for filament can be overwhelming. There are dozens of brands and hundreds of colors to choose from. However, there’s a select few considered to be among the best, offering tight dimensional tolerances and producing consistent results.
Overture is the new king of budget filament. If you’re on the fence and can’t decide, this is a safe bet in the $20 price range. It also comes with a resealable bag for storage and a BuildTak style print surface. Hatchbox and eSun are also great brands, catering to the 3D Printer industry for more than 6 years.
For first time users, stick with something inexpensive and well reviewed. Premium options like Priline’s Carbon Fiber PETG make gorgeous prints, but use something cheap to dial in your settings first.
PLA is the first filament we use, and it’s often our reference point for other plastics. As such, most are familiar with bed leveling using a sheet of notebook paper (thickness: 0.1mm), where the first layer needs to be smushed into the build plate.
PETG on the other hand works best with a slightly larger gap between the nozzle and bed. If the nozzle is too close, it won’t flow properly and may cause the extruder to jam. If the nozzle is too far, the filament won’t stick to the heated bed. For best results, fold the notebook paper to double the thickness, or substitute it with an index card.
PETG filament has a higher melting point than PLA. It flows best between 230-260C, and heated bed adhesion between 80-90C (depends on brand). Every roll of filament is different to some degree, check the Manufacturer’s suggested temperature range listed on the side.
Nozzle Temperature: 230C – 260C
Bed Temperature: 80C – 90C
As with any new filament, it’s always advised to print a Temperature Tower first. This will give you an idea how it looks, feels and prints at incremental temperatures. If the nozzle is too cold, layers will not bond well and split apart (delaminate). If the nozzle is too hot, it will cause excessive stringing, oozing and blobbing.
Should you find the print temperatures are unstable and fluctuating, do a PID Tune on your hotend. It will recalibrate the Kp, Ki and Kd values based on your current hardware, stabilizing the readings for best results.
PETG Fan Speeds
Does PETG need a cooling fan? No, it will print anywhere from 0-100% fan speed depending on your intended goal. The amount of cooling should be chosen based on the purpose of the part.
Low Fan Speed: The less cooling used, the stronger the part will be. The molten plastic essentially melts into the previous layers, providing exceptional adhesion to one another. The downside is that this can lower the aesthetic quality, a trade off for much stronger parts.
As can be seen in the image, bridges and overhangs will suffer the most without proper cooling. To address this problem, it is recommended to use the Bridging Fan Speed Override setting in Simplify3D or a similar feature within your desired slicer software.
High Fan Speed: The faster the part is cooled, the better it will look when finished. This is often the best choice for vanity prints such as masks, vases and other aesthetically pleasing designs. It will not offer the same level of durability as prints that set at room temperature, however the overall surface finish will be a drastic improvement.
The temperate tower on the left was printed at 100% fan with a 50mm blower fan and the Dii Cooler, where the tower on the right was printed using the low powered stock fan. The higher powered fan causes the plastic to set quickly, which prevents the bridges from sagging and overhangs from warping at the edges.
Printing a different filament is all about finding the right balance of settings. While there is a small learning curve, it’s a considerably better choice for most applications. There is no getting around the need to experiment, but the following should work as guidelines when building your own configurations.
|Setting Name||Setting Value|
|Print Speed||Use a slow speed for the first layer to ensure proper adhesion to the build plate. This should generally be around 25% of your normal print speed.|
Start with 40 mm/s as the base speed and increase this gradually until you find the perfect speed for your printer.
Print Speed (Layer 1): 10 mm/s
Print Speed (Layer 2+): 40 mm/s
|Print Temperature||The print temperature will affect the object’s appearance and durability. The recommend temperatures below are median values, tune as needed. More heat to the extruder will increase the flow of plastic (and increase stringing), where 245C is a good starting point.|
Print Temperature: 245C
|Bed Temperature||Bed Temperature: 85C|
|Retraction Distance||PETG filament is prone to stringing, where the proper retraction distance will help to minimize this. Start with these settings and tune as needed. Increase if stringing is present, decrease if you experience clogs.|
Retraction Distance (Bowden – Stock): 6.0 mm
Retraction Distance (Bowden – All Metal): 3.5 mm
Retraction Distance (Direct Drive- Stock): 2.0 mm
Retraction Distance (Direct Drive- All Metal): 1.0 mm
|Fan Speed||Make sure the first layer is set to 0% to ensure proper adhesion. From layer 2 and on, choose the fan speed based on the purpose of the part.|
Lower fan speeds for strength and higher fan speeds for aesthetics. The “Bridge Fan Speed Override” is essential for good bridges.
Fan Speed (Layer 1): 0%
Fan Speed (Layer 2+): See Details Above
Bridging Fan Speed Override: 100%
|First Layer||Use Skirt: Enabled|
Skirt Outlines: 2
First Layer Height: 90%
First Layer Width: 100%