PETG and warping
Understanding and Solving Warping in 3D Printing with PETG
Warping is a common challenge faced by 3D printing enthusiasts. Essentially, warping occurs when parts of your printed object lift off the build plate, distorting your print. While every material has its own set of peculiarities, this article will focus on Polyethylene Terephthalate Glycol (PETG), a popular filament choice due to its strength, clarity, and flexibility.
Why Does PETG Warp?
At the crux of the warping issue is the differential in cooling rates. When extruded filament cools unevenly, it causes internal stresses which, in turn, make the material contract at different rates. This differential in contraction can cause the corners or edges of a print to curl upwards, leading to warping.
For PETG, this is slightly puzzling because PETG is less prone to warping compared to other materials like ABS. However, it’s not entirely immune, especially when specific conditions are met.
Solutions to Warping with PETG
Optimal Bed Temperature
The first line of defense against warping is getting your bed temperature right. For PETG, a heated bed is crucial. A bed temperature ranging from 70°C to 90°C usually provides good adhesion and reduces warping potential. Remember, maintaining a steady temperature is just as important as reaching the optimal range.
Build Surface Material
The choice of build surface can significantly affect adhesion. While many swear by the effectiveness of borosilicate glass plates, others recommend build surfaces like PEI sheets for PETG. Blue painter’s tape or glue stick can also be used on the build plate to improve adhesion.
First Layer Settings
The first layer is foundational for the rest of your print. Ensuring that the initial layer is slightly squished against the bed improves adhesion. Thus, calibrating the nozzle height and setting the first layer height slightly lower than the rest can be beneficial.
Enclosed Printing Area
An enclosed printer or at least a draft-free printing environment can ensure consistent cooling, which is especially important for larger prints. By protecting the print from drafts and sudden temperature changes, you can mitigate the risk of warping.
Decrease Cooling Fan Speed
Unlike materials like PLA, PETG doesn’t benefit from rapid cooling. It’s often recommended to either completely turn off the cooling fan for the first few layers or to run it at a reduced speed.
Slow Down Printing Speed
Printing at a slower speed ensures consistent layer adhesion, especially for the initial layers. A slower speed can give PETG more time to bond with the previous layer, thus reducing potential stress points that can lead to warping.
Use Brims or Rafts
These are additional structures printed around or under the object to improve bed adhesion. They increase the surface area of the initial layers, ensuring that the print sticks well to the bed.
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