PETG is the best alternative for PLA because it’s somewhat easy to print and has similar ABS properties. Its slight flexibility, heat resistance, and strength make it attractive for every 3D printer user. Yet, it has some problems like PETG corners lifting, stringing, warping, elephant foot, etc.
In this article, we start with the most common solutions to the PETG corners lifting problem. You can try each answer as you read or use it as a checklist.
Level The Bed
The unleveled bed surface is the first and most common cause of corner lifting (warpage). Imagine the moment that molten filament comes out of the hot end and spreads through the bed. Suppose the distance between the hot end and the surface varies. In that case, the filament squishes in some zones but loses its connection to others. This phenomenon causes weak bed adhesion and increases the chance of warpage.
The process may vary slightly based on your 3D printer’s mechanism, and some 3D printers have automatic bed leveling features. However, the main idea is to bring the nozzle’s tip to four corners of the bed and adjust the distance to the point that a standard A4 paper can hardly pass through the gap. After the four corners, you can repeat the process several times to make sure it’s perfectly leveled.
Some people prefer to use thicker business cards to provide more significant gaps. However, after using ordinary paper and adjusting the z offset, you’re good to go.
Adjust The Z Offset
Z offset is the distance between the z home position on a 3D printer and the hot end’s tip. In theory, It matches the distance between the print bed and the hot end. Some errors make it slightly different.
The easiest way to adjust z offset is to use your slicer’s settings. You can also set it using the generated G-code, though.
There are many free and premium slicer softwares available in the market, and each one’s interface differs from other ones. The z offset parameter’s exact location varies in every slicer, so you need to find the parameter in your slicer. A value of 0.2 should be acceptable. Still, there is a way to find the best value for your case.
Getting an even first layer is an excellent sign of correct z offsets. If the filament is too squished, you should increase the parameter. In contrast, if the z offset is too high, the filament won’t stick to the bed, and you can easily remove it with your fingers.
Improve Bed Adhesion
Bed adhesion is to force that prevents the corners from popping up and lift. There are many ways to improve adhesion. One option is to put an even layer of blue painter’s tape on the surface. You can also add an extra layer of glue to it. This way, the first layers will stick much better. The only drawback of this method is that you should remove the old tape and add a new layer once in a while.
Another method is to spread a thin layer of PVA glue stick on the print bed to improve adhesion. To do this, first, apply a thin layer over the surface, then use a flat card to make it more even. It would be best to use a colorless glue stick brand to avoid adding contaminants or color to the print. Make sure:
- The applied layer isn’t very thick, so that it affects the bed leveling process.
- After printing, wipe off the glue from the surface and wash it using soap and warm water once in a while. The remaining materials can drastically reduce bed adhesion.
- The glue layer will cover the whole printing area. Bare surfaces can create permanent bonds with the print.
Turn Off The Cooling Fans
Imagine a 3D printer starts to print the first layer. In this stage, the hot and melted filament is first in contact with the hot end, then spread on the heated bed. The first layers will keep their temperature around the temperature of the heated bed until the process finishes. However, this situation changes a little for the upper layers.
As the nozzle goes up, the upper layers go away from the heated bed. Now, a hot nozzle is the source of heat for the layers. So they are cooler than the first layers and the highest layers. This situation can create temperature contours causing internal stress and tensions. Internal pressure is the number one cause of PETG corner lifting.
Materials like PETG with higher printing temperatures have more tendency to induce internal stresses. Cooling fans can increase the temperature gradient and severe the warpage.
Increase Base Area
A bigger base area will improve the bed adhesion. This way, the corners won’t easily pop up and lift. There are two main ways to increase this area.
The first option is to add a brim to your slicer settings. This feature is a thin layer of filament that is attached to the perimeter. Another way is to add some mouse ears. They are small circles near the corners that, again, increase the surface area.
As mentioned before, temperature differences are the main reason for print warpage and lifted corners. Hence, even a slight draft over the print can lift a corner from its blowing side. Make sure that the 3D printer is in a windless room.
Ues An Enclosure
An enclosure is a simple box that keeps the printing area warm, avoids unwanted drafts, and keeps hot devices away from children and animals. Using the chamber has the same effect as turning off the cooling fans. It eliminates the temperature gradients at some levels. You can either buy an enclosure or create one.
A 3D printer can be as simple as cardboard or a box, but you should consider some tips while creating one. The primary purpose of an enclosure is to make the temperature around the heated bed more homogeneous. Other factors like safety, accessibility, dust protection, aesthetics, cost, reducing toxic fumes, and noise reduction may be your secondary concerns.
Putting the whole components of the 3d printer may cause excess heat to the mainboard and electronic components. Hence, it would be best to separate these parts if you can rewire them.
Unlike PETG, high temperature can degrade PLA filament or the printed part, so it’s a good idea to make a vent or window for the enclosure. You can seal it while using PETG.
FDM 3d printers use hot nozzles and heating elements. It can cause a fire if left in a room. An enclosure made of non-flammable materials (for example, metal and glass) can eliminate this issue. In contrast, plastics and cartons can be the fuel of the fire.
Adjust Nozzle And Bed Temperatures
The actual nozzle temperature is something that users usually forget to calibrate because printing with overheated plastic is much more comfortable and improves layer adhesion.
Extruder temperature’s impression is also similar to cooling fan effects. Both change the filament temperature, so low extruder temperature acts as a powerful cooling fan. It makes the filament more solid and reduces its adhesion at the same time. In contrast, the high temperature causes the plastic to become liquid and improves bed adhesion. Remember, we need the bed adhesion to stick the object to the surface.
In conclusion, Extruder temperature should be adjusted to a value that has all of the advantages. This way, the output will be at its best quality. The best value varies for different filaments. Even distinct brands or spools may react differently.
For example, two manufacturers may use different additives for their PETG filament to get unique properties. Thus, for one case, PETG corners lifting is minimum in 235oC while the other works best in 245oC.
Dry Your Filament
It’s a good habit to dry filaments before putting them into work. Some filament materials are more sensitive to moisture, and some are less affected by it. In my experience, PETG is in the middle of this spectrum. However, wet PETG can have a significant impact on print quality and ruin its shape.
The first and most effective way to know if your filament is wet is to listen to the extruder sounds. If you hear a noise like popping and cracking, it’s mostly because of wet filaments. The next sign is the random bubbles inside the melted filament after it leaves the nozzle. These are the apparent signs of wet filaments.
However, if the moisture level is low, It may only affect the printing quality by stringing, oozing, and rough bridges. For example, live in a place with a relative humidity lower than 30%, and you put the PETG filament spools in a room. You may only see more stringing or warping without extra bubbles or a noisy nozzle. So, low humidity won’t affect the printing quality that much.
Depending on the amount of absorbed water, humidity can cause different problems at different levels. The least problem you can face is to have more stringing around edges and rough corners. Surface quality may fall, and the layer adhesion drops. Hence, it will affect the overall print quality. However, a little moisture won’t create bubbles and popping sounds, and mechanical property changes will be minor.
PETG doesn’t absorb too much water; Especially if you keep them in a low humidity place, there won’t be severe changes. As a rule of thumb, if the relative humidity is around 30% or less, there is no need to dry PETG. For example, if you live in Nevada or Colorado, the humidity level is ok.
Decrease Printing Speed
Slower prints have more time to release heat and cool down uniformly. Thus, 3D printing materials like PETG as low as 30 mm/s can eliminate many problems like corner lifting, rough surfaces, and even print fails.
If Lifting Happens In One Side:
If only one corner lifts from the surface, the most probable causes are excess draft and uneven bed.