KEY TAKEAWAYS
- 3D print warping occurs when parts of the print curl upwards away from the build surface.
- Warping impacts the appearance and functionality of printed objects.
- Causes of warping include printer settings, bed adhesion, material properties, and ambient temperature.
3D print warping is a common issue where parts of your print curl upwards. As a result of uneven cooling or bed adhesion issues, the bottom layers of a 3D print start to curl upwards. Wapring affects both the appearance and functionality of the finished object.
Incorrect printer settings, poor bed adhesion, and external factors like the ambient temperature of the printing environment can cause prints to warp during the printing process. It’s also important to understand that filament materials like ABS, ASA, PC, and nylon are prone to warping due to their inherent properties and cooling behaviors.
Let’s take a look at some easy ways to prevent warping in your 3D prints
What Causes 3D Print Warping
3D print warping occurs when the layers of your print contract and deform during the cooling process. The contraction causes parts of the print to curl upwards and away from the build platform.
Thermoplastics expand when heated and shrink as they cool, in a process called thermal expansion. The temperature changes cause expansion and cooling, creating movement in the molten filament as it cures and adheres to the printed object’s printing bed and previous layers. When layers of the print cool and shrink at different rates, the bottom layers curl upwards, losing their grip on the print bed.
While warping occurs at the first few layers of the print, it can happen at any point during the printing process. Warping can even arise towards the end of printing as the top layers of material shrink.
The most common cause of warping is the cooling rate of your print. When sections of the printed object cool too quickly, tensions emerge within the layers as they contract. The cooling causes contractions, especially at the print’s corners, which cause the part to curl and lift from the print surface.
Poor bed adhesion is another factor that causes warping in your prints. If the extruded plastic doesn’t adhere to the printing plate, it will likely peel away from the print surface as the plastic cools.
How to Prevent Warping
Print With a Heated Bed
A heated build plate prevents warping by maintaining a consistent temperature throughout the printing process. Heated beds prevent the material from cooling too quickly, which can cause warping.
Setting the appropriate print bed temperature for your chosen thermoplastic filament is essential. Filament manufacturers provide suggested temperature settings, which you can find on the filament spool.
Bed Leveling
Proper bed leveling is essential for good first-layer adhesion and preventing warping. If the bed is not leveled correctly, your print will start with inconsistent first-layer adhesion. As the part cools and contracts, the inconsistent adhesion leads to warping.
Ensure you manually level the bed or any auto-leveling system every 5-10 prints. It’s also a good idea to clean the printing platform with isopropyl alcohol, as dirt, debris, and filament residue can prevent the bottom layers of your part from bonding.
Use a Brim or Raft
Adding a brim or raft to your 3D print gives it more surface area to adhere to the build plate. The wider base improves the grip on the build surface, reducing the likelihood of warping as it cools.
A brim is a narrow, flat layer extending from the model, while a raft is a separate horizontal layer printed underneath the model. We recommend using a brim instead of a raft, as rafts ruin the underside of the print.
Mouse ears are another structure that increases the surface area at the corners of your print, which are most prone to warping. Mouse ears are very effective but aren’t available in most slicing software. If you want to experiment with mouse ears, you can design them in CAD software.
Use Bed Adhesives
Bed adhesives, such as glue sticks, hairspray, painter’s tape, or specialty products, can help improve the adhesion of your 3D prints to the build surface.
Stronger first-layer adhesion can be enough to stop your print from warping. Ensure that you apply an even coat of adhesive and clean your build plate before and after printing. Remember to relevel the bed and adjust the Z-offset if you’re using a thicker adhesive like painter’s tape.
Choosing the Right Build Surface
Choosing the right build plate can significantly improve first-layer bed adhesion. Popular build surfaces include PEI (Polyetherimide), glass, Kapton tape, and polypropylene.
In my experience, a glass plate provides the best first-layer adhesion, providing an even heat distribution across the heated print bed. If you think bed adhesion is causing the warping of your 3D print, try upgrading to a glass print bed.
Adjust Cooling
Slowing the cooling process for extruded filament prevents warping in 3D prints. Cooling fans help regulate the temperature of the printed material, ensuring it doesn’t cool too quickly and cause issues.
While cooling is essential, too much cooling leads to poor adhesion, as the rapid cooling and contraction cause the print to curl upwards. You can prevent warping by turning off or lowering the cooling fan speed.
For most prints, the fans should be off for the first 5-10 layers of the print. I recommend lowering the fan speed by 20% for the rest of the print.
Use an Enclosure
Keeping your FDM printers in an enclosure is an effective way to stabilize the printing environment and protect your prints from drafts, changes in room temperature, and other external factors that can lead to warping.
An enclosure maintains a consistent ambient temperature around your print, slowing the cooling process and reducing the risk of distortion.
Lower Printing Speed
Lowering the printing speed gives more time for the filament to bond to previous layers and the print bed. Allowing the filament more time to bond and adhere lessens the tension in the object as the filament cools.
Using a lower print speed for the first few layers of the print gives the filament more time to adhere to the print bed properly. The slower speed also prevents the nozzle from pulling the melted filament as it moves, improving print quality.
3D Printing Materials Prone to Warping
Some materials are more prone to warping than others. As a general rule of thumb, materials that require a higher printing temperature are more prone to warping and shrinkage because the temperature difference is more extreme as they cool.
Filament materials with higher-temperature printing often require heated beds, bed adhesives, and printing enclosures to minimize warping and shrinking.
The following is a list of 3D printing materials prone to warping:
- ABS (Acrylonitrile Butadiene Styrene) is a common material in 3D printing, known for its strength and durability. ABS is prone to warping, caused by its higher printing temperature of 220–250 °C. To reduce warping when printing with ABS, use a heated build platform and an enclosed printer.
- ASA (Acrylic Styrene Acrylonitrile) is similar to ABS but offers better durability and higher UV resistance. ASA is one of the best filaments for outdoor applications, but, like ABS, the filament is prone to warping.
- Nylon is a synthetic polymer that is flexible, strong, and wear-resistant. The filament has a reputation for being difficult to print, primarily because of its high shrink rate while it cools. As a result, nylon filament is exceptionally prone to shrinkage as it cools.
- PETG (Polyethylene Terephthalate Glycol) has gained popularity due to its toughness and ability to produce high-quality prints. Although PETG is considered less prone to warping than ABS, it can still suffer from this issue if not properly managed. Maintaining optimal printing temperatures, using a heated bed, and ensuring good adhesion to the build plate will all help to minimize warping with PETG.
- PC (Polycarbonate) is a high-performance material known for its strength, rigidity, and high heat resistance. The favorable mechanical properties are why PC is commonly used in engineering applications. However, PC is a high-temperature material prone to warping due to its high shrinkage rate when cooling. To minimize warping while working with this material, it’s essential to use a heated build platform, maintain a consistent ambient temperature, and ensure proper bed adhesion.
In summary, some common 3D printing materials, like ABS, ASA, Nylon, and PC, are more prone to warping due to their shrinkage characteristics during the cooling process. PLA, PETG, and flexible filaments like TPU may also warp, but less frequently.
It’s essential to understand the tendencies of each material and adjust your printing techniques accordingly to prevent warping and achieve successful, high-quality prints.
How to Fix a Warped 3D Print
Most cases of 3D print warping are not fixable. But if the warping is minor, fixing it using a DIY method may be possible.
Below are the steps you can take to fix warping:
- Grab a flat metal surface, like a frying pan.
- Place the print warp side down in the same orientation it was printed.
- Using a hair dryer on high heat, warm the frying pan and print. Move the hair dryer in circular motions to evenly heat the entire part. You can also use a heat gun on small prints, but we prefer the hair dryer because its lower temperature makes it easier to get an even heat across the print.
- After 1-2 minutes, the print should be malleable.
- Gently press down on the print to bend the first layer back into a flat shape.
- Repeat steps 1-5 until the bottom of the print flattens.
Some people suggest placing the print back on the heated bed. We don’t recommend this method because the heated build plate only heats the first few layers.
After testing both methods, we’ve found that heating the entire print on a metal surface provides the best chance at fixing a warped part.
Frequently Asked Questions
Why Are My 3D Prints Curling Up At The Edges?
Curling occurs due to material shrinkage during printing when your 3D prints cool unevenly. The uneven cooling causes the plastic to contract, forcing edges to warp and lift away from the build plate. Several factors can lead to this issue, such as incorrect printer settings, inadequate bed adhesion, and fluctuations in ambient temperature.
How Do I Stop PLA From Warping On A Glass Bed?
To prevent PLA from warping on a glass bed, ensure the print surface is clean, and you’re using a heated bed. You can further improve first-layer adhesion by using bed adhesives like hairspray, glue sticks, or painter’s tape.
