3D Prints Warping or Curling Up? Here’s How to Prevent It

Key Takeaways

• What is warping and curling? They are problems that occur when 3D prints cool unevenly and contract, causing the corners or edges to lift up.
• How to prevent warping and curling? There are several solutions, such as using a heated bed, an enclosure, a fan, an adhesive, a brim or a raft, and adjusting the print speed and Z-offset.
• Which filaments are more prone to warping and curling? ABS, ASA, Nylon, and PC are more sensitive to cooling than PLA and PETG, and require higher temperatures and better adhesion.
• How to fix warped or curled prints? You can try to heat up the print in a metal pan with a hairdryer and press it down until it flattens. This may not work for thick or large prints.

Warping is one of the most common problems encountered in 3D printing. It causes the corners of your prints to curl up, making them look worse, and can even cause your print to pop off the heated bed and fail completely.

The main reason for warping is cooling too quickly after 3D printing, which causes contraction and stress, especially at the corners. The key to controlling warping is slow and steady cooling.

By the end of this guide, you’ll be back to producing crisp prints without any warping or curling – so let’s walk through it. I’ve also included a sneaky trick to recover your warped prints at the end.

1. Extruder Temperature
2. Heated Bed
3. Enclosure Temperature
4. Ambient room temperature
5. Adjust cooling fans
6. Use the right adhesive
7. Clean Your Build Surface
8. Slow down print speed
9. Print with brims or rafts
10. Print with mouse ears
11. Print with rounded corners
12. Check your Z-Offset

What Causes Warping or Curling?

3D printer warping problems typically occur when an object cools unevenly after printing, usually from cooling too quickly.

Cooling causes contraction, and this contraction causes stress along the object’s lateral surfaces. The quicker the cooling occurs, the greater the stress on the object.

This stress is greatest at corners where two sides meet. There, the pulling stress exerted on both sides causes the corner of the object to deform and pull up and inward. The result is not pleasing to the eye and usually makes the object unusable.

The Best Ways to Prevent 3D Print Warping and Curling

1. Correct Temperature Settings

The following temperature settings affect warping:

• Extruder temperature
• Heated bed temperature
• Enclosure temperature
• Control the room’s temperature
• Adjust cooling fans

Extruder Temperature – For Your Filament Material

Different filaments are more prone to warping than others. PLA barely warps, and doesn’t even require a heated bed, while ABS is very prone to warping.

If you get warping with PLA on a heated bed, you’re probably printing too hot. If you’re getting warping with ABS, the heated bed is probably not hot enough.

Hot first layers can also cause an issue called elephant’s foot, which you can see below:

Heated Bed

Heated beds maintain a high temperature, so printed layers cool far more slowly. This reduces the stress caused by contraction from faster cooling, which reduces warping.

However, some heated beds do not cover the entire 3D printer bed, so the edges of larger prints may not get hot enough to prevent warping. The diagram below shows the common causes of warping:

For another example, check out this thermal image of a very popular model of 3D printer:

The target temp for this bed is 50°C, notice the cooler area in the center. Commonly this is where people normally place smaller prints. So you may be getting small prints warping, but larger prints staying flat and printing fine. This is because of uneven heating on the heated bed.

Also, if your bed is made of particularly thick aluminum or glass, the thermometer may incorrectly read the full temperature before the surface of the bed has fully heated up. For this issue, wait an extra 10 mins after the bed reads the correct temperature before starting.

Enclosure Temperature

Another way to prevent filament from warping is to keep the ambient print space warm. The best way to do this is by using an enclosure, which is essentially a containment chamber for your 3D printer.

While not needed for PLA and PETG, enclosures are highly recommended when printing ABS and other higher-temp filaments like Nylon and PC. Enclosures trap heat around the print space, which helps prevent warping because the material will cool more slowly when it leaves the hot end, and the layers won’t contract like they would in a cold environment.

While an enclosure alone typically is sufficient for preventing filament from warping, you might need an additional heating element to ensure the enclosure temperature is warm enough. This is usually only necessary if you live in a cold area where it’s more difficult to keep a space warm, and any mini space heater will work.

Ambient room temperature

Slow and steady cooling is essential to preventing warping, so eliminating all drafts while printing is very important. Close any windows or doors that could let drafts in and lead to cold air cooling the print too quickly.

I recommend 3D printing in the room with the steadiest ambient temperature. If your printing location is especially drafty, I recommend a 3D printer enclosure to keep the temperature stable and keep cold air out.

Filaments like ASA are very sensitive to cooling, so print ASA in a warm ambient area with no drafts to prevent warping and cracking.

Adjust cooling fans

The part cooling fans on your 3D printer are another potential cause of warping on 3D prints. If the fan settings are too high (faster), the melted filament will cool too quickly when it leaves the nozzle, causing the material to contract and the layers to warp.

As such, one of the most effective strategies for preventing warping is lowering the fan speed in your 3D slicer settings.

I recommend starting by lowering the fan speed by 20% from its original value, as this usually does the trick. However, if you’re printing ABS, I suggest turning the part cooling fan completely off as this material is more prone to warping than most.

2. Maximize Adhesion: Use the right adhesive and clean your print bed

Use the right adhesive

Using the right 3D printer adhesive is the most important step you can take to eliminate warping. Most printers come with a glass or aluminum build surface that is durable, but also far too smooth.

Extruded filaments have nothing to grab onto when they encounter smooth surfaces. The result is that warping caused by cooling becomes more pronounced.

The solution is to use build surfaces that enhance adhesion. Here are some good options:

• Painter’s tape and Kapton tape both work well to reduce warping in PLA and ABS.
• Hairspray increases build surface adhesion, but it is messy and has limited durability.
• Glue stick is similar to hairspray but is less messy.
• A mixture of ABS slurry or ABS juice on your bed can significantly improve ABS adhesion, which should significantly aid adhesion. 
• PEI sheets attach to your build surface and give excellent adhesion to almost every filament material (except Nylon). PEI is one of the best bed surfaces for avoiding warping.
• Tufnol is an ideal bed adhesive for printing Nylon without warping.

Clean Your Build Surface

Dirt and grease on your print surface reduce adhesion and cause warping. Make sure that your build surface is as clean as possible before you begin printing.

An ammonia-based product like Windex or Halford’s Glass Cleaner works great to remove grease and fingerprints from the build surface. Isopropyl alcohol and water solution also work well.

3. Optimize Your Slicer Settings

These are the key 3D printing settings to prevent warping:

• Reduce print speed
• Print with brims or rafts
• Print with mouse ears
• Print with rounded corners
• Check your z-offset

Slow down print speed

One of the easiest ways to prevent warping is to slow down the print speed in your 3D slicer. By slowing down the printing process, the melted material will have more time to cool down, which reduces the chances of warping.

While you could lower the standard print speed setting in your 3D slicer to combat warping, you really only need to lower the first layer print speed. This setting controls the print speed for only the first few layers of your print, which are the ones most relevant to warping. Plus, by only slowing down the first few layers rather than every layer, you save a lot of print time.

The typical first-layer print speed for PLA and ABS is 20 mm/s. But, if you’re experiencing warping at this speed, I recommend lowering the first layer print speed to 10 or 15 mm/s.

And, if this doesn’t work, you can lower the main print speed setting by 5 or 10 mm/s as a supplemental solution.

Print with brims or rafts

If your print has a low surface area and is proving hard to stick down it may also be worth printing a brim or raft around your print to encourage extra adhesion to the bed.

Brims and rafts are special structures that are added to your model when it’s sliced, and they help the bottom of the print stick to the print surface. Of the two options, rafts are more effective for promoting bed adhesion, but brims consume less filament material. You can check out our article all about brims and rafts to learn more.

Here’s an example:

Print with mouse ears

Similar to a brim or raft, “mouse ears” are another removable structure that can help improve the bed adhesion of your 3D prints. Mouse ears, also called “brim ears”, are small circle features added to the corners of the base of your 3D model.

Mouse ears features are super effective at preventing warping because the corners of a model are the most likely to contract and warp.

Most 3D slicers don’t offer mouse ears as a standard adhesion assistant that you can simply add to a model with a setting. However, you can use mouse ears by manually designing them into your model using basic CAD software like TinkerCAD or Onshape.

Print with rounded corners

Another interesting way to prevent curling at the corners is to design objects that have rounded corners.

Rounded corners warp less than sharp corners, as they distribute the stress better and over a wider area when cooling.

Check Your Z-Offset

The Z-offset on your 3D printer is a setting that controls the vertical position of the nozzle during the printing process. If set too high, the nozzle will be too far away from the print surface and the melted filament won’t stick well enough to the print surface, causing bed adhesion issues such as warping.

As such, it’s important that you check your printer’s Z-offset and lower the value if necessary. You can view and adjust the Z-offset value on your printer’s LCD interface or through a 3D slicer like Cura.

If you think the Z-offset might be too high, I recommend lowering the value in increments of 0.05 mm and checking after each adjustment. As you do this, keep in mind that you never want your extruder nozzle to come too close to the build surface, as this would prevent the filament from flowing out and cause under-extrusion.

How To Recover & Fix a Warped Print

While not all warped prints can be fixed, if the print bottom warping is slight – and your print isn’t too thick or large in volume you might just be able to salvage it. 

To do this, you’ll need to heat up the print close to its glass transition temperature (where it’ll get just soft enough to mold back down).

You’ll need a large metal surface, like a frying pan, big enough to place the print bed side down (just the way up it came off your print bed).

Get a hairdryer and place the print in the pan. Heat it up on full power, and move the dryer around to evenly heat it.

After a minute or so, you can turn off the dryer and you should be able to hold the print down to bend it back to a flat shape. You’ll need to hold it for a few minutes until it’s cooled a bit.

Repeat this process until it works sufficiently. Don’t bother just putting the print back on a heated bed, or worse heating the pan – because this will just heat the bottom of the print. You’ll need to heat it up evenly all over. 

FAQs:

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