ABS Curling Or Warping: 5 Proven Fixes (Do This!)

ABS is one of the 3D printing materials most notorious for warping. This defect can single-handedly ruin your otherwise perfect prints, so knowing how to prevent it can help you avoid the loss of time and material.

The material’s high melting point is the main cause of ABS curling. This filament type can remain solid at temperatures above 100°C, and it solidifies quickly after extrusion. Thus, the layers don’t have time to adhere to one another properly, and the corners warp. 

This guide covers the most common warping reasons and shows you how to fix the issue.

Why Is ABS Prone To Warping?

ABS curling majorly happens due to the material’s temperature sensitivity and fast shrinkage.

Bad adhesion due to a dirty or poorly leveled build plate can also lead to curling, especially in the first layers. 

Temperature Sensitivity  

ABS is one of the most temperature-sensitive materials, suffering when the hot end or bed temperature is too low. 

This type of plastic has a melting point of about 200°C, meaning that you must set the nozzle temperature higher than that to ensure proper extrusion.

At the same time, the bed temperature is equally important. An unheated bed would cool off the material too fast, preventing adhesion. 

Other things to consider are the fan settings and the room temperature. ABS is one of the few materials that requires no cooling; the part fan should be turned off completely, while the nozzle fan should be set at no more than 50%. 

You should keep the room temperature constant and preferably around 86°F. A room temperature could work if the printer is perfectly calibrated, but it shouldn’t go under 77°F.

Shrinkage 

While ABS overhang curling is almost always due to low heat retention, ABS curling up in random spots can happen due to shrinkage. 

In fact, this material can shrink up to 11% when cooling down. Shrinkage happens because ABS is an amorphous thermoplastic. As it heats up during the melting process, the material loses density and expands. 

When it cools down, its density increases again and its volume is reduced. This isn’t a problem as long as the material shrinks uniformly. 

Yet, if the bed is heated unevenly or, for whatever reason, parts of the material cool down faster than others, you’ll likely see it warp.

Slicing Issues 

ABS curls up due to its temperature sensitivity and amorphous nature. So, you may not even consider the settings in your slicer other than temperature and cooling.

The truth is, however, that an incorrect layer thickness or a too fast feed can also be responsible for the ABS edges curling up. 

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How To Prevent ABS From Curling

Knowing why ABS curls is the first step to fixing the issue.

To troubleshoot the problem, start with the printer settings and work your way from there, following the steps below.

1. Calibrate the Printer 

ABS is one of the most difficult thermoplastics due to its sensitivity to temperature fluctuations. The material also requires a higher hot end temperature and a properly heated bed. 

The table below shows the average settings for printing with ABS. You may have to slightly adjust them based on the filament brand, printer, and printing conditions: 

Setting	Value
Nozzle temperature	220°C to 250°C
Bed temperature	90°C to 110°C
Print speed for first	30-45 mm/s
Print speed	60 mm/s
Fan settings	0%

Using the ranges in the table it should be easy to find the perfect calibration for your printer and filament brand. A thing to keep in mind regarding the fan is that you can allow for low-level cooling, as long as you can control the fan speed. 

In this case, setting the fan to 10% to 20% instead of turning it off completely can help prevent overhanging and reduce sagging. If you can’t control the fan power on your printer, turning it off completely is the best thing to do.

2. Level the Bed 

Improper bed leveling is one of the most common causes of first-layer warping when printing with ABS. not only would an uneven bed affect adhesion, but it can also lead to uneven cooling and curling due to shrinking defects. 

As a rule of thumb, you should level the printer bed before starting each new print. You should do that because moving the build plate is easy when removing a printed object from the bed.

There are various ways to level the build surface, but the simplest is by calibrating it manually with a piece of paper. 

1. From your printer’s software menu, select Auto Home to home the print head, then select Disable Steppers. 
2. Using the turning wheels on your printer, lower the nozzle over the adjustment screw until there is only enough space to slide a sheet of paper between it and the bed. 
3. Repeat on each corner, and then double-check to make sure everything is adjusted properly.

3. Use a Support Structure 

Using 3D printing supports is an easy way to prevent warping, especially of the first layer. 

Brims and rafts are especially useful when printing large or delicate parts. The former is ideal for tall, thin structures or particularly large models.

When selecting brims, the machine prints several rings of plastic around your item that enhance support for the first layer while preventing curling. 

Rafts are used when you want to print an entirely new structure under the model. They are ideal for any size print, and are relatively easy to remove.

In addition to support structures, you could also try to improve bed adhesion with enhancers such as glue sticks, painter’s tape, or hairspray. As for the bed surface, ABS is best printed on PEI or a temperate glass surface.

4. Use an Enclosure 

Calibrating the nozzle and bed temperature is the first step to successfully printing with ABS. However, it can sometimes be hard to maintain the room temperature constant or prevent currents of air.

This is where an enclosure steps in, providing a controlled environment for your printer. 

For the best results, you should avoid opening the enclosure throughout the process. It is also best if you could print the entire object in one go, to prevent the total shrinkage of the printed part before continuing from where you left off. 

5. Dry Filament 

If you’re not exactly new to 3D printing, you likely learned by now that drying the filament before printing is crucial.

If you’re new and didn’t know about it, it’s time to find out that ABS is a hygroscopic material that requires drying in the same way PETG does.

Like PETG, ABS absorbs moisture from the air. If the material is wet when you start printing, the water evaporates and creates air bubbles in the extruded filament.

These bubbles add up to the troubles caused by temperature sensitivity and shrinkage, increasing the risk of warping and curling. 

There are various ways to dry ABS filament. The best method is in a filament dryer; these boxes can be set to dry a specific type of filament, wicking moisture without affecting quality.

Alternatively, you could dry the spool in the kitchen oven or in a food dehydrator. 

ABS shouldn’t be dried on a heated bed, nor should it be left in the sun, as the UV rays can compromise its structure.

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ABS Curling In Ender 3 (Pro/V2) and Voron 3D Printers

Like most 3D printing defects, you may notice that ABS curling is more frequent on certain printers. Two of the most affected models are the Ender 3 (Pro/V2) and Voron. 

In Ender 3, you may notice ABS curling even if the printer is calibrated correctly. If you’ve tried all tips for printing ABS in Ender 3 and nothing works, the problem could be insufficient bed adhesion.

A way to fix this is by making your own ABS glue by melting a small quantity of filament in acetone (acetone should have a concentration between 90% and 100%, so nail polish won’t work, but you can find the real deal at chemical stores). 

Smear this “glue” onto the build plate and let it dry before printing. Using an enclosure could also improve results, regardless of the glue type you’re using.

If you’re using a Voron printer, you may have to forget about the fan off advice. On this printer, ABS prints with good results when you’re using an enclosure with the fan set between 30% and 50%.

Before printing, you should also make sure everything is preheated properly. Leave the printer on for at least 10 minutes after heating the nozzle and bed before starting extrusion. 

On this printer, you should also make sure that the temperature inside the enclosure is at least 93°F at all times.

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Frequently Asked Questions

Does ABS warp more than PLA?

Yes, ABS warps more than PLA.

Even if PLA is more brittle and degrades faster in sunlight, it gives fewer problems during printing compared to ABS.

Is ABS toxic to print?

No, ABS is not considered toxic during printing. This is a food-grade material that you can use to make containers.

However, keep in mind that the fumes contain microplastic particles, and their effect on human health is not fully known. Thus, you should avoid breathing these fumes.

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Wrapping Up

ABS is a highly temperature-sensitive material. It is also amorphous, expanding as it heats and shrinking as it cools. Moreover, it is hygroscopic. All these features can make it a nightmare to print with, due to warping and curling. 

To prevent ABS curling, make sure the printer is calibrated correctly for the material you’re using. If possible, use an enclosure and apply adhesion enhancers to the build surface. Using rafts and brims could also help improve print quality when nothing else seems to solve the problem.