How to Stop Your 3D Prints from Curling Mid-Print

Curling is one of the most frustrating problems in 3D printing. You start a print with great first-layer adhesion, but then—midway through the print—corners begin to lift, edges warp, and by the time the part is done (if it finishes at all), it’s uneven, distorted, or cracked.

This issue, known as curling or warping, doesn’t just affect print aesthetics—it can ruin mechanical function, dimensional accuracy, and part stability.

In this comprehensive guide, you’ll learn why 3D prints curl mid-print, how to identify the root cause, and how to stop it from happening using proven techniques for all major filaments.

What Is Curling in 3D Printing?

Curling happens when one part of a printed layer cools faster or contracts more than the rest, pulling upward and detaching from the build plate or from the previous layers.

There are two main types of curling:

• Edge Curling: Corners or borders lift mid-print, especially on flat parts.
• Layer Curling: Higher layers lift or distort, often near overhangs or sharp corners.

Curling may begin subtly but worsen as the print progresses, often leading to:

• Failed prints
• Nozzle collisions
• Cracked or warped components
• Misaligned layers

Why Do 3D Prints Curl? Understanding the Science

Curling is a result of thermal contraction and uneven cooling.

How It Happens:

1. Hot plastic is extruded and adheres to the layer or bed below.
2. As it cools, it shrinks slightly.
3. If cooling happens unevenly—such as in corners or near fans—this causes internal tension.
4. That tension pulls the corners upward, breaking adhesion or warping upper layers.

Filament type, bed temperature, print speed, cooling settings, and part geometry all contribute.

Common Causes of Mid-Print Curling

Let’s explore the most common causes—and how to identify each one.

1. Uneven Cooling from Fans

Excessive part cooling fans cause corners and upper layers to cool too quickly. This is especially problematic for high-temp materials like ABS or Nylon.

Signs:

• Corners curl upward mid-way through the print.
• Curling starts after several layers, not immediately.

Solution:

• Reduce fan speed for mid-layers in your slicer.
• For ABS, disable the part cooling fan entirely.
• Use gradual fan ramping—start with fans off, then slowly increase after the first few layers.

2. Low Bed Temperature

If the bed cools too quickly or doesn’t stay warm enough mid-print, adhesion weakens and corners lift.

Signs:

• First few layers look fine, then edges peel up at layer 10 or 20+.
• Happens more on larger or flat-bottomed parts.

Solution:

• Increase bed temperature to the upper end of your filament’s recommended range.
• Keep the bed temperature consistent throughout the entire print.
• Add insulation under your heated bed to maintain temperature.

3. Incorrect Cooling Settings for the Filament

Some materials are more prone to curling than others.

Solution:

• Adjust fan speed based on filament type.
• Print inside an enclosure for high-temperature materials like ABS, ASA, or Nylon to trap heat.

4. Sharp Corners and Wide Bases

Part geometry plays a big role. Sharp corners contract more as they cool, leading to curling. Flat, wide parts are especially vulnerable.

Signs:

• Curling is isolated to sharp corners or large flat areas.
• Rounded prints stay flat, but square ones don’t.

Solution:

• Add fillets or chamfers in your design to soften sharp corners.
• Use brims or rafts to improve corner adhesion.
• Round the bottom edges slightly in CAD to reduce stress points.

5. Inconsistent Print Speeds and Layer Times

Printing large layers too fast can cause uneven cooling. Conversely, small layers with insufficient cooling time can also deform.

Solution:

• Slow down the print speed, especially for wide areas.
• Use minimum layer time settings to avoid overheating small layers.
• Enable Z-hop to prevent curled edges from being knocked loose.

6. Incorrect or Uneven Bed Leveling

Even if your first layer looks fine, small differences in Z-height across the bed can cause inconsistent bonding that fails later.

Signs:

• Warping begins on one side or corner.
• First layer is too thin in one spot and too thick in another.

Solution:

• Re-level your bed carefully and recheck your mesh (if using ABL).
• Print a bed leveling test pattern to confirm even adhesion.
• Check for bed warping and use mesh compensation if needed.

7. Ambient Temperature or Drafts

Cold air or temperature fluctuations during the print lead to thermal stress and layer warping.

Solution:

• Enclose your printer in an acrylic or DIY enclosure.
• Avoid printing near open windows, vents, or fans.
• Preheat your room or enclosure if printing in a cold environment.

How to Fix Curling Mid-Print: A Step-by-Step Troubleshooting Plan

Use this structured approach to resolve curling:

Step 1: Recalibrate the First Layer

• Re-check bed leveling and Z-offset.
• Use a brim or raft to anchor corners.
• Apply an adhesive like glue stick or Magigoo if needed.

Step 2: Adjust Print Cooling

• Reduce part cooling fan speed after the first few layers.
• Use slicer settings to gradually ramp up cooling.
• For ABS, ASA, or Nylon, disable cooling and use an enclosure.

Step 3: Tune Bed Temperature

• Increase bed temp by 5–10°C above your current setting.
• Make sure the bed stays at target temp throughout the print.
• Insulate the bed underside for stable heat.

Step 4: Modify Your Slicer Settings

• Slow down outer wall speed to improve bonding and surface quality.
• Increase flow rate for better layer adhesion.
• Enable ironing or extra overlap for flat surfaces.

Step 5: Redesign Problem Areas

• Add mouse ears or brims in slicer to keep corners down.
• Modify the model to round sharp corners or reduce cross-section width at the base.
• Use gradual overhang angles rather than steep drops.

Advanced Tips for Curling Prevention

If you’ve tried the basics and still struggle with curling, here are more expert-level solutions.

Use a Heated Chamber or Passive Enclosure

Materials like ABS and Nylon benefit from printing in a heated or enclosed environment. Enclosures stabilize temperature and prevent rapid cooling.

• DIY enclosures can be made from IKEA Lack tables, acrylic sheets, or polycarbonate panels.
• Keep electronics cooled separately if temperatures exceed 50°C.

Apply Build Plate Adhesives Strategically

Different adhesives suit different materials:

Clean the bed regularly and reapply adhesives to avoid residue build-up or uneven adhesion.

Use Draft Shields or Skirts

Enable draft shields in your slicer to print an extra wall around the part, blocking airflow and drafts. This stabilizes temperature and helps tall or thin parts stay consistent.

Upgrade Your Bed Surface

Your bed surface material makes a difference:

• Glass beds are great for PLA but may cause PETG to stick too well.
• Textured PEI sheets offer consistent adhesion for PLA, PETG, and TPU.
• Garolite (G10) works well with Nylon and other technical materials.

Make sure the surface is flat and clean.

Common Myths About Curling

“It’s always a bed leveling issue.”
Not always. Many prints start well but warp due to mid-print cooling, poor geometry, or wrong settings.

“I need more fan to cool the print.”
Too much fan is a problem for materials like ABS or Nylon. Controlled cooling is key.

“Brims solve everything.”
Brims help, but they’re only part of the solution. Temperature, geometry, and cooling still matter.

Frequently Asked Questions (FAQ)

Why does my print curl halfway up instead of on the bed?
This is usually caused by excessive cooling or layer separation from internal stress. Reduce fan speed and check ambient temperature.

Do flexible filaments curl?
TPU and other flexibles rarely curl due to their low shrink rate, but improper cooling or overhangs can still cause distortion.

How do I know if it’s my filament?
Low-quality or moisture-laden filament can cause inconsistent extrusion and poor layer bonding, which contributes to curling. Always store filament dry and buy from trusted brands.

Can I fix a print that started curling mid-print?
Sometimes. Pause the print, apply glue to the lifted edge, and resume carefully. However, this is rarely a permanent solution.

Conclusion

Curling can be a stubborn and frustrating issue in 3D printing, especially when it happens mid-print after hours of progress. But with the right diagnosis and a few key adjustments, you can eliminate curling for good.

Focus on controlling heat, managing cooling, refining your part design, and ensuring strong bed adhesion. Whether you’re printing PLA, ABS, PETG, or Nylon, the strategies in this guide will help you print smoother, flatter, and more reliable parts.

Take the time to dial in your settings, test different solutions, and keep refining your process. With patience and practice, curling will become a problem of the past.