PLA (Polylactic Acid) is one of the most popular 3d printing filaments, prized for its ease of use and eco-friendly composition. But even seasoned makers occasionally struggle with curled edges and warped prints—an issue that can compromise part quality, functionality, and aesthetics. If you’ve found yourself wondering how to flatten curled edges in PLA or prevent them from happening in the first place, you’re in the right place.
In this in-depth guide, we’ll explore why PLA edges curl, how to fix it mid-print (or after), and the top strategies to avoid this frustrating issue altogether. Whether you’re a hobbyist or a pro, these expert-backed insights will help you get smooth, flat prints every time.
What Causes PLA to Curl at the Edges?
Before you fix curled PLA edges, it’s important to understand why curling happens. PLA curling, also known as “warping” or “edge lift,” typically occurs due to temperature fluctuations, poor bed adhesion, or environmental factors.
Key causes include:
- Poor first-layer adhesion: If the first layer doesn’t stick well, corners lift as the print progresses.
- Incorrect bed temperature: A bed that’s too cold won’t keep PLA adhered during cooling.
- Fast cooling rate: Drafts or fans cooling PLA too quickly can cause uneven shrinkage.
- Uneven or dirty print bed: An unlevel surface or greasy build plate can reduce contact and adhesion.
Knowing the cause lets you apply the right fix, so let’s get into that.
How to Flatten Curled PLA Edges (Fixes & Techniques)
1. Use a Heated Bed at the Right Temperature
PLA typically adheres well between 50°C and 60°C. Start with 60°C and reduce only if necessary. A heated bed slows cooling and promotes better edge retention.
Pro Tip: If your printer doesn’t have a heated bed, try using blue painter’s tape or a glue stick for a better grip.
2. Level Your Print Bed Perfectly
Uneven surfaces cause poor contact, making edges more prone to curling. Use a piece of paper or feeler gauge to ensure uniform nozzle height across the bed.
Bonus: Consider auto-bed levelling systems like BLTouch or CR Touch for more consistent calibration.
3. Slow Down Cooling and Use an Enclosure
Turn down or redirect part-cooling fans during the first few layers. Enclosures help maintain ambient temperature and eliminate drafts.
Related Term: Warping in PLA due to airflow or sudden temperature drops is a common failure mode.
4. Apply Adhesion Promoters
Use adhesives like:
- Glue stick (Elmer’s or similar)
- Hairspray (unscented and strong hold)
- Magigoo or Layerneer Bed Weld for more professional applications
Apply a thin layer before printing to enhance stickiness.
5. Print with a Brim or Raft
These built-in slicer settings create a temporary base around your model to improve first-layer grip and prevent edge lift.
- Brim: Adds outer rings for stability
- Raft: Lays down a full base layer under the print
In Cura: Go to Build Plate Adhesion > Select Brim or Raft
6. Increase First Layer Temperature & Flow Rate
Raise the nozzle temperature by 5-10°C for the first layer. Slightly increase flow rate (e.g., 105%) to ensure good squish and adhesion.
7. Sand or Heat-Treat Post-Print Edges
If curling occurs late in a print and minor, you can:
- Use a heat gun to warm curled areas and press them flat gently
- Place under a heavy, flat object while still warm to reset the shape
- Sand down curled corners for cosmetic improvement
These post-processing techniques work best for non-functional or decorative parts.
Preventative Measures for PLA Edge Curling
Fixing is great, but prevention is better. Here are long-term strategies to minimise edge curling:
- Store PLA in a dry environment: Moist filament causes inconsistent extrusion
- Use a PEI sheet, BuildTak, or textured bed for improved grip
- Print slower for the first layer: Speeds between 20-30 mm/s improve accuracy
- Enable skirt or brim: Adds thermal stability at the start
- Upgrade cooling control: Dual-fan setups or directional ducts help regulate airflow
Consistency is key. Once you dial in the perfect settings, save them as profiles in your slicer (e.g., Cura, PrusaSlicer).
Real-World Applications: Why Flat Edges Matter
- Functional Prints: Enclosures, gears, brackets, and cases need flat bases for proper alignment
- Aesthetic Models: Displays, toys, and art prints look better when not warped or curled
- Print Bed Reusability: Curling can damage print beds or leave residue over time.
Whether you’re printing miniatures or machine parts, flat prints mean stronger adhesion, better fit, and fewer reprints.
READ MORE – 3d Printing Christmas Star: Ultimate Guide to Festive Creations
FAQs:
Q1: Why does my PLA print keep lifting at the corners?
A: This is likely due to poor bed adhesion, uneven bed levelling, or too fast cooling. Check the bed temperature and surface, and use a brim or glue stick.
Q2: Can I fix a curled PLA print after it finishes?
A: Yes. Apply heat gently with a heat gun or hot water, then press flat. Be cautious to avoid melting details.
Q3: Does glue stick really help with PLA prints curling?
A: Absolutely. It enhances bed adhesion and is a go-to method for many 3d printing enthusiasts.
Q4: Should I disable the cooling fan to prevent PLA warping?
A: Not entirely. Reduce fan speed for the first few layers, then return to 100%. Full disabling may affect overhangs and details.
Q5: What build plate surface is best for PLA?
A: PEI sheets, glass with glue, and textured spring steel sheets all offer excellent PLA adhesion.
Useful Tools & Resources
- Cura Slicer Settings Guide (Official Ultimaker)
- MatterHackers PLA Printing Guide
- Prusa Knowledge Base on Warping
Internal Links for Further Reading
- How to Calibrate the First Layer in 3d Printing
- Best Build Surfaces for PLA
- Top 3d Printer Upgrades for Better Adhesion
Conclusion:
Flattening curled edges in PLA 3d printing is completely manageable with the proper techniques, tools, and mindset. From levelling your bed to adjusting cooling and using adhesion aids, every detail matters. As you gain experience and test different materials, your prints will look better and perform better.
Start with one or two changes and iterate until you find your perfect setup. A little patience and tweaking go a long way in mastering PLA printing!
