Why Prints Warp
Warping happens when the bottom of a print cools and contracts faster than the top. The bottom contracts, pulling the corners up off the bed. Severe warping causes the print to detach mid-job; mild warping leaves you with curled corners that look ugly.
The materials most prone to warping:
| Material | Warp Risk | Mitigation |
|---|---|---|
| ABS | Severe | Enclosure required |
| ASA | Severe | Enclosure required |
| Nylon | Severe | Enclosure + drying |
| PETG | Moderate | Brim + heated bed |
| PLA | Mild | Usually a bed-adhesion issue |
| TPU | Rare | Doesn’t really warp |
If you’re printing ABS on an open-frame printer, the fundamental issue is the printer, not your settings. No amount of brims, glue, or temperature tweaking will fully fix a $200 bedslinger trying to print ABS in a 22°C room.
The Real Fix: Enclosure
The fundamental cause of warping is temperature differential between the top and bottom of the print. The fix is to eliminate that differential by keeping the entire print at a consistent elevated temperature.
That’s what an enclosed printer does. The chamber holds 40-60°C, so the bottom layers don’t cool faster than the top layers.
If you’re getting persistent warping with ABS or ASA, the answer is a real enclosed printer. See Best Enclosed 3D Printer for current recommendations.
Workarounds for Open-Frame Printers
If you’re stuck with an open printer and need to fight warping, here’s the order of operations:
1. Maximize Bed Temperature
Push the bed to its maximum:
- ABS: 110°C
- PETG: 90°C
- PLA: 70°C (most printers cap here)
Hot beds keep the lowest layers above the glass transition temperature longer, reducing the rate of contraction.
2. Add a Brim or Raft
- Brim: 8-12 line outline around the base. Adds 30 seconds per print.
- Raft: Full sacrificial first layer. Adds 5-15 minutes and wastes filament. Reserve for severe cases.
3. Use the Right Adhesion Aid
- PLA on PEI: Nothing needed
- PETG on PEI: Glue stick (use as release agent — PETG sticks too well to PEI and can chip it)
- ABS on PEI: Glue stick or ABS slurry (ABS dissolved in acetone, painted on the bed)
- Nylon on PEI: Glue stick
4. Eliminate Drafts
Open windows, ceiling fans, AC vents — anything blowing room-temperature air on the printer accelerates cooling and worsens warping.
For DIY cases:
- Place the printer in a closet or alcove
- Build a tent enclosure from PVC pipe and plastic sheeting (cheap, surprisingly effective)
- Use the IKEA Lack table mod (popular DIY enclosure)
5. Disable Cooling Fans for ABS
For ABS, the part cooling fan should be off (or very low — 10% max). Cooling fans accelerate the temperature differential and worsen warping.
For PLA: the opposite — fans should be at 100%.
6. Reduce First-Layer Width and Slow It Down
Wider first-layer lines + slower first-layer speed = better adhesion. Try:
- First-layer line width: 120-150% of nozzle diameter (so 0.48-0.60mm for a 0.4mm nozzle)
- First-layer speed: 20mm/s
Warping by Print Geometry
Some prints warp more than others, even with identical settings:
High-Risk Geometry
- Large flat bases — more contraction = more lift
- Sharp 90° corners — concentrate warping forces
- Tall thin walls — flex and amplify warping
- Narrow contact area on tall prints — physics is against you
Lower-Risk Geometry
- Small parts (under 50mm)
- Rounded bases — distribute warping forces
- Heavy infill near the base — adds mass to resist contraction
- Multiple smaller parts vs one large part
If a model warps repeatedly, try splitting it into smaller pieces and gluing them after. Smaller prints warp less.
Materials That Won’t Warp
If warping is killing you and you need a result, switch to a material that doesn’t warp:
- PLA — almost never warps
- PLA+ — almost never warps
- PETG — mild warping, manageable
- PCTG — PETG variant with even less warping
- Tough PLA — engineering-grade PLA blends
For functional parts that you’d normally make in ABS, PETG or PLA+ often work — they’re not as heat-resistant, but they print on any printer without an enclosure.
See PLA vs ABS and PETG vs ABS for material trade-offs.
When You’ve Done Everything and It Still Warps
If you’ve enclosed the printer, maxed the bed, used a brim, switched materials, and it still warps:
- Bed surface is contaminated or worn — wipe with IPA, replace if PEI is scratched
- Bed isn’t actually at the temperature it reports — check with an IR thermometer
- Print is structurally cursed — too large for your printer’s capabilities
For severe cases, large ABS prints simply require commercial-grade equipment (heated chambers above 80°C). That’s a $2000+ printer, not a $400 one.
Related Issues
- First Layer Not Sticking — the bigger sibling of warping
- How to Fix Bed Adhesion — general adhesion problems
- Best Enclosed 3D Printer — if you’ve decided to fix it the right way