How to Print ABS Without Warping or Cracking
Contents
A part printed in ABS keeps its shape at temperatures where PLA would soften, and it also takes impacts well. The trouble starts during the print: ABS shrinks as it cools, corners lift (warping) and tall parts can crack along layer lines (layer separation). The good news is that the fixes are well known: a warm, closed environment, little cooling and a solid first layer. Add ventilation for the smell and particles released during printing.
Safety and ventilation
ABS gives off a noticeable smell and fine particles (UFPs) while printing. These can be irritating.
- Run the printer in a well-ventilated room, away from where you live.
- If you can, add an air purifier with carbon and HEPA filters to the enclosure, or set up a fan system that vents the enclosure air outside.
- Do not stay next to the printer for long while it prints.
- Avoid printing ABS in areas where children and pets spend time.
Enclosure
An enclosure warms the air around the printer so the part cools more slowly and evenly. It is the single most effective measure for ABS.
- The target is an internal temperature of about 40–50 °C. A heated bed alone gets there in a short time.
- You can use a printer that comes with an enclosure, a printer tent, or a wooden or acrylic enclosure.
- Preheating the enclosure with the heated bed for 10–15 minutes before starting works well.
- Keep electronics (power supply, control board) outside the enclosure if possible. Running for long periods in a hot environment shortens their life.
- A smoke detector near the enclosure is a good safety measure. Make sure the enclosure material is non-flammable or slow-burning.
- Open the enclosure door when printing PLA. A hot environment can cause clogs with PLA.
Recommended settings
| Setting | Value |
|---|---|
| Nozzle temperature | 230–260 °C (depends on brand) |
| Bed temperature | 95–110 °C |
| Part cooling fan | 0–20%, 30–50% on bridges and overhangs |
| Print speed | Medium, start at 40–60 mm/s |
| First layer speed | 15–20 mm/s |
| Brim | 5–10 mm |
| Enclosure temperature | 40–50 °C |
Find the right temperature for your own filament by printing a temperature tower.
Build surface
- PEI (textured or smooth): The most practical surface for ABS. It grips well at around 100 °C, and the part releases by itself as it cools. Clean the surface with IPA.
- Glass: Does not hold ABS well on its own. It needs glue stick or a bed adhesive made for ABS.
- ABS slurry: A mixture made by dissolving a little ABS in acetone. Apply a thin coat to the glass. Acetone is highly flammable and its fumes are irritating, so use it only in a ventilated area and away from flames.
Preventing warping and cracking
- Preheat the enclosure and the bed.
- Cut off drafts completely. Do not open the enclosure until the print has finished and the part has cooled.
- Use a brim or corner discs.
- Keep the part cooling fan low.
- On large parts, round off sharp corners. Stress concentrates most at sharp corners.
- When the print is done, let the part cool slowly inside the enclosure. Taking a hot part straight into cold air can crack it.
ASA: a sun-resistant alternative
ASA prints very much like ABS but resists UV light far better. ABS yellows and turns brittle in the sun over time, while ASA keeps its color and strength. ASA is the usual choice for parts that will be used outdoors. Print settings and safety precautions are the same as for ABS.
Smoothing with acetone vapor
Because ABS dissolves in acetone, acetone vapor lightly melts the surface of the part, closing layer lines and giving a glossy finish.
- Acetone is highly flammable. Keep it away from heat sources, sparks and hot surfaces.
- Do this only outdoors or in a very well-ventilated space. Do not breathe the vapor.
- Fine details can be lost and dimensions can change.
- Never heat acetone directly to speed up the vapor.
This process is risky. If you are not sure, sanding and primer paint is a safer way to smooth the surface.
Common problems
| Problem | Fix |
|---|---|
| Corners lift | Enclosure, brim, heat the bed, lower the fan |
| Horizontal cracks in tall parts | Raise the enclosure temperature, turn the fan off, raise the temperature by 5–10 °C |
| Part pulls off the bed | Raise the bed temperature, clean the surface, slow the first layer |
| Bad smell | Add ventilation and a filter |
Frequently asked questions
I do not have an enclosure. Can I print ABS?
Small, low parts can be printed, but warping and cracking are very likely on larger parts. If you have no enclosure and do not need heat resistance, PETG is a more practical choice.
Which is stronger, ABS or PETG?
Impact strength is similar. ABS handles heat better, while PETG is easier to print and holds up better against moisture and many chemicals. Unless heat resistance is critical, PETG is usually the more practical choice.