In short
- First layer: the nozzle a sheet of paper above the bed, a clean bed and a slower start.
- Warping: a brim, a warm bed, no draughts, and a closed enclosure for ABS and ASA.
- Strings: dry filament, retraction and a temperature at the low end of the label's range.
- Most problems start with a dirty bed or damp filament.
The first layer won't stick to the bed
The whole print depends on the first layer. The nozzle should press the filament lightly onto the bed, but not so hard that it scratches it.
A cross-section of the first layer, with the filament lines seen from the side.
What to check:
- Nozzle height. The old method is a sheet of paper between the nozzle and the bed that should drag slightly. Printers with automatic levelling do this themselves, so you only need to adjust the height offset (Z offset).
- A clean bed. One fingerprint is enough to stop PLA from sticking. Wash the plate with warm water and washing-up liquid or wipe it with isopropyl alcohol.
- Speed. Print the first layer more slowly, for example 20–30 mm/s, and without the fan.
- Bed temperature. The range for your material is on the materials pages.
The corners lift (warping)
Cooling plastic shrinks. The upper layers pull the edges inwards and the corners lift off the bed. It happens most often with ABS, ASA and large, flat parts.
A brim helps. It's a few millimetres of thin layer around the model that increases the area holding on to the bed, and you peel it off by hand after printing. A warmer bed also helps, and for ABS and ASA a closed printer enclosure. Avoid draughts and an open window next to the printer.
If you can change the model, round off sharp corners and split very large flat parts into smaller ones.
A warped print usually can't be saved. Stop the print as soon as the corners start to lift.
Strings between parts
When the nozzle travels over an empty space, a little molten filament oozes out and leaves a thin string. The simulator shows how much each cause matters:
Lots of strings. Dry the filament and turn on retraction.
Each of these causes adds strings, moisture and no retraction the most. Switch the settings to see.
- The most common cause is damp filament. See how to dry it.
- Retraction pulls the filament back before a travel move. Too little leaves strings. Too much can clog the nozzle and leave holes in the walls.
- Lower the temperature by 5–10 °C, but don't go below the range on the spool's label.
- A short blast from a heat gun removes the odd hair.
If you'd rather have a finished part than tune the settings, upload the file in our quote. You'll see the price straight away, with no account needed.