A first layer that sticks

What a good first layer looks like

The lines are slightly flattened and touch each other, with no gaps between them and no ridges. You can see the single lines, but you can't push a fingernail between them.

• Round lines that lie loose next to each other: the nozzle is too high.
• A see-through, rough layer, or ridges pushed up between the lines: the nozzle is too low.
• Good on one side and bad on the other: the bed is not level. Run the bed leveling of your printer.

A clean bed fixes most problems

Grease from your fingers is the most common reason a print lets go. Wash the plate with warm water and dish soap, dry it with a clean towel and touch only the edges. Wiping with isopropyl alcohol between prints helps, but soap removes more.

Settings that help

• Print the first layer slowly: 20–30 mm/s.
• Bed temperature: about 60 °C for PLA, 70–80 °C for PETG, 90–100 °C for ABS and ASA.
• Keep the part cooling fan off for the first layer or two. Most slicer profiles already do this.
• A first layer of 0.2–0.28 mm is more forgiving than a thin one.

Warping: corners that lift

Plastic shrinks as it cools, and on a long flat part that pulls the corners up. PLA does this a little, ABS and ASA a lot.

• Add a brim of 5–8 mm in the slicer. It gives the edges more grip and peels off afterwards.
• Keep drafts away from the printer. An enclosure makes the biggest difference for ABS and ASA.
• Large flat models, such as signs and trays, are the ones to watch. Rounded corners lift less than sharp ones.

Small or tall parts

A part with a small footprint, such as a tall pin or a cable clip on its edge, can be knocked over by the nozzle. A brim helps here too. Printing several at once also helps, because each layer gets more time to cool.

Too much grip

PETG can stick so well to a smooth PEI plate that it damages it. Use a textured plate, or a thin layer of glue stick as a release layer. Let the plate cool before you remove a print: most parts then let go on their own.