Common Beginner Mistakes

Mistakes on any printer

1. Skipping the maker's setup

New printers come with a setup wizard, calibration routine and slicer profiles made for that machine. Prusa, for example, recommends running the self-test on a new CORE One+ even though the printer was tested at the factory. Skipping that step, or starting from a random profile found online, removes the one known-good baseline you have. Run the wizard, use the maker's slicer profile, and print the maker's own test file before anything else. Your First FDM Print walks through the order.

2. Changing several settings at once

When a print goes wrong, it is tempting to change temperature, speed, retraction and cooling together. If the next print improves, you do not know which change helped; if it gets worse, you do not know which hurt. Change one setting, print, compare. Calibration has an order for the same reason: OrcaSlicer's calibration guide says to follow its tests in sequence because each test builds on the results of the ones before it, and to repeat filament calibration for each new filament.

3. Trusting a model's size

A model file does not guarantee the size you expect, especially one drawn by someone else. Check the dimensions in the slicer before printing anything that has to fit; the unit problem is explained in STL, 3MF, OBJ, STEP and G-code.

4. Not checking the preview

The slicer's layer preview shows supports, gaps, thin walls and parts floating in mid-air before you spend hours printing them. Step through it every time you slice something new.

FDM mistakes

5. A greasy bed

Prusa's setup guide names a greasy print sheet as the number one cause of prints detaching from the surface, and says to degrease it with isopropyl alcohol if you have touched it. Handle the sheet by its edges, and clean it with what your sheet maker approves. Prusa adds that you do not have to clean before every print if you have not touched the surface.

6. Crushing the first layer to make it stick

When a print will not stick, lowering the nozzle until the first layer is squashed flat seems to work. Prusa specifically warns against compensating for poor adhesion this way. A good first layer is flattened but not crushed, with no gaps and no ridges; see First Layer Fundamentals. If it still will not stick at the right height, the cause is elsewhere (cleaning, temperature, surface), and First Layer Won't Stick lists them in order.

7. Ignoring wet filament

Prusa states that most FDM materials are hygroscopic and that moisture can cause poor layer adhesion, blobs, bubbling and smoke during extrusion. Beginners often chase these symptoms with slicer settings when the spool is the problem. Store filament sealed with desiccant, and dry it when the symptoms appear. See Drying and Storing Filament.

8. Using someone else's temperatures

Temperatures, speeds and retraction that work on another person's printer with another brand of filament are not a setting for yours. Start from your slicer's profile for the filament and the range printed on the spool or the maker's data sheet, then tune with a temperature test.

9. Walking away from a first print

Watch at least the first layer of every new print. A bad first layer is cheap to stop and fix in the first minutes, and expensive to discover hours later.

Resin mistakes

10. Handling resin with bare hands

Formlabs warns that skin contact with liquid resin may cause an allergic skin reaction. Wear nitrile or neoprene gloves (Formlabs says not latex) when handling liquid resin, printer parts or unwashed prints.

11. Cleaning skin with alcohol

Isopropyl alcohol cleans prints, but Formlabs says not to use alcohol, hand sanitizer or other solvents to remove resin from skin. Wash with soap and water.

12. Never pour resin or rinse liquid down the drain

Formlabs says liquid resin, resin dissolved in solvent, partially cured resin and anything contaminated with liquid resin must be disposed of according to environmental regulations. That includes rinse water from water-washable resin. See Setting Up a Safe Workspace.

13. Storing resin badly

Formlabs advises storing resin according to its SDS, away from direct sunlight, in a dry, cool, well-ventilated place, and pouring it into a separate opaque container rather than leaving it in the tank for long-term storage.