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3D Printing Troubleshooting Guide

Find your print problem, see what usually causes it, and follow the fixes in order. Covers 21 common FDM and resin issues.

Print not sticking to the bed

The first layer peels up, drags around or the print comes loose partway through.

FDM

Likely causes

  • Nozzle too far from the bed (Z offset)
  • Dirty or greasy build plate
  • Bed not level or not hot enough
  • First layer printing too fast

How to fix it

  1. Wash the plate with warm water and dish soap, then avoid touching it
  2. Lower the Z offset in small steps until the first layer is slightly squished
  3. Run bed leveling and raise bed temperature by 5 °C
  4. Slow the first layer to around 20 to 30 mm/s
  5. Add a brim, or use glue stick for PETG and nylon

Warping and lifting corners

Corners or edges of the part curl up off the bed as the print grows.

FDM

Likely causes

  • Plastic shrinking as it cools
  • Drafts or a cold room
  • Weak bed adhesion
  • Material that needs an enclosure, such as ABS or ASA

How to fix it

  1. Use an enclosure for ABS, ASA, nylon and PC
  2. Add a brim or mouse ears on corners
  3. Increase bed temperature within the material range
  4. Reduce part cooling fan for the first layers
  5. Keep the printer away from fans, windows and air conditioning

Stringing and oozing

Fine hairs or webs of plastic stretch between separate parts of the model.

FDM

Likely causes

  • Nozzle temperature too high
  • Retraction too short or too slow
  • Wet filament
  • Slow travel moves

How to fix it

  1. Lower nozzle temperature in 5 °C steps
  2. Increase retraction distance or speed a little at a time
  3. Dry the filament, especially PETG and TPU
  4. Enable travel avoid crossing perimeters and increase travel speed
  5. Print a stringing test after each change

Under extrusion

Gaps between lines, thin walls, missing layers or a spongy, weak print.

FDM

Likely causes

  • Partial nozzle clog
  • Temperature too low for the speed
  • Printing faster than the hotend can melt
  • Worn extruder gear or slipping filament
  • Tangled spool or too much feed friction

How to fix it

  1. Raise nozzle temperature by 5 to 10 °C
  2. Slow down or lower the volumetric flow limit
  3. Clean or replace the nozzle
  4. Check extruder tension and gear for ground filament dust
  5. Make sure the spool turns freely
  6. Calibrate flow rate and E-steps

Over extrusion

Blobby surfaces, rough top layers, ridges and parts that come out oversized.

FDM

Likely causes

  • Flow rate set too high
  • Incorrect filament diameter in the slicer
  • E-steps too high

How to fix it

  1. Run a flow rate calibration and lower flow in small steps
  2. Confirm filament diameter is set to 1.75 mm (or 2.85 mm)
  3. Recalibrate E-steps

Clogged nozzle

Little or no plastic comes out, or the extruder clicks and skips.

FDM

Likely causes

  • Burnt material or debris in the nozzle
  • Heat creep softening filament too early
  • Nozzle too close to the bed on the first layer
  • Abrasive filament through a brass nozzle

How to fix it

  1. Heat the nozzle and do a cold pull with nylon or PLA
  2. Clear it with a cleaning needle while hot
  3. Replace the nozzle if the clog stays
  4. Check the hotend cooling fan is working
  5. Use a hardened steel nozzle for carbon fiber and glow filaments

Layer shifting

Part of the print is offset sideways, as if the layers suddenly jumped.

FDM

Likely causes

  • Loose belts or pulleys
  • Nozzle hitting a curled up part
  • Moving too fast with high acceleration
  • Motors or drivers overheating

How to fix it

  1. Tighten belts and check pulley set screws
  2. Reduce speed and acceleration
  3. Fix warping or curling that the nozzle can hit
  4. Enable Z hop on travel moves
  5. Make sure nothing blocks the print head or bed

Elephant's foot

The bottom few layers bulge outward wider than the rest of the part.

FDM

Likely causes

  • Nozzle too close on the first layer
  • Bed temperature too high
  • Heavy part pressing on soft lower layers

How to fix it

  1. Raise the Z offset slightly
  2. Lower bed temperature by 5 °C
  3. Use elephant foot compensation in the slicer
  4. Add a small chamfer to the bottom edge of your model

Ghosting and ringing

Faint ripples repeat on the surface next to sharp corners, holes or text.

FDM

Likely causes

  • Printer vibrating at high speed
  • Loose frame, belts or print head
  • High acceleration

How to fix it

  1. Enable or calibrate input shaping if your printer supports it
  2. Lower acceleration and outer wall speed
  3. Tighten frame bolts and belts
  4. Place the printer on a solid, heavy surface

Z banding

Regular horizontal lines or ridges run up the sides of the print.

FDM

Likely causes

  • Wobble in the Z lead screw
  • Bed temperature swinging up and down
  • Layer height not matching Z motor steps

How to fix it

  1. Check the Z rod for bends and clean and lubricate it
  2. Tune the bed heater (PID tune)
  3. Use layer heights that are multiples of your Z step size, such as 0.12, 0.16 or 0.2 mm

Gaps or holes in top layers

Top surfaces look bumpy or show holes over the infill, sometimes called pillowing.

FDM

Likely causes

  • Too few top layers
  • Infill too sparse
  • Weak cooling for the top surface

How to fix it

  1. Increase top layers to 5 or more, or set a top thickness around 0.8 to 1 mm
  2. Raise infill density a little
  3. Increase part cooling fan speed for top layers
  4. Turn on ironing for flat tops

Poor overhangs and bridges

Drooping, curled or messy edges where the model extends over empty space.

FDM

Likely causes

  • Not enough cooling
  • Speed too high or too low for the bridge
  • Overhang angle too steep without supports

How to fix it

  1. Increase part cooling fan speed
  2. Tune bridge speed and flow in the slicer
  3. Add supports for overhangs beyond about 45 degrees
  4. Rotate the model to reduce overhangs

Supports are hard to remove

Supports fuse to the model and leave rough or damaged surfaces.

FDM

Likely causes

  • Support Z distance too small
  • Support interface too dense
  • Temperature too high

How to fix it

  1. Increase support top Z distance to about one layer height
  2. Use support interfaces or tree supports
  3. Try a different material for interfaces where your printer supports it
  4. Lower nozzle temperature slightly

Spaghetti mess

The print breaks loose and the printer extrudes tangled strands into the air.

FDM

Likely causes

  • Print detached from the bed
  • Tall thin part knocked over
  • Missing supports

How to fix it

  1. Fix bed adhesion first
  2. Add a brim to tall, narrow parts
  3. Add supports where needed
  4. Use a printer with failure detection if you print unattended

Blobs and zits on the surface

Small bumps appear on outer walls, often lined up where layers start.

FDM

Likely causes

  • Seam position at random points
  • Oozing during retraction
  • Pressure building up at layer changes

How to fix it

  1. Set seam position to aligned or rear
  2. Tune retraction and enable wipe on retract
  3. Calibrate pressure advance

Popping sounds and bubbles

You hear crackling while printing and see rough, bubbly lines.

FDM

Likely causes

  • Moisture inside the filament

How to fix it

  1. Dry the filament in a filament dryer or oven at a safe temperature for that material
  2. Store spools sealed with desiccant afterward

Resin print not sticking to the build plate

The print stays stuck to the FEP film or the vat instead of the plate.

Resin

Likely causes

  • Build plate not leveled
  • Bottom exposure time too short
  • Plate surface too smooth
  • Resin or room too cold

How to fix it

  1. Re-level the build plate using the manufacturer method
  2. Increase bottom exposure time
  3. Lightly sand the build plate if it is very smooth
  4. Warm the room and resin to about 20 to 30 °C

Layer separation in resin prints

Layers split apart, or the print shows cracks and shifted sections.

Resin

Likely causes

  • Normal exposure time too short
  • Lift speed too fast
  • Loose build plate or vat
  • Poorly supported large cross sections

How to fix it

  1. Increase normal exposure time a little
  2. Reduce lift speed
  3. Tighten the build plate and vat screws
  4. Hollow and tilt large models to reduce suction forces

Resin supports failing

Parts of the model are missing or supports break off during printing.

Resin

Likely causes

  • Supports too thin or too few
  • Islands with no support
  • Lift forces too high

How to fix it

  1. Use medium or heavy supports for heavier areas
  2. Check the slicer for unsupported islands
  3. Tilt the model at an angle
  4. Reduce lift speed

Cloudy or damaged FEP film

Prints fail in the same spot, or the film looks scratched, cloudy or punctured.

Resin

Likely causes

  • Worn or scratched FEP
  • Cured resin left in the vat after a failure
  • Tools used inside the vat

How to fix it

  1. Replace the FEP film when it is cloudy, dented or damaged
  2. After a failed print, clear cured bits with a plastic scraper or a quick full screen exposure
  3. Never use metal tools inside the vat

Sticky or tacky resin prints

The print stays sticky or soft after washing and curing.

Resin

Likely causes

  • Incomplete washing
  • Not enough UV curing
  • Old or contaminated alcohol

How to fix it

  1. Wash in two stages, first dirty then clean alcohol
  2. Let prints dry fully before curing
  3. Cure longer under UV, turning the part for even coverage
  4. Replace saturated isopropyl alcohol

No problems match. Try a different word, such as warping or clog.

Quick checklist before every print

  • Clean the build plate
  • Check the first layer as it prints
  • Confirm the right material profile is selected
  • Make sure the spool turns freely
  • Use dry filament
  • Check the nozzle is clean
  • Confirm supports where overhangs need them
  • For resin: stir the resin and check the FEP

Many problems come down to the material. Check the right settings in the Material Guide, or look up a term in the Glossary.