Misprint Library

Name the failure.
Change one thing.

Match an illustrated FFF clue to 20 rule-based hypothesis paths, then choose one controlled observation or maker procedure.

Find a failure pattern Open Evidence Lab
  • 20rule-based FFF patterns
  • 3patterns per comparison
  • 1variable per test
Read the pattern in the print Three illustrative line studies show a lifted edge, a sideways shift, and regular layers. They are visual cues, not a diagnosis. 01 / LIFT02 / SHIFT03 / COMPARE THE LAYERS
Visible cues are starting evidence, not proof of one root cause.

01 Diagnostic field

Start with what the print is showing you.

Use plain-language clues first. Timing and next-tool filters narrow the field without pretending an illustration proves the cause.

Need to move straight to a tool?

Print never really starts

For an FFF print, record the exact plate, material, profile, and first-layer symptom, then use the printer or profile maker's calibration procedure.

Print Analysis

Failure happens mid-print

Record the first failed layer and inspect the stopped job for detachment, collision, motion, feed-path, or support evidence before changing settings.

Start Print Analysis

Surface looks ugly

Compare the mark with the sliced seam and travel paths, then inspect material condition and the qualified process profile.

Print Analysis

Same defect appears on the same model feature

Treat it as possible file risk. Upload the STL/3MF to Check File or use Saved Upload first for questionable files.

Get a Print Score

02 Pattern atlas

Twenty patterns. One clue at a time.

Each entry separates what is visible from what is merely plausible, then names a first test and the change to avoid while the diagnosis is still open.

How to read these illustrations

These are teaching illustrations, not measured test specimens or diagnosed customer prints. A resemblance does not prove a cause. Confirm the process, observe the failed job, and use the applicable manufacturer procedure.

Loose white filament loops and beads dragged across the build plate instead of fused first-layer lines.
Bed start
Setup / first layer Impact depends on the job

First Layer Not Sticking

The print will not bond to the bed, curls immediately, or drags loose during the first pass.

Appearance cue

The illustration shows loose, unfused first-layer lines; it does not identify which setup variable caused them.

See hypotheses, first observation, and next tool
Looks like
  • Loose lines
  • corners lifting immediately
  • filament beads instead of flattening
Possible causes
  • Z offset too high
  • dirty or wrong build surface
  • bed too cool
  • first layer too fast
  • too much early cooling
First useful test

Identify the exact plate and profile, follow the maker's preparation and first-layer calibration procedure, and change only the variable that procedure identifies.

Do not start a long print until a small patch sticks cleanly.
Best next tool Print Analysis
Thin white rectangular print lifted and bowed away from the build plate at its corners.
Lifted corners
Adhesion / cooling Impact depends on the job

Warping / Lifted Corners

Edges or corners pull upward after a few layers and may eventually knock the nozzle into the part.

Appearance cue

Lifted corners are visible, but the image alone cannot distinguish adhesion, cooling, drafts, or material shrinkage.

See hypotheses, first observation, and next tool
Looks like
  • Corners curl up
  • part bows off the plate
  • later nozzle collision
Possible causes
  • Poor bed adhesion
  • drafts
  • too much cooling
  • material shrinkage
  • footprint too small
First useful test

Record the exact material, plate, profile, orientation, and ambient conditions; compare them with manufacturer guidance and change one supported variable in a short test.

Do not increase nozzle temperature blindly; prove bed grip and draft control first.
Best next tool Print Analysis
Close-up of a white calibration block whose first few layers flare beyond the straight walls above.
Bulged base
First layer / heat Impact depends on the job

Elephant's Foot

The bottom edge bulges wider than the rest of the part, making fitted parts hard to assemble.

Appearance cue

The narrow bottom-layer flare is visible; Z offset, bed heat, and first-layer flow still require controlled tests.

See hypotheses, first observation, and next tool
Looks like
  • Squashed bottom
  • wide first layers
  • holes near the bed too tight
Possible causes
  • Z offset too low
  • bed too hot
  • too much first-layer flow
  • first-layer line width too high
First useful test

Use the printer or profile maker's first-layer calibration and compare a small specimen before changing dimensions or temperatures.

Do not redesign tolerances until the first-layer squish is under control.
Best next tool Print Analysis
Dense fine filament hairs stretched between two white printed towers.
Travel strings
Surface quality Impact depends on the job

Stringing / Oozing

Thin hairs or strands stretch between travel moves, posts, holes, or separate towers.

Appearance cue

Hairs between towers are visible; moisture, heat, retraction, travel, and residual nozzle pressure can look similar.

See hypotheses, first observation, and next tool
Looks like
  • Fine hairs
  • wisps between features
  • small drool marks after travel
Possible causes
  • Wet filament
  • nozzle too hot
  • retraction too low
  • slow travel
  • poor wipe or residual nozzle pressure
First useful test

Follow the exact product's storage or drying procedure, or compare with known-conditioned material, before using the slicer's retraction or temperature calibration.

Do not chase retraction settings if the filament is popping or moisture is likely.
Best next tool Print Analysis
Close-up of a white printed cylinder with scattered bumps and a raised vertical seam.
Surface bumps
Surface quality Impact depends on the job

Blobs, Zits, and Seam Scars

Small bumps, pock marks, or scars show up on the outside wall, often near the seam.

Appearance cue

Bumps and seam marks are visible; correlate them with seam or pause positions before naming a cause.

See hypotheses, first observation, and next tool
Looks like
  • Random bumps
  • seam lumps
  • tiny craters
  • pause marks
Possible causes
  • Pressure buildup
  • over-extrusion
  • pause behavior
  • wet filament
  • seam placement
First useful test

Inspect seam placement and the sliced preview, then correlate each bump with a seam or pause before changing one proven cause.

Do not sand or post-process before you know whether the slicer is creating the artifact.
Best next tool Print Analysis
White printed tower with its upper section abruptly offset sideways from the lower section.
Shifted layer
Motion system Impact depends on the job

Layer Shift

A section of the print suddenly steps sideways, leaving the model offset above a certain layer.

Appearance cue

The abrupt X/Y offset is visible; belts, pulleys, collision, motion settings, cables, and spool drag still need inspection.

See hypotheses, first observation, and next tool
Looks like
  • Stair-step side
  • sudden X/Y offset
  • top half no longer lines up
Possible causes
  • Loose belt
  • loose pulley screw
  • toolhead collision
  • speed too high
  • snagged cable or spool
First useful test

Follow the printer maker's shutdown and motion-system inspection procedure, then inspect the failed layer for collision, obstruction, drive, cable, or feed-path evidence before changing the motion profile.

Do not rerun the same long job at the same speed after a shift.
Best next tool Print Analysis
Close-up of a white printed part with gaps and separated extrusion lines in its walls.
Missing lines
Extrusion path Impact depends on the job

Under-Extrusion / Gaps

Walls look thin, weak, separated, or partially missing because not enough plastic is being laid down.

Appearance cue

Separated lines and gaps are visible; the restricted or miscalibrated extrusion source is not visible.

See hypotheses, first observation, and next tool
Looks like
  • Gaps in walls
  • weak layers
  • dull thin lines
  • infill not touching walls
Possible causes
  • Partial clog
  • drive tension or calibration error
  • worn drive gear
  • restricted filament path
  • temperature too low
  • tangled spool
First useful test

Use the printer maker's feed-path inspection and extrusion-calibration procedure; record skipping, grinding, or inconsistent flow without forcing material.

Do not raise speed until the extrusion path is proven stable.
Best next tool Print Analysis
Close-up of a white cube with swollen rounded corners and heavy ridges from excess material flow.
Too much flow
Extrusion / calibration Impact depends on the job

Over-Extrusion / Rough Walls

Too much material creates ridges, rough walls, swollen dimensions, or scraped top surfaces.

Appearance cue

Swollen ridges suggest excess delivered material; confirm flow calibration before diagnosing the source.

See hypotheses, first observation, and next tool
Looks like
  • Rough sides
  • thick walls
  • top surface ridges
  • nozzle dragging
Possible causes
  • Flow multiplier too high
  • incorrect filament diameter
  • extruder calibration error
  • excess first-layer squish when limited to the bottom layers
First useful test

Use the slicer or printer maker's flow-calibration procedure for the exact material and extrusion system before changing other settings.

Do not compensate with random speed changes before flow is checked.
Best next tool Print Analysis
White extrusion line that changes from full flow to intermittent gaps and then stops beneath a printer nozzle.
Flow blocked
Nozzle / hotend Impact depends on the job

Clogged Nozzle / Missing Extrusion

Extrusion suddenly becomes intermittent, thins, or stops even though the printer is still commanding material.

Controlled extrusion cue

The illustration shows interrupted flow. It does not identify a blockage, temperature issue, heat creep, drive problem, or feed-path cause.

See hypotheses, first observation, and next tool
Looks like
  • No plastic
  • thin intermittent line
  • extruder clicking
  • extrusion stops mid-line
Possible causes
  • Debris in nozzle
  • heat creep
  • degraded material
  • temperature too low
  • restricted filament feed path
First useful test

Use the printer maker's unloading, cooling, and unclog procedure for the installed hotend; stop if the procedure's temperature or force limits cannot be confirmed.

Do not keep forcing filament while the extruder is grinding.
Best next tool Print Analysis
Print with clean lower walls and sparse upper extrusion beside a softened, swollen filament plug, consistent with a possible heat-creep jam.
Late extrusion loss
Thermal / cooling Impact depends on the job

Extrusion Stops After Warm-Up / Possible Heat Creep

The print starts normally, then extrusion fades or jams after the hotend has been warm; heat creep is one possible cause.

Appearance + timing cue

Clean lower layers, later extrusion loss, and a swollen plug are consistent with heat creep, but other restrictions can overlap.

See hypotheses, first observation, and next tool
Looks like
  • Fails after time
  • PLA softens in feed path
  • extruder click after a warmup period
Possible causes
  • Weak hotend cooling
  • enclosure too warm
  • retraction too high
  • nozzle too hot
  • slow high-detail print
First useful test

Use the printer maker's hotend-cooling and feed-path checks, then compare the material and enclosure conditions with the qualified profile. Change one documented variable per test.

Do not assume it is a slicer-only issue when the timing is heat-related.
Best next tool Print Analysis
Close-up of a white wall with repeated ripples trailing a sharp printed feature.
Ripple marks
Motion / vibration Impact depends on the job

Ringing / Ghosting

Echo-like ripples appear after corners, text, holes, or sudden direction changes.

Pattern cue

Ripples trailing a sharp edge support ringing; motion settings and mechanical looseness still need isolation.

See hypotheses, first observation, and next tool
Looks like
  • Repeating ripples
  • shadows after sharp edges
  • wavy walls near corners
Possible causes
  • High acceleration
  • loose belts
  • light frame vibration
  • input-shaping mismatch
  • unstable table
First useful test

Follow the machine maker's motion-system inspection, then use its ringing or input-shaping calibration for the active toolhead and profile.

Do not change extrusion settings for a vibration pattern.
Best next tool Print Analysis
White printed cylinder with regularly repeating horizontal bands around its wall.
Horizontal bands
Z motion Impact depends on the job

Z-Banding / Ribbing

Horizontal bands repeat up the side of the print, often at regular intervals.

Pattern cue

Regular horizontal bands are visible; band spacing and mechanical inspection are needed to find the Z-axis or extrusion source.

See hypotheses, first observation, and next tool
Looks like
  • Repeating rings
  • periodic wall thickness changes
  • visible horizontal ribbing
Possible causes
  • Bent or misaligned lead screw
  • coupler misalignment
  • binding Z axis
  • wheel or rail play
  • regular extrusion or temperature variation
First useful test

Print a plain vertical wall or cylinder and check whether the band spacing is regular.

Do not blame the STL until the same banding appears on simple calibration geometry.
Best next tool Print Analysis
Bridge-test frame whose unsupported horizontal spans droop into curved strands.
Sagging span
Cooling / orientation Impact depends on the job

Bridging / Sagging

Unsupported spans droop, curl, or form messy hanging strands between two points.

Appearance cue

Unsupported strands visibly sag; bridge length, flow ratio, cooling, speed, and orientation require slicer or calibration review.

See hypotheses, first observation, and next tool
Looks like
  • Drooping bridge
  • messy underside
  • strings under a gap
Possible causes
  • Bridge too long
  • bridge flow ratio wrong
  • insufficient cooling
  • temperature or speed mismatch
  • orientation not helping
First useful test

Use a bridge specimen and the slicer's documented calibration, changing one supported variable within the material and machine limits.

Do not add supports everywhere until you know which spans actually need them.
Best next tool Print Analysis
White printed part with collapsed, torn support columns and a damaged supported underside.
Failed support
Support strategy Impact depends on the job

Support Collapse / Support Scarring

Supports can collapse or detach before holding an overhang; separately, support contact can fuse too strongly and scar the part.

Appearance cue

This image shows collapsed supports and underside damage. Fused or scarred supports are a separate branch and may need the opposite contact-gap adjustment.

See hypotheses, first observation, and next tool
Looks like
  • Failed overhang
  • scarred underside
  • supports fused to part
  • support tower knocked loose
Possible causes
  • Bad orientation
  • support gap wrong
  • too little interface
  • weak support footprint
  • material cooling mismatch
First useful test

In the target slicer, separate a support-collapse case from a fused-contact case, inspect the generated toolpaths, and change one documented support variable.

Do not accept a quote until cleanup time and visible support marks are included.
Best next tool Print Analysis
Unsupported white overhang edges curling upward with rough tips.
Curled edge
Cooling / geometry Impact depends on the job

Overhang Curling

Edges on overhangs curl upward and can eventually catch the nozzle.

Appearance cue

The upturned edges are visible; cooling, temperature, layer time, angle, and orientation still require a controlled comparison.

See hypotheses, first observation, and next tool
Looks like
  • Upturned overhang
  • rough curled corners
  • nozzle catches raised edge
Possible causes
  • Overhang too steep
  • cooling too low
  • too hot
  • layer time too short
  • orientation problem
First useful test

Compare cooling, speed, layer time, and orientation in the target slicer's preview and calibration workflow; change one supported variable within product and machine limits.

Do not keep retrying if the nozzle is visibly striking curled material.
Best next tool Print Analysis
White wall test with a complete thick reference wall and progressively thinner features that print incomplete or break.
Wall check
Model geometry Impact depends on the job

Thin Walls / Fragile Details

Tiny walls, pins, text, or decorative features disappear, break, or print weaker than expected.

Feature-size illustration

The progression shows the thinnest features failing; actual minimum printable width depends on nozzle, line width, material, orientation, and slicer.

See hypotheses, first observation, and next tool
Looks like
  • Missing small features
  • weak tabs
  • single-line walls
  • fragile text
Possible causes
  • Wall below printable line width
  • shallow Z detail below layer height
  • bad scale
  • orientation creates weak layer direction
First useful test

Measure local wall and feature dimensions in CAD or a wall-thickness tool, then verify generated wall paths and omitted features in the target slicer.

Do not promise strength or crisp detail until wall thickness is checked.
Best next tool Target slicer / CAD
White stair-like print resting on dense support material, with a rough supported underside caused by an inefficient orientation.
Angle risk
Model setup Impact depends on the job

Bad Orientation

A chosen orientation can increase support demand, expose layer lines, or place layers poorly for the intended load.

Process illustration

The image demonstrates excess support and a rough supported face; the best orientation depends on strength, cosmetics, time, and machine.

See hypotheses, first observation, and next tool
Looks like
  • Unnecessary supports
  • weak tabs across layer lines
  • long print time
  • bad surface finish
Possible causes
  • Part laid on the wrong face
  • strength direction ignored
  • cosmetic face supported
  • overhangs not minimized
First useful test

In the target slicer, compare candidate orientations for generated supports, estimated job outputs, accessible surfaces, and documented load requirements.

Do not quote only from the first orientation the slicer chooses.
Best next tool Target slicer
White FDM-printed mounting bracket on a black textured build plate with a large missing wall, exposed hollow interior, and ragged open seam.
Open shell
File risk Impact depends on the job

Open Edges / Non-Manifold Mesh

The model has open boundaries, self-intersections, zero-thickness regions, inverted faces, or other topology that does not describe a clean solid.

Appearance cue

The open seam and missing wall are an illustration. Mesh checks can report open-boundary and non-manifold counts, but no single check proves printability or every topology condition.

See hypotheses, first observation, and next tool
Looks like
  • Slicer fills weird areas
  • missing walls
  • inside-out surfaces
  • repair warning
Possible causes
  • Bad export
  • unrepaired generated or scanned mesh
  • self-intersections
  • boolean operation leftovers
  • open or overlapping shells
First useful test

For an STL or supported 3MF selected for direct analysis, run Check File. Use Saved Upload for a separate custody and configured-review record when needed; after any repair, export and recheck the exact revised file.

Do not sell or quote from a mesh that the slicer repairs unpredictably.
Best next tool Check File
Large and miniature versions of the same white bracket beside calipers, illustrating a scale mismatch.
Scale check
File scale / pricing input Impact depends on the job

Scale / Unit Problems

The model imports far too small, too large, or at a size that does not match customer intent.

Scale comparison

The same bracket is shown at two sizes; the intended real-world dimension must come from the customer or source evidence.

See hypotheses, first observation, and next tool
Looks like
  • Tiny import
  • oversized part
  • wrong wall thickness
  • surprise material cost
Possible causes
  • STL unit ambiguity
  • inch/mm mismatch
  • marketplace export issue
  • customer gave no target size
First useful test

Confirm one real-world dimension with the customer before repairing or quoting the file.

Do not assume STL units are correct just because the preview looks normal.
Best next tool Check File
Close-up of a white print with rough pits, bubbles, and stringing consistent with possible filament moisture.
Pits, bubbles, and stringing
Material condition Impact depends on the job

Wet Filament / Popping Surface

The print has tiny pits, steam pops, rough texture, weak layers, or excessive stringing.

Appearance cue

Pits, bubbles, and stringing are consistent with moisture but not unique to it; compare with a known-dry spool.

See hypotheses, first observation, and next tool
Looks like
  • Popping sounds
  • rough matte texture
  • bubbles
  • extra stringing
  • weak layers
Possible causes
  • Filament absorbed moisture
  • humid or open storage
  • hygroscopic material
  • drying or storage conditions were insufficient
First useful test

Follow the exact product's storage or drying procedure, or compare with known-conditioned material, before changing slicer settings.

Do not keep increasing retraction to hide moisture symptoms.
Best next tool Print Analysis

03 Controlled handoff

When to stop guessing.

Keep the next test separate and recoverable. Evidence Lab records a selected pattern, one bounded test, and what changed in its own dedicated workspace.

Open Evidence Lab Keep browsing failure patterns

Evidence Lab is a separate route; it is not appended to this library.

Visual or machine evidence

Photos, first layers, failed supports, and printer or material symptoms.

Open Print Analysis

Untrusted source file

Internet downloads, customer files, OBJ/AMF intake, or work that needs a saved review receipt.

Create Saved Upload
Need a default starting point? Start Print Analysis Run Print Score on an STL/3MF