Vat photopolymerization failures may appear visually similar while arising from different or interacting process mechanisms. This atlas provides a structured diagnostic framework connecting observed outcomes, candidate mechanisms, variables to check and possible corrective actions.
The atlas complements exposure calibration through CRT and dimensional verification through the Structured Calibration methodology.
The atlas is intended to guide diagnosis, not to assign a unique root cause from visual appearance alone.
Effective troubleshooting may require combining visual inspection with exposure data, dimensional measurements and knowledge of geometry-dependent process conditions.
Relevant variables include:
- printer irradiance and optical distribution;
- exposure time and layer thickness;
- material curing behaviour;
- resin viscosity and temperature;
- geometry and support strategy; and
- resin renewal conditions inside the vat.
Failure diagnosis within the SSF engineering methodology
(application • geometry • load conditions)
↓
Exposure calibration
Curing Rate Control System (CRT)
↓
Dimensional verification
Structured Calibration
↓
Failure interpretation
Photopolymer Printing Failure Atlas
↓
Mechanical screening
SMSP
↓
Application-specific validation
Failure Taxonomy in Vat Photopolymerization
Within this engineering framework, common printing anomalies are grouped into four principal diagnostic domains.
The categories are intended to organize troubleshooting. A single observed failure may involve more than one domain.
Exposure-related failures
Exposure conditions that may be insufficient or excessive relative to the material curing response.
Mechanical failures
Peel, adhesion or other mechanical loading that may exceed the strength or deformation tolerance of the printed structure.
Optical failures
Optical penetration, scattering or excessive cure growth that may affect feature definition and dimensional behaviour.
Transport failures
Resin flow, renewal or trapped-resin conditions that may affect layer formation or localized curing behaviour.
Photopolymer Process Stability Triangle
As a simplified process-engineering model, printing behaviour can be considered through three interacting process domains:
dose • cure depth • kinetics
△
Mechanics
peel forces • adhesion • green strength
△
Resin transport
renewal • viscosity • trapped resin
The model is intended to structure investigation rather than imply that each defect belongs exclusively to one process domain.
- Exposure-related imbalance may contribute to undercure, overcure, optical bleeding or dimensional drift.
- Mechanical imbalance may contribute to support collapse, tearing, delamination or fracture during peel.
- Transport-related imbalance may contribute to trapped-resin effects, voids or incomplete layer formation.
Several domains may interact in the same failure.
Failure Diagnostic Tree
The following simplified decision tree identifies useful variables to investigate from an observed symptom.
Is there no printed part on the build plate?
→ Check bottom exposure and build-plate adhesion first
→ See: Why SLA and LCD Resin Prints Fail and Why Resin Prints Stick to the FEP Instead of the Build Plate
Is the part splitting or detaching during printing?
→ Check cure state, support behaviour, adhesion and peel loading
→ See: Layer Delamination in SLA Printing and Support Failure in Resin Printing
Are edges rounded or micro-features disappearing?
→ Check exposure, cure depth and optical behaviour
→ See: Overcuring in SLA and LCD Resin Printing and Loss of Micro-Features in Resin 3D Printing
Is the part dimensionally larger or drifting?
→ Check cumulative exposure and other dimensional contributors
→ See: Resin Shrinkage and Dimensional Drift in Vat Photopolymerization
Are there bubbles, voids or unexpected internal cured regions?
→ Check resin transport, trapped air, drainage and resin renewal
→ See: Bubbles and Voids in Resin Printing
Is surface quality poor or irregular?
→ Check resin condition, recoating behaviour, particles and geometry-dependent flow
→ See: Surface Roughness in Resin Printing
Diagnostic Matrix for Vat Photopolymerization Failures
The matrix below connects common observed failures with process domains that may warrant investigation.
The entries are diagnostic candidates, not automatic root-cause determinations.
| Failure type | Exposure variables | Optical variables | Mechanical variables | Resin-transport variables | Related article |
|---|---|---|---|---|---|
| No part on build plate | Check insufficient exposure | – | Check initial adhesion | – | Why SLA and LCD Resin Prints Fail |
| Part stuck to FEP | Check bottom-cure condition | – | Check plate / release-film adhesion balance and peel loading | – | Why Resin Prints Stick to the FEP Instead of the Build Plate |
| Supports bending | Check cure state | – | Check support stiffness and peel loading | – | Support Failure in Resin Printing |
| Supports snapping | Check excessive exposure | – | Check brittle fracture and support geometry | – | Support Failure in Resin Printing |
| Rounded edges | Check excessive exposure | Check cure depth | – | – | Overcuring in SLA and LCD Resin Printing |
| Fine details disappearing | Check exposure relative to feature scale | Check light scattering / attenuation | – | – | Loss of Micro-Features in Resin 3D Printing |
| Z-axis dimensional growth | Check cumulative exposure | Check stray-light contribution | – | Check retained resin where relevant | Resin Shrinkage and Dimensional Drift in Vat Photopolymerization |
| Internal cavities curing | Check accumulated exposure | Check scattering / optical penetration | – | Check trapped resin and renewal | Bubbles and Voids in Resin Printing |
| Surface roughness anomalies | Check where relevant | Check where relevant | Check where relevant | Check recoating, resin renewal, particles and contamination | Surface Roughness in Resin Printing |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
The purpose of the matrix is to narrow the variables to investigate and support targeted verification rather than random parameter adjustment.
CRT exposure data and dimensional measurements can help determine whether an exposure-related or dimensional mechanism is consistent with the observed defect.
Quick Diagnostic Reference
| If you observe | Candidate mechanism | Check first | Related article |
|---|---|---|---|
| No part on build plate | Insufficient bottom exposure or insufficient initial adhesion | Bottom exposure and build-plate condition | Why SLA and LCD Resin Prints Fail |
| Part stuck to FEP | Undercure or adhesion imbalance | Bottom layers, plate preparation and release behaviour | Why Resin Prints Stick to the FEP Instead of the Build Plate |
| Supports bending | Insufficient green strength or excessive loading | Exposure and support configuration | Support Failure in Resin Printing |
| Rounded edges | Excessive cure growth | Exposure relative to layer thickness and feature size | Overcuring in SLA and LCD Resin Printing |
| Features disappearing | Optical scattering, cure growth or insufficient attenuation | Exposure and resin optical behaviour | Loss of Micro-Features in Resin 3D Printing |
| Internal cavities curing | Accumulated exposure in trapped or poorly renewed resin | Geometry, orientation, drainage and exposure | Bubbles and Voids in Resin Printing |
| Surface roughness anomalies | Recoating instability, contamination, particles or geometry-dependent process effects | Resin condition, vat cleanliness, geometry and renewal | Surface Roughness in Resin Printing |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
Visual Classification of Common Photopolymer Printing Failures
The table below links common visual outcomes with candidate mechanisms and the corresponding detailed section.
| Visual symptom | Typical appearance | Candidate mechanism | See section |
|---|---|---|---|
| No printed object | Empty build plate after printing | Exposure below effective curing condition and/or insufficient initial adhesion | Section 1 |
| Resin film stuck to FEP | Thin cured layer remaining on release film | Bottom-exposure or adhesion imbalance | Section 1 |
| Part splits during printing | Model partially attached to plate and partially stuck to FEP | Cure-state / peel-load mismatch | Section 2 |
| Supports bending | Thin supports visibly flexing | Low green stiffness and/or excessive mechanical loading | Section 3 |
| Supports snapping | Supports breaking during printing | Brittle behaviour, excessive loading or support-related factors | Section 3 |
| Part thicker than expected | Measured Z dimension larger than nominal | Cumulative exposure or other dimensional-growth mechanisms | Section 4 |
| Rounded edges | Sharp corners appear smooth or swollen | Excessive exposure and/or cure depth | Section 5 |
| Fine details disappear | Engraved text or micro-features missing | Optical scattering, cure growth or insufficient attenuation | Section 5 |
| Internal cavities curing | Unexpected solid material inside hollow regions | Accumulated exposure in retained resin, including pseudo-lake-type behaviour | Section 6 |
| Surface roughness anomalies | Irregular texture, unstable finish or granular appearance | Recoating, particles, contamination or local process instability | Section 7 |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
1. No Part on Build Plate
This failure mode may be associated with exposure below the effective curing condition, insufficient first-layer strength or insufficient adhesion between the initial printed layers and the build plate.
Related articles: Why SLA and LCD Resin Prints Fail | Troubleshooting Resin 3D Printing Failures | Why Resin Prints Stick to the FEP Instead of the Build Plate
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| No part on build plate, cured resin stuck to FEP | Insufficient bottom cure and/or insufficient plate adhesion | Check bottom exposure, bottom layers and plate condition |
| No visible curing | Exposure below the effective curing condition | Check exposure against CRT curing behaviour |
| Part detaches after first layers | Initial adhesion or early-layer strength may be insufficient | Review plate condition, bottom cure and early-layer behaviour |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
2. Part Splitting Between Plate and FEP
This defect may indicate a mismatch between cure state, printed-part strength, adhesion and peel loading.
Depending on the observed morphology, undercure, excessive cure, release-film adhesion or other mechanical variables may warrant investigation.
Related articles: Layer Delamination in SLA Printing | Why SLA and LCD Resin Prints Fail | Troubleshooting Resin 3D Printing Failures
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| Soft tearing fracture | Insufficient cure or green strength may contribute | Check exposure and printed green state |
| Brittle fracture | Excessive cure or intrinsically brittle behaviour may contribute | Review exposure and material behaviour |
| Strong adhesion to FEP | Exposure, viscosity or release conditions may contribute | Review exposure, temperature and release behaviour |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
3. Support Deformation or Tearing
Support-related failures may involve insufficient early mechanical strength, support geometry, peel loading or brittle fracture.
Related article: Support Failure in Resin Printing
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| Supports bend | Insufficient green stiffness and/or excessive loading | Check exposure and support configuration |
| Supports collapse | Insufficient support stiffness or geometry | Review exposure and support design |
| Supports snap | Brittle fracture and/or excessive mechanical loading | Review exposure, geometry and material behaviour |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
4. Z-Axis Dimensional Growth
Measured Z thickness above nominal may be consistent with cumulative exposure, optical effects, retained-resin curing or other workflow-dependent dimensional contributions.
Related article: Resin Shrinkage and Dimensional Drift in Vat Photopolymerization
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| Part thicker than nominal | Excessive or secondary curing may contribute | Check exposure and dimensional calibration |
| Progressive thickening | Cumulative exposure may contribute | Review exposure and optical-control strategy |
| Loss of fine Z details | Excessive cure growth may contribute | Review exposure relative to layer thickness |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
5. XY Bleeding and Loss of Resolution
This group of failures may involve excessive cure growth, optical scattering or insufficient attenuation of projected light within the material.
Related articles: Overcuring in SLA and LCD Resin Printing | Loss of Micro-Features in Resin 3D Printing
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| Rounded edges | Excessive exposure or cure growth may contribute | Check exposure against dimensional calibration |
| Engravings disappear | Optical scattering or insufficient attenuation may contribute | Review optical behaviour and Fine Tuning strategy where applicable |
| Fine features merge | Excessive cured depth may contribute | Review exposure using CRT and calibration results |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
6. Trapped Resin Curing (Pseudo-Lake Effect)
Complex geometries with restricted resin renewal may retain resin across multiple exposure cycles.
Under such conditions, accumulated stray exposure may contribute to unintended localized curing.
Related articles: Bubbles and Voids in Resin Printing | Troubleshooting Resin 3D Printing Failures
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| Internal cavities partially cured | Accumulated exposure in retained resin may contribute | Review exposure, geometry and drainage |
| Unexpected internal solidification | Restricted resin renewal may contribute | Review orientation, drainage and renewal conditions |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
7. Surface Roughness Anomalies
Surface roughness anomalies may be associated with unstable recoating, resin contamination, trapped particles, incomplete layer formation or geometry-dependent process instability.
Related article: Surface Roughness in Resin Printing
| Observed outcome | Candidate mechanism | Possible corrective action / check |
|---|---|---|
| Granular or irregular surface texture | Particles, debris or resin contamination may contribute | Inspect resin and vat cleanliness |
| Unstable matte or rough finish | Recoating instability or incomplete surface formation may contribute | Review resin renewal and process stability |
| Localized surface roughness | Geometry-dependent recoating or trapped material may contribute | Review orientation, drainage and resin-flow conditions |
Mobile: scroll horizontally to view all columns. The first column remains visible while scrolling.
Recommended Troubleshooting Method
The Failure Atlas should be used as an investigation framework rather than a one-step diagnostic lookup.
- Observe the failure and document where and when it appears.
- Classify the symptom using the relevant Atlas category.
- Identify candidate mechanisms supported by the observed morphology and process context.
- Check relevant variables using CRT, dimensional measurements and workflow information where applicable.
- Modify deliberately one relevant variable where practical.
- Repeat and verify whether the failure changes consistently with the proposed mechanism.
Where several variables change simultaneously, it becomes more difficult to determine which change affected the result.
Failure Atlas versus Root-Cause Confirmation
The Atlas helps prioritize likely process domains and candidate mechanisms.
It does not automatically prove root cause from visual appearance alone.
Root-cause confidence increases when the proposed mechanism is consistent with several forms of evidence, such as:
- failure morphology;
- failure location;
- CRT curing behaviour;
- dimensional measurements;
- printer and exposure conditions;
- geometry;
- support configuration;
- resin renewal behaviour; and
- controlled response to a corrective change.
Common SLA, DLP and LCD Printing Failures Explained
SLA, DLP and LCD vat-photopolymerization systems share related physical process stages and can therefore show comparable classes of printing anomalies.
Common failure modes include:
- No part on the build plate – may involve insufficient bottom exposure or insufficient initial adhesion.
- Part stuck to FEP or release film – may involve bottom-exposure balance, release behaviour or insufficient build-plate adhesion.
- Support collapse during printing – may involve insufficient green stiffness, support configuration or excessive peel loading.
- Rounded edges and loss of XY resolution – may involve excessive cure growth or optical behaviour relative to the feature scale.
- Loss of fine engraved features – may involve optical scattering, cure growth or insufficient attenuation.
- Z-axis dimensional growth – may involve cumulative exposure and other workflow-dependent dimensional effects.
- Unexpected internal curing – may occur where retained resin accumulates exposure over multiple layers.
- Surface roughness anomalies – may involve recoating instability, particles, contamination or local process effects.
Effective troubleshooting combines observation with structured exposure calibration using the 3Dresyns® Curing Rate Control System (CRT) and dimensional verification using the Structured Calibration methodology.
Relationship with SMSP and Final Validation
Failure diagnosis should be completed before interpreting printed mechanical behaviour.
A part affected by undercure, dimensional drift, support instability or other unresolved process failures may not provide a meaningful basis for mechanical comparison.
After the workflow is sufficiently stable:
- SMSP can provide comparative empirical mechanical screening; and
- application-specific validation can evaluate the final material-process-part system under its relevant use conditions.
Failure diagnosis is therefore an intermediate engineering stage rather than final validation.
Important Limitations
The Photopolymer Printing Failure Atlas does not by itself provide:
- automatic root-cause confirmation;
- a guarantee that one listed corrective action will solve every apparently similar failure;
- standardized mechanical validation;
- universal printer settings;
- dimensional certification;
- regulatory validation; or
- qualification of the customer's final Product.
Observed failures should be interpreted within the actual material, printer, geometry and process conditions.
Related Technical Articles
The following articles provide more detailed discussion of individual failure modes already represented in the Atlas:
- Why SLA and LCD Resin Prints Fail: Understanding Photopolymer Printing Defects
- Troubleshooting Resin 3D Printing Failures
- Why Resin Prints Stick to the FEP Instead of the Build Plate
- Layer Delamination in SLA Printing
- Support Failure in Resin Printing
- Resin Shrinkage and Dimensional Drift in Vat Photopolymerization
- Overcuring in SLA and LCD Resin Printing
- Loss of Micro-Features in Resin 3D Printing
- Surface Roughness in Resin Printing
- Bubbles and Voids in Resin Printing
Related Documentation
- Photopolymer Engineering System
- Structured Selection Framework (SSF)
- Curing Rate Control System
- Structured Calibration
- Fine-Tuning Additives
- Structured Mechanical Screening Protocol
- 3Dresyns® Engineering Resources
For technical support contact info@3Dresyns.com