3Dresyns® Photopolymer Printing Failure Atlas

Part of the 3Dresyns® Structured Selection Framework (SSF)

The Structured Selection Framework (SSF) provides a systematic engineering methodology for selecting, calibrating and validating photopolymer materials in vat photopolymerization additive manufacturing.

SSF is part of the broader 3Dresyns® Photopolymer Engineering System, which connects material selection, curing kinetics, dimensional calibration, failure analysis and mechanical validation.

Material Selection Guide – engineering methodology for photopolymer material selection Material Selection Guide →
Engineering Resin Selection Tool – mechanical comparison of material systems Engineering Resin Selection Tool →
Curing Rate Control System (CRT) – exposure calibration and curing kinetics CRT methodology →
Structured calibration methodology – dimensional verification in X, Y and Z Structured calibration →
Structured Mechanical Screening Protocol (SMSP) – empirical validation of printed material behaviour SMSP →

Learn more about the framework: Structured Selection Framework →

3Dresyns® Photopolymer Printing Failure Atlas

Vat photopolymerization printing failures often appear visually similar while originating from different underlying mechanisms. This atlas provides a structured diagnostic framework linking observed outcomes, probable physical causes and corrective actions.

This atlas forms the troubleshooting reference of the 3Dresyns® Photopolymer Engineering System and complements the exposure calibration methodology provided by CRT and the dimensional verification workflow described in the Structured calibration methodology.

Effective troubleshooting typically requires combining visual inspection with exposure calibration data, dimensional measurements and understanding of geometry-dependent process conditions.

Failures should always be interpreted within the context of:

printer irradiance and optical distribution
exposure time and layer thickness
resin viscosity and temperature
geometry and support strategy
resin renewal conditions inside the vat

Failure diagnosis within the SSF engineering methodology

Material selection (application • geometry • load conditions)
↓
Exposure calibration Curing Rate Tables (CRT)
↓
Dimensional verification Structured calibration
↓
Failure interpretation Photopolymer Printing Failure Atlas
↓
Mechanical validation SMSP

Failure taxonomy in vat photopolymerization

Although printing failures may appear visually different, most vat photopolymerization defects originate from a limited number of physical mechanisms.

Within the 3Dresyns engineering methodology, failures can be classified into four principal categories:

Exposure failures
Incorrect energy dose relative to resin curing kinetics.

Mechanical failures
Mechanical stresses during peel exceeding the strength of partially cured material.

Optical failures
Light scattering or excessive cure depth reducing dimensional accuracy.

Transport failures
Resin renewal limitations causing cumulative stray curing.

Photopolymer process stability triangle

From a process-engineering perspective, most vat photopolymerization failures can be understood as the result of imbalance between three governing process domains:

Exposure
dose • cure depth • kinetics
△
Mechanics
peel forces • adhesion • green strength
△
Resin transport
renewal • viscosity • trapped resin

Stable printing requires these three process domains to remain in practical balance. If one domain becomes dominant or insufficient relative to the others, characteristic defects begin to appear.

Exposure-dominated instability commonly leads to undercure, overcure, optical bleeding or dimensional drift.
Mechanical-dominated instability commonly leads to support collapse, tearing, delamination or fracture during peel.
Transport-dominated instability commonly leads to trapped curing, pseudo-lake effects, voids or incomplete layer formation.

This triangle provides a simplified engineering model for understanding why different visible failures may still belong to the same underlying process imbalance.

Failure diagnostic tree

The following simplified decision tree helps users move from visual symptom to the most probable process domain involved.

Is there no printed part on the build plate?
→ Check bottom exposure and build plate adhesion
→ 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 strength versus peel forces
→ See: Layer Delamination in SLA Printing and Support Failure in Resin Printing

Are edges rounded or micro-features disappearing?
→ Check optical bleeding, cure depth and scattering
→ See: Overcuring in SLA and LCD Resin Printing and Loss of Micro-Features in Resin 3D Printing

Is the part dimensionally larger or drifting over time?
→ Check cumulative exposure and shrinkage behaviour
→ See: Resin Shrinkage and Dimensional Drift in Vat Photopolymerization

Are there bubbles, voids or internal cured regions?
→ Check resin transport, trapped air and resin renewal
→ See: Bubbles and Voids in Resin Printing

Is surface quality poor or irregular?
→ Check recoating behaviour, particles and surface instability
→ See: Surface Roughness in Resin 3D Printing

Root cause matrix for vat photopolymerization failures

Most printing failures in SLA, DLP and LCD vat photopolymerization systems originate from a limited number of physical variables.

The matrix below connects the most common printing defects with the process variables most likely responsible for the failure.

Failure type	Exposure dose	Optical behaviour	Mechanical stresses	Resin transport	Related article
No part on build plate	Low	–	–	–	Why SLA and LCD Resin Prints Fail
Part stuck to FEP	Low or incorrect bottom cure	–	Peel adhesion imbalance	–	Why Resin Prints Stick to the FEP Instead of the Build Plate
Supports bending	Low	–	High peel stress	–	Support Failure in Resin Printing
Supports snapping	High	–	Brittle behaviour	–	Support Failure in Resin Printing
Rounded edges	High	Excess cure depth	–	–	Overcuring in SLA and LCD Resin Printing
Fine details disappearing	Medium-high	Light scattering	–	–	Loss of Micro-Features in Resin 3D Printing
Z-axis dimensional growth	High cumulative exposure	Stray light	–	–	Resin Shrinkage and Dimensional Drift in Vat Photopolymerization
Internal cavities curing	Accumulated stray exposure	Light scattering	–	Poor resin renewal	Bubbles and Voids in Resin Printing
Surface roughness anomalies	Variable	Variable	Variable	Recoating instability / particles	Surface Roughness in Resin 3D Printing

Understanding which physical variable is responsible for the failure allows users to implement targeted corrective actions rather than trial-and-error parameter adjustments.

Exposure calibration using the 3Dresyns® Curing Rate Control System (CRT) and dimensional verification using the 3Dresyns® structured calibration methodology are typically required to identify the dominant root cause.

Quick diagnostic reference

If you observe	Most probable cause	Check first	Related article
No part on build plate	Insufficient bottom exposure	Bottom exposure time	Why SLA and LCD Resin Prints Fail
Part stuck to FEP	Undercure or adhesion imbalance	Bottom layers and plate preparation	Why Resin Prints Stick to the FEP Instead of the Build Plate
Supports bending	Undercured resin	Exposure time	Support Failure in Resin Printing
Rounded edges	Overexposure	Exposure relative to layer thickness	Overcuring in SLA and LCD Resin Printing
Features disappearing	Optical scattering	Resin optical properties	Loss of Micro-Features in Resin 3D Printing
Internal cavities curing	Trapped resin exposure	Geometry orientation	Bubbles and Voids in Resin Printing
Surface roughness anomalies	Recoating instability or particles	Resin condition and vat cleanliness	Surface Roughness in Resin 3D Printing

Visual classification of common photopolymer printing failures

In practice, users often identify printing problems based on visible symptoms. The table below connects common visual outcomes with their most probable physical origin and the section of this atlas where the failure is explained in detail.

Visual symptom	Typical appearance	Most probable mechanism	See section
No printed object	Empty build plate after printing	Exposure below curing threshold	Section 1
Resin film stuck to FEP	Thin cured layer remaining on release film	Insufficient bottom exposure or poor adhesion balance	Section 1
Part splits during printing	Model partially attached to plate and partially stuck to FEP	Incorrect exposure or excessive peel stress	Section 2
Supports bending	Thin supports visibly flexing during printing	Undercured resin with low mechanical stiffness	Section 3
Supports snapping	Supports breaking suddenly	Overexposure causing brittle behaviour	Section 3
Part thicker than expected	Measured Z dimension larger than nominal	Cumulative stray exposure	Section 4
Rounded edges	Sharp corners appear smooth or swollen	Overexposure or excessive cure depth	Section 5
Fine details disappear	Engraved text or micro-features missing	Optical scattering or insufficient absorber	Section 5
Internal cavities curing	Unexpected solid material inside hollow regions	Trapped resin exposure ("pseudo-lake effect")	Section 6
Surface roughness anomalies	Irregular texture, unstable finish or granular appearance	Recoating instability, debris or surface process instability	Section 7

1. No part on build plate

This failure mode is commonly associated with exposure below the resin curing threshold or insufficient adhesion during the first printed layers. It is often the earliest sign that the exposure baseline is not aligned with the material kinetics defined by CRT.

Observed outcome	Likely cause	Corrective action
No part on build plate, cured resin stuck to FEP	Insufficient bottom exposure	Increase bottom exposure time or bottom layers
No visible curing	Exposure below curing threshold	Increase exposure according to CRT
Part detaches after first layers	Poor adhesion	Adjust plate surface or bottom cure

2. Part splitting between plate and FEP

This defect often indicates a mismatch between cure strength and peel forces. Depending on morphology, the underlying mechanism may be undercure, overcure or excessive adhesion to the release film.

Observed outcome	Diagnosis	Corrective action
Soft tearing fracture	Undercure	Increase exposure
Brittle fracture	Overcure	Reduce exposure
Strong adhesion to FEP	Overexposure or viscosity	Reduce exposure or increase temperature

3. Support deformation or tearing

Support-related failures generally reflect insufficient early mechanical strength, excessive peel loading or brittle fracture caused by overexposure.

Related article: Support Failure in Resin Printing

Observed outcome	Diagnosis	Corrective action
Supports bend	Low mechanical strength	Increase exposure
Supports collapse	Low modulus during curing	Increase exposure or reinforce supports
Supports snap	Brittle fracture	Reduce exposure

4. Z-axis dimensional growth

Excess thickness in printed parts is frequently caused by cumulative stray exposure during printing.

Observed outcome	Diagnosis	Corrective action
Part thicker than nominal	Secondary curing	Reduce exposure
Progressive thickening	Cumulative stray exposure	Reduce exposure or add light blockers
Loss of fine Z details	Overexposure	Reduce exposure

5. XY bleeding and loss of resolution

This group of failures is usually linked to excessive cure depth, optical scattering or insufficient attenuation of projected light within the resin.

Observed outcome	Diagnosis	Corrective action
Rounded edges	Overexposure	Reduce exposure
Engravings disappear	Optical scattering	Add light blockers
Fine features merge	Excess cure depth	Adjust exposure via CRT

6. Trapped resin curing (pseudo-lake effect)

Complex geometries with limited resin renewal may accumulate stray exposure across multiple layers.

Observed outcome	Diagnosis	Corrective action
Internal cavities partially cured	Accumulated stray exposure	Reduce exposure or redesign geometry
Unexpected internal solidification	Poor resin renewal	Improve drainage or orientation

7. Surface roughness anomalies

Surface roughness anomalies may result from unstable recoating, resin contamination, trapped particles, incomplete layer formation or process instability affecting the surface state of the printed part.

Related article: Surface Roughness in Resin 3D Printing

Observed outcome	Diagnosis	Corrective action
Granular or irregular surface texture	Particles, debris or resin contamination	Filter resin and inspect vat cleanliness
Unstable matte or rough finish	Recoating instability or incomplete surface formation	Verify resin renewal and process stability
Localized surface roughness	Geometry-dependent recoating or trapped material	Review orientation, drainage and resin flow conditions

Common SLA, DLP and LCD printing failures explained

Vat photopolymerization systems such as SLA, DLP and LCD printers share similar physical printing mechanisms and therefore exhibit comparable types of printing failures. Most anomalies arise from an imbalance between optical exposure, resin curing kinetics, mechanical stresses during peeling and resin renewal within complex geometries.

Understanding the physical origin of these failures is essential to achieving reliable printing, dimensional accuracy and repeatable results.

The most common vat photopolymerization printing failures include:

No part on the build plate – usually caused by insufficient bottom exposure or poor adhesion between the first layers and the build plate.
Part stuck to FEP or release film – typically related to incorrect bottom exposure balance or insufficient adhesion to the build plate.
Support collapse during printing – often caused by insufficient exposure leading to low mechanical strength during the early curing stage.
Rounded edges and loss of XY resolution – generally caused by overexposure or excessive cure depth relative to the layer thickness.
Loss of fine engraved features – commonly produced by optical scattering or insufficient light absorption within the resin.
Z-axis dimensional growth – often associated with cumulative stray exposure during long prints.
Unexpected internal curing – may occur when trapped resin inside cavities accumulates stray exposure over many layers, sometimes referred to as the pseudo-lake effect.
Surface roughness anomalies – may arise from recoating instability, particles, contamination or local process imbalance.

Effective troubleshooting requires combining visual inspection with structured exposure calibration using the 3Dresyns® Curing Rate Control System (CRT) and dimensional verification using the 3Dresyns® structured calibration methodology.

Together, these tools allow users to identify the physical origin of printing anomalies and implement corrective adjustments within a structured engineering workflow.