Each printer model (and, in many cases, different units of the same model) delivers different light power across the printing area (vat/resin tank). Variations of ~300% or higher are common and directly impact curing, printing settings, and final part quality.
Why printer power variability matters
Light power differences across the vat and between printers affect polymer conversion (the fraction of monomer converted into polymer) and the amount of residual uncured monomers and other extractables. Too-low power and/or too-short exposure can leave elevated residuals, impacting safety and biocompatibility, especially for regulated medical applications.
Not all printers meet the quality requirements for printing biocompatible resin systems by SLA, DLP, LCD, and Inkjet printing technologies.
FDA guidance: variability across machines of the same model
The FDA guidance document Technical Considerations for Additive Manufactured Medical Devices highlights that optimal settings can vary significantly, including across machines of the same model.
Optimal settings and parameters for a single model of a machine can vary greatly when printing different devices or components. Furthermore, optimal settings and parameters can vary between machines of the same model even when printing the same devices or components.
Evidence: measured power differences (LCD & mLCD)
Below are representative examples of light power variability measured across the vat (corner value / center value). Light meters and their spectral response range influence readings; therefore, comparisons must consider wavelength and calibration.
| Printer technology | Printer model | Power across vat (mW/cm2) |
|---|---|---|
| Standard multicolor LCD | Anycubic Photon Zero | 0.27 / 0.30 |
| Standard multicolor LCD | Longer Orange 30 | 0.29 / 0.31 |
| Standard multicolor LCD | Anycubic Photon S | 0.43 / 0.46 |
| Monochrome LCD (mLCD) | Phrozen Sonic Mini 4K | 0.60 / 0.70 |
| Monochrome LCD (mLCD) | Phrozen Sonic Mighty 4K | 0.79 / 0.93 |
| Monochrome LCD (mLCD) | Phrozen XL Mono 4K | 1.05 / 1.30 |
| Monochrome LCD (mLCD) | Creality LD-002H | 1.40 / 1.80 |
| Monochrome LCD (mLCD) | Anycubic Photon Mono X | 1.70 / 1.90 |
Example highlighted on this page: Phrozen Sonic Mini (0.6 mW/cm2) vs Anycubic Mono X (1.7 mW/cm2) measured using a UV-420-type meter (375–475 nm, peak around 420 nm).
- Example UV-420-type meter specification reference: UV-365/420 portable UV radiometer
Variability within the same printer model (unit-to-unit)
| Same model (mLCD) | Power across vat (mW/cm2) |
|---|---|
| Commercial mono 4K printer unit 1 | 1.05 / 1.15 |
| Commercial mono 4K printer unit 2 | 1.10 / 1.30 |
Why different light meters can report different values
Measuring the same printer with different meters can yield different readings because spectral response range, peak wavelength, and calibration conditions differ between instruments.
| Printer | Meter type | Measured power (mW/cm2) |
|---|---|---|
| Anycubic Photon Mono X | UV-420-type meter (375–475 nm, peak ~420 nm) | 1.70 / 1.90 |
| Anycubic Photon Mono X | Chitu Systems meter (402–407 nm, peak ~405 nm) | 8.7 / 7.5 |
Recommended affordable 405 nm meter option: Chitu Systems UV meter for resin 3D printers.
DLP printer power ranges can be even broader
DLP printers can deliver light power across the vat from approximately 0.5 mW/cm2 up to 30 mW/cm2 or higher for many commercial DLP systems. This range has a major impact on exposure settings and conversion profiles.
Power decay, spatial distribution, and maintenance protocols
Printer light power naturally decays over time and is typically higher in the center than in corners and edges. Professional printing protocols should include light power monitoring, calibration, and maintenance to ensure consistent process performance.
Learn more: Do you want to go in depth? Let’s unlock the black box!
Working curve context: Ec and Dp require consistent measurements
For professional printing, consistent readings are required to build a reliable working curve and to determine critical energy Ec (mJ/cm2) and penetration depth Dp (µm or mm) for a given resin system.
For additional fundamentals and practical context: Fundamentals of Stereolithography by 3Dresyns.
How to obtain reliable settings: IFU and calibration methodology
This variability can be addressed using our Instructions for Use (IFU) and calibration methodology to obtain reliable settings under real printer conditions.
A curing rate table can be ordered per resin. It reports cured thickness at a defined wavelength and at multiple exposure times (e.g., 5, 10, 15, 20, 25, 50, 75, 100 seconds) to accelerate settings identification and improve reproducibility.
Conclusion
- Different printer models (and units) deliver different light power across the vat.
- Spatial non-uniformity (center vs corners) and power decay affect conversion, settings, and final performance.
- Different light meters can produce different readings; wavelength and calibration must be considered.
- Professional workflows should include measurement, calibration, and validated protocols, supported by IFUs and resin-specific characterization.
Note: values expressed as corner / center across the vat to reflect power variability across the printing area.