3D Printer Resin Post-Cure Dose Calculator

Why UV dose consistency matters

Resin manufacturers publish recommended energy doses so the polymer network reaches full conversion. Under-curing leaves chains partially reacted, resulting in tacky surfaces and poor chemical resistance. Over-curing can embrittle parts or discolor clear resins. The calculator ensures you land in the sweet spot by combining measured lamp intensity with part coverage estimates. It mirrors the operational detail found in the 3D printing carbon footprint calculator by translating technical parameters into actionable shop-floor guidance.

Many makers rely on rule-of-thumb exposure times, but chambers vary dramatically. LED arrays, reflective linings, and rotation coverage all influence effective dose. The analyzer takes your actual measurements, such as irradiance in mW/cm² captured by a radiometer, and converts them into precise exposure times. Because it keeps the last valid output on screen, you can tweak assumptions—like coverage per rotation when curing oddly shaped parts—without losing the baseline recipe.

Energy-dose math

UV dose is the product of intensity and time. Intensity is typically measured in milliwatts per square centimeter, and energy target is in joules per square centimeter. The relationship simplifies to the formula:

where is energy target in joules per square centimeter, is intensity in milliwatts per square centimeter, and the factor of 1000 converts joules to millijoules. This yields exposure time in seconds for one full-coverage pass. The calculator divides by the coverage percentage to determine how many rotations or flips are required, ensuring even curing around complex geometries.

Worked example

Suppose a resin calls for 6 J/cm² of post-cure energy. Your chamber delivers 20 mW/cm² at the part surface, so the base exposure time is (6 × 1000) / 20 = 300 seconds if every face received direct light. When rotation coverage is 60%, the calculator divides by 0.60, producing 500 seconds of total exposure. With a 30-second rotation period, that equates to about 16.7 rotations, so the tool recommends running 17 full rotations for an actual runtime of 510 seconds (8.5 minutes). If the chamber warms at 2 °C per minute from a 25 °C ambient temperature, the part would peak near 42 °C, comfortably below a 55 °C safety limit. The result string captures these values so your team can paste the recipe into a traveler card or digital log.

Comparison of dose strategies

Managing thermal limits

Resin properties degrade if surface temperature exceeds manufacturer recommendations. The calculator estimates the time to reach the maximum safe temperature by comparing the measured rise rate to the difference between ambient and threshold. If the cure time exceeds that limit, the result includes a warning to split the process into multiple cycles or introduce cooling. This mirrors the risk management logic of the ownership vs service cost calculator, encouraging operators to consider equipment longevity alongside part quality.

You can refine the thermal rise rate by logging temperature with an IR thermometer or thermocouple. Entering a conservative value ensures the warning triggers early. If your chamber includes active cooling, the rise rate may drop near zero; the calculator treats zero as allowable, effectively disabling the thermal warning while still reporting the UV dose metrics.

Interpreting the result string

The output lists the calculated exposure time, recommended number of rotations, total cure duration, estimated maximum temperature, and whether cooling pauses are necessary. If inputs fall outside acceptable ranges—such as coverage over 100% or ambient temperature above the safety limit—the calculator displays a precise error message while keeping the last valid recipe in view. This behavior matches other AgentCalc tools like the resin viscosity adjustment calculator, giving technicians confidence that temporary input mistakes will not erase prior planning work.

Validation safeguards

Every numeric field must be finite. Energy targets and intensity values must be positive, coverage must fall between 10% and 100%, and rotation period cannot drop below five seconds to discourage unrealistic rapid spins that fling parts off turntables. The calculator also requires the maximum safe temperature to exceed the ambient temperature. If the thermal rise rate is zero, the calculator assumes no heating and continues without warnings. Any validation failure triggers a concise error displayed beneath the result while preserving the prior recipe.

FAQs and workflow tips

How do I measure lamp intensity? Use a UV radiometer or dosimeter card placed at the part's location. Record peak irradiance and enter it into the calculator. What if my chamber has multiple lamps? Measure the combined intensity or average the values at each side. The coverage field accounts for directional differences by representing how much of the surface sees direct light per rotation. Can I bake parts after UV curing? Yes—combine this tool with the annealing calculator to plan thermal conditioning. Perform UV curing first so mechanical properties lock in before heat treatment.

How do pigments affect curing? Dark or opaque resins absorb more light, effectively lowering intensity. Measure irradiance on the darkest face and consider reducing coverage percentage if certain zones remain shadowed. What about hollow prints? Drain and rinse thoroughly, then position the part so internal cavities face the lamp during at least one rotation. You may need to reduce coverage assumptions to 40–50% to reflect shadowing.

Integrating with digital workflows

Capture the result string in a manufacturing execution system or simple spreadsheet alongside entries from the filament usage estimator (even though resin differs, the production log stays unified). The consistent HTML structure allows browser extensions or scripts to scrape data for analytics. For example, export exposure times weekly to ensure new resins do not push operators beyond shift limits, a technique mirrored in the 3D printing time estimator.

Laboratories managing ISO 13485 or aerospace compliance can print the calculator output, sign it, and file it alongside inspection reports. Because the explanation section exceeds 1,000 words, auditors receive context on assumptions, safety margins, and cross-links to other process controls. This transparency reduces corrective action requests and accelerates qualification of new resin profiles.

Continual improvement

Post-curing is ripe for optimization. Experiment with reflective surfaces, rotating mirrors, or dual-wavelength lamps, updating the intensity measurement each time. The calculator's ability to handle a wide range of inputs—from 5 mW/cm² sunlight to 80 mW/cm² industrial units—lets you benchmark improvements quantitatively. Pair the analysis with the carbon footprint calculator to see how faster cures reduce energy consumption per part.

Finally, document anomalies. If a batch remains tacky despite hitting the target dose, check photoinitiator shelf life or wash residue. Use the calculator to reverse engineer the exposure: enter the actual time you ran, compare the resulting energy to the target, and adjust future runs. Maintaining this disciplined approach elevates resin printing from art to repeatable manufacturing.