Resin Exposure Time Calculator
Layer and bottom exposure plus Jacob's-curve cure depth from resin critical energy, penetration depth, printer LED power and layer height. Flags under-cure (delamination) and over-cure (brittle, blooming).
Stop burning resin on validation matrices. This calculator turns a resin's two working-curve constants — critical exposure (Ec) and penetration depth (Dp) — together with your printer's measured LED power into a normal layer exposure, a bottom-layer exposure, and the actual cure depth you'll get. It then tells you whether that cure depth bonds safely to the previous layer or risks delamination or over-cure.
curl -X POST https://toolsamurai.com/api/v1/resin-printing/exposure-time-calculator \ -H "Authorization: Bearer sk_live_•••••••••••••••" \ -H "Content-Type: application/json" \ -d '{ "resin_cure_energy_mj_cm2": 8, "resin_penetration_depth_um": 200, "printer_led_power_mw_cm2": 4.5, "layer_height_um": 50, "overcure_target_um": 30, "bottom_exposure_multiplier": 8, "bottom_layer_count": 6 }'
The method behind the numbers
Photopolymer cure follows the Jacobs working curve: cure depth Cd = Dp · ln(E / Ec), where E is the delivered energy density and Ec is the smallest dose that cures the resin at all. To bond a new layer you need to cure slightly deeper than the layer height — that over-cure margin is what fuses each layer to the one below.
The tool sets a target cure depth of layer height plus your over-cure margin, solves the curve for the required energy, then divides by the printer's LED power density to get a time in seconds (mJ/cm² ÷ mW/cm² = s). Bottom layers simply multiply that time by your bottom multiplier. Finally it reports the resulting cure depth and the adhesion headroom (cure depth minus layer height): too little and layers can separate; far too much and you get blooming, loss of fine detail, and brittle parts.
See it in practice
A typical Anycubic-Standard-like profile on a modern mono LCD.
- resin_cure_energy_mj_cm2
- 8
- resin_penetration_depth_um
- 200
- printer_led_power_mw_cm2
- 4.5
- layer_height_um
- 50
- overcure_target_um
- 30
- bottom_exposure_multiplier
- 8
- bottom_layer_count
- 6
A tougher, more absorbing resin printed thick on a 5 mW/cm² Saturn-class printer.
- resin_cure_energy_mj_cm2
- 15
- resin_penetration_depth_um
- 150
- printer_led_power_mw_cm2
- 5
- layer_height_um
- 100
- overcure_target_um
- 40
- bottom_exposure_multiplier
- 8
- bottom_layer_count
- 8
Frequently asked questions
Where do I get Ec and Dp for my resin?
Some manufacturers publish them; otherwise you derive them from a working-curve test — cure single layers at several exposures, measure the cured thickness, and fit Cd against ln(E). The slope is Dp and the x-intercept gives Ec. Standard 405 nm resins land around Ec 5–15 mJ/cm² and Dp 100–250 µm.
How do I find my printer's LED power density?
A UV radiometer placed on the LCD reads it directly in mW/cm². If you can't measure it, use the figures in the help text as a starting point — Mars 3 Pro ≈ 3.4, Saturn 3 ≈ 5.0, Mono M5s ≈ 4.5 — and treat the result as a starting exposure to fine-tune.
My result is longer than my resin's recommended time. Why?
Vendor times assume a reference LED power (often ~4 mW/cm²) and a specific layer height. If your over-cure target or layer height is higher, or your Dp lower, the calculator asks for more energy. Lower the over-cure margin toward 20–30 µm, or confirm your Dp, and the time drops.
What's a healthy adhesion headroom?
Roughly 30–100 µm of cure depth beyond the layer height is the comfortable band. Below ~10 µm you risk layer separation; above ~150 µm you're over-curing — fine detail washes out and the part gets brittle.
Embed Resin Exposure Time Calculator on your site
Sign in to configure the live preview, theme, defaults, locked inputs, and analytics ID from the embed dashboard.