When an LCD 3D printer’s building platform retracts, it is important to allow enough time for resin to stabilize before the UV lights turn on — the time required for this is called light-off delay.
This is extremely important if you want to print out sharper 3D models with higher-resolution.
To calculate the optimal lift-off delay, we need to know the lifting distance, lifting speed, and retract speed set as the print parameters. This usually is around 2-3 seconds.
Here's a quick explainer of what these are:
1. Lifting Distance: Lifting distance from the build platform
2. Lifting Speed: Lifting speed from the build platform
3. Retract Speed: Retracting speed from the build platform
4. Light-off Delay: Time it takes for the build platform to retract + Additional time for resin to stabilize
For this, we have to figure out the lifting time and retracting time. This will equal the total moving time. Divide the lifting distance with the lifting speed per second. Then divide the lifting distance with the retract speed per second. Subtract the two numbers together and you will find out how long it takes for resin in your printer's resin vat to stabilize.
Here's an example for you:
1️. Lifting Distance: 6mm
2️. Lifting Speed: 80mm/min (1.33mm/s)
3️. Retract Speed: 200mm/min (3.33mm/s)
4️. Light-off Delay: 9s
Lift Time = Approximately 4.5s
Retract Time = Approximately 1.8s
Resin Moving Time = Approximately 6.3s
The formula will look like this: