SLA / Resin 3D printers usually need some form of post curing with additional UV light to strengthen the model and to cure excess resin that is not washed away. A strip of UV LED lights inside a paint can provide the right spectrum and intensity of UV light that cures parts quickly and evenly.
After building a DIY SLA / resin 3D printer, we tried several methods to post-cure the parts after printing. Some methods such as those described on the Madesolid blog worked, but were not perfect solutions.
This little project was quick, easy to execute and only cost about $40-$50.
Other common post-cure methods include:
- Submerging a part in water and using the Sun: Drawbacks I experienced were uneven cure, too fast cure that caused cracking and was hard to control.
Regardless of light curing method, a 3-4 minute Isopropyl Alcohol wash or similar part cleaning procedure is needed before UV post-cure.
To make a cheap and effective UV curing oven You'll need:
- (1) strip of UV Ultraviolet LEDs like these.
Non-waterproof strips without the clear doming may provide more UV light
- (1) Matching Power Supply like this
- Soldering & light duty wiring tools
- One gallon paint can or similarly sized container.
- Foil tape (optional)
*Some Ultraviolet LED strips come with power supplies and don't require additional wiring.*
1) Wire the power supply to the LED strip, by cutting and stripping the 2 positive (red) and negative (black) ends of the small round connector.
2) Solder the corresponding positive and negative wires to the LED terminal.
3) Plug-in and test your LEDs with a few drops of UV resin. It may take several minutes for only a few LEDs to cure the resin. The more closely they are clustered together, the more intense the light and faster the cure times will be.
4) Make the inside of your container reflective with some foil tape to increase light intensity. A metal paint can works great because the even, round shape and it's ability to dissipate heat through the can from the LEDs.
5) Use double sided scotch tape to mount the LEDs to the inside of the container as close as possible. Space rows less than a centimeter apart. A 5 meter LED strip will just about perfectly fill up the walls of a paint can. Typically, LED strips can also be cut or added to.
*Optional* Make a small tray by wrapping foil tape to a round piece of cardboard. SLA / resin 3D prints can be sticky before post-cure. UV resin irritates the eyes and skin. Always use gloves!
We found that (1) 5 meter LED strip (wavelength:395-405nm) coiled inside a paint can was sufficient to cure parts in about 10-20 minutes. Rotating parts at least once or twice to expose the bottom every 10 minutes was also helpful.
*The UV oven should not be closed while in use. Be sure your part does not have excessive Isopropyl Alcohol on it. This could be a fire hazzard.*
*Parts cured this type of UV oven had less powerdering, more even color and seemed to last longer.*
*We have an unconfirmed hypothesis that extra heat inside the chamber may help with curing.*
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