I’m looking for the turntable…but can’t find anything…where did you fin it?
I have no idea where you got the idea that if it isn’t 405nm it isn’t any good.
Formlabs themselves have stated that 385nm is perfectly suitable for curing their resins (which is the wavelength of the nail dying UV lamps I used and Formlabs recommended in their cardboard cure box video). Formlabs wrote:
"Resin photo initiators are sensitive to a range of wavelengths in the spectrum. … Using a 390-395nm wavelength cure box (or any cure box in the UVA range –– 400 to 315nm) is good for post curing our resin."
To clear up any confusion, Formlabs did a study on the effects of different wavelengths: https://formlabs.com/media/upload/How-Mechanical-Properties-of-SLA-3D-Prints-Are-Affected-by-UV-Curing.pdf
As it is, 405 produces the best cure the fastest; however, other wavelengths will cure (albeit over a logarithmically longer period of time). Higher cure temperature is better (Figure 10/11) but more radiant power than the recommended 1.25 mW/cm2 is not (Figure 12).
To summarize what you want:
- 405 nm wavelength LED Array
- 60deg C cure ambient temperature (standard resin) and 45 deg C cure ambient temperature (tough resin)
- not much higher OR lower than 1.25 mW/cm2 per surface (hard to measure, but still impactful)
A lower wavelength is detrimental, but still acceptable.
With this in mind, building a chamber is very difficult which is why it would be nice for formlabs to supply them
What about the one B9 is selling, albeit a little pricey, it seems to be the only one available specifically for our needs.
Why not the NextDent (Netherlands) post-cure unit (if you are thinking B9), since that is where most of the resin is originating? I am using the nail lamps, or ESPE Visio Beta Vario (vacuum + fluorescent tubes) when I need absolute gorgeous surface. It takes the phosphors inside the fluorescent lamps longer to burn away than it does the LEDs, just because of the surface area difference and method of deposition.
When I built my chamber, I got a temperature controllable hotplate, 3 of these (https://eprocurement.newark.com/ledengin/lz1-10ua00-u7/high-brightness-led-violet-5w/dp/48T1407?in_merch=Popular Products/), and a few 25W resistors to pair up with a 12V DC powersupply. I high-temp epoxied them to the roof of a paint can, plugged it in, and now it cures. Looks terrible (especially compared to AtlasBrace’s beauty), but you can fill it with water, cure per the formlabs specs, and walk away with a good part.
How is the light power measured? I am planning to use a 20w 16LED lamp others have used in microwave setups. 20 total watts will be 1.25w per LED, but that isn’t the same as mW either.
Technically what formlabs is measuring or trying to control is called irradiance. The irradiance is determined by surface area of your part and your power source.
To measure this, you would need a meter that reads an output of “Lux”, or Lumens per square meter, then convert it to milliwatts per square centimeter. Sorry for the late reply!
In that case, wouldn’t an ever-changing amount of light be required due to varying sizes of parts? A 1 cm cube vs. a max volume cube would have drastically different surface area, therefore, different power requirements. If this is true, then the FL Cure station isn’t any better than most DIY boxes with a turntable and 20w, 405nm UV lamp as the power remains the same for all surface areas.
I don’t know if you remember or not but im building this box and was wondering if you bypassed the timer and if you did how? I can’t seem to get it to stay on longer than the 30 minute mark.
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Did you figure out how to bypass the timer? I also have that issue. Thanks!
How did you bypass the timer? It seems that it cannot stay longer than 30 minutes. Thanks.