Hardener for UV sensitive resin

Hello everyone

as promised, we want to compare the load capacity of FDM-printed parts with those printed from resin in a follow-up article. When we removed the sample from our new 3D printer, we found that we had to have the print piece hardened even further. In order not to be dependent on daylight, we have come up with a device for curing. According to the manufacturer, this best hardens the resin at 405nm. This wavelength is located at the outer end of the UV spectrum. In principle, we have come up with two solutions for this: on the one hand, there are LEDs, on the other hand, gas discharge tubes emit the light in the required spectrum. The LEDs are now sold as black light light strips, the cheap possibility of a gas discharge tube is likely to be a hardener for nail polish (in nail salons). We have found both LED strips and nail hardeners in the 20€ price segment.


However, we wanted to implement a solution immediately and not need another hardware purchase, which is why we want to use an insect trap for this purpose.

We dismantled the device and removed the board with tube and sockets. Gas discharge lamps therefore require a ballast, which is why we simply continue to use the board, we have only removed the wires and bridges for the high-voltage connection.


We use for this project:

  • our mini power supply with 5V
  • Insect trap
  • Turntables and stand from our laser cutter
  • Aluminium foil as reflector
  • 5V geared motor from our Robo-Car Kit
  • a switch box from the DIY market
  • div. Cables and shrink tubes
  • lots of hot glue and spray glue for the aluminium foil

Since we already use existing products today and also many things that have different sizes in every hardware store, we do not provide downloads for the project, as they would not fit right away anyway. We have bought a lot of amazon and various DIY stores in the last weeks and months and processed them manually. In other words, we used the components we just had at hand.

First we removed the case:

The board removed:

The bracket of the tube was welded, but we were able to remove all the components we wanted to use for our project without any damage:

Together with one of our mini power supplies 5V, we installed the board in a switch box. The engine used also had a current consumption of only 100mA under load. The mini power supply delivers 5V/3W, so it is suitable for our project.

From the used motor we had to remove the second side of the shaft and glue a side window to ensure a safe, straight grip and to prevent the shaft from wounding at the switch board during operation. Afterwards, we fastened it with the help of hot glue and also used the adhesive as a balancing mass, so that the turntable is later in the water and runs round.

Since we only had 3mm of material available we had to attach a spacer. This was coated with PTFE on the back. 3D printing of an adapter would have taken too long. In the CAM software, we just changed the size of the turntable.

Since the tube used was relatively weak with only 4watts, we turned the side walls into a reflector (aluminium foil and spray glue).

Practice tip: A rescue blanket reflects better than aluminium foil


In the last step, only the mechanical assembly took place:


If the plate rotates too fast (depending on the motor), a PWM module intermediary. Later we will stick the ordered LEDs on the top.

Until the next post :)


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