UV projection printer for PCBs and item marking

This tool can project UV mask and cure paint on various objects, including PCB prototypes, 3D prints, panels and household items

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A tool which can be used to print etching masks for PCB prototypes, print artwork on household objects, create item and panel markings (also on 3D prints, tested with PET-G material) and more.


This tool currently has a form of a 3D-printed UV lamp holder with a magnetic frame (3d printed with magnets embedded) to hold inkjet- or laser-printed transparency films with exposure masks, or 3D printed masks for simpler designs and shapes.

It can be used to print etching masks for PCB prototypes, print artwork on household objects, create item and panel markings (also on 3D prints, tested with PET-G material) and more.

It can be considered as a low-cost, easy to prepare alternative for screen printing or pad printing for one-off production or prototyping.

Advantages of this method

  • No additional chemicals required to develop the artwork
  • Works fine for prototypes and one-off projects - only few steps required, very low initial cost
  • Ability to print on uneven/curved surfaces
  • Multitude of uses: etching masks for PCBs, printing on objects, item and panel markings
  • Contact-less exposure


  • How to get a powerful and even UV light to retain sharp edges of artwork
  • Setting proper exposure time
  • Scaling the project up for larger objects
  • Replacing static UV mask with LCD (WIP)

How does this process work

The exposure process is contactless, ie. the mask is not touching the object that is being printed on. Object needs to be covered with inexpensive UV-curable soldermask or another type of UV paint with a brush or rubber roller. Mask is rised few milimiters so it doesn't touch the paint. UV light comes from a single point, a power LED placed directly in the center of the holder, and such type of lighting doesn't create too much optical distortion and retains sharp edges of the artwork.

Future perspectives

In current stage this tool uses either a transparency film or 3D-printed stencil as UV mask. Future improvements may include replacing the printed mask with a monochrome LCD, which would make the print preparation process entirely digital, using optical zoom to scale the printed artwork, automatically distorting the mask to accomodate for curved objects.


3D model of the top part

Standard Tesselated Geometry - 69.03 kB - 08/07/2023 at 18:03



3D model of the bottom part

Standard Tesselated Geometry - 3.21 kB - 08/07/2023 at 18:03


  • 1 × USB connector or DC jack for power
  • 1 × MT3608 Step-Up converter
  • 1 × 1W 1Ohm resistor in series with LED
  • 1 × 396nm 5W UV LED power LED, two light elements in single package, 6,8V - 7,2V
  • 1 × LED heatsink

  • Printing "Hello World"

    Wojciech "adalbert" J10/09/2023 at 14:55 0 comments

    Did another test print. "Hello world" exposed with a transparency film onto the case of a hot glue gun.

    The exposure time was 18 minutes. Slightly longer than usual, i am still experimenting with the timing. However such a long time was not necessary, the text came out slightly overexposed - the letters are a bit thicker than in the exposure mask, because the longer you expose, the more the edges of the artwork expand. Staying around the 10 minute mark seems to be optimal. The artwork expansion could also be accounted for in the design stage.

  • Improving the curing process

    Wojciech "adalbert" J10/08/2023 at 23:30 0 comments

    It would be great if the curing process could be done quicker than 10-15 minutes or so, which it currently takes. 

    And the curing of UV paint can indeed be accelerated. With some heat and airflow, to be specific. I did try to spread some UV paint on test surfaces and exposed it under UV light with no mask, and a hot air gun set to temperature around 150C. And it did harden much quicker, which was to be expected, as I have already known that soldermask curing can be accelerated with heat (i learned that fact when I was using the UV soldermask for PCB repairs).

    However the problem here is that the printing surface is covered with the exposure mask. Therefore "injecting" hot air under the mask could be challenging, but maybe it won't be impossible. Maybe some optics could be used to project the artwork from further away, leaving enough space for fans and heating elements.

    Such paint curing acceleration system is something I should think about in the context of developing an "advanced" version of the printing machine (with the exposure mask displayed on an electronic screen).

  • BOM

    Wojciech "adalbert" J10/08/2023 at 23:11 0 comments

    The prototype is quite inexpensive:

    396nm 5W UV LED $5
    MT3608 Step-Up converter $2
    1W 1Ohm resistor $0.1
    USB or barrel jack connector
    45x45x10mm heatsink
    3D printed case~$2 (filament)

    It should be possible to build such a device spending less than $15 (if you have your own 3D printer, however an improvised case made out of cardboard or other materials could also work).

    There is an added cost for each print, because of the need of printing a transparency film for the exposure mask, but that shouldn't cost a lot.

    The UV paint/soldermask is obviously also needed, but it is inexpensive and lasts for long. A 10ml container costs around $2-$5. There are various suppliers, i am using "Mechanic UV Solder Mask" which is available in various colors. Such paint is often available in stores which supply equipment for electronic repair shops, as it is often used to repair soldermask layers (but it is not used too much for actual printing!)

  • Powering the LED

    Wojciech "adalbert" J10/08/2023 at 22:56 0 comments

    The power circuit is pretty simple in the current prototype:

    Obviously the LED needs to have some way of current limiting. Instead of using more sophisticated control circuit, I decided to just use an off-the-shelf DC-DC converter module to match the voltage closely to the LED forward voltage, with a very small value resistor in series to limit the current (1 Ohm in this case). There will be around 0,5W loss on the resistor or so, but I find such value to be acceptable.

    There is no dimming, PWM control or other functionalities, but that's not needed, as we always want to expose the image at the full power.

    The circuit can use either step-down or step-up converters, depending on the power source (ex. 5V USB would need a step-up converter, while 12V PSU would need a step-down converter). An universal step-up/down would also likely be suitable (you can even use an adjustable bench PSU, but that would definitely be a less compact solution).

  • LED choice

    Wojciech "adalbert" J10/08/2023 at 22:43 0 comments

    I wanted to use a sharp UV point light source, so after going through various options I chose a module named EP-U4545R-A3_PCB. It is an LED already soldered to a star-type heatspreader. The specification is as follows:

    • 5W power
    • wavelength in 390-410nm range (396nm as measured by the seller)
    • Vf 6,8-7,2V (two LEDs in single package)
    • 120 degree lens

    The wavelength is suitable for the UV soldermask/paint that I am using. 120 degree lens allows to cover a wide area with the UV light, minimizing potential hot-spots.

    5W is also quite a lot of power for a small LED module like this one, therefore an additional heatsink must also be attached to the metal heatspreader. I glued one with some typical single-part white heatsink glue.

  • Testing print durability

    Wojciech "adalbert" J10/08/2023 at 22:09 0 comments

    I tested the print durability by scrubbing a ceramic cup with a set of 3 brushes: nylon, brass and steel.

    The nylon brush left the print intact.

    Nylon brush

    The print started to come off when I was using the brass brush, however the process was gradual. The print was not flaking off. First some scratches were created on the surface, turning pieces of the paint to the dust, then the surface of the mug was slowly being revealed.

    Brass brush

    Steel brush worked similairly to the brass brush.

    Steel brush
    Effects of using a steel brush (around 30 seconds of scrubbing)

    The test shows that the print remains fine when it comes into contact with plastic surfaces, but it can be scratched with metal tools. That was to be expected, and it should be kept in mind that if the print was on a plastic surface, the plastic surface would also get damaged by metal tools. So the durability of the print seems to be fine for normal use cases.

    Also, because ceramic materials are hard, it is actually possible to remove the print without damaging the original material, and replace the artwork with another one.

  • Video overview

    Wojciech "adalbert" J08/08/2023 at 12:52 0 comments

    Here is a short video which shows the entire printing process:

  • Printing on 3D prints

    Wojciech "adalbert" J08/08/2023 at 12:01 0 comments

    Here is a test print on a 3D-printed PETG panel:

    I started by coating the panel with some UV paint.

    This is the mask that will be used:

    I exposed the mask for 25 minutes:

    Cleaning-up the unexposed paint:

    The letters and lines came out pretty thick, that may mean that 25 minutes might have been slightly too long and shorter exposure time would be fine.

  • Concept of "Advanced" version

    Wojciech "adalbert" J08/07/2023 at 18:02 0 comments

    An advanced version of this tool could have a mono LCD screen instead of the transparency film.

    Below is a concept art:

  • Building a prototype

    Wojciech "adalbert" J08/07/2023 at 18:01 0 comments

    First version of this tool consists of two 3D-printed parts: the top part holds the heatsink and UV LED, and provides some distance to the mask which will be placed in the bottom.

    The distance is needed to have the light spread evenly, as I'm using only a single relatively high-powered LED, as opposed to an array of LEDs. A single LED seems to be a much cheaper option than so-called "parallel UV light sources", which consists of multiple LEDs and additional optics.

    The bottom part is a simple square frame with embedded magnets. The top part also has a pair of magnets, and the mask can be clamped between those two parts.

    STL files of the design are attached in the project repository.

View all 10 project logs

  • 1
    UV printing on PCBs

    Clean the PCB surface with fine-grain sandpaper or another abrasive material and wipe it with isopropyl alcohol. Apply UV-curable soldermask and spread it evenly with a rubber roller.

    Clamp the transparency film in the magnetic frame of the tool and position the tool over the piece of PCB painted with uv-paint. If the transparency film is smaller than the frame, you can extend it using few pieces of tape.

    Expose the image for around 25 minutes (the time can vary depending on the power of the LED, transmittance of the transparency film and thickness of the paint; it's generally better to over-expose the image rater than under-expose it).

    Now clean the unexposed paint with isopropyl alcohol:

    Final result should be good enough even for SMD components. I was able to route a trace between 0805 pads in my test piece, which is a fine result for hand-made prototypes.

    Now the PCB can be etched using typical methods, eg. sodium persulfate or ferric chloride.
    The mask can be then removed, depending on the type of paint that was used, with acetone or mechanically (sandpaper or scraping off).

    The same method can also be used to print an actual soldermask, or even text on the PCB.

  • 2
    UV printing on other items

    It is possible to print on various objects, as long as they have surface from which the excessive paint can be wiped off (eg. 3D printed parts, cases, panels, household items). A mug will be used as an example in this instruction.

    The surface of the object needs to be cleaned with isopropyl alcohol. A layer of UV-curable paint then needs to be applied with a brush. I'm using white UV soldermask, which has pretty thick structure and spreads easily on the objects, without leaving large brush marks.

    Now the mask needs to be attached. In case of flat objects, the process would be the same as with PCBs, and the mask would be attached to the magnetic frame. However in this case the object is curved, and the easiest method is to bend the mask and attach the sides with pieces of tape, leaving an airgap of few milimeters.

    Now it's time to expose the mask. This time I used a 3d-printed mask, which has perfect transmittance of UV light (unlike transparency films, which cause some losses), so the exposure time can be slighty shorter. Around 15 minutes should be fine.

    After exposing the mask can be removed, and the unexposed paint can be wiped off with isopropyl alcohol.

View all instructions

Enjoy this project?



thanhbachle2766 wrote 08/11/2023 at 10:00 point

The resolution of a monochrome LCD can vary depending on the specific model and manufacturer. It is typically measured in pixels, such as 128x64 or 192x128. 

  Are you sure? yes | no

Steve Hernandez wrote 08/10/2023 at 18:24 point

what's the resolution of the monochrome lcd? 

  Are you sure? yes | no

Wojciech "adalbert" J wrote 08/10/2023 at 19:22 point

i didn't use the LCD in the prototype yet as noted, just transparency films, but the resolution of available screens is really high, e.g. 3840x2160 on 5.5 inch screen. This is the same kind of screens that are used in resin 3D printers

  Are you sure? yes | no

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