UV-LED Parts
Overview
Wiring one of these boxes will typically take an entire rainy Saturday. Nothing is hard to do, but it can be tedious and involves a lot of cutting, stripping, and connecting wires. Please use standard wiring colors! If you ever sell or give your box away, using a non-standard wire color scheme will confuse anyone who needs to work on your box in the future. This means for the AC wiring - use black wire for Load (L), white wire for Neutral (N), and green wire for ground (G). In European countries, brown wire is used for Load (L), and blue wire is used for Neutral (N). For DC wiring, use red wire for DC positive (+) and black wire for DC negative (-).
Wiring Diagram
I have a wiring schematic diagram that can be downloaded here.
LED Strip options
The first decision you must make is the type and quantity of UV-LED strips you need to purchase. Note that 365nm wavelength strips are the best option for most alternative processes. Longer wavelength 385-405nm strips do not work for photopolymer and are slower for processes like palladium and salt printing.
The LED strip recommendations below assume you are building a ‘2X speed’ box, which is how InkJet Mall refers to its LED strip-spacing options. This option means the Inkjet mall strips are spaced 11mm (7/16”) apart. For most people, this offers plenty of speed and will likely be twice as fast as the fluorescent tube box it is replacing. Typical palladium exposure times using this configuration are 3 to 3-1/2 minutes. The main reason for increasing the speed is for processes that need a lot of light and have long exposures - processes such as salt printing or DTP photopolymer gravure. The standard assembled boxes we sell at Mountain Intaglio have 4 reels per box and are spaced 9mm between strips. I guess they could be called 3X speed boxes.
SuperlightingLED
This company sells UV-LED strips both directly on their website and through Amazon. They are a good options for those looking for the best price on UV-LED strips.
Recently, a friend brought by some of these 365nm LED strips that he had located online. We decided to test them against the pricier options already installed in my exposure boxes. I have a UV light meter, and we tested the output of these diodes against the Inkjet Mall strips. The bottom line is that they seem to be a very similar product. They have the same LED type and LED density per meter. If you specify the 0.5W/diode strip, the light output is almost identical.
But the big shock is the price - they are ¼ the price that Inkjet Mall sells theirs for! Your 2X speed (11mm spacing between strips) total LED cost would be ~ $114 including shipping, versus over $638 for the inkjet Mall strips. A 4X speed box would require $228 worth of strips versus $1276!
I have used both the Inkjet Mall strips and the SuperlightingLED strips in boxes I have built. Both the Inkjet Mall and SuperlightingLED strips use a 2835 LED diode to emit the light at the proper wavelength. The key difference is the resistor that is used between each set of 3 diodes on the chip. The latest Inkjet Mall strips I have purchased have a 68ohm resistor versus a 100ohm resistor for the SuperlightingLEDs. The Superlighting product listing indicates 40-60W/reel of power consumption, so a 3-reel (2X speed) box would require a 300W or better power supply (240Watts allowing for a 20% safety factor). A 4X speed (6 reels) would need a 600W power supply.
This represents a huge savings in the cost of building an exposure box!
Here is the website - be sure and specify 365nm lights and 0.5W/diode - these options are a $18 upcharge over the default listing. There is a pull down selection box on their web page.
The SuperlightingLED strips use 40-60W of power per reel.
One thing to be aware of is that some strips have the positive/negative markings on the strip reversed. The way to tell if this is the case is by looking at the color of the wire connected to the strip at the factory. The red wire indicates DC+. A few years ago, I received strips with the red wire soldered to the side of the strip marked with a ‘-‘! When you test a strip and it does not immediately light up when you apply the 12V DC power, try reversing the connectors and see if it works.
3, 4, 5 or 6 five-meter reels of SuperLighting LED
Inkjet Mall
The UV-LED strips can be bought from Inkjet Mall here:
3 five-meter reels of 365nm UV-LED lights
3 reels are needed for the normal 2X speed version, and 6 reels for the super-fast 4X version for the 20x30 box. Note that you will need more connectors, and a larger transformer if you build the super-fast version:
The InkJet Mall strips use 50W of per reel.
Waveform Lighting UV strips
3 five-meter reels of 365nm UV-LED Waveform Lighting strips
The Waveform Lighting UV strips use 72W of power per reel.
The Waveform Lighting UV strips are 10mm wide versus 8mm for the other two options. You will not be able to pack as many strips into the box as either of the other two options because of this increased width.
Comparison of 2X speed LED strip options
| LED strip type | # of reels for 2X speed | total for strips | total watts |
|---|---|---|---|
| SuperlightingLED | 3 | $114 | 180W |
| InkJet Mall | 3 | $638 | 150W |
| Waveform Lighting | 3 | $735 | 216W |
LED driver / power supply / transformer
The choice of transformer will depend on the type and quantity of strips you decide to use:
\[{\text{wattage needed}}\ge {\text{watts per reel} \times \text{number of reels} \over 0.80 \text{ safety factor}}\]For example, the Superlighting LED strips consume 60W/reel. Four reels works out to be 240W, and then dividing by 80% safety factor means that a 300W power supply is needed. Always buy one with more power than you need. This is why we have the safety factor included in the calculation!
The box design will take either a 350W or a 600W transformer. The decision for which transformer to buy will depend on how many reels of lights you decide you need.
Meanwell 350W Transformer for 2X speed box using 3 reels of Inkjet Mall or Superlighting LED strips
600W Meanwell LRS-600-12 for 4X speed box using 6 reels of Inkjet Mall or Superlighting LED strips
Amazon
These connectors for the 3-pole connections take up less space and are easy to use: 3 pole connectors
Note that if you opt for the 4X speed box with 48 strips, you will need twice as many connectors!
Also note that if you opt for using the Waveform Lighting strips, they are wider 10mm strips and will need different connectors:
Assorted metric screws, nuts and washers
If you don’t want all these extra nuts, bolts and washers cluttering your workbench, this is what you need if you elect to buy them locally at hardware or home supply store:
- 12 M4-20 pan head machine screws for the 60mm x 10mm thin profile fans or
- 12 M4-35 pan head machine screws for the 60mm x 25mm Noctua fans
- 4 M4-8 pan head machine screws to mount the 600W power supply
- 12 M4 nuts
- 16 M4 washers
Heat-shrink fork connectors for connecting both AC and DC wire to the power supply
Universal power cord to supply wall current to box
Cable clips to keep wires tidy
McMaster Carr sells an easy-to-wire inlet plug module that will save you time and trouble during the wiring of the box. The box is designed to take this snap-in module.
The boxes also have 4 ready-to-go holes that will mount the 350W and 600W Meanwell transformers directly to the box with four M4 screws going from the outside.
Any 60mm 12V computer fan will work - just be sure that the M4 screws you use are long enough to accomodate the thickness of the fan.
- OR -
3 Noctua super quiet 60mm x 25mm fans This fan is slightly chunkier but runs more quietly.
I also highly recommend using metal fan guards on the exterior of the box to prevent someone from sticking a finger into the fan and hurting both the fan and the finger! Metal fan guards
14 gauge wire for all the wiring of components. You can get it from McMaster Carr, or locally at a hardware or big box store. McMaster has minimum 25’ lengths for black, white and green, and red. You will have some left-over wire. The actual wire needs are 3’ of white, 18’ of black, 2’ of green and 7’ of red. Shop around locally if you want to economize on your wire use.
A wire-cutting guide is available here.
Rubber edge beading for bottom of box
3M Double-stick tape for attaching terminal blocks
Other options for connectors
If you want a little more work or need longer wire leads to the LEDs, these are an option: snap in connectors