None of my 3D printers came with a solution to illuminate the build plate/room. But since I mostly print or work on my current main printer (SecKit SK-Go) in the evening/nights, I needed the light situation fixed.

Quick list of requirements:

  • Two strips installed underneath the left and right arm of the Y-plane (it’s a CoreXY printer)
  • Focus on white light, RGB would just be a plus/toyish to show status or sth.
  • Programmable if possible, fine, but no hard requirement

A bit of research later, the most commonly used strips seem to be NeoPixel or equivalents (WS2812 or SK6812), where every single pixel can be controlled. Most of the strips are RGB only. Not ideal, since white was most important to me. Usually that calls for another microcontroller like an Arduino to drive them. Some strips can be connected directly to an BTT SKR 1.3/1.4 for example. Marlin has support for that and even the LPC RepRap firmware port I use on my SKR 1.3 can handle NeoPixel style RGB strips, but with limitations (no light changes on movements, since the controller is tied up with calculation work for the print). There also RGBW variants of these types of strips, but they definitely need an additional controller. So in the end I decided against sth. programmable. It’s a nice gimmick and maybe I will use that feature with a smaller array of LEDs.

New requirements:

  • Simple White-only LED strip with a high density of LEDS
  • Non-programmable
  • Way to change brightness quickly with a physical knob
  • Driven directly from the PSU with 24 V

The LED strip

I quickly found a nice strip with a COB (chip-on-board) light source. Not only this come packed with 480 leds per meter, but features a continous phospor layer on top.

This combination leads to a perfect continous light source, even dimmed down. It basically looks like a flattened fluorescent tube. Additional advantages include a very wide angle of beam (160 deg) and a high CRI (color rendering index) of 95, meaning it’s representing colors of objects that reflect it’s light very faithfully. Really cool!

This is the strip I bought: COB LED strip 24V white 12,7W/m cold-white.

I also ordered a alumninum profile along with it to house the strip, protect it from mechanical forces and aid in cooling it. More on that later…

PWM Controller

I wanted a way to quickly turn/off/dim the light on its own. Most of the PWM controllers look very cheap and assigned with a short life span. I found one type, that looked slightly less sketchy. Luckily it works very well and features a nice chunky click when switched on/off.

Search for “pwm 1203BK” on Ebay or Amazon and you’ll find offerings. It’s slighly bigger in board size than the real sketchy ones, but features a heat sink and a reasonable layout.

How to mount it to the printer

Since I had the eletronic parts down I looked for parts that others designed to mount LED strips. Thingiverse didn’t disappoint in finding some models, but with most of these you end up printing parts that the adhesive backside of the strip is glued on. That works mechanically sure, but after the lecture of the strip’s data sheet, that didn’t seem to be a good idea. Such bright LEDs and in such a high density should be installed onto an appropriate aluminum profile, that acts as heat sink. Along with the other advantages that offers protection, and as great as this strip looked, the optics of some semi-translucent cover looks better.

Plus only two small angled brackets needed to be contructed to hold the profile in place.

Hidden in the shadows of the Y-plane arms it should be mounted onto the 2020 extrusions. So it’s well above the build plate, out of harms way from all moving parts. Angled at 60 degrees to the build plate.

This is the design I came up with and I’m quite happy with it: LED mounting bracket.

Conclusion

Overall that was a very worthy addition to my printer! All parts together set me back around 25 Euro, which is more than most led strips (+ profile, pwm controller, wiring) would cost for these short lengths (2 x 35 cm), but in my opinion it’s a bargain considering the quality of the light source and how it eases working a darkened room on the printer.