Laser Cut K40 LED position indicator

thingiverse

This is a device designed to help precisely position your laser beam regardless of material height, focus, or coordinates. Unlike head-mounted laser pointers or beam combiners, this tool does not add any weight or complexity to the system, nor does it reduce the beam's power. It also helps determine a rough focal depth. I did not invent this device; instead, I created my own laser-cut version of an existing design by Scorch and before him, Peter Jensen. As I do not have access to a 3D printer, I thought it would be beneficial for laser cutter owners to be able to create this device, which should also be much faster. This device is made from parts that can be easily obtained, so you don't have to sacrifice a flashlight. Scorch's video about his version of the device is available here, where he covers the theory and installation: https://www.youtube.com/watch?v=r4GfdS4GDqs To create this device, you will need: * 4x 5mm clear LEDs (not diffuse), which do not have to be superbrights but that would probably be better * A 1k resistor (calculate your own value if you use different LEDs or source voltage) * Wire and ideally connectors for the 24V tap * A magnet or other method of attaching to the frame (I used a hard drive magnet) * Soldering iron, solder, and basic skills * Probably a hot glue gun I added a connection to the end of the internal LEDs that came with my K40, which are at 24V. It is generally not advisable to add any load to the stock power supply, but these only use a tiny amount of power. Superbrights may be different. I used a two-prong connector so I can disconnect power or remove it entirely. The LEDs are wired in series (shorter leg is ground) around the loop (do not connect the loop!), and the resistor is on the ground side. Use heatshrink to keep it from shorting on the case. Glue the ring onto the base part so it's raised and won't short or catch on the edge of the hole. It might slide down over time with vibration, though it is easy to re-align, so you might prefer velcro or whatever, just make sure it can be removed for laser/mirror re-alignment. Alignment: start by powering the LEDs and position the ring in the middle of the beam hole. Move it so you can see all 4 LEDs on the material. Do a test fire so you can see where the beam hits. Without moving the head or material, adjust the ring until it "targets" the hit point. This is somewhat tricky as the image is reflected and reversed through the mirrors and lens. Try covering one LED at a time to see where that lands on the material and move towards/away from that. Focus: this can give you a rough idea of where the focal point is - you simply move the material or lens holder up or down until the image of the LEDs looks sharpest. This is not perfect because 1) the LEDs are a short distance away from the actual beam origin, and 2) for cutting, you want the focal point in the middle of the material. You can just move the head/material closer to correct this, but if you have a measurement tool, just use that. Possibly improvement: try to mount the LEDs around the actual laser opening, so it will be more accurate, and won't shift!