"Waveguide" Bedside Reading Lamp cnc

cults3d

I acquired some 10 mm acrylic glass (PMMA, also known as plexi glass) from a donor. Working with this material on a small CNC can be challenging due to the tendency of chips to melt and clog the end mill, resulting in breaking the bit. A solution is to reduce the spindle speed, increase the feed rate, and make fast shallow passes. Adding some water mixed with methylated spirits or washing-up liquid helps cool the cutter, although it increases the mess even more when using compressed air to clean out the cutting channel. The sides, especially the edges where light enters and exits, must be sanded smooth and polished clear. The design of this lamp is based on two principles that give it an unusual appearance: first, the waveguide principle based on total reflection of light inside a material; second, the possibility of bending acrylic glass when heated to a certain degree. To achieve a defined curvature, I created a negative form out of plywood. After placing the acrylic glass in an oven at approximately 170 °C for 10 minutes (based on the thickness: one minute per millimeter of thickness), it can be bent with ease. It is essential to wear gloves and be aware that the material will take some time to cool down, during which it remains soft and can lose its shape. The light source used was an IKEA Ledberg Spotlight. I stripped away all the plastics and removed the small diffuser. The base is made from walnut, but any other hardwood or even plywood of sufficient thickness would work equally well. A circle of funky foam provides a secure stand for the lamp. Cutting was done using my desktop CNC machine by Stepcraft. Acrylic glass should be cut with a single flute endmill. For hard wood, I used a 3 mm end mill specifically designed for cutting wood. Please note that the STL file is intended solely for viewing purposes and will not print correctly. Visit https://www.zenziwerken.de/en/ for more interesting designs.