Educational gear cutting

thingiverse

Educational gear cutting Gears are usually made milling with a tool. The the gear in this project is created by virtual milling with a virtual tool. (As opposed to the standard gear creation in CAD programs that directly extrude a gear that is calculated by formulas). The attached file is written in Lua that can be interpreted and rendered by IceSL. It's not compatible to OpenSCAD (IceSL renderes in real-time, there are no extra buttons to preview or render). It produces an involute gear, with a few steps: -Prepare a raw cylinder to be milled (blank, not rendered per default, color red) -Prepare the milling tool, a trapezoid (Tool, raw) -Prepare a shifted tool (Tool, shifted) -Prepare a complex tool (Tool, complex) -Display the gear The 'raw' tool would be very thin, and it would be moved perpendicular to the cylinder, cutting two tooth flanks at once. These flanks would have the exact same shape as the tool, i.e. they would be straight. Additionally the cylinder is rotated slowly in one direction while the tool is moved along a tangent of the cylinder in the same direction. This changes one tooth flank, giving it an involute shape. In the program I've taken another approach to simplify the teeth creation: The raw tool has the same width as the gear, eliminating the need for perpendicular movement. Based on that 'raw' tool a 'shifted' tool is created: That 'shifted' tool is based on the 'raw' tool by adding shifted and rotated samples of the raw tool - just the same way as if it was moved along a tangent of the cylinder while rotating the cylinder. Using this 'shifted' tool it is possible to cut two tooth flanks with a single operation, without the need to rotate the cylinder. The slider 'Shift in %' makes it possible to change the shift in real time and see the effect on 'shifted' tool and the resulting gear. Then the 'shifted' tool is cloned a few times into a 'complex' tool that is used to cut all teeth at once, and the gear is done. The source offers a few more things to tweak, like helical, herringbone or arc teeth forms...feel free to play with it...have fun! References Source for IceSL:https://members.loria.fr/Sylvain.Lefebvre/icesl/ It's biggest advantage over OpenSCAD - real-time rendering - is also it's biggest disadvantage, as it requires on a modern graphics card. There's also a WebGL-based version available, which I cannot recommend for this very complex script (much too slow due to javascript and WebGL overhead). Scripting documentation for IceSL:https://gforge.inria.fr/plugins/mediawiki/wiki/icesl/index.php/Scripting Lua:https://www.lua.org/ Required graphic cards: [tested] GeForce GTX 480 / 580 / 680 / 970 / Titan [tested] GeForce GT 555M [tested] Intel HD 4400, 4600 [tested] AMD Radeon 290X (with limitations)