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Freecad 0.19 tutorial pdf3/30/2024 Typically, instructions are a G-code dialect. These produce real-world 3D objects on CNC machines such as mills, lathes, lasercutters, or similar. One approach to creating a Rhino script, that would include a number of gear types, would be to begin with the “Gear Workbench” script for FreeCAD written by “looo” on Github (see my post of Nov 20 above for link).The Path Workbench is used to produce machine instructions for CNC machines from a FreeCAD 3D model. What I can say is that in the posts above, there are links to a good number of strong reference materials to look at. made one for Grasshopper, and I would leave it to him to vouch for the mathematical foundation of his approach and its accuracy. It really needs someone with better math and scripting skills than mine to perhaps write a Rhino script. This topic does seem to attract a fair bit of interest. The reason I switched over is that the earlier method did not seem to be geometrically accurate. As I noted in my post of November 2020 above, I later favoured use of the module called “Gear Workbench” in FreeCAD, which provides a nice nurbs model. ![]() I eventually moved away from the method that I explained above in September 2020. I’d be interested to hear how it goes for you. PS, if you make your Grasshopper gear also in FC, and export to Rhino, you can compare the FC version with your GH version and see where the geometry diverges. Normal Diametral Pitch of 6 is module 0.166667) (but note that module defaults to ‘thousandths’ so need to multiply by 1000) You could probably use a lot of looos’ script for the maths side of it.Īs to using FreeCAD just to get a one-off job done (make in FC Gear Workbench, export to Step, then into Rhino), I made myself a note on how to make the helical gear (because I am not a regular FreeCAD user, so will forget how I did it). ![]() If you want to improve Rhino’s ability in this area, by writing a script, these resources above would be the starting point. He’s also responsive if you ask him anything, either on Github or the FreeCAD forum. He has the maths under control, and the gears are theoretically accurate, i.e. This is the work of a fellow named ‘looo’, who has a Github page for the script: ![]() I also found a good online method screed by one Ross Korsky, who wrote a helical gear script for Autodesk Fusion – Helical Gear Generator.īut as I say, I was impressed by the FreeCAD ‘Gear Workbench’. ![]() SDP/SI 2019, Elements of Metric Gear Technology.īeyond that, Radzevich 2012, Dudley’s Handbook of Practical Gear Design and Manufacture seems to be floating around the web as a pdf (just saying), and Google Books has large parts of Maitra 1994 Handbook of Gear Design, 2nd ed. I did try to follow the theory of helical gears, but I concluded that for me, to really understand it was a deep project that I could not pursue. taking a 2D involute gear profile, copying it say 1-inch above, rotating that top one a bit and lofting the result, won’t make a good meshing gear. If you get into it, the problem is around getting the tooth profile right – it is at the normal to the angle of the tooth. Short answer is, in the end I used the suggestion of above, and modeled my helical gears in FreeCAD, the open-source nurbs modeler. I am not sure that I can comment actually.
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